Universal Serial Bus

Power Delivery Specification

Revision: 3.0
Version: 1.1
Release date: 12 January 2017

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 1

 Editors
Bob Dunstan Renesas Electronics Corp.
Richard Petrie DisplayLink

Contributors
Charles Wang ACON, Advanced-Connectek, Inc.
Conrad Choy ACON, Advanced-Connectek, Inc.
Steve Sedio ACON, Advanced-Connectek, Inc.
Vicky Chuang ACON, Advanced-Connectek, Inc.
Joseph Scanlon Advanced Micro Devices
Caspar Lin Allion Labs, Inc.
Casper Lee Allion Labs, Inc.
Howard Chang Allion Labs, Inc.
Greg Stewart Analogix Semiconductor, Inc.
Mehran Badii Analogix Semiconductor, Inc.
Bill Cornelius Apple
Colin Whitby-Strevens Apple
Corey Axelowitz Apple
Corey Lange Apple
Dave Conroy Apple
David Sekowski Apple
Girault Jones Apple
James Orr Apple
Jason Chung Apple
Jennifer Tsai Apple
Karl Bowers Apple
Keith Porthouse Apple
Matt Mora Apple
Paul Baker Apple
Reese Schreiber Apple
Sameer Kelkar Apple
Sasha Tietz Apple
Scott Jackson Apple
Sree Raman Apple
William Ferry Apple
Zaki Moussaoui Apple
Bernard Shyu Bizlink Technology, Inc.
Eric Wu Bizlink Technology, Inc.
Morphy Hsieh Bizlink Technology, Inc.
Shawn Meng Bizlink Technology Inc.
Tiffany Hsiao Bizlink Technology, Inc.
Weichung Ooi Bizlink Technology, Inc.
Michal Staworko Cadence Design Systems, Inc.
Alessandro Ingrassia Canova Tech

Page 2 USB Power Delivery Specification Revision 3.0, Version 1.1

 Andrea Colognese Canova Tech
Davide Ghedin Canova Tech
Matteo Casalin Canova Tech
Nicola Scantamburlo Canova Tech
Yi-Feng Lin Canyon Semiconductor
YuHung Lin Canyon Semiconductor
Anup Nayak Cypress Semiconductor
Jagadeesan Raj Cypress Semiconductor
Pradeep Bajpai Cypress Semiconductor
Rushil Kadakia Cypress Semiconductor
Steven Wong Cypress Semiconductor
Subu Sankaran Cypress Semiconductor
Sumeet Gupta Cypress Semiconductor
Venkat Mandagulathar Cypress Semiconductor
Adolfo Montero Dell Inc.
Bruce Montag Dell Inc.
Gary Verdun Dell Inc.
Merle Wood Dell Inc.
Mohammed Hijazi Dell Inc.
Siddhartha Reddy Dell Inc.
Dan Ellis DisplayLink
Jason Young DisplayLink
Kevin Jacobs DisplayLink
Peter Burgers DisplayLink
Richard Petrie DisplayLink PD Chair/Device Policy Lead
Abel Astley Ellisys
Chuck Trefts Ellisys
Emmanuel Durin Ellisys
Mario Pasquali Ellisys
Tim Wei Ellisys
Chien-Cheng Kuo Etron Technology, Inc.
Jack Yang Etron Technology, Inc.
Richard Crisp Etron Technology, Inc.
Shyanjia Chen Etron Technology, Inc.
TsungTa Lu Etron Technology, Inc.
Christian Klein Fairchild Semiconductor
Oscar Freitas Fairchild Semiconductor
Souhib Harb Fairchild Semiconductor
AJ Yang Foxconn / Hon Hai
Fred Fons Foxconn / Hon Hai
Steve Sedio Foxconn / Hon Hai
Terry Little Foxconn / Hon Hai
Bob McVay Fresco Logic Inc.
Christopher Meyers Fresco Logic Inc.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 3

 Tom Burton Fresco Logic Inc.
Dian Kurniawan Fresco Logic Inc.
Adam Rodriguez Google Inc.
Alec Berg Google Inc.
David Schneider Google Inc.
Jim Guerin Google Inc.
Juan Fantin Google Inc.
Ken Wu Google Inc.
Mark Hayter Google Inc.
Nithya Jagannathan Google Inc.
Todd Broch Google Inc.
Vincent Palatin Google Inc.
Mike Engbretson Granite River Labs
Rajaraman V Granite River Labs
Alan Berkema Hewlett Packard
Lee Atkinson Hewlett Packard
Rahul Lakdawala Hewlett Packard
Robin Castell Hewlett Packard
Roger Benson Hewlett Packard
Ron Schooley Hewlett Packard
Suketu Partiwala Hewlett Packard
Vaibhav Malik Hewlett Packard
Walter Fry Hewlett Packard
Bob Dunstan Intel Corporation PD Chair/Protocol WG Lead
Brad Saunders Intel Corporation
Chee Lim Nge Intel Corporation
Christine Krause Intel Corporation
Dan Froelich Intel Corporation
David Harriman Intel Corporation
David Hines Intel Corporation
David Thompson Intel Corporation
Guobin Liu Intel Corporation
Harry Skinner Intel Corporation
Henrik Leegaard Intel Corporation
Jervis Lin Intel Corporation
John Howard Intel Corporation
Karthi Vadivelu Intel Corporation
Leo Heiland Intel Corporation
Maarit Harkonen Intel Corporation
Nge Chee Lim Intel Corporation
Paul Durley Intel Corporation
Rahman Ismail Intel Corporation System Policy Lead
Ronald Swartz Intel Corporation
Sarah Sharp Intel Corporation

Page 4 USB Power Delivery Specification Revision 3.0, Version 1.1

 Scott Brenden Intel Corporation
Sridharan Ranganathan Intel Corporation
Steve McGowan Intel Corporation
Tim McKee Intel Corporation PD Chair/Compliance Lead
Toby Opferman Intel Corporation
Jia Wei Intersil Corporation
Kenta Minejima Japan Aviation Electronics Industry Ltd. (JAE)
Mark Saubert Japan Aviation Electronics Industry Ltd. (JAE)
Toshio Shimoyama Japan Aviation Electronics Industry Ltd. (JAE)
Brian Fetz Keysight Technologies Inc.
Babu Mailachalam Lattice Semiconductor Corp
Gianluca Mariani Lattice Semiconductor Corp
Joel Coplen Lattice Semiconductor Corp
Thomas Watza Lattice Semiconductor Corp
Vesa Lauri Lattice Semiconductor Corp
Daniel H Jacobs LeCroy Corporation
Jake Jacobs LeCroy Corporation
Kimberley McKay LeCroy Corporation
Mike Micheletti LeCroy Corporation
Roy Chestnut LeCroy Corporation
Tyler Joe LeCroy Corporation
Phil Jakes Lenovo
Dave Thompson LSI Corporation
Alan Kinningham Luxshare-ICT
Daniel Chen Luxshare-ICT
Josue Castillo Luxshare-ICT
Scott Shuey Luxshare-ICT
Chris Yokum MCCI Corporation
Geert Knapen MCCI Corporation
Terry Moore MCCI Corporation
Velmurugan Selvaraj MCCI Corporation
Brian Marley Microchip Technology Inc.
Dave Perchlik Microchip Technology Inc.
Don Perkins Microchip Technology Inc.
John Sisto Microchip Technology Inc.
Josh Averyt Microchip Technology Inc.
Kiet Tran Microchip Technology Inc.
Mark Bohm Microchip Technology Inc.
Matthew Kalibat Microchip Technology Inc.
Mick Davis Microchip Technology Inc.
Rich Wahler Microchip Technology Inc.
Ronald Kunin Microchip Technology Inc.
Shannon Cash Microchip Technology Inc.
Anthony Chen Microsoft Corporation

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 5

 Dave Perchlik Microsoft Corporation
David Voth Microsoft Corporation
Geoff Shew Microsoft Corporation
Jayson Kastens Microsoft Corporation
Kai Inha Microsoft Corporation
Marwan Kadado Microsoft Corporation
Michelle Bergeron Microsoft Corporation
Rahul Ramadas Microsoft Corporation
Randy Aull Microsoft Corporation
Shiu Ng Microsoft Corporation
Timo Toivola Microsoft Corporation
Toby Nixon Microsoft Corporation
Vivek Gupta Microsoft Corporation
Yang You Microsoft Corporation
Dan Wagner Motorola Mobility Inc.
Ben Crowe MQP Electronics Ltd.
Pat Crowe MQP Electronics Ltd.
Sten Carlsen MQP Electronics Ltd.
Frank Borngräber Nokia Corporation
Kai Inha Nokia Corporation
Pekka Leinonen Nokia Corporation
Richard Petrie Nokia Corporation PD Vice-Chair/Device Policy Lead
Sten Carlsen Nokia Corporation Physical Layer WG Lead
Abhijeet Kulkarni NXP Semiconductors
Ahmad Yazdi NXP Semiconductors
Bart Vertenten NXP Semiconductors
Dong Nguyen NXP Semiconductors
Guru Prasad NXP Semiconductors
Ken Jaramillo NXP Semiconductors
Krishnan TN NXP Semiconductors
Michael Joehren NXP Semiconductors
Robert de Nie NXP Semiconductors
Rod Whitby NXP Semiconductors
Vijendra Kuroodi NXP Semiconductors
Robert Heaton Obsidian Technology
Bryan McCoy ON Semiconductor
Christian Klein ON Semiconductor
Cor Voorwinden ON Semiconductor
Edward Berrios ON Semiconductor Power Supply WG Lead
Oscar Freitas ON Semiconductor
Tom Duffy ON Semiconductor
Craig Wiley Parade Technologies Inc.
Aditya Kulkarni Power Integrations
Rahul Joshi Power Integrations

Page 6 USB Power Delivery Specification Revision 3.0, Version 1.1

 Ricardo Pregiteer Power Integrations
Chris Sporck Qualcomm, Inc.
Craig Aiken Qualcomm, Inc.
George Paparrizos Qualcomm, Inc
Giovanni Garcea Qualcomm, Inc
James Goel Qualcomm, Inc
Joshua Warner Qualcomm, Inc
Narendra Mehta Qualcomm, Inc.
Terry Remple Qualcomm, Inc.
Will Kun Qualcomm, Inc.
Yoram Rimoni Qualcomm, Inc.
Atsushi Mitamura Renesas Electronics Corp.
Bob Dunstan Renesas Electronics Corp.
Dan Aoki Renesas Electronics Corp.
Kiichi Muto Renesas Electronics Corp.
Masami Katagiri Renesas Electronics Corp.
Nobuo Furuya Renesas Electronics Corp.
Patrick Yu Renesas Electronics Corp.
Peter Teng Renesas Electronics Corp.
Philip Leung Renesas Electronics Corp.
Steve Roux Renesas Electronics Corp.
Tetsu Sato Renesas Electronics Corp.
Toshifumi Yamaoka Renesas Electronics Corp.
Chunan Kuo Richtek Technology Corporation
Heinz Wei Richtek Technology Corporation
Tatsuya Irisawa Ricoh Company Ltd.
Akihiro Ono Rohm Co. Ltd.
Chris Lin Rohm Co. Ltd.
Hidenori Nishimoto Rohm Co. Ltd.
Kris Bahar Rohm Co. Ltd.
Manabu Miyata Rohm Co. Ltd.
Ruben Balbuena Rohm Co. Ltd.
Takashi Sato Rohm Co. Ltd.
Vijendra Kuroodi Rohm Co. Ltd.
Yusuke Kondo Rohm Co. Ltd.
Matti Kulmala Salcomp Plc
Toni Lehimo Salcomp Plc
Tong Kim Samsung Electronics Co. Ltd.
Alvin Cox Seagate Technology LLC Cab Con WG Lead
John Hein Seagate Technology LLC
Marc Noblitt Seagate Technology LLC
Ronald Rueckert Seagate Technology LLC
Tony Priborsky Seagate Technology LLC
Chin Chang Semtech Corporation

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 7

 Kafai Leung Silicon Laboratories, Inc.
Abhishek Sardeshpande SiliConch Systems Private Limited
Jaswanth Ammineni SiliConch Systems Private Limited
Kaustubh Kumar SiliConch Systems Private Limited
Pavitra Balasubramanian SiliConch Systems Private Limited
Rakesh Polasa SiliConch Systems Private Limited
Vishnu Pusuluri SiliConch Systems Private Limited
John Sisto SMSC
Ken Gay SMSC
Mark Bohm SMSC
Richard Wahler SMSC
Shannon Cash SMSC
Tim Knowlton SMSC
William Chiechi SMSC
Bob Dunstan Specwerkz
Fabien Friess ST-Ericsson
Giuseppe Platania ST-Ericsson
Jean-Francois Gatto ST-Ericsson
Milan Stamenkovic ST-Ericsson
Nicolas Florenchie ST-Ericsson
Patrizia Milazzo ST-Ericsson
Christophe Lorin ST-Microelectronics
John Bloomfield ST-Microelectronics
Massimo Panzica ST-Microelectronics
Meriem Mersel ST-Microelectronics
Nathalie Ballot ST-Microelectronics
Pascal Legrand ST-Microelectronics
Patrizia Milazzo ST-Microelectronics
Richard O’Connor ST-Microelectronics
Zongyao Wen Synopsys, Inc.
Joan Marrinan Tektronix
Kimberley McKay Teledyne-LeCroy
Matthew Dunn Teledyne-LeCroy
Tony Minchell Teledyne-LeCroy
Anand Dabak Texas Instruments
Bill Waters Texas Instruments
Bing Lu Texas Instruments
Deric Waters Texas Instruments Physical Layer WG Lead
Grant Ley Texas Instruments
Ingolf Frank Texas Instruments
Ivo Huber Texas Instruments
Javed Ahmad Texas Instruments
Jean Picard Texas Instruments
Martin Patoka Texas Instruments

Page 8 USB Power Delivery Specification Revision 3.0, Version 1.1

 Mike Campbell Texas Instruments
Scott Jackson Texas Instruments
Srinath Hosur Texas Instruments
Steven Tom Texas Instruments
Chris Yokum Total Phase
Brad Cox Ventev Mobile
Colin Vose Ventev Mobile
Dydron Lin VIA Technologies, Inc.
Fong-Jim Wang VIA Technologies, Inc.
Jay Tseng VIA Technologies, Inc.
Rex Chang VIA Technologies, Inc.
Terrance Shih VIA Technologies, Inc.
Jeng Cheng Liu Weltrend Semiconductor
Wayne Lo Weltrend Semiconductor
Charles Neumann Western Digital Technologies, Inc.
Curtis Stevens Western Digital Technologies, Inc.
John Maroney Western Digital Technologies, Inc.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 9

 Revision History

Revision Version Comments Issue Date

1.0 1.0 Initial release Revision 1.0 5 July, 2012

1.0 1.1 Including errata through 31-October-2012 31 October 2012

1.0 1.2 Including errata through 26-June-2013 26 June, 2013

1.0 1.3 Including errata through 11-March-2014 11 March 2014

2.0 1.0 Initial release Revision 2.0 11 August 2014

2.0 1.1 Including errata through 7-May 2015 7 May 2015

2.0 1.2 Including errata through 25-March-2016 25 March 2016

2.0 1.3 Including errata through 11-January-2017 11 January 2017

3.0 1.0 Initial release Revision 3.0 11 December 2015

3.0 1.0a Including errata through 25-March-2016 25 March 2016

3.0 1.1 Including errata through 12-January-2016 12 January 2017

Page 10 USB Power Delivery Specification Revision 3.0, Version 1.1

INTELLECTUAL PROPERTY DISCLAIMER
THIS SPECIFICATION IS PROVIDED TO YOU “AS IS” WITH NO WARRANTIES WHATSOEVER, INCLUDING ANY
WARRANTY OF MERCHANTABILITY, NON-INFRINGEMENT, OR FITNESS FOR ANY PARTICULAR PURPOSE. THE
AUTHORS OF THIS SPECIFICATION DISCLAIM ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY
PROPRIETARY RIGHTS, RELATING TO USE OR IMPLEMENTATION OF INFORMATION IN THIS SPECIFICATION. THE
PROVISION OF THIS SPECIFICATION TO YOU DOES NOT PROVIDE YOU WITH ANY LICENSE, EXPRESS OR
IMPLIED, BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS.

Please send comments via electronic mail to techsup@usb.org

For industry information, refer to the USB Implementers Forum web page at http://www.usb.org

All product names are trademarks, registered trademarks, or service marks of their respective owners.
Copyright © 2010-2017 Apple Inc, Hewlett-Packard Company, Intel Corporation, Microsoft Corporation, Renesas,
STMicroelectronics, and Texas Instruments
All rights reserved.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 11

Table of Contents

Editors....................................................................................................................... 2
Contributors .............................................................................................................. 2
Revision History........................................................................................................10
INTELLECTUAL PROPERTY DISCLAIMER ......................................................................11
Table of Contents .....................................................................................................12
List of Tables ............................................................................................................21
List of Figures ...........................................................................................................27
1. Introduction .......................................................................................................35
1.1 Overview ......................................................................................................................................................................................... 35
1.2 Purpose ............................................................................................................................................................................................ 36
1.3 Scope ................................................................................................................................................................................................. 36
1.4 Conventions ................................................................................................................................................................................... 36
1.4.1 Precedence................................................................................................................................................................................ 36
1.4.2 Keywords................................................................................................................................................................................... 36
1.4.3 Numbering ................................................................................................................................................................................ 38
1.5 Related Documents .................................................................................................................................................................... 38
1.6 Terms and Abbreviations........................................................................................................................................................ 39
1.7 Parameter Values ........................................................................................................................................................................ 45
1.8 Changes From Revision 2.0 .................................................................................................................................................... 46
1.9 Compatibility with Revision 2.0........................................................................................................................................... 46
2. Overview ...........................................................................................................47
2.1 Introduction................................................................................................................................................................................... 47
2.2 Section Overview ........................................................................................................................................................................ 48
2.3 Revision 2.0 Changes and Compatibility ......................................................................................................................... 49
2.3.1 Changes From Revision 2.0 .............................................................................................................................................. 49
2.3.2 Compatibility with Revision 2.0 ..................................................................................................................................... 49
2.4 USB Power Delivery Capable Devices ............................................................................................................................... 50
2.5 SOP* Communication ................................................................................................................................................................ 51
2.5.1 Introduction ............................................................................................................................................................................. 51

Page 12 USB Power Delivery Specification Revision 3.0, Version 1.1

 2.5.2 SOP* Collision Avoidance .................................................................................................................................................. 51
2.5.3 SOP Communication ............................................................................................................................................................. 51
2.5.4 SOP’/SOP’’ Communication with Cable Plugs .......................................................................................................... 51
2.6 Operational Overview ............................................................................................................................................................... 53
2.6.1 Source Operation ................................................................................................................................................................... 53
2.6.2 Sink Operation ........................................................................................................................................................................ 55
2.6.3 Cable Plugs ................................................................................................................................................................................ 56
2.7 Architectural Overview ............................................................................................................................................................ 58
2.7.1 Policy ........................................................................................................................................................................................... 60
2.7.2 Message Formation and Transmission ....................................................................................................................... 61
2.7.3 Collision Avoidance .............................................................................................................................................................. 61
2.7.4 Power supply ........................................................................................................................................................................... 62
2.7.5 DFP/UFP .................................................................................................................................................................................... 62
2.7.6 VCONN Source ........................................................................................................................................................................... 62
2.7.7 Cable and Connectors .......................................................................................................................................................... 63
2.7.8 Interactions between Non-PD, BC and PD devices................................................................................................ 63
2.7.9 Power Rules ............................................................................................................................................................................. 63
3. USB Type-A and USB Type-B Cable Assemblies and Connectors ...........................64
4. Electrical Requirements ......................................................................................65
4.1 Interoperability with other USB Specifications ........................................................................................................... 65
4.2 Dead Battery Detection / Unpowered Port Detection .............................................................................................. 65
4.3 Cable IR Ground Drop (IR Drop) ......................................................................................................................................... 65
4.4 Cable Type Detection ................................................................................................................................................................ 65
5. Physical Layer.....................................................................................................66
5.1 Physical Layer Overview ......................................................................................................................................................... 66
5.2 Physical Layer Functions......................................................................................................................................................... 66
5.3 Symbol Encoding......................................................................................................................................................................... 67
5.4 Ordered Sets .................................................................................................................................................................................. 68
5.5 Transmitted Bit Ordering ....................................................................................................................................................... 69
5.6 Packet Format............................................................................................................................................................................... 70
5.6.1 Packet Framing ....................................................................................................................................................................... 70
5.6.2 CRC ............................................................................................................................................................................................... 72
5.6.3 Packet Detection Errors ..................................................................................................................................................... 74

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 13

 5.6.4 Hard Reset................................................................................................................................................................................. 74
5.6.5 Cable Reset ............................................................................................................................................................................... 75
5.7 Collision Avoidance.................................................................................................................................................................... 75
5.8 Biphase Mark Coding (BMC) Signaling Scheme ........................................................................................................... 76
5.8.1 Encoding and signaling ....................................................................................................................................................... 76
5.8.2 Transmit and Receive Masks ........................................................................................................................................... 79
5.8.3 Transmitter Load Model .................................................................................................................................................... 86
5.8.4 BMC Common specifications............................................................................................................................................ 87
5.8.5 BMC Transmitter Specifications..................................................................................................................................... 87
5.8.6 BMC Receiver Specifications ............................................................................................................................................ 90
5.9 Built in Self-Test (BIST) ........................................................................................................................................................... 94
5.9.1 BIST Carrier Mode................................................................................................................................................................. 94
5.9.2 BIST Test Data ......................................................................................................................................................................... 94
6. Protocol Layer ....................................................................................................95
6.1 Overview ......................................................................................................................................................................................... 95
6.2 Messages ......................................................................................................................................................................................... 95
6.2.1 Message Construction ......................................................................................................................................................... 95
6.3 Control Message ........................................................................................................................................................................ 106
6.3.1 GoodCRC Message ............................................................................................................................................................... 107
6.3.2 GotoMin Message................................................................................................................................................................. 107
6.3.3 Accept Message .................................................................................................................................................................... 107
6.3.4 Reject Message...................................................................................................................................................................... 108
6.3.5 Ping Message ......................................................................................................................................................................... 108
6.3.6 PS_RDY Message .................................................................................................................................................................. 108
6.3.7 Get_Source_Cap Message ................................................................................................................................................. 108
6.3.8 Get_Sink_Cap Message ....................................................................................................................................................... 108
6.3.9 DR_Swap Message ............................................................................................................................................................... 109
6.3.10 PR_Swap Message................................................................................................................................................................ 109
6.3.11 VCONN_Swap Message...................................................................................................................................................... 110
6.3.12 Wait Message ......................................................................................................................................................................... 110
6.3.13 Soft Reset Message.............................................................................................................................................................. 111
6.3.14 Not_Supported Message ................................................................................................................................................... 112
6.3.15 Get_Source_Cap_Extended Message ........................................................................................................................... 112

Page 14 USB Power Delivery Specification Revision 3.0, Version 1.1

 6.3.16 Get_Status Message............................................................................................................................................................. 112
6.3.17 FR_Swap Message................................................................................................................................................................ 112
6.3.18 Get_PPS_Status ...................................................................................................................................................................... 113
6.3.19 Get_Country_Codes ............................................................................................................................................................. 113
6.4 Data Message .............................................................................................................................................................................. 113
6.4.1 Capabilities Message .......................................................................................................................................................... 114
6.4.2 Request Message.................................................................................................................................................................. 123
6.4.3 BIST Message ......................................................................................................................................................................... 128
6.4.4 Vendor Defined Message ................................................................................................................................................. 129
6.4.5 Battery_Status Message .................................................................................................................................................... 152
6.4.6 Alert Message ........................................................................................................................................................................ 153
6.4.7 Get_Country_Info Message .............................................................................................................................................. 155
6.5 Extended Message .................................................................................................................................................................... 155
6.5.1 Source_Capabilities_Extended Message ................................................................................................................... 156
6.5.2 Status Message ...................................................................................................................................................................... 160
6.5.3 Get_Battery_Cap Message ................................................................................................................................................ 162
6.5.4 Get_Battery_Status Message ........................................................................................................................................... 162
6.5.5 Battery_Capabilities Message ........................................................................................................................................ 163
6.5.6 Get_Manufacturer_Info Message .................................................................................................................................. 164
6.5.7 Manufacturer_Info Message ........................................................................................................................................... 164
6.5.8 Security Messages ............................................................................................................................................................... 165
6.5.9 Firmware Update Messages ........................................................................................................................................... 166
6.5.10 PPS_Status Message ............................................................................................................................................................ 166
6.5.11 Country_Codes Message ................................................................................................................................................... 168
6.5.12 Country_Info Message ....................................................................................................................................................... 168
6.6 Timers ............................................................................................................................................................................................ 169
6.6.1 CRCReceiveTimer ................................................................................................................................................................ 169
6.6.2 SenderResponseTimer...................................................................................................................................................... 169
6.6.3 Capability Timers ................................................................................................................................................................ 170
6.6.4 Wait Timers and Times .................................................................................................................................................... 170
6.6.5 Power Supply Timers ........................................................................................................................................................ 171
6.6.6 NoResponseTimer............................................................................................................................................................... 172
6.6.7 BIST Timers ............................................................................................................................................................................ 173
6.6.8 Power Role Swap Timers ................................................................................................................................................. 173

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 15

 6.6.9 Soft Reset Timers................................................................................................................................................................. 173
6.6.10 Hard Reset Timers .............................................................................................................................................................. 173
6.6.11 Structured VDM Timers ................................................................................................................................................... 174
6.6.12 VCONN Timers ........................................................................................................................................................................ 175
6.6.13 tCableMessage....................................................................................................................................................................... 176
6.6.14 DiscoverIdentityTimer...................................................................................................................................................... 176
6.6.15 Collision Avoidance Timers ............................................................................................................................................ 176
6.6.16 tFRSwapInit............................................................................................................................................................................ 176
6.6.17 Chunking Timers.................................................................................................................................................................. 176
6.6.18 Programmable Power Supply Timers ....................................................................................................................... 177
6.6.19 Time Values and Timers................................................................................................................................................... 178
6.7 Counters ........................................................................................................................................................................................ 181
6.7.1 MessageID Counter ............................................................................................................................................................. 181
6.7.2 Retry Counter ........................................................................................................................................................................ 181
6.7.3 Hard Reset Counter ............................................................................................................................................................ 182
6.7.4 Capabilities Counter ........................................................................................................................................................... 182
6.7.5 Discover Identity Counter ............................................................................................................................................... 182
6.7.6 VDMBusyCounter ................................................................................................................................................................ 182
6.7.7 Counter Values and Counters ........................................................................................................................................ 182
6.8 Reset ................................................................................................................................................................................................ 183
6.8.1 Soft Reset and Protocol Error ........................................................................................................................................ 183
6.8.2 Hard Reset............................................................................................................................................................................... 185
6.8.3 Cable Reset ............................................................................................................................................................................. 185
6.9 Collision Avoidance.................................................................................................................................................................. 186
6.10 Message Discarding ................................................................................................................................................................. 186
6.11 State behavior ............................................................................................................................................................................. 187
6.11.1 Introduction to state diagrams used in Chapter 6 ............................................................................................... 187
6.11.2 State Operation ..................................................................................................................................................................... 187
6.11.3 List of Protocol Layer States........................................................................................................................................... 210
6.12 Message Applicability ............................................................................................................................................................. 212
6.12.1 Applicability of Control Messages ............................................................................................................................... 213
6.12.2 Applicability of Data Messages ..................................................................................................................................... 214
6.12.3 Applicability of Extended Messages ........................................................................................................................... 215
6.12.4 Applicability of Structured VDM Commands ......................................................................................................... 216

Page 16 USB Power Delivery Specification Revision 3.0, Version 1.1

 6.12.5 Applicability of Reset Signaling .................................................................................................................................... 217
6.12.6 Applicability of Fast Role Swap signal....................................................................................................................... 217
6.13 Value Parameters ...................................................................................................................................................................... 218
7. Power Supply ................................................................................................... 219
7.1 Source Requirements .............................................................................................................................................................. 219
7.1.1 Behavioral Aspects ............................................................................................................................................................. 219
7.1.2 Source Bulk Capacitance .................................................................................................................................................. 219
7.1.3 Types of Sources .................................................................................................................................................................. 219
7.1.4 Source Transitions .............................................................................................................................................................. 220
7.1.5 Response to Hard Resets ................................................................................................................................................. 224
7.1.6 Changing the Output Power Capability..................................................................................................................... 225
7.1.7 Robust Source Operation ................................................................................................................................................. 225
7.1.8 Output Voltage Tolerance and Range ........................................................................................................................ 226
7.1.9 Charging and Discharging the Bulk Capacitance on VBUS ................................................................................. 227
7.1.10 Swap Standby for Sources ............................................................................................................................................... 227
7.1.11 Source Peak Current Operation .................................................................................................................................... 228
7.1.12 Source Capabilities Extended Parameters .............................................................................................................. 229
7.1.13 Fast Role Swap ...................................................................................................................................................................... 231
7.1.14 Non-application of VBUS Slew Rate Limits ................................................................................................................ 232
7.2 Sink Requirements ................................................................................................................................................................... 233
7.2.1 Behavioral Aspects ............................................................................................................................................................. 233
7.2.2 Sink Bulk Capacitance ....................................................................................................................................................... 233
7.2.3 Sink Standby .......................................................................................................................................................................... 233
7.2.4 Suspend Power Consumption ....................................................................................................................................... 234
7.2.5 Zero Negotiated Current .................................................................................................................................................. 234
7.2.6 Transient Load Behavior ................................................................................................................................................. 234
7.2.7 Swap Standby for Sinks .................................................................................................................................................... 234
7.2.8 Sink Peak Current Operation ......................................................................................................................................... 234
7.2.9 Robust Sink Operation ...................................................................................................................................................... 235
7.2.10 Fast Role Swap ...................................................................................................................................................................... 236
7.3 Transitions ................................................................................................................................................................................... 237
7.3.1 Increasing the Current ...................................................................................................................................................... 238
7.3.2 Increasing the Voltage....................................................................................................................................................... 240

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 17

 7.3.3 Increasing the Voltage and Current ............................................................................................................................ 242
7.3.4 Increasing the Voltage and Decreasing the Current ........................................................................................... 244
7.3.5 Decreasing the Voltage and Increasing the Current ........................................................................................... 246
7.3.6 Decreasing the Current ..................................................................................................................................................... 248
7.3.7 Decreasing the Voltage ..................................................................................................................................................... 250
7.3.8 Decreasing the Voltage and the Current .................................................................................................................. 252
7.3.9 Sink Requested Power Role Swap ............................................................................................................................... 254
7.3.10 Source Requested Power Role Swap.......................................................................................................................... 257
7.3.11 GotoMin Current Decrease.............................................................................................................................................. 260
7.3.12 Source Initiated Hard Reset............................................................................................................................................ 262
7.3.13 Sink Initiated Hard Reset ................................................................................................................................................. 264
7.3.14 No change in Current or Voltage .................................................................................................................................. 266
7.3.15 Fast Role Swap ...................................................................................................................................................................... 268
7.3.16 Increasing the Programmable Power Supply Voltage ....................................................................................... 270
7.3.17 Decreasing the Programmable Power Supply Voltage ...................................................................................... 272
7.3.18 Changing the Source PDO or APDO............................................................................................................................. 274
7.4 Electrical Parameters .............................................................................................................................................................. 276
7.4.1 Source Electrical Parameters......................................................................................................................................... 276
7.4.2 Sink Electrical Parameters .............................................................................................................................................. 280
7.4.3 Common Electrical Parameters .................................................................................................................................... 281
8. Device Policy .................................................................................................... 282
8.1 Overview ....................................................................................................................................................................................... 282
8.2 Device Policy Manager ........................................................................................................................................................... 282
8.2.1 Capabilities ............................................................................................................................................................................. 283
8.2.2 System Policy ......................................................................................................................................................................... 283
8.2.3 Control of Source/Sink ..................................................................................................................................................... 283
8.2.4 Cable Detection..................................................................................................................................................................... 283
8.2.5 Managing Power Requirements ................................................................................................................................... 284
8.2.6 Use of “Unconstrained Power” bit with Batteries and AC supplies............................................................. 286
8.2.7 Interface to the Policy Engine........................................................................................................................................ 288
8.3 Policy Engine ............................................................................................................................................................................... 289
8.3.1 Introduction ........................................................................................................................................................................... 289
8.3.2 Atomic Message Sequence Diagrams ......................................................................................................................... 289

Page 18 USB Power Delivery Specification Revision 3.0, Version 1.1

 8.3.3 State Diagrams ...................................................................................................................................................................... 428
9. States and Status Reporting.............................................................................. 513
9.1 Overview ....................................................................................................................................................................................... 513
9.1.1 PDUSB Device and Hub Requirements ..................................................................................................................... 515
9.1.2 Mapping to USB Device States ....................................................................................................................................... 515
9.1.3 PD Software Stack ............................................................................................................................................................... 518
9.1.4 PDUSB Device Enumeration ........................................................................................................................................... 518
9.2 PD Specific Descriptors .......................................................................................................................................................... 520
9.2.1 USB Power Delivery Capability Descriptor ............................................................................................................. 520
9.2.2 Battery Info Capability Descriptor .............................................................................................................................. 521
9.2.3 PD Consumer Port Capability Descriptor ................................................................................................................ 522
9.2.4 PD Provider Port Capability Descriptor ................................................................................................................... 522
9.3 PD Specific Requests and Events ....................................................................................................................................... 524
9.3.1 PD Specific Requests .......................................................................................................................................................... 524
9.4 PDUSB Hub and PDUSB Peripheral Device Requests .............................................................................................. 525
9.4.1 GetBatteryStatus .................................................................................................................................................................. 525
9.4.2 SetPDFeature ......................................................................................................................................................................... 526
10. Power Rules .................................................................................................. 528
10.1 Introduction................................................................................................................................................................................. 528
10.2 Source Power Rules ................................................................................................................................................................. 528
10.2.1 Source Power Rule Considerations............................................................................................................................. 528
10.2.2 Normative Voltages and Currents ............................................................................................................................... 529
10.2.3 Optional Voltages/Currents ........................................................................................................................................... 532
10.2.4 Power sharing between ports ....................................................................................................................................... 533
10.3 Sink Power Rules ...................................................................................................................................................................... 533
10.3.1 Sink Power Rule Considerations .................................................................................................................................. 533
10.3.2 Normative Sink Rules ........................................................................................................................................................ 534
A. CRC calculation................................................................................................. 535
A.1 C code example........................................................................................................................................................................... 535
A.2 Table showing the full calculation over one Message ............................................................................................. 537
B. PD Message Sequence Examples ...................................................................... 538
B.1 External power is supplied downstream ...................................................................................................................... 538
B.2 External power is supplied upstream ............................................................................................................................. 542

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 19

B.3 Giving back power .................................................................................................................................................................... 549
C. VDM Command Examples ................................................................................ 561
C.1 Discover Identity Example ................................................................................................................................................... 561
C.1.1 Discover Identity Command request ......................................................................................................................... 561
C.1.2 Discover Identity Command response – Active Cable ....................................................................................... 561
C.1.3 Discover Identity Command response – Hub ........................................................................................................ 562
C.2 Discover SVIDs Example........................................................................................................................................................ 564
C.2.1 Discover SVIDs Command request ............................................................................................................................. 564
C.2.1 Discover SVIDs Command response .......................................................................................................................... 564
C.3 Discover Modes Example ...................................................................................................................................................... 566
C.3.1 Discover Modes Command request ............................................................................................................................ 566
C.3.2 Discover Modes Command response ......................................................................................................................... 566
C.4 Enter Mode Example ............................................................................................................................................................... 568
C.4.1 Enter Mode Command request ..................................................................................................................................... 568
C.4.2 Enter Mode Command response .................................................................................................................................. 568
C.4.1 Enter Mode Command request with additional VDO ......................................................................................... 569
C.5 Exit Mode Example................................................................................................................................................................... 570
C.5.1 Exit Mode Command request ........................................................................................................................................ 570
C.5.2 Exit Mode Command response ..................................................................................................................................... 570
C.6 Attention Example .................................................................................................................................................................... 572
C.6.1 Attention Command request.......................................................................................................................................... 572
C.6.2 Attention Command request with additional VDO ............................................................................................. 572
D. BMC Receiver Design Examples ..................................................................... 574
D.1 Finite Difference Scheme ...................................................................................................................................................... 574
D.1.1 Sample Circuitry................................................................................................................................................................... 574
D.1.2 Theory ....................................................................................................................................................................................... 574
D.1.3 Data Recovery ....................................................................................................................................................................... 576
D.1.4 Noise Zone and Detection Zone .................................................................................................................................... 577
D.2 Subtraction Scheme ................................................................................................................................................................. 578
D.2.1 Sample Circuitry................................................................................................................................................................... 578
D.2.2 Output of Each Circuit Block .......................................................................................................................................... 578
D.2.3 Subtractor Output at Power Source and Power Sink ......................................................................................... 578
D.2.4 Noise Zone and Detection Zone .................................................................................................................................... 579

Page 20 USB Power Delivery Specification Revision 3.0, Version 1.1

List of Tables
Table 1-1 Terms and Abbreviations .......................................................................................................................................................................... 39
Table 5-1 4b5b Symbol Encoding Table .................................................................................................................................................................. 67
Table 5-2 Ordered Sets..................................................................................................................................................................................................... 68
Table 5-3 Validation of Ordered Sets ........................................................................................................................................................................ 68
Table 5-4 Data Size............................................................................................................................................................................................................. 69
Table 5-5 SOP ordered set .............................................................................................................................................................................................. 70
Table 5-6 SOP’ ordered set ............................................................................................................................................................................................. 71
Table 5-7 SOP’’ ordered set ............................................................................................................................................................................................ 71
Table 5-8 SOP’_Debug ordered set ............................................................................................................................................................................. 72
Table 5-9 SOP’’_Debug ordered set ............................................................................................................................................................................ 72
Table 5-10 CRC-32 Mapping.......................................................................................................................................................................................... 73
Table 5-11 Hard Reset ordered set ............................................................................................................................................................................ 74
Table 5-12 Cable Reset ordered set ........................................................................................................................................................................... 75
Table 5-13 Rp values used for Collision Avoidance ........................................................................................................................................... 76
Table 5-14 BMC Tx Mask Definition, X Values ...................................................................................................................................................... 81
Table 5-15 BMC Tx Mask Definition, Y Values ...................................................................................................................................................... 81
Table 5-16 BMC Rx Mask Definition .......................................................................................................................................................................... 86
Table 5-17 BMC Common Normative Requirements ........................................................................................................................................ 87
Table 5-18 BMC Transmitter Normative Requirements ................................................................................................................................. 88
Table 5-19 BMC Receiver Normative Requirements ......................................................................................................................................... 90
Table 6-1 Message Header ............................................................................................................................................................................................. 96
Table 6-2 Revision Interoperability during an Explicit Contract ................................................................................................................ 99
Table 6-3 Extended Message Header ..................................................................................................................................................................... 100
Table 6-4 Use of Unchunked Message Supported bit ..................................................................................................................................... 102
Table 6-5 Control Message Types ............................................................................................................................................................................ 106
Table 6-6 Data Message Types .................................................................................................................................................................................. 113
Table 6-7 Power Data Object...................................................................................................................................................................................... 115
Table 6-8 Augmented Power Data Object ............................................................................................................................................................ 115
Table 6-9 Fixed Supply PDO - Source..................................................................................................................................................................... 117
Table 6-10 Fixed Power Source Peak Current Capability ............................................................................................................................ 119
Table 6-11 Variable Supply (non-Battery) PDO - Source ............................................................................................................................. 119
Table 6-12 Battery Supply PDO - Source .............................................................................................................................................................. 119
Table 6-13 Programmable Power Supply APDO - Source ............................................................................................................................ 120
Table 6-14 Fixed Supply PDO - Sink ....................................................................................................................................................................... 121
USB Power Delivery Specification Revision 3.0, Version 1.1 Page 21
Table 6-15 Variable Supply (non-Battery) PDO - Sink .................................................................................................................................. 122
Table 6-16 Battery Supply PDO - Sink ................................................................................................................................................................... 122
Table 6-17 Programmable Power Supply APDO - Sink ................................................................................................................................. 123
Table 6-18 Fixed and Variable Request Data Object....................................................................................................................................... 123
Table 6-19 Fixed and Variable Request Data Object with GiveBack Support..................................................................................... 123
Table 6-20 Battery Request Data Object .............................................................................................................................................................. 124
Table 6-21 Battery Request Data Object with GiveBack Support ............................................................................................................ 125
Table 6-22 Programmable Request Data Object .............................................................................................................................................. 125
Table 6-23 BIST Data Object....................................................................................................................................................................................... 129
Table 6-24 Unstructured VDM Header .................................................................................................................................................................. 130
Table 6-25 Structured VDM Header ....................................................................................................................................................................... 131
Table 6-26 Structured VDM Commands ............................................................................................................................................................... 132
Table 6-27 SVID Values ................................................................................................................................................................................................. 132
Table 6-28 Commands and Responses .................................................................................................................................................................. 134
Table 6-29 ID Header VDO .......................................................................................................................................................................................... 135
Table 6-30 Product Types (UFP) .............................................................................................................................................................................. 136
Table 6-31 Product Types (Cable Plug) ................................................................................................................................................................ 137
Table 6-32 Product Types (DFP) .............................................................................................................................................................................. 137
Table 6-33 Cert Stat VDO ............................................................................................................................................................................................. 137
Table 6-34 Product VDO ............................................................................................................................................................................................... 138
Table 6-35 Passive Cable VDO ................................................................................................................................................................................... 138
Table 6-36 Active Cable VDO...................................................................................................................................................................................... 140
Table 6-37 AMA VDO ..................................................................................................................................................................................................... 142
Table 6-38 Discover SVIDs Responder VDO ....................................................................................................................................................... 143
Table 6-39 Battery Status Data Object (BSDO) ................................................................................................................................................ 152
Table 6-40 Alert Data Object ..................................................................................................................................................................................... 153
Table 6-41 Country Code Data Object .................................................................................................................................................................... 155
Table 6-42 Extended Message Types ..................................................................................................................................................................... 155
Table 6-43 Source Capabilities Extended Data Block (SCEDB) ................................................................................................................. 156
Table 6-44 Status Data Block (SDB) ....................................................................................................................................................................... 160
Table 6-45 Get Battery Cap Data Block (GBCDB) ............................................................................................................................................ 162
Table 6-46 Get Battery Status Data Block (GBSDB) ....................................................................................................................................... 163
Table 6-47 Battery Capability Data Block (BCDB) .......................................................................................................................................... 163
Table 6-48 Get Manufacturer Info Data Block (GMIDB) .............................................................................................................................. 164
Table 6-49 Manufacturer Info Data Block (MIDB) ......................................................................................................................................... 165
Table 6-50 PPS Status Data Block (PPSSDB) ..................................................................................................................................................... 167

Page 22 USB Power Delivery Specification Revision 3.0, Version 1.1

Table 6-51 Country Codes Data Block (CCDB) ................................................................................................................................................. 168
Table 6-52 Country Info Data Block (CIDB) ....................................................................................................................................................... 168
Table 6-53 Time Values ................................................................................................................................................................................................ 179
Table 6-54 Timers ........................................................................................................................................................................................................... 180
Table 6-55 Counter parameters ............................................................................................................................................................................... 182
Table 6-56 Counters ....................................................................................................................................................................................................... 183
Table 6-57 Response to an incoming Message (except VDM).................................................................................................................... 184
Table 6-58 Response to an incoming VDM .......................................................................................................................................................... 184
Table 6-59 Message discarding ................................................................................................................................................................................. 186
Table 6-60 Protocol Layer States ............................................................................................................................................................................. 210
Table 6-61 Applicability of Control Messages ................................................................................................................................................... 213
Table 6-62 Applicability of Data Messages .......................................................................................................................................................... 214
Table 6-63 Applicability of Extended Messages ............................................................................................................................................... 215
Table 6-64 Applicability of Structured VDM Commands ............................................................................................................................. 216
Table 6-65 Applicability of Reset Signaling ........................................................................................................................................................ 217
Table 6-66 Applicability of Fast Role Swap signal ........................................................................................................................................... 217
Table 6-67 Value Parameters..................................................................................................................................................................................... 218
Table 7-1 Sequence Description for Increasing the Current ...................................................................................................................... 239
Table 7-2 Sequence Description for Increasing the Voltage ....................................................................................................................... 241
Table 7-3 Sequence Diagram for Increasing the Voltage and Current................................................................................................... 243
Table 7-4 Sequence Description for Increasing the Voltage and Decreasing the Current ........................................................... 245
Table 7-5 Sequence Description for Decreasing the Voltage and Increasing the Current ........................................................... 247
Table 7-6 Sequence Description for Decreasing the Current ..................................................................................................................... 249
Table 7-7 Sequence Description for Decreasing the Voltage ...................................................................................................................... 251
Table 7-8 Sequence Description for Decreasing the Voltage and the Current ................................................................................... 253
Table 7-9 Sequence Description for a Sink Requested Power Role Swap ............................................................................................ 255
Table 7-10 Sequence Description for a Source Requested Power Role Swap .................................................................................... 258
Table 7-11 Sequence Description for a GotoMin Current Decrease........................................................................................................ 261
Table 7-12 Sequence Description for a Source Initiated Hard Reset...................................................................................................... 263
Table 7-13 Sequence Description for a Sink Initiated Hard Reset ........................................................................................................... 265
Table 7-14 Sequence Description for no change in Current or Voltage ................................................................................................ 267
Table 7-15 Sequence Description for Fast Role Swap ................................................................................................................................... 268
Table 7-16 Sequence Description for Increasing the Programmable Power Supply Voltage .................................................... 270
Table 7-17 Sequence Description for Decreasing the Programmable Power Supply Voltage ................................................... 272
Table 7-18 Sequence Description for Changing the Source PDO or APDO .......................................................................................... 274
Table 7-19 Source Electrical Parameters ............................................................................................................................................................. 276

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 23

Table 7-20 Sink Electrical Parameters .................................................................................................................................................................. 280
Table 7-21 Common Source/Sink Electrical Parameters ............................................................................................................................. 281
Table 8-1 Basic Message Flow ................................................................................................................................................................................... 290
Table 8-2 Potential issues in Basic Message Flow ........................................................................................................................................... 291
Table 8-3 Basic Message Flow with CRC failure ............................................................................................................................................... 292
Table 8-4 Interruptible and Non-interruptible AMS ...................................................................................................................................... 294
Table 8-5 Steps for a successful Power Negotiation ....................................................................................................................................... 296
Table 8-6 Steps for a GotoMin Negotiation ......................................................................................................................................................... 299
Table 8-7 Steps for a Soft Reset ................................................................................................................................................................................ 301
Table 8-8 Steps for Source initiated Hard Reset ............................................................................................................................................... 304
Table 8-9 Steps for Sink initiated Hard Reset .................................................................................................................................................... 307
Table 8-10 Steps for Source initiated Hard Reset – Sink long reset ........................................................................................................ 310
Table 8-11 Steps for a Successful Source Initiated Power Role Swap Sequence .............................................................................. 314
Table 8-12 Steps for a Successful Sink Initiated Power Role Swap Sequence ................................................................................... 319
Table 8-13 Steps for a Successful Fast Role Swap Sequence ...................................................................................................................... 324
Table 8-14 Steps for Data Role Swap, UFP operating as Sink initiates .................................................................................................. 328
Table 8-15 Steps for Data Role Swap, UFP operating as Source initiates ............................................................................................. 330
Table 8-16 Steps for Data Role Swap, DFP operating as Source initiates............................................................................................. 332
Table 8-17 Steps for Data Role Swap, DFP operating as Sink initiates .................................................................................................. 334
Table 8-18 Steps for Source to Sink VCONN Source Swap ............................................................................................................................. 337
Table 8-19 Steps for Sink to Source VCONN Source Swap ............................................................................................................................. 340
Table 8-20 Steps for Source Alert to Sink ............................................................................................................................................................ 342
Table 8-21 Steps for Sink Alert to Source ............................................................................................................................................................ 344
Table 8-22 Steps for a Sink getting Source status Sequence....................................................................................................................... 346
Table 8-23 Steps for a Source getting Sink status Sequence....................................................................................................................... 348
Table 8-24 Steps for a Sink getting Source PPS status Sequence ............................................................................................................. 350
Table 8-25 Steps for a Sink getting Source capabilities Sequence ........................................................................................................... 352
Table 8-26 Steps for a Dual-Role Source getting Dual-Role Sink’s capabilities as a Source Sequence .................................. 354
Table 8-27 Steps for a Source getting Sink capabilities Sequence ........................................................................................................... 356
Table 8-28 Steps for a Dual-Role Sink getting Dual-Role Source capabilities as a Sink Sequence ........................................... 358
Table 8-29 Steps for a Sink getting Source extended capabilities Sequence ...................................................................................... 360
Table 8-30 Steps for a Dual-Role Source getting Dual-Role Sink extended capabilities Sequence .......................................... 362
Table 8-31 Steps for a Sink getting Source Battery capabilities Sequence .......................................................................................... 364
Table 8-32 Steps for a Source getting Sink Battery capabilities Sequence .......................................................................................... 366
Table 8-33 Steps for a Sink getting Source Battery status Sequence ..................................................................................................... 368
Table 8-34 Steps for a Source getting Sink Battery status Sequence ..................................................................................................... 370

Page 24 USB Power Delivery Specification Revision 3.0, Version 1.1

Table 8-35 Steps for a Source getting Sink’s Port Manufacturer information Sequence .............................................................. 372
Table 8-36 Steps for a Source getting Sink’s Port Manufacturer information Sequence .............................................................. 374
Table 8-37 Steps for a Source getting Sink’s Battery Manufacturer information Sequence ....................................................... 376
Table 8-38 Steps for a Source getting Sink’s Battery Manufacturer information Sequence ....................................................... 378
Table 8-39 Steps for a VCONN Source getting Sink’s Port Manufacturer information Sequence ............................................... 380
Table 8-40 Steps for a Source getting Country Codes Sequence............................................................................................................... 382
Table 8-41 Steps for a Source getting Sink’s Country Codes Sequence ................................................................................................. 384
Table 8-42 Steps for a VCONN Source getting Sink’s Country Codes Sequence .................................................................................. 386
Table 8-43 Steps for a Source getting Country Information Sequence.................................................................................................. 388
Table 8-44 Steps for a Source getting Sink’s Country Information Sequence .................................................................................... 390
Table 8-45 Steps for a VCONN Source getting Sink’s Country Information Sequence...................................................................... 392
Table 8-46 Steps for a Source requesting a security exchange with a Sink Sequence ................................................................... 394
Table 8-47 Steps for a Sink requesting a security exchange with a Source Sequence ................................................................... 396
Table 8-48 Steps for a Vconn Source requesting a security exchange with a Cable Plug Sequence ........................................ 398
Table 8-49 Steps for a Source requesting a firmware update exchange with a Sink Sequence................................................. 400
Table 8-50 Steps for a Sink requesting a firmware update exchange with a Source Sequence................................................. 402
Table 8-51 Steps for a Vconn Source requesting a firmware update exchange with a Cable Plug Sequence ..................... 404
Table 8-52 Steps for DFP to UFP Discover Identity ........................................................................................................................................ 406
Table 8-53 Steps for Source Port to Cable Plug Discover Identity ........................................................................................................... 408
Table 8-54 Steps for DFP to Cable Plug Discover Identity ........................................................................................................................... 410
Table 8-55 Steps for DFP to UFP Enter Mode .................................................................................................................................................... 412
Table 8-56 Steps for DFP to UFP Exit Mode ........................................................................................................................................................ 414
Table 8-57 Steps for DFP to Cable Plug Enter Mode ....................................................................................................................................... 417
Table 8-58 Steps for DFP to Cable Plug Exit Mode .......................................................................................................................................... 419
Table 8-59 Steps for UFP to DFP Attention ......................................................................................................................................................... 421
Table 8-60 Steps for BIST Carrier Mode Test..................................................................................................................................................... 424
Table 8-61 Steps for BIST Test Data Test ............................................................................................................................................................. 426
Table 8-62 Policy Engine States................................................................................................................................................................................ 506
Table 9-1 USB Power Delivery Type Codes......................................................................................................................................................... 520
Table 9-2 USB Power Delivery Capability Descriptor .................................................................................................................................... 520
Table 9-3 Battery Info Capability Descriptor ..................................................................................................................................................... 521
Table 9-4 PD Consumer Port Descriptor .............................................................................................................................................................. 522
Table 9-5 PD Provider Port Descriptor ................................................................................................................................................................. 523
Table 9-6 PD Requests .................................................................................................................................................................................................. 524
Table 9-7 PD Request Codes ....................................................................................................................................................................................... 524
Table 9-8 PD Feature Selectors ................................................................................................................................................................................. 524

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 25

Table 9-9 Battery Status Structure.......................................................................................................................................................................... 525
Table 9-10 Battery Wake Mask ................................................................................................................................................................................. 526
Table 9-11 Charging Policy Encoding .................................................................................................................................................................... 527
Table 10-1 Considerations for Sources ................................................................................................................................................................. 528
Table 10-2 Normative Voltages and Currents ................................................................................................................................................... 529
Table 10-3 Fixed Supply PDO – Source 5V .......................................................................................................................................................... 530
Table 10-4 Fixed Supply PDO – Source 9V .......................................................................................................................................................... 531
Table 10-5 Fixed Supply PDO – Source 15V ....................................................................................................................................................... 531
Table 10-6 Fixed Supply PDO – Source 20V ....................................................................................................................................................... 531
Table 10-7 Programmable Power Supply PDOs and APDOs based on the PDP ................................................................................ 532
Table 10-8 Programmable Power Supply Voltage Ranges .......................................................................................................................... 533
Table B-1 External power is supplied downstream ........................................................................................................................................ 539
Table B-2 External power is supplied upstream .............................................................................................................................................. 542
Table B-3 Giving back power ..................................................................................................................................................................................... 549
Table C-1 Discover Identity Command request from Initiator Example .............................................................................................. 561
Table C-2 Discover Identity Command response from Active Cable Responder Example .......................................................... 561
Table C-3 Discover Identity Command response from Hub Responder Example............................................................................ 563
Table C-4 Discover SVIDs Command request from Initiator Example................................................................................................... 564
Table C-5 Discover SVIDs Command response from Responder Example .......................................................................................... 564
Table C-6 Discover Modes Command request from Initiator Example ................................................................................................. 566
Table C-7 Discover Modes Command response from Responder Example ........................................................................................ 566
Table C-8 Enter Mode Command request from Initiator Example .......................................................................................................... 568
Table C-9 Enter Mode Command response from Responder Example ................................................................................................. 568
Table C-10 Enter Mode Command request from Initiator Example ....................................................................................................... 569
Table C-11 Exit Mode Command request from Initiator Example ........................................................................................................... 570
Table C-12 Exit Mode Command response from Responder Example .................................................................................................. 570
Table C-13 Attention Command request from Initiator Example ............................................................................................................ 572
Table C-14 Attention Command request from Initiator with additional VDO Example................................................................ 572

Page 26 USB Power Delivery Specification Revision 3.0, Version 1.1

List of Figures
Figure 2-1 Logical Structure of USB Power Delivery Capable Devices ..................................................................................................... 50
Figure 2-2 Example SOP’ Communication between VCONN Source and Cable Plug(s) ...................................................................... 52
Figure 2-3 USB Power Delivery Communications Stack .................................................................................................................................. 58
Figure 2-4 USB Power Delivery Communication Over USB ........................................................................................................................... 59
Figure 2-5 High Level Architecture View ................................................................................................................................................................ 60
Figure 5-1 Interpretation of ordered sets ............................................................................................................................................................... 68
Figure 5-2 Transmit Order for Various Sizes of Data ........................................................................................................................................ 69
Figure 5-3 USB Power Delivery Packet Format ................................................................................................................................................... 70
Figure 5-4 CRC 32 generation....................................................................................................................................................................................... 73
Figure 5-5 Line format of Hard Reset ....................................................................................................................................................................... 75
Figure 5-6 Line format of Cable Reset ...................................................................................................................................................................... 75
Figure 5-7 BMC Example ................................................................................................................................................................................................. 76
Figure 5-8 BMC Transmitter Block Diagram ......................................................................................................................................................... 77
Figure 5-9 BMC Receiver Block Diagram ................................................................................................................................................................ 77
Figure 5-10 BMC Encoded Start of Preamble ........................................................................................................................................................ 77
Figure 5-11 Transmitting or Receiving BMC Encoded Frame Terminated by Zero with High-to-Low Last Transition .. 78
Figure 5-12 Transmitting or Receiving BMC Encoded Frame Terminated by One with High-to-Low Last Transition .... 78
Figure 5-13 Transmitting or Receiving BMC Encoded Frame Terminated by Zero with Low to High Last Transition.... 79
Figure 5-14 Transmitting or Receiving BMC Encoded Frame Terminated by One with Low to High Last Transition ..... 79
Figure 5-15 BMC Tx ‘ONE’ Mask .................................................................................................................................................................................. 80
Figure 5-16 BMC Tx ‘ZERO’ Mask................................................................................................................................................................................ 80
Figure 5-17 BMC Rx ‘ONE’ Mask when Sourcing Power .................................................................................................................................. 83
Figure 5-18 BMC Rx ‘ZERO’ Mask when Sourcing Power................................................................................................................................ 83
Figure 5-19 BMC Rx ‘ONE’ Mask when Power neutral ..................................................................................................................................... 84
Figure 5-20 BMC Rx ‘ZERO’ Mask when Power neutral ................................................................................................................................... 84
Figure 5-21 BMC Rx ‘ONE’ Mask when Sinking Power ..................................................................................................................................... 85
Figure 5-22 BMC Rx ‘ZERO’ Mask when Sinking Power .................................................................................................................................. 85
Figure 5-23 Transmitter Load Model for BMC Tx from a Source ................................................................................................................ 86
Figure 5-24 Transmitter Load Model for BMC Tx from a Sink ..................................................................................................................... 87
Figure 5-25 Transmitter diagram illustrating zDriver ..................................................................................................................................... 89
Figure 5-26 Inter-Frame Gap Timings...................................................................................................................................................................... 89
Figure 5-27 Example Multi-Drop Configuration showing two DRPs ......................................................................................................... 92
Figure 5-28 Example Multi-Drop Configuration showing a DFP and UFP .............................................................................................. 92
Figure 5-29 Test Data Frame ........................................................................................................................................................................................ 94
Figure 6-1 USB Power Delivery Packet Format including Control Message Payload ........................................................................ 95
USB Power Delivery Specification Revision 3.0, Version 1.1 Page 27
Figure 6-2 USB Power Delivery Packet Format including Data Message Payload .............................................................................. 96
Figure 6-3 USB Power Delivery Packet Format including an Extended Message Header and Payload ................................... 96
Figure 6-4 Example Security_Request sequence Unchunked (Chunked bit = 0) .............................................................................. 102
Figure 6-5 Example byte transmission for Security_Request Message of Data Size 7 (Chunked bit is set to 0) ............... 102
Figure 6-6 Example byte transmission for Security_Response Message of Data Size 7 (Chunked bit is set to 0) ............ 103
Figure 6-7 Example Security_Request sequence Chunked (Chunked bit = 1) ................................................................................... 104
Figure 6-8 Example Security_Request Message of Data Size 7 (Chunked bit set to 1) .................................................................. 105
Figure 6-9 Example Chunk 0 of Security_Response Message of Data Size 30 (Chunked bit set to 1)..................................... 105
Figure 6-10 Example byte transmission for a Security_Request Message Chunk request (Chunked bit is set to 1) ...... 105
Figure 6-11 Example Chunk 1 of Security_Response Message of Data Size 30 (Chunked bit set to 1) .................................. 106
Figure 6-12 Example Capabilities Message with 2 Power Data Objects ............................................................................................... 114
Figure 6-13 BIST Message ........................................................................................................................................................................................... 128
Figure 6-14 Vendor Defined Message .................................................................................................................................................................... 129
Figure 6-15 Discover Identity Command response ........................................................................................................................................ 135
Figure 6-16 Example Discover SVIDs response with 3 SVIDs .................................................................................................................... 143
Figure 6-17 Example Discover SVIDs response with 4 SVIDs .................................................................................................................... 143
Figure 6-18 Example Discover SVIDs response with 12 SVIDs followed by an empty response ............................................. 144
Figure 6-19 Example Discover Modes response for a given SVID with 3 Modes.............................................................................. 144
Figure 6-20 Successful Enter Mode sequence ................................................................................................................................................... 145
Figure 6-21 Enter Mode sequence Interrupted by Source Capabilities and then Re-run ............................................................ 146
Figure 6-22 Unsuccessful Enter Mode sequence due to NAK .................................................................................................................... 146
Figure 6-23 Exit Mode sequence .............................................................................................................................................................................. 148
Figure 6-24 Attention Command request/response sequence ................................................................................................................. 148
Figure 6-25 Command request/response sequence ...................................................................................................................................... 149
Figure 6-26 Enter/Exit Mode Process ................................................................................................................................................................... 151
Figure 6-27 Battery_Status Message ...................................................................................................................................................................... 152
Figure 6-28 Alert Message ........................................................................................................................................................................................... 153
Figure 6-29 Get_Country_Info Message................................................................................................................................................................. 155
Figure 6-30 Source_Capabilities_Extended Message ...................................................................................................................................... 156
Figure 6-31 Status Message ........................................................................................................................................................................................ 160
Figure 6-32 Get_Battery_Cap Message .................................................................................................................................................................. 162
Figure 6-33 Get_Battery_Status Message ............................................................................................................................................................. 162
Figure 6-34 Battery_Capabilities Message........................................................................................................................................................... 163
Figure 6-35 Get_Manufacturer_Info Message..................................................................................................................................................... 164
Figure 6-36 Manufacturer_Info Message .............................................................................................................................................................. 164
Figure 6-37 Security_Request Message................................................................................................................................................................. 165

Page 28 USB Power Delivery Specification Revision 3.0, Version 1.1

Figure 6-38 Security_Response Message ............................................................................................................................................................. 166
Figure 6-39 Firmware_Update_Request Message ............................................................................................................................................ 166
Figure 6-40 Firmware_Update_Response Message......................................................................................................................................... 166
Figure 6-41 PPS_Status Message .............................................................................................................................................................................. 167
Figure 6-42 Country_Codes Message ..................................................................................................................................................................... 168
Figure 6-43 Country_Info Message.......................................................................................................................................................................... 168
Figure 6-44 Outline of States...................................................................................................................................................................................... 187
Figure 6-45 References to states .............................................................................................................................................................................. 187
Figure 6-46 Chunking architecture Showing Message and Control Flow ............................................................................................ 188
Figure 6-47 Chunked Rx State Diagram ................................................................................................................................................................ 190
Figure 6-48 Chunked Tx State Diagram ................................................................................................................................................................ 193
Figure 6-49 Chunked Message Router State Diagram ................................................................................................................................... 197
Figure 6-50 Common Protocol Layer Message transmission State Diagram ..................................................................................... 199
Figure 6-51 Source Protocol Layer Message transmission State Diagram .......................................................................................... 202
Figure 6-52 Sink Protocol Layer Message transmission State Diagram ............................................................................................... 204
Figure 6-53 Protocol layer Message reception .................................................................................................................................................. 205
Figure 6-54 Hard/Cable Reset ................................................................................................................................................................................... 207
Figure 7-1 Placement of Source Bulk Capacitance .......................................................................................................................................... 219
Figure 7-2 Transition Envelope for Positive Voltage Transitions ............................................................................................................ 220
Figure 7-3 Transition Envelope for Negative Voltage Transitions .......................................................................................................... 221
Figure 7-4 PPS Positive Voltage Transitions ...................................................................................................................................................... 222
Figure 7-5 PPS Negative Voltage Transitions..................................................................................................................................................... 223
Figure 7-6 Expected PPS Ripple Relative to an LSB ........................................................................................................................................ 223
Figure 7-7 PPS Programmable Voltage and Foldback ................................................................................................................................... 224
Figure 7-8 Source VBUS and VCONN Response to Hard Reset ........................................................................................................................ 225
Figure 7-9 Application of vSrcNew and vSrcValid limits after tSrcReady ............................................................................................ 227
Figure 7-10 Source Peak Current Overload ........................................................................................................................................................ 228
Figure 7-11 Holdup Time Measurement .............................................................................................................................................................. 230
Figure 7-12 VBUS Power during Fast Role Swap ................................................................................................................................................ 231
Figure 7-13 VBUS detection and timing during Fast Role Swap .................................................................................................................. 232
Figure 7-14 Placement of Sink Bulk Capacitance ............................................................................................................................................. 233
Figure 7-15 Transition Diagram for Increasing the Current ...................................................................................................................... 238
Figure 7-16 Transition Diagram for Increasing the Voltage ....................................................................................................................... 240
Figure 7-17 Transition Diagram for Increasing the Voltage and Current ............................................................................................ 242
Figure 7-18 Transition Diagram for Increasing the Voltage and Decreasing the Current ........................................................... 244
Figure 7-19 Transition Diagram for Decreasing the Voltage and Increasing the Current ........................................................... 246

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 29

Figure 7-20 Transition Diagram for Decreasing the Current ..................................................................................................................... 248
Figure 7-21 Transition Diagram for Decreasing the Voltage...................................................................................................................... 250
Figure 7-22 Transition Diagram for Decreasing the Voltage and the Current................................................................................... 252
Figure 7-23 Transition Diagram for a Sink Requested Power Role Swap ............................................................................................ 254
Figure 7-24 Transition Diagram for a Source Requested Power Role Swap ...................................................................................... 257
Figure 7-25 Transition Diagram for a GotoMin Current Decrease .......................................................................................................... 260
Figure 7-26 Transition Diagram for a Source Initiated Hard Reset ........................................................................................................ 262
Figure 7-27 Transition Diagram for a Sink Initiated Hard Reset.............................................................................................................. 264
Figure 7-28 Transition Diagram for no change in Current or Voltage................................................................................................... 266
Figure 7-29 Transition Diagram for Fast Role Swap ...................................................................................................................................... 268
Figure 7-30 Transition Diagram for Increasing the Programmable Power Supply Voltage ....................................................... 270
Figure 7-31 Transition Diagram for Decreasing the Programmable Power Supply Voltage ...................................................... 272
Figure 7-32 Transition Diagram for Changing the Source PDO or APDO ............................................................................................. 274
Figure 8-1 Example of daisy chained displays ................................................................................................................................................... 287
Figure 8-2 Basic Message Exchange (Successful) ............................................................................................................................................ 289
Figure 8-3 Basic Message flow indicating possible errors........................................................................................................................... 290
Figure 8-4 Basic Message Flow with Bad CRC followed by a Retry ......................................................................................................... 292
Figure 8-5 Successful Power Negotiation ............................................................................................................................................................ 295
Figure 8-6 Successful GotoMin operation ............................................................................................................................................................ 299
Figure 8-7 Soft Reset ...................................................................................................................................................................................................... 301
Figure 8-8 Source initiated Hard Reset ................................................................................................................................................................. 303
Figure 8-9 Sink Initiated Hard Reset ...................................................................................................................................................................... 306
Figure 8-10 Source initiated reset - Sink long reset........................................................................................................................................ 309
Figure 8-11 Successful Power Role Swap Sequence Initiated by the Source ..................................................................................... 313
Figure 8-12 Successful Power Role Swap Sequence Initiated by the Sink ........................................................................................... 318
Figure 8-13 Successful Fast Role Swap Sequence ............................................................................................................................................ 323
Figure 8-14 Data Role Swap, UFP operating as Sink initiates .................................................................................................................... 327
Figure 8-15 Data Role Swap, UFP operating as Source initiates ............................................................................................................... 330
Figure 8-16 Data Role Swap, DFP operating as Source initiates ............................................................................................................... 332
Figure 8-17 Data Role Swap, DFP operating as Sink initiates .................................................................................................................... 334
Figure 8-18 Source to Sink VCONN Source Swap ............................................................................................................................................... 336
Figure 8-19 Sink to Source VCONN Source Swap ............................................................................................................................................... 339
Figure 8-20 Source Alert to Sink .............................................................................................................................................................................. 342
Figure 8-21 Sink Alert to Source .............................................................................................................................................................................. 344
Figure 8-22 Sink Gets Source Status ....................................................................................................................................................................... 346
Figure 8-23 Source Gets Sink Status ....................................................................................................................................................................... 348

Page 30 USB Power Delivery Specification Revision 3.0, Version 1.1

Figure 8-24 Sink Gets Source PPS Status.............................................................................................................................................................. 350
Figure 8-25 Sink Gets Source’s Capabilities ........................................................................................................................................................ 352
Figure 8-26 Dual-Role Source Gets Dual-Role Sink’s Capabilities as a Source .................................................................................. 354
Figure 8-27 Source Gets Sink’s Capabilities ........................................................................................................................................................ 356
Figure 8-28 Dual-Role Sink Gets Dual-Role Source’s Capabilities as a Sink ........................................................................................ 358
Figure 8-29 Sink Gets Source’s Extended Capabilities .................................................................................................................................. 360
Figure 8-30 Dual-Role Source Gets Dual-Role Sink’s Extended Capabilities ...................................................................................... 362
Figure 8-31 Sink Gets Source’s Battery Capabilities ....................................................................................................................................... 364
Figure 8-32 Source Gets Sink’s Battery Capabilities ....................................................................................................................................... 366
Figure 8-33 Sink Gets Source’s Battery Status................................................................................................................................................... 368
Figure 8-34 Source Gets Sink’s Battery Status................................................................................................................................................... 370
Figure 8-35 Source Gets Sink’s Port Manufacturer Information .............................................................................................................. 372
Figure 8-36 Sink Gets Source’s Port Manufacturer Information .............................................................................................................. 374
Figure 8-37 Source Gets Sink’s Battery Manufacturer Information........................................................................................................ 376
Figure 8-38 Sink Gets Source’s Battery Manufacturer Information........................................................................................................ 378
Figure 8-39 VCONN Source Gets Cable Plug’s Manufacturer Information ............................................................................................. 380
Figure 8-40 Source Gets Sink’s Country Codes.................................................................................................................................................. 382
Figure 8-41 Sink Gets Source’s Country Codes.................................................................................................................................................. 384
Figure 8-42 VCONN Source Gets Cable Plug’s Country Codes ...................................................................................................................... 386
Figure 8-43 Source Gets Sink’s Country Information..................................................................................................................................... 388
Figure 8-44 Sink Gets Source’s Country Information..................................................................................................................................... 390
Figure 8-45 VCONN Source Gets Cable Plug’s Country Information ......................................................................................................... 392
Figure 8-46 Source requests security exchange with Sink .......................................................................................................................... 394
Figure 8-47 Sink requests security exchange with Source .......................................................................................................................... 396
Figure 8-48 Vconn Source requests security exchange with Cable Plug .............................................................................................. 398
Figure 8-49 Source requests firmware update exchange with Sink ....................................................................................................... 400
Figure 8-50 Sink requests firmware update exchange with Source ....................................................................................................... 402
Figure 8-51 Vconn Source requests firmware update exchange with Cable Plug............................................................................ 404
Figure 8-52 DFP to UFP Discover Identity........................................................................................................................................................... 406
Figure 8-53 Source Port to Cable Plug Discover Identity ............................................................................................................................. 408
Figure 8-54 DFP to Cable Plug Discover Identity ............................................................................................................................................. 410
Figure 8-55 DFP to UFP Enter Mode ...................................................................................................................................................................... 412
Figure 8-56 DFP to UFP Exit Mode .......................................................................................................................................................................... 414
Figure 8-57 DFP to Cable Plug Enter Mode ......................................................................................................................................................... 416
Figure 8-58 DFP to Cable Plug Exit Mode ............................................................................................................................................................ 419
Figure 8-59 UFP to DFP Attention ........................................................................................................................................................................... 421

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 31

Figure 8-60 BIST Carrier Mode Test ....................................................................................................................................................................... 423
Figure 8-61 BIST Test Data Test ............................................................................................................................................................................... 425
Figure 8-62 Outline of States...................................................................................................................................................................................... 428
Figure 8-63 References to states .............................................................................................................................................................................. 428
Figure 8-64 Example of state reference with conditions ............................................................................................................................. 428
Figure 8-65 Example of state reference with the same entry and exit .................................................................................................. 429
Figure 8-66 Source Port Policy Engine State Diagram................................................................................................................................... 430
Figure 8-67 Sink Port State Diagram ...................................................................................................................................................................... 436
Figure 8-68 Source Port Soft Reset and Protocol Error State Diagram ................................................................................................. 441
Figure 8-69 Sink Port Soft Reset and Protocol Error Diagram .................................................................................................................. 442
Figure 8-70 Source Port Not Supported Message State Diagram ............................................................................................................. 444
Figure 8-71 Sink Port Not Supported Message State Diagram .................................................................................................................. 445
Figure 8-72 Source Port Ping State Diagram ...................................................................................................................................................... 446
Figure 8-73 Source Port Source Alert State Diagram ..................................................................................................................................... 446
Figure 8-74 Sink Port Source Alert State Diagram .......................................................................................................................................... 447
Figure 8-75 Sink Port Sink Alert State Diagram................................................................................................................................................ 447
Figure 8-76 Source Port Sink Alert State Diagram .......................................................................................................................................... 448
Figure 8-77 Sink Port Get Source Capabilities Extended State Diagram .............................................................................................. 448
Figure 8-78 Source Give Source Capabilities Extended State Diagram ................................................................................................. 449
Figure 8-79 Sink Port Get Source Status State Diagram ............................................................................................................................... 449
Figure 8-80 Source Give Source Status State Diagram .................................................................................................................................. 450
Figure 8-81 Source Port Get Sink Status State Diagram ............................................................................................................................... 450
Figure 8-82 Sink Give Sink Status State Diagram ............................................................................................................................................. 451
Figure 8-83 Sink Port Get Source PPS Status State Diagram ...................................................................................................................... 451
Figure 8-84 Source Give Source PPS Status State Diagram ......................................................................................................................... 452
Figure 8-85 Get Battery Capabilities State Diagram ....................................................................................................................................... 452
Figure 8-86 Give Battery Capabilities State Diagram ..................................................................................................................................... 453
Figure 8-87 Get Battery Status State Diagram ................................................................................................................................................... 453
Figure 8-88 Give Battery Status State Diagram ................................................................................................................................................. 454
Figure 8-89 Get Manufacturer Information State Diagram ......................................................................................................................... 454
Figure 8-90 Give Manufacturer Information State Diagram ....................................................................................................................... 455
Figure 8-91 Get Country Codes State Diagram .................................................................................................................................................. 455
Figure 8-92 Give Country Codes State Diagram ................................................................................................................................................ 456
Figure 8-93 Get Country Information State Diagram ..................................................................................................................................... 456
Figure 8-94 Give Country Information State Diagram ................................................................................................................................... 457
Figure 8-95 Send security request State Diagram ........................................................................................................................................... 457

Page 32 USB Power Delivery Specification Revision 3.0, Version 1.1

Figure 8-96 Send security response State Diagram ........................................................................................................................................ 458
Figure 8-97 Security response received State Diagram ................................................................................................................................ 458
Figure 8-98 Send firmware update request State Diagram ........................................................................................................................ 459
Figure 8-99 Send firmware update response State Diagram ..................................................................................................................... 459
Figure 8-100 Firmware update response received State Diagram.......................................................................................................... 460
Figure 8-101: DFP to UFP Data Role Swap State Diagram ........................................................................................................................... 461
Figure 8-102: UFP to DFP Data Role Swap State Diagram ........................................................................................................................... 463
Figure 8-103: Dual-Role Port in Source to Sink Power Role Swap State Diagram ........................................................................... 466
Figure 8-104: Dual-role Port in Sink to Source Power Role Swap State Diagram ............................................................................ 469
Figure 8-105: Dual-Role Port in Source to Sink Fast Role Swap State Diagram ................................................................................ 472
Figure 8-106: Dual-role Port in Sink to Source Fast Role Swap State Diagram ................................................................................. 475
Figure 8-107 Dual-Role (Source) Get Source Capabilities diagram ........................................................................................................ 477
Figure 8-108 Dual-Role (Source) Give Sink Capabilities diagram ........................................................................................................... 478
Figure 8-109 Dual-Role (Sink) Get Sink Capabilities State Diagram ...................................................................................................... 478
Figure 8-110 Dual-Role (Sink) Give Source Capabilities State Diagram ............................................................................................... 479
Figure 8-111 Dual-Role (Source) Get Source Capabilities Extended State Diagram....................................................................... 479
Figure 8-112 Dual-Role (Source) Give Sink Capabilities diagram ........................................................................................................... 480
Figure 8-113 VCONN Swap State Diagram .......................................................................................................................................................... 481
Figure 8-114 Initiator to Port VDM Discover Identity State Diagram .................................................................................................... 484
Figure 8-115 Initiator VDM Discover SVIDs State Diagram ........................................................................................................................ 485
Figure 8-116 Initiator VDM Discover Modes State Diagram ...................................................................................................................... 486
Figure 8-117 Initiator VDM Attention State Diagram .................................................................................................................................... 487
Figure 8-118 Responder Structured VDM Discover Identity State Diagram ...................................................................................... 488
Figure 8-119 Responder Structured VDM Discover SVIDs State Diagram .......................................................................................... 489
Figure 8-120 Responder Structured VDM Discover Modes State Diagram ......................................................................................... 490
Figure 8-121 Receiving a Structured VDM Attention State Diagram ..................................................................................................... 491
Figure 8-122 DFP VDM Mode Entry State Diagram ........................................................................................................................................ 492
Figure 8-123 DFP VDM Mode Exit State Diagram ............................................................................................................................................ 493
Figure 8-124 UFP Structured VDM Enter Mode State Diagram ................................................................................................................ 494
Figure 8-125 UFP Structured VDM Exit Mode State Diagram .................................................................................................................... 495
Figure 8-126 Cable Ready VDM State Diagram ................................................................................................................................................. 496
Figure 8-127 Cable Plug Soft Reset State Diagram .......................................................................................................................................... 497
Figure 8-128 Cable Plug Hard Reset State Diagram........................................................................................................................................ 497
Figure 8-129 DFP Soft Reset or Cable Reset of a Cable Plug State Diagram........................................................................................ 498
Figure 8-130 UFP Source Soft Reset of a Cable Plug State Diagram........................................................................................................ 499
Figure 8-131 Source Startup Structured VDM Discover Identity State Diagram.............................................................................. 500

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 33

Figure 8-132 Cable Plug Structured VDM Enter Mode State Diagram ................................................................................................... 502
Figure 8-133 Cable Plug Structured VDM Exit Mode State Diagram ...................................................................................................... 503
Figure 8-134 BIST Carrier Mode State Diagram ............................................................................................................................................... 504
Figure 9-1 Example PD Topology ............................................................................................................................................................................ 514
Figure 9-2 Mapping of PD Topology to USB........................................................................................................................................................ 515
Figure 9-3 USB Attached to USB Powered State Transition........................................................................................................................ 516
Figure 9-4 Any USB State to USB Attached State Transition (When operating as a Consumer) ............................................... 517
Figure 9-5 Any USB State to USB Attached State Transition (When operating as a Provider) .................................................. 517
Figure 9-6 Any USB State to USB Attached State Transition (After a USB Type-C Data Role Swap)....................................... 518
Figure 9-7 Software stack on a PD aware OS ..................................................................................................................................................... 518
Figure 9-8 Enumeration of a PDUSB Device ....................................................................................................................................................... 519
Figure 10-1 Source Power Rule Illustration ....................................................................................................................................................... 529
Figure 10-2 Source Power Rule Example............................................................................................................................................................. 530
Figure B-1 External Power supplied downstream .......................................................................................................................................... 538
Figure B-2 External Power supplied upstream ................................................................................................................................................. 542
Figure B-3 Giving Back Power ................................................................................................................................................................................... 549
Figure D-1 Circuit Block of BMC Finite Difference Receiver ....................................................................................................................... 574
Figure D-2 BMC AC and DC noise from VBUS at Power Sink ...................................................................................................................... 575
Figure D-3 Sample BMC Signals (a) without [USB 2.0] SE0 Noise (b) with [USB 2.0] SE0 Noise............................................... 575
Figure D-4 Scaled BMC Signal Derivative with 50ns Sampling Rate....................................................................................................... 576
Figure D-5 BMC Signal and Finite Difference Output with Various Time Steps ................................................................................ 576
Figure D-6 Output of Finite Difference in dash line and Edge Detector in solid line ...................................................................... 577
Figure D-7 Noise Zone and Detect Zone of BMC Receiver ........................................................................................................................... 577
Figure D-8 Circuit Block of BMC Subtraction Receiver ................................................................................................................................. 578
Figure D-9 (a) Output of LPF1 and LPF2 (b) Subtraction of LPF1 and LPF2 Output ...................................................................... 578
Figure D-10 Output of the BMC LPF1 in blue dash curve and the Subtractor in red solid curve.............................................. 579

Page 34 USB Power Delivery Specification Revision 3.0, Version 1.1

1. Introduction
USB has evolved from a data interface capable of supplying limited power to a primary provider of power with a data
interface. Today many devices charge or get their power from USB ports contained in laptops, cars, aircraft or even
wall sockets. USB has become a ubiquitous power socket for many small devices such as cell phones, MP3 players and
other hand-held devices. Users need USB to fulfill their requirements not only in terms of data but also to provide
power to, or charge, their devices simply, often without the need to load a driver, in order to carry out “traditional”
USB functions.
There are however, still many devices which either require an additional power connection to the wall, or exceed the
USB rated current in order to operate. Increasingly, international regulations require better energy management due
to ecological and practical concerns relating to the availability of power. Regulations limit the amount of power
available from the wall which has led to a pressing need to optimize power usage. The USB Power Delivery
Specification has the potential to minimize waste as it becomes a standard for charging devices that are not satisfied
by [USBBC 1.2].
Wider usage of wireless solutions is an attempt to remove data cabling but the need for “tethered” charging remains.
In addition, industrial design requirements drive wired connectivity to do much more over the same connector.
USB Power Delivery is designed to enable the maximum functionality of USB by providing more flexible power
delivery along with data over a single cable. Its aim is to operate with and build on the existing USB ecosystem;
increasing power levels from existing USB standards, for example Battery Charging, enabling new higher power use
cases such as USB powered Hard Disk Drives (HDDs) and printers.
With USB Power Delivery the power direction is no longer fixed. This enables the product with the power (Host or
Peripheral) to provide the power. For example, a display with a supply from the wall can power, or charge, a laptop.
Alternatively, USB power bricks or chargers are able to supply power to laptops and other battery powered devices
through their, traditionally power providing, USB ports.
USB Power Delivery enables hubs to become the means to optimize power management across multiple peripherals
by allowing each device to take only the power it requires, and to get more power when required for a given
application. For example battery powered devices can get increased charging current and then give it back
temporarily when the user’s HDD requires spinning up. Optionally the hubs can communicate with the PC to enable
even more intelligent and flexible management of power either automatically or with some level of user intervention.
USB Power Delivery allows Low Power cases such as headsets to negotiate for only the power they require. This
provides a simple solution that enables USB devices to operate at their optimal power levels.
The Power Delivery Specification, in addition to providing mechanisms to negotiate power also can be used as a side-
band channel for standard and vendor defined messaging. Power Delivery enables alternative modes of operation by
providing the mechanisms to discover, enter and exit Alternate Modes. The specification also enables discovery of
cable capabilities such as supported speeds and current levels.

1.1 Overview
This specification defines how USB Devices can negotiate for more current and/or higher or lower voltages over the
USB cable (using the USB Type-C CC wire as the communications channel) than are defined in the [USB 2.0], [USB 3.1],
[USB Type-C 1.2] or [USBBC 1.2] specifications. It allows Devices with greater power requirements than can be met
with today’s specification to get the power they require to operate from VBUS and negotiate with external power
sources (e.g. Wall Warts). In addition, it allows a Source and Sink to swap power roles such that a Device could supply
power to the Host. For example, a display could supply power to a notebook to charge its battery.
The USB Power Delivery Specification is guided by the following principles:
Works seamlessly with legacy USB Devices
Compatible with existing spec-compliant USB cables
Minimizes potential damage from non-compliant cables (e.g. ‘Y’ cables etc.)
Optimized for low-cost implementations

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 35

This specification defines mechanisms to discover, enter and exit Modes defined either by a standard or by a
particular vendor. These Modes can be supported either by the Port Partner or by a cable connecting the two Port
Partners.
The specification defines mechanisms to discover the capabilities of cables which can communicate using Power
Delivery.
This specification adds a mechanism to swap the data roles such that the upstream facing Port becomes the
downstream facing Port and vice versa. It also enables a swap of the end supplying VCONN to a powered cable.

1.2 Purpose
The USB Power Delivery specification defines a power delivery system covering all elements of a USB system
including: Hosts, Devices, Hubs, Chargers and cable assemblies. This specification describes the architecture,
protocols, power supply behavior, connectors and cabling necessary for managing power delivery over USB at up to
100W. This specification is intended to be fully compatible and extend the existing USB infrastructure. It is intended
that this specification will allow system OEMs, power supply and peripheral developers adequate flexibility for
product versatility and market differentiation without losing backwards compatibility.
USB Power Delivery is designed to operate independently of the existing USB bus defined mechanisms used to
negotiate power which are:
 [USB 2.0], [USB 3.1] in band requests for high power interfaces.
 [USBBC 1.2] mechanisms for supplying higher power (not mandated by this specification).
 [USB Type-C 1.2] mechanisms for supplying higher power
Initial operating conditions remain the USB Default Operation as defined in [USB 2.0], [USB 3.1], [USB Type-C 1.2] or
[USBBC 1.2].
 The DFP sources vSafe5V over VBUS.
 The UFP consumes power from VBUS.

1.3 Scope
This specification is intended as an extension to the existing [USB 2.0], [USB 3.1], [USB Type-C 1.2] and [USBBC 1.2]
specifications. It addresses only the elements required to implement USB Power Delivery. It is targeted at power
supply vendors, manufacturers of [USB 2.0], [USB 3.1], [USB Type-C 1.2] and [USBBC 1.2] Platforms, Devices and
cable assemblies.
Normative information is provided to allow interoperability of components designed to this specification.
Informative information, when provided, illustrates possible design implementation.

1.4 Conventions
1.4.1 Precedence
If there is a conflict between text, figures, and tables, the precedence Shall be tables, figures, and then text.

1.4.2 Keywords
The following keywords differentiate between the levels of requirements and options.

1.4.2.1 Conditional Normative

Conditional Normative is a keyword used to indicate a feature that is mandatory when another related feature has
been implemented. Designers are mandated to implement all such requirements, when the dependent features have
been implemented, to ensure interoperability with other compliant Devices.

Page 36 USB Power Delivery Specification Revision 3.0, Version 1.1

 1.4.2.2 Deprecated
Deprecated is a keyword used to indicate a feature, supported in previous releases of the specification, which is no
longer supported.

1.4.2.3 Discarded
Discard, Discards and Discarded are equivalent keywords indicating that a Packet when received Shall be thrown
away by the PHY Layer and not passed to the Protocol Layer for processing. No GoodCRC Message Shall be sent in
response to the Packet.

1.4.2.4 Ignored
Ignore, Ignores and Ignored are equivalent keywords indicating Messages or Message fields which, when received,
Shall result in no special action by the receiver. An Ignored Message Shall only result in returning a GoodCRC
Message to acknowledge Message receipt. A Message with an Ignored field Shall be processed normally except for
any actions relating to the Ignored field.

1.4.2.5 Invalid
Invalid is a keyword when used in relation to a Packet indicates that the Packet’s usage or fields fall outside of the
defined specification usage. When Invalid is used in relation to an Explicit Contract it indicates that a previously
established Explicit Contract which can no longer be maintained by the Source. When Invalid is used in relation to
individual K-codes or K-code sequences indicates that the received Signaling falls outside of the defined specification.

1.4.2.6 May
May is a keyword that indicates a choice with no implied preference.

1.4.2.7 May Not

May Not is a keyword that is the inverse of May. Indicates a choice to not implement a given feature with no implied
preference.

1.4.2.8 N/A
N/A is a keyword that indicates that a field or value is not applicable and has no defined value and Shall Not be
checked or used by the recipient.

1.4.2.9 Optional/Optionally/Optional Normative

Optional, Optionally and Optional Normative are equivalent keywords that describe features not mandated by this
specification. However, if an Optional feature is implemented, the feature Shall be implemented as defined by this
specification.

1.4.2.10 Reserved
Reserved is a keyword indicating reserved bits, bytes, words, fields, and code values that are set-aside for future
standardization. Their use and interpretation May be specified by future extensions to this specification and Shall
Not be utilized or adapted by vendor implementation. A Reserved bit, byte, word, or field Shall be set to zero by the
sender and Shall be Ignored by the receiver. Reserved field values Shall Not be sent by the sender and Shall be
Ignored by the receiver.

1.4.2.11 Shall/Normative
Shall and Normative are equivalent keywords indicating a mandatory requirement. Designers are mandated to
implement all such requirements to ensure interoperability with other compliant Devices.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 37

 1.4.2.12 Shall Not
Shall Not is a keyword that is the inverse of Shall indicating non-compliant operation.

1.4.2.13 Should
Should is a keyword indicating flexibility of choice with a preferred alternative; equivalent to the phrase “it is
recommended that…”.

1.4.2.14 Should Not

Should Not is a keyword is the inverse of Should; equivalent to the phrase “it is recommended that implementations
do not…”.

1.4.2.1 Valid
Valid is a keyword that is the inverse of Invalid indicating either a Packet, Signaling that fall within the defined
specification or an Explicit Contract that can be maintained by the Source.

1.4.3 Numbering
Numbers that are immediately followed by a lowercase "b" (e.g., 01b) are binary values. Numbers that are
immediately followed by an uppercase "B" are byte values. Numbers that are immediately followed by a lowercase
"h" (e.g., 3Ah) or are preceded by “0x” (e.g. 0xFF00) are hexadecimal values. Numbers not immediately followed by
either a "b", “B”, or "h" are decimal values.

1.5 Related Documents

 [USB 2.0] – Universal Serial Bus Specification, Revision 2.0, plus ECN and Errata
http://www.usb.org/developers/docs/usb20_docs/.
 [USB 3.1] – Universal Serial Bus 3.1 Specification, Revision 1 plus ECN and Errata (this includes the entire
document release package including the OTG&EH v3.0 specification). www.usb.org/developers/docs.
 [USBTypeCAuthentication 1.0], Universal Serial Bus Type-C Authentication Specification, Revision 1.0, March 25,
2016. www.usb.org/developers/docs.
 [USBPDFirmwareUpdate 1.0], Universal Serial Bus Power Delivery Firmware Update Specification, Revision 1.0.
www.usb.org/developers/docs. Expected publication date H2 2016.
 [USBBC 1.2] – Universal Serial Bus Battery Charging Specification, Revision 1.2 plus Errata (referred to in this
document as the Battery Charging specification). www.usb.org/developers/devclass_docs#approved.
 [USBBridge 1.0] – Universal Serial Bus Type-C Bridge Specification, Revision 1.0, March 25, 2016.
www.usb.org/developers/docs.
 [USBTypeCBridge 1.0] – Universal Serial Bus Type-C Bridge Specification, Revision 1.0, March 25, 2016.
www.usb.org/developers/docs.
 [USBPD 2.0] – Universal Serial Bus Power Delivery Specification, Revision 2, Version 1.2, March 25, 2016.
www.usb.org/developers/docs.
 [USBPDCompliance] – USB Power Delivery Compliance Plan version 1.0
http://www.usb.org/developers/docs/devclass_docs/.
 [USB Type-C 1.2] – Universal Serial Bus Type-C Cable and Connector Specification, Revision 1.2, March 25, 2016.
www.usb.org/developers/docs.
 [IEC 60958-1] IEC 60958-1 Digital Audio Interface Part:1 General Edition 3.0 2008-09 www.iec.ch
 [IEC 60950-1] IEC 60950-1:2005 Information technology equipment – Safety – Part 1: General requirements:
Amendment 1:2009, Amendment 2:2013
 [IEC 62368-1] IEC 62368-1 Audio/Video, information and communication technology equipment – Part 1: Safety
requirements

Page 38 USB Power Delivery Specification Revision 3.0, Version 1.1

 [IEC 63002] Draft CD for IEC 63002 Identification and Communication Interoperability Method for External DC
Power Supplies Used With Portable Computing Devices.
 [ISO 3166] ISO 3166 international Standard for country codes and codes for their subdivisions.
http://www.iso.org/iso/home/standards/country_codes.htm.

1.6 Terms and Abbreviations

This section defines terms used throughout this document. For additional terms that pertain to the Universal Serial
Bus, see Chapter 2, “Terms and Abbreviations,” in [USB 2.0], [USB 3.1], [USB Type-C 1.2] and [USBBC 1.2].

Table 1-1 Terms and Abbreviations

Term Description
Active Cable A cable with a USB Plug on each end at least one of which is a Cable Plug supporting SOP’,
that also incorporates data bus signal conditioning circuits. The cable supports the
Structured VDM Discover Identity Command to determine its characteristics in addition to
other Structured VDM Commands (Electronically Marked Cable see [USB Type-C 1.2]).
Active Mode A Mode which has been entered and not exited.
Alternate Mode As defined in [USB Type-C 1.2]. Equivalent to Mode in the PD Specification.
Alternate Mode Adapter A PDUSB Device which supports Alternate Modes as defined in [USB Type-C 1.2]. Note that
(AMA) since an AMA is a PDUSB Device it has a single UFP that is only addressable by SOP Packets.
Alternate Mode Controller A DFP that supports connection to AMAs as defined in [USB Type-C 1.2]. A DFP that is an
(AMC) AMC can also be a PDUSB Host.
Augmented Power Data Data Object used to expose a Source Port’s power capabilities or a Sink’s power requirements
Object (APDO) as part of a Source_Capabilities or Sink_Capabilities Message respectively. Programmable
Power Supply Data Object is defined.
Atomic Message Sequence A fixed sequence of Messages as defined in Section 8.3.2 typically starting and ending in one
(AMS) of the following states: PE_SRC_Ready, PE_SNK_Ready or PE_CBL_Ready. An AMS can be
Interruptible or Non-interruptible.
Attach Mechanical joining of the Port Pair by a cable.
Attached USB Power Delivery ports which are mechanically joined with USB cable.
Battery A power storage device residing behind a Port that can either be a source or sink of power.
Battery Supply A power supply that directly applies the output of a Battery to VBUS. This is exposed by the
Battery Supply PDO (see Section 6.4.1.2.4)
Binary Frequency Shift A Signaling Scheme now Deprecated in this specification. BFSK used a pair of discrete
Keying (BFSK) frequencies to transmit binary (0s and 1s) information over VBUS. See [USBPD 2.0] for
further details.
Biphase Mark Coding Modification of Manchester coding where each zero has one transition and a one has two
(BMC) transitions (see [IEC 60958-1]).
BIST Built In Self-Test – Power Delivery testing mechanism for the PHY Layer.
BIST Data Object (BDO) Data Object used by BIST Messages.
BIST Mode A BIST receiver or transmitter test mode enabled by a BIST Message.
Cable Plug Term used to describe a PD Capable element in a Multi-Drop system addressed by SOP’/SOP’’
Packets. Logically the Cable Plug is associated with a USB plug at one end of the cable. In a
practical implementation the electronics might reside anywhere in the cable.
Cable Reset This is initiated by Cable Reset Signaling from the DFP. It restores the Cable Plugs to their
default, power up condition and resets the PD communications engine to its default state. It
does not reset the Port Partners but does restore VCONN to its Attachment state.
Chunk A MaxExtendedMsgChunkLen (26 byte) or less portion of a Data Block. Data Blocks can be
sent either as a single Message or as a series of Chunks.
Chunking The process of breaking up a Data Block larger than MaxExtendedMsgLegacyLen (26-bytes)
into two of more Chunks.
Cold Socket A Port that does not apply vSafe5V on VBUS until a Sink is Attached.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 39

Term Description
Command Request and response pair defined as part of a Structured Vendor Defined Message (see
Section 6.4.4.2)
Configuration Channel (CC) Single wire used by the BMC PHY Layer Signaling Scheme (see [USB Type-C 1.2]).
Connected USB Power Delivery ports that have exchanged a Message and a GoodCRC Message response
using the USB Power Delivery protocol so that both Port Partners know that each is PD
Capable.
Consumer The capability of a PD Port (typically a Device’s UFP) to sink power from the power
conductor (e.g. VBUS). This corresponds to a USB Type-C Port with Rd asserted on its CC Wire.
Consumer/Provider A Consumer with the additional capability to act as a Provider. This corresponds to a Dual-
Role Port with Rd asserted on its CC Wire.
Continuous BIST Mode A BIST Mode where the Port or Cable Plug being tested sends a continuous stream of test
data.
Constant Voltage (CV) A mode in which the Source output Voltage remains constant as the load changes.
Contract An agreement on both power level and direction reached between a Port Pair. A Contract
could be explicitly negotiated between the Port Pair or could be an Implicit power level
defined by the current state. While operating in Power Delivery mode there will always be
either an Explicit or Implicit Contract in place. The Contract can only be altered in the case of
a (re-)negotiation, Power Role Swap, Data Role Swap, Hard Reset or failure of the Source.
Control Message A Message is defined as a Control Message when the Number of Data Objects field in the
Message Header is set to 0. The Control Message consists only of a Message Header and a
CRC.
Current Foldback (CF) A current limiting feature for a Source. When the Sink attempts to draw more current from
the Source than the requested current foldback value, the Source reduces its output voltage
so the current it supplies remains at or below the requested value.
Data Block An Extended Message payload data unit. The size of each type of Data Block is specified as a
series of bytes up to MaxExtendedMsgLen bytes in length. This is distinct from a Data Object
used by a Data Message which is always a 32-bit object.
Data Message A Data Message consists of a Message Header followed by one or more Data Objects. Data
Messages are easily identifiable because the Number of Data Objects field in the Message
Header is a non-zero value.
Data Object A Data Message payload data unit. This 32 bit object contains information specific to
different types of Data Message. Power, Request, BIST and Vendor Data Objects are defined.
Data Role Swap Process of exchanging the DFP (Host) and UFP (Device) roles between Port Partners using
the [USB Type-C 1.2] connector.
Dead Battery A device has a Dead Battery when the Battery in a device is unable to power its functions.
Detach Mechanical unjoining of the Port Pair by removal of the cable.
Detached USB Power Delivery ports which are no longer mechanically joined with USB cable.
Device When lower cased (device), it refers to any USB product, either USB Device or USB Host.
When in upper case refers to a USB Device (Peripheral or Hub).
Device Policy Manager Module running in a Source or Sink that applies Local Policy to each Port in the Device via the
(DPM) Policy Engine.
Discovery Process Command sequence using Structured Vendor Defined Messages resulting in identification of
the Port Partner, its supported SVIDs and Modes.
Downstream Facing Port Indicates the Port’s position in the USB topology which typically corresponds to a USB Host
(DFP) root Port or Hub downstream Port as defined in [USB Type-C 1.2]. At connection the Port
defaults to operation as a USB Host (when USB Communication is supported) and Source.
Dual-Role Data (DRD) Capability of operating as either a DFP or UFP.
Dual-Role Data Port A Port Capable of operating as DRD..
Dual-Role Power (DRP) Capability of operating as either a Source or Sink.
Dual-Role Power Device A product containing one or more Dual-Role Power Ports that are capable of operating as
either a Source or a Sink.
Dual-Role Power Port A Port capable of operating as a DRP.

Page 40 USB Power Delivery Specification Revision 3.0, Version 1.1

Term Description
End of Packet (EOP) K-code marker used to delineate the end of a packet.
Enter Mode Process Command sequence using Structured Vendor Defined Messages resulting in the Port Partners
entering a Mode.
Error Recovery Error recovery process as defined in [USB Type-C 1.2].
Exit Mode Process Command sequence using Structured Vendor Defined Messages resulting in the Port Partners
exiting a Mode.
Explicit Contract An agreement reached between a Port Pair as a result of the Power Delivery negotiation
process. An Explicit Contract is established (or continued) when a Source sends an Accept
Message in response to a Request Message sent by a Sink followed by a PS_RDY Message
indicating that the power supply is ready; this corresponds to the PE_SRC_Ready state for a
Source Policy Engine and the PE_SNK_Ready state for a Sink Policy Engine. The Explicit
Contract can be altered through the re-negotiation process. All Port pairs are required to
make an Explicit Contract.
Extended Message (EM) A Message containing Data Blocks. The Extended Message is defined by the Extended field in
the Message Header being set to one and contains an Extended Message Header immediately
following the Message Header.
Extended Message Header Every Extended Message contains a 16-bit Extended Message Header immediately following
the Message Header containing information about the Data Block and any Chunking being
applied.
Fast Role Swap Process of exchanging the Source and Sink roles between Port Partners rapidly due to the
disconnection of an external power supply.
Fixed Battery A Battery that is not easily removed or replaced by an end user e.g. requires a special tool to
access or is soldered in.
Fixed Supply A well-regulated fixed voltage power supply. This is exposed by the Fixed Supply PDO (see
Section 6.4.1.2.2)
Frame Generic term referring to an atomic communication transmitted by PD such as a Packet, Test
Frame or Signaling.
Hard Reset This is initiated by Hard Reset Signaling from either Port Partner. It restores VBUS to USB
Default Operation and resets the PD communications engine to its default state in both Port
Partners as well as in any Attached Cable Plugs. It restores both Port Partners to their default
Data Roles and returns the VCONN Source to the Source Port.
HDD A Hard Disk Drive.
Hot Swappable Battery A Battery that is easily accessible for a user to remove or change for another Battery.
ID Header VDO The VDO in a Discover Identity Command immediately following the VDM Header. The ID
Header VDO contains information corresponding to the Power Delivery Product.
Implicit Contract An agreement on power levels between a Port Pair which occurs, not as a result of the Power
Delivery negotiation process, but as a result of a Power Role Swap or Fast Role Swap.
Implicit Contracts are transitory since the Port pair is required to immediately negotiate an
Explicit Contract after the Power Role Swap. An Implicit Contract Shall be limited to USB
Type-C Current (see [USB Type-C 1.2]).
Initiator The initial sender of a Command request in the form of a query.
Interruptible An AMS that, on receiving a Protocol Error, returns to the appropriate ready state in order to
process the incoming Message is said to be Interruptible. Every AMS is Interruptible until the
first Message in the AMS has been sent (a GoodCRC Message has been received). An AMS of
Vendor Messages is Interruptible during the entire sequence.
IoC The negotiated current value as defined in [IEC 63002].
IR Drop The voltage drop across the cable and connectors between the Source and the Sink. It is a
function of the resistance of the ground and power wire in the cable plus the contact
resistance in the connectors times the current flowing over the path.
K-code Special symbols provided by the 4b5b coding scheme. K-codes are used to signal Hard Reset
and Cable reset, and delineate Packet boundaries.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 41

Term Description
Local Policy Every PD Capable device has its own Policy, called the Local Policy that is executed by its
Policy Engine to control its power delivery behavior. The Local Policy at any given time
might be the default policy, hard coded or modified by changes in operating parameters or
one provided by the system Host or some combination of these. The Local Policy Optionally
can be changed by a System Policy Manager.
LPS Limited Power Supply as defined in [IEC 62368-1].
Message The packet payload consisting of a Message Header for Control Messages and a Message
Header and data for Data Messages and Extended Messages as defined in Section 6.
Message Header Every Message starts with a 16-bit Message Header containing basic information about the
Message and the PD Port’s Capabilities.
Messaging Communication in the form of Messages as defined in Chapter 6.
Modal Operation State where there are one or more Active Modes. Modal Operation ends when there are no
longer any Active Modes.
Mode Operation defined by a Vendor or Standard’s organization, which is associated with a SVID,
whose definition is outside the scope of USB-IF specifications. Entry to and exit from the
Mode uses the Enter Mode and Exit Mode Processes. Modes are equivalent to “Alternate
Modes” as described in [USB Type-C 1.2].
Multi-Drop Refers to a Power Delivery system with one or more Cable Plugs where communication is to
the Cable Plugs rather than the Port Partner. Multi-Drop systems share the Power Delivery
communication channel with the Port Partners.
Negotiation This is the PD process whereby:
1. The Source advertises its capabilities.
2. The Sink requests one of the advertised capabilities.
3. The Source acknowledges the request and alters its output to satisfy the request.
The result of the negotiation is a Contract for power delivery/consumption between the Port
Pair.
Non-interruptible An AMS that, on receiving a Protocol Error, generates either a Soft Reset or Hard Reset. Any
power related AMS is Non-interruptible once the first Message in the AMS has been sent (a
GoodCRC Message has been received).
OCP Over-Current Protection
OTP Over-Temperature Protection
OVP Over-Voltage Protection
Packet One entire unit of PD communication including a Preamble, SOP*, payload, CRC and EOP as
defined in Section 5.6.
Passive Cable Cable with a USB Plug on each end at least one of which is a Cable Plug supporting SOP’ that
does not incorporate data bus signal conditioning circuits. Supports the Structured VDM
Discover Identity to determine its characteristics (Electronically Marked Cable see [USB
Type-C 1.2]). Note this specification does not discuss Passive Cables which are not
Electronically Marked Cables.
PD USB Power Delivery
PD Capable A Port that supports USB Power Delivery.
PD Connection See Connected.
PD Power (PDP) The output power of a Source, as specified by the manufacturer and expressed in Fixed
Supply PDOs as defined in Section 10.
PDUSB USB Device Port or USB Host Port that is both PD capable and capable of USB
Communication. See also PDUSB Host, PDUSB Device and PDUSB Hub.
PDUSB Device A USB Device with a PD Capable UFP. A PDUSB Device is only addressed by SOP Packets.
PDUSB Host A USB Host which is PD Capable on at least one of its DFPs. A PDUSB Host is only addressed
by SOP Packets.
PDUSB Hub A port expander USB Device with a UFP and one or more DFPs which is PD Capable on at
least one of its Ports. A PDUSB Hub is only addressed by SOP Packets.
PDUSB Peripheral A USB Device with a PD Capable UFP which is not a PDUSB Hub. A PDUSB Peripheral is only
addressed by SOP Packets.

Page 42 USB Power Delivery Specification Revision 3.0, Version 1.1

Term Description
PHY Layer The Physical Layer responsible for sending and receiving Messages across the USB Type-C CC
wire between a Port Pair.
Policy Policy defines the behavior of PD capable parts of the system and defines the capabilities it
advertises, requests made to (re)negotiate power and the responses made to requests
received.
Policy Engine (PE) The Policy Engine interprets the Device Policy Manager’s input in order to implement Policy
for a given Port and directs the Protocol Layer to send appropriate Messages.
Port An interface typically exposed through a receptacle, or via a plug on the end of a hard-wired
captive cable. USB Power Delivery defines the interaction between a Port Pair.
Port Pair Two Attached PD Capable Ports.
Port Partner A Contract is negotiated between a Port Pair connected by a USB cable. These ports are
known as Port Partners.
Power Conductor The wire delivering power from the Source to Sink. For example USB’s V BUS.
Power Consumer See Consumer
Power Data Object (PDO) Data Object used to expose a Source Port’s power capabilities or a Sink’s power requirements
as part of a Source_Capabilities or Sink_Capabilities Message respectively. Fixed, Variable
and Battery Power Data Objects are defined.
Power Delivery Mode Operation after a Contract has initially been established between a Port pair. This mode
persists during normal Power Delivery operation, including after a Power Role Swap. Power
Delivery mode can only be exited by Detaching the ports, applying a Hard Reset or by the
Source removing power (except when power is removed during the Power Role Swap
procedure).
Power Provider See Provider
Power Reserve Power which is kept back by a Source in order to ensure that it can meet total power
requirements of Attached Sinks on at least one Port.
Power Role Swap Process of exchanging the Source and Sink roles between Port Partners.
Preamble Start of a transmission which is used to enable the receiver to lock onto the carrier. The
Preamble consists of a 64-bit sequence of alternating 0s and 1s starting with a "0" and ending
with a "1" which is not 4b5b encoded.
Product Type Product categorization returned as part of the Discover Identity Command.
Product Type VDO VDO identifying a certain Product Type in the ID Header VDO of a Discover Identity
Command.
Programmable Power A power supply whose output voltage can be programmatically adjusted in small increments
Supply (PPS) over its advertised range. The PPS also has a programmable output current fold back. The
capabilities of the PPS are exposed by the Programmable Power Supply APDO (see Section
6.4.1.2.5).
Protocol Error An unexpected Message during an Atomic Message Sequence. A Protocol Error during a Non-
interruptible AMS will result in either a Soft Reset or a Hard Reset. A Protocol Error during
an Interruptible AMS will result in a return to the appropriate ready state where the Message
will be handled.
Protocol Layer The entity that forms the Messages used to communicate information between Port Partners.
Provider A capability of a PD Port (typically a Host, Hub, or Wall Wart DFP) to source power over the
power conductor (e.g. VBUS). This corresponds to a USB Type-C Port with Rp asserted on its
CC Wire.
Provider/Consumer A Provider with the additional capability to act as a Consumer. This corresponds to a Dual-
Role Power Port with Rp asserted on its CC Wire.
PS1, PS2 Classification of electrical power as defined in [IEC 62368-1].
Rd Pull-down resistor on the USB Type-C CC wire used to indicate that the Port is a Sink (see
[USB Type-C 1.2]).
Reattach Attach of the Port Pair by a cable after a previous Detach.
Re-negotiation A process wherein one of the Port Partners wants to alter the negotiated Contract.
Request Data Object (RDO) Data Object used by a Sink Port to negotiate a Contact as a part of a Request Message.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 43

Term Description
Re-run Start an Interruptible AMS again from the beginning after a Protocol Error.
Responder The receiver of a Command request sent by an Initiator that replies with a Command
response.
Rp Pull-up resistor on the USB Type-C CC wire used to indicate that the Port is a Source (see
[USB Type-C 1.2]).
Safe Operation Sources must have the ability to tolerate vSafe5V applied by both Port Partners.
Signaling A Preamble followed by an ordered set of four K-codes used to indicate a particular line
symbol e.g. Hard Reset as defined in Section 5.4.
Signaling Scheme Physical mechanism used to transmit bits. Only the BMC Signaling Scheme is defined in this
specification. Note: the BFSK Signaling Scheme supported in previous Revisions of this
specification has been Deprecated.
Single-Role Port A Port that is a Port only capable of operating as a Source or Sink, but not both.
Sink The Port consuming power from VBUS; most commonly a Device.
Sink Directed Charge A charging scheme whereby the Sink connects the Source to its battery through safety and
other circuitry.
Sink Directed Charge has two different modes of operation:
 When the Current Foldback feature is not activated, the Sink controls the Source’s
output current by adjusting the Source’s output voltage
 When the Current Foldback feature is activated, the Source automatically controls its
output current by adjusting its output voltage.
The Sink is responsible for managing the current so as not to exceed the advertised capability
of the Source and to protect itself from over-current events.
Soft Reset A process that resets the PD communications engine to its default state.
SOP Communication Communication using SOP Packets also implies that a Message sequence is being followed.
SOP Packet Any Power Delivery Packet which starts with an SOP.
SOP* Communication Communication with a Cable Plug using SOP* Packets, also implies a Message sequence is
being followed.
SOP* Packet A term referring to any Power Delivery Packet starting with either SOP, SOP’ or SOP’’.
SOP’ Communication Communication with a Cable Plug using SOP’ Packets, also implies that a Message sequence is
being followed.
SOP’ Packet Any Power Delivery Packet which starts with an SOP’ used to communicate with a Cable Plug.
SOP’’ Communication Communication with a Cable Plug using SOP’’ Packets, also implies that a Message sequence
is being followed.
SOP’’ Packet Any Power Delivery Packet which starts with an SOP’’ used to communicate with a Cable
Plug when SOP’ Packets are being used to communicate with the other Cable Plug.
Source A role a Port is currently taking to supply power over VBUS; most commonly a Host or Hub
downstream port.
Standard ID (SID) 16-bit unsigned value assigned by the USB-IF to a given industry standard.
Standard or Vendor ID Generic term referring to either a VID or a SID. SVID is used in place of the phrase “Standard
(SVID) or Vendor ID”.
Start of Packet (SOP) K-code marker used to delineate the start of a packet. Three start of packet sequences are
defined: SOP, SOP’ and SOP’’, with SOP* used to refer to all three in place of SOP/SOP’/SOP’’.
System Policy Overall system policy generated by the system, broken up into the policies required by each
Port Pair to affect the system policy. It is programmatically fed to the individual devices for
consumption by their Policy Engines.
System Policy Manager Module running on the USB Host. It applies the System Policy through communication with
(SPM) PD capable Consumers and Providers that are also connected to the Host via USB.
Test Frame Frame consisting of a Preamble, SOP*, followed by test data (See Section 5.9).
Test Pattern Continuous stream of test data in a given sequence (See Section 5.9)
Tester The Tester is assumed to be a piece of test equipment that manages the BIST testing process
of a PD UUT.
Unexpected Message Message that a Port supports but has been received in an incorrect state.

Page 44 USB Power Delivery Specification Revision 3.0, Version 1.1

Term Description
Unit Interval (UI) The time to transmit a single data bit on the wire.
Unit Under Test (UUT) The PD device that is being tested by the Tester and responds to the initiation of a particular
BIST test sequence.
Unrecognized Message Message that a Port does not understand e.g. a Message using a ReservedMessage type, a
Message defined by a higher specification Revision than the Revision this Port supports, or an
Unstructured Message for which the VID is not recognized.
Unsupported Message Message that a Port recognizes but does not support. This is a Message defined by the
specification but which is not supported by this Port.
Upstream Facing Port Indicates the Port’s position in the USB topology typically a Port on a Device as defined in
(UFP) [USB Type-C 1.2]. At connection the Port defaults to operation as a USB Device (when USB
Communication is supported) and Sink.
USB Attached State Synonymous with the [USB 2.0]] and [USB 3.1] definition of the Attached state
USB Default Operation Operation of a Port at Attach or after a Hard Reset where the DFP Source applies vSafe0V or
vSafe5V on VBUS and the UFP Sink is operating at vSafe5V as defined in [USB 2.0], [USB 3.1],
[USB Type-C 1.2] or [USBBC 1.2].
USB Device Either a hub or a peripheral device as defined in [USB 2.0] and [USB 3.1].
USB Host The host computer system where the USB host controller is installed as defined in [USB 2.0]
and [USB 3.1].
USB Powered State Synonymous with the [USB 2.0] and [USB 3.1] definition of the powered state.
USB Safe State State of the USB Type-C connector when there are pins to be re-purposed (see [USB Type-C
1.2]) so they are not damaged by and do not cause damage to their Port Partner.
USB Type-A Term used to refer to any A plug or receptacle including Micro-A plugs and Standard-A plugs
and receptacles. Micro-AB receptacles are assumed to be a combination of USB Type-A and
USB Type-B.
USB Type-B Terms used to refer to any B-plug or receptacle including Micro-B plugs and Standard-B
plugs and receptacles, including the PD and non-PD versions. Micro-AB receptacles are
assumed to be a combination of USB Type-A and USB Type-B.
USB Type-C Term used to refer to the USB Type-C connector plug or receptacle as defined in [USB Type-C
1.2].
USB-IF PD SID (PD SID) Standard ID allocated to this specification by the USB Implementer’s Forum.
Variable Supply A very poorly regulated power supply that is not a Battery. This is exposed by the Variable
Supply PDO (see Section 6.4.1.2.3).
VCONN Powered Accessory An accessory that is powered from VCONN to operate in a Mode (see [USB Type-C 1.2]).
VCONN Source The USB Type-C Port responsible for sourcing VCONN.
VCONN Swap Process of exchanging the VCONN Source between Port Partners.
VDM Header The first Data Object following the Message Header in a Vendor Defined Message. The VDM
Header contains the SVID relating to the VDM being sent and provides information relating to
the Command in the case of a Structured VDM (see Section 6.4.4).
Vendor Data Object (VDO) Data Object used to send Vendor specific information as part of a Vendor_Defined Message.
Vendor Defined Message PD Data Message defined for vendor/standards usage. These are further partitioned into
(VDM) Structured VDM Messages, where Commands are defined in this specification, and
Unstructured VDM Messages which are entirely Vendor Defined (see Section 6.4.4).
Vendor ID (VID) 16-bit unsigned value assigned by the USB-IF to a given Vendor.
VI Same as power (i.e. voltage * current = power)
Wall Wart A power supply or “power brick” that is plugged into an AC outlet. It supplies DC power to
power a device or charge a Battery.

1.7 Parameter Values

The parameters in this specification are expressed in terms of absolute values. For details of how each parameter is
measured in compliance please see [USBPDCompliance].

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 45

 1.8 Changes From Revision 2.0
This specification includes the following updates:
 PD Power rules (also applied to [USBPD 2.0]).
 Mechanisms to avoid collisions and simplify communication.
 Support for [IEC 63002] included extended power supply capabilities and status.
 Battery capabilities and status.
 Ability to perform a fast power role swap.
 Support for [USBTypeCAuthentication 1.0] and [USBPDFirmwareUpdate 1.0].
The following have been Deprecated from this specification:
 The BFSK signaling scheme.
 Definitions of Standard/Micro A/B cables and connectors.
 Dead battery operation for A/B Ports.
 Profiles (replaced by PD Power Rules).
The following have been moved to other specifications:
 System Policy which is now defined in [USBTypeCBridge 1.0].
For more details see Section 2.3.1.

1.9 Compatibility with Revision 2.0

Revision 3.0 of the USB Power Delivery specification is designed to be fully interoperable with [USBPD 2.0] systems
using BMC signaling over the [USB Type-C 1.2] connector and to be compatible with Revision 2.0 hardware.
Please see Section 2.3.2 for more details of the mechanisms defined to enable compatibility.

Page 46 USB Power Delivery Specification Revision 3.0, Version 1.1

 2. Overview
This section contains no Normative requirements.

2.1 Introduction
In USB Power Delivery, pairs of directly Attached ports negotiate voltage, current and/or direction of power flow over
the USB cable, using the USB Type-C connector’s CC wire as the communications channel. The mechanisms used,
operate independently of other USB methods used to negotiate power.
USB Power Delivery also acts as a side-band channel enabling support for Standard or Vendor defined Modal
Operation. Modes are associated with a Standard or Vendor ID (SVID). Power Delivery Structured VDM Messages can
be used to discover supported SVIDs and Modes and then to enter and exit Modes as required. Multiple Active Modes
can also be in operation at the same time.
Any Contract negotiated using this specification, supersedes any and all previous power contracts established
whether from standard [USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2] mechanisms. While in Power Delivery
Mode there will be a Contract in place (either Explicit or Implicit) determining the power level available and the
direction of that power. The Port Pair remains in Power Delivery Mode until the Port Pair is Detached, there is a Hard
Reset or the Source removes power (except during a Power Role Swap or Fast Role Swap when the initial Source
removes power in order to for the new Source to apply power).
An Explicit Contract is negotiated by the process of the Source sending a set of Capabilities, from which the Sink is
required to request a particular capability and then the Source accepting this request.
An Implicit Contract is the specified level of power allowed in particular states (i.e. during and after a Power Role
Swap or Fast Role Swap). Implicit Contracts are temporary; Port Pairs are required to immediately negotiate an
Explicit Contract.
Each Provider has a Local Policy, governing power allocation to its Ports. Sinks also have their own Local Policy
governing how they draw power. A System Policy can be enacted over USB that allows modification to these local
policies and hence management of overall power allocation in the system.
When PD Capable devices are Attached to each other, the DFPs and UFPs initially default to standard USB Default
Operation. The DFP supplies vSafe5V and the UFP draws current in accordance with the rules defined by [USB 2.0],
[USB 3.1], [USB Type-C 1.2] or [USBBC 1.2] specifications. After Power Delivery negotiation has taken place power
can be supplied at higher, or lower, voltages and higher currents than defined in these specifications. It is also
possible to perform a Power Role Swap or Fast Role Swap to exchange the power supply roles such that the DFP
receives power and the UFP supplies power, to perform a Data Role Swap such that the DFP becomes the UFP and
vice-versa and to perform a VCONN Swap to change the end supplying VCONN to the cable.
Prior to an Explicit Contract the Source can discover the capabilities of the Attached cable assembly. This is important
for [USB Type-C 1.2] where 5A cabling is marked as well as other details of the cable assembly such as the supported
speed. Cable discovery occurs on initial Attachment of a Port Pair, before an Explicit Contract has been established
where the DFP is the Source. It is also possible to carry out cable discovery after a Power Role Swap or Fast Role Swap
prior to establishing an Explicit Contract, where the UFP is the Source and an Implicit Contract is in place.
Once an Explicit Contract is in place only the DFP is permitted to communicate with the Attached cable assembly. This
communication can consist of discovering capabilities but can also include discover of SVIDs, Modes and the
entering/exiting of Modes supported by the cable assembly.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 47

 2.2 Section Overview
This specification contains the following sections:

Section 1 Introduction, conventions used in the document, list of terms and abbreviations, references and details
of parameter usage.

Section 2 Overview of the document including a description of the operation of PD and the architecture.

Section 3 Mechanical and electrical characteristics of the cables and connectors used by PD. Section
Deprecated. See [USBPD 2.0] for legacy PD connector specification.

Section 4 Electrical requirements for Dead Battery operation and cable detection.

Section 5 Details of the PD PHY Layer requirements

Section 6 Protocol Layer requirements including the Messages, timers, counters and state operation.

Section 7 Power supply requirements for both Providers and Consumers.

Section 8 Device Policy Manager requirements.

Policy Engine Message sequence diagrams and state diagrams

Section 9 USBPD Device requirements including mapping of VBUS to USB states.

System Policy Manager requirements including descriptors, events and requests.

Section 10 Rated Output Power definitions for PD.

Appendix A Example CRC calculations.

Appendix B Scenarios illustrating Device Policy Manager operation.

Appendix C Examples of Structured VDM usage.

Page 48 USB Power Delivery Specification Revision 3.0, Version 1.1

 2.3 Revision 2.0 Changes and Compatibility
2.3.1 Changes From Revision 2.0
The following is a summary of the major changes between this specification (USB PD Revision 3.0) and [USBPD 2.0]:
 Support for both Revision 2.0 and Revision 3.0 operation mandated for products to ensure backwards
compatibility with existing products (see Section 6.2.1.1.5).
 Profiles Deprecated and replaced with PD Power Rules (see Section 2.7.9).
o Change also applied to [USBPD 2.0].
 BFSK support Deprecated including legacy cables, legacy connectors, legacy dead battery operation and related
test modes.
 Extended Messages with a data payload of up to 260 bytes defined (see Section 6.2.1.2):
o Support for Chunking of Extended Messages to [USBPD 2.0] size mandated to enable compatibility with
legacy PD hardware.
 Only the VCONN Source is allowed to communicate with the Cable Plugs (see Section 2.5.4).
 Source coordinated collision avoidance scheme to enable either the Source or Sink to initiate an Atomic Message
Sequence (AMS):
o [USB Type-C 1.2] Rp resistor values used by the Source to indicate when the Sink can/cannot initiate an AMS
to either the Source or a Cable Plug (see Section 2.7.3).
o Either the Source or Sink can initiate a Structured Vendor Defined AMS.
o Either the Source or the Sink can communicate with the Cable Plugs provided they are sourcing V CONN.
 Limitations on timing for Attention Commands removed:
o Fast Role Swap defined to enable externally powered docks and hubs to rapidly switch to bus power when
their external power supply is removed (see Section 6.3.17).
 Additional status and discovery of:
o Power Supply extended capabilities and status.
o Battery capabilities and status.
o Manufacturer defined information.
 Changes to fields in the Passive Cable, Active Cable and AMA VDOs indicated by a change in the Structured VDM
Version to 2.0 (see Section 6.4.4.2).
 Support for USB Security related requests and responses (see [USBTypeCAuthentication 1.0]).
 Support for USB PD firmware update requests and responses (see [USBPDFirmwareUpdate 1.0]).
 System Policy now references [USBTypeCBridge 1.0].

2.3.2 Compatibility with Revision 2.0

Revision 3.0 of the USB Power Delivery specification is designed to be fully interoperable with [USBPD 2.0] systems
using BMC signaling over the [USB Type-C 1.2] connector and to be compatible with Revision 2.0 hardware.
This specification mandates that all Revision 3.0 systems fully support Revision 2.0 operation. They must discover the
supported Revision used by their Port Partner and any connected Cable Plugs and revert to operation using the lowest
common Revision number (see Section 6.2.1.1.5).
This specification defines Extended Messages containing data of up to 260 bytes (see Section 6.2.1.2). These Messages
will be larger than expected by existing PHY HW. To accommodate Revision 2.0 based systems a Chunking
mechanism is mandated such that Messages are limited to Revision 2.0 sizes unless it is discovered that both systems
support the longer Message lengths.
This specification includes changes to the Vendor Defined Objects (VDO) used in the discovery of passive/active
marked cables and Alternate Mode Adapters (AMA) (see Section 6.4.4.2). To enable systems to determine which VDO
format is being used the Structured Vendor Defined Message (SVDM) version number has been incremented to 2.0.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 49

Version numbers have also been incorporated into the VDOs themselves to facilitate future changes if these become
necessary.

2.4 USB Power Delivery Capable Devices

Some examples of USB Power Delivery capable devices can be seen in Figure 2-1 (a Host, a Device, a Hub, and a
Charger). These are given for reference only and do not limit the possible configurations of products that can be built
using this specification.

Figure 2-1 Logical Structure of USB Power Delivery Capable Devices

USB Host USB Device USB Hub USB Charger

External UFP External UFP External External

power power power power

Power Power Power Power

Storage Storage Storage Storage

DFP DFP DFP

Legend Multiple Power

Multiple Power
inputs/outputs outputs

Optional Optional
Power input Feature
Power input

Each USB Power Delivery capable device is assumed to be made up of at least one Port. Providers are assumed to
have a Source and Consumers a Sink. Each device contains one, or more, of the following components:
 UFPs that:
o Sink power.
o Optionally source power (a Dual-Role Power Device).
o Optionally communicate via USB.
o Communicate using SOP Packets.
o Optionally Communicate using SOP* Packets.
 DFPs that:
o Source power.
o Optionally Sink power (a Dual-Role Power Device).
o Optionally communicate via USB.
o Communicate using SOP Packets.
o Optionally Communicate using SOP* Packets.
 A Source that can be:
o An external power source e.g. AC.
o Power Storage (e.g. Battery).
o Derived from another Port (e.g. bus-powered Hub).

Page 50 USB Power Delivery Specification Revision 3.0, Version 1.1

 A Sink that can be:
o Power Storage (e.g. a Battery).
o Used to power internal functions.
o Used to power devices Attached to other devices (e.g. a bus-powered Hub).
 A Vconn Source that:
o Can be either Port Partner, either the DFP/UFP or Source/Sink.
o Powers the Cable Plug(s).
o Is the only Port allowed to talk to the Cable Plug(s) at any given time.

2.5 SOP* Communication

2.5.1 Introduction
The Start of Packet (or SOP) is used as an addressing scheme to identify whether the Communications were intended
for one of the Port Partners (SOP Communication) or one of the Cable Plugs (SOP’/SOP’’ Communication). SOP/SOP’
and SOP’’ are collectively referred to as SOP*. The term Cable Plug in the SOP’/SOP’’ Communication case is used to
represent a logical entity in the cable which is capable of PD Communication and which might or might not be
physically located in the plug.
The following sections describe how this addressing scheme operates for Port to Port and Port to Cable Plug
Communication.

2.5.2 SOP* Collision Avoidance

For all SOP* the Source co-ordinates communication in order to avoid bus collisions by allowing the Sink to initiate
messaging when it does not need to communicate itself. Once an Explicit Contract is in place the Source indicates to
the Sink that it can initiate a message sequence. This sequence can be communication with the Source or with one of
the Cable Plugs. As soon as the Source itself needs to initiate a message sequence this will be indicated to the Sink.
The Source then waits for any outstanding Sink SOP* Communication to complete before initiating a message
sequence itself.

2.5.3 SOP Communication

SOP Communication is used for Port to Port communication between the Source and the Sink. SOP Communication is
recognized by both Port Partners but not by any intervening Cable Plugs. SOP Communication takes priority over
other SOP* Communications since it is critical to complete power related operations as soon as possible. Message
sequences relating to power are also allowed to interrupt other sequences to ensure that negotiation and control of
power is given priority on the bus.

2.5.4 SOP’/SOP’’ Communication with Cable Plugs

SOP’ Communication is recognized by electronics in one Cable Plug which is the Cable Plug that detected VCONN at
Attach (see [USB Type-C 1.2]). SOP’’ Communication can also be supported when SOP’ Communication is also
supported. SOP’’ Communication is recognized by the electronics in the Cable Plug that did not detect V CONN at Attach.
The Vconn Source is the DFP/Source at Attach although all of these roles can later be swapped using PD messaging.
SOP Communication between the Port Partners is not recognized by the Cable Plug. Figure 2-2 outlines the usage of
SOP* Communications between a VCONN Source (DFP/UFP) and the Cable Plugs.
All SOP* Communications take place over a single wire (CC). This means that the SOP* Communication periods must
be coordinated to prevent important communication from being blocked. For a product which does not recognize
SOP/SOP’ or SOP’’ Packets, this will look like a non-idle channel, leading to missed packets and retries.
Communications between the Port Partners take precedence meaning that communications with the Cable Plug can
be interrupted, but will not lead to a Soft or Hard Reset.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 51

When no Contract or an Implicit Contract is in place (e.g. after a Power Role Swap or Fast Role Swap) the Source
(which can be either the DFP or UFP but must also be the VcONN Source) can communicate with a Cable Plug using
SOP’ Packets in order to discover its characteristics (see Figure 2-2). During this phase all communication with the
Cable Plug is initiated and controlled by the Source which acts to prevent conflicts between SOP* Packets. The Sink
does not communicate with the Cable Plug, even if it is the DFP, and Discards any SOP’ Packets received.
When an Explicit Contract is in place the VcONN Source (either the DFP or the UFP) can communicate with the Cable
Plug(s) using SOP’/SOP’’ Packets (see Figure 2-2). During this phase all communication with the Cable Plug is
initiated and controlled by the VCONN Source which acts to prevent conflicts between SOP* Packets. The Port that is
not the VCONN Source does not communicate with the Cable Plug and does not recognize any SOP’/SOP’’ Packets
received. Only the DFP, when acting as a VCONN Source, is allowed to send SOP* in order to control the entry and
exiting of Modes and to manage Modal Operation.

Figure 2-2 Example SOP’ Communication between VCONN Source and Cable Plug(s)

Cable Cable
VCONN Source Plug1 Plug1
VCONN Electronically Marked Cable
(DFP/UFP) (SOP’) (SOP’’)

SOP’
signaling

SOP’’
signaling

SOP signaling

1 Cable Plug can be physically Attached to either the DFP or UFP.

Page 52 USB Power Delivery Specification Revision 3.0, Version 1.1

 2.6 Operational Overview
A USB Power Delivery Port supplying power is known as a Source and a Port consuming power is known as a Sink.
There is only one Source Port and one Sink Port in each PD connection between Port Partners. At Attach the Source
Port (the Port with Rp asserted see [USB Type-C 1.2]) is also the DFP and VCONN Source. At Attach the Sink Port (the
Port with Rd asserted) is also the UFP and is not the VCONN Source.
The Source/Sink roles, DFP/UFP roles and VCONN Source role can all subsequently be swapped orthogonally to each
other. A Port that supports both Source and Sink roles is called a Dual-Role Power Port (DRP). A Port that supports
both DFP and UFP roles is called a Dual-Role Data Port (DRD).
When USB Communications Capability is supported in the DFP role then the Port will also be able to act as a USB Host.
Similarly when USB Communications Capability is supported in the UFP role then the Port will also be able to act as a
USB Device.
The following sections describe the high level operation of ports taking on the roles of DFP, UFP, Source and Sink.
These sections do not describe operation that is not allowed; however if a certain behavior is not described then it is
probably not supported by this specification.
For details of how PD maps to USB states in a PDUSB Device see Section 9.1.2.

2.6.1 Source Operation

The Source operates differently depending on Attachment status:
 At Attach (no PD Connection or Contract):
o For a Source-only Port the Source detects Sink Attachment.
o For a DRP that toggles the Port becomes a Source Port on Attachment of a Sink
o The Source then typically sets VBUS to vSafe5V.
 Before PD Connection (no PD Connection or PD Contract):
o Prior to sending Source_Capabilities Messages the Source can detect the type of cabling Attached and can
alter its advertised capabilities depending on the type of cable detected:
 The Source attempts to communicate with one of the Cable Plugs using SOP’ Packets. If the Cable Plug
responds then communication takes place.
 The default capability of a USB Type-C cable is 3A, but SOP’ Communication is used to discover other
capabilities of the cable.
o The Source periodically advertises its capabilities by sending Source_Capabilities Messages every
tTypeCSendSourceCap.
 Establishing PD Connection (no PD Connection or Contract):
o Presence of a PD Capable Port Partner is detected either:
 By receiving a GoodCRC Message in response to a Source_Capabilities Message.
 By receiving Hard Reset Signaling.
 Establishing Explicit Contract (PD Connection but no Explicit Contract or Implicit Contract after a Power Role
Swap or Fast Role Swap):
o The Source receives a Request Message from the Sink and responds with an Accept Message, if this is a Valid
request, followed by a PS_RDY Message when its power supply is ready to source power at the agreed level.
At this point an Explicit Contract has been agreed.
o A DFP does not generate SOP’ or SOP’’ Packets, is not required to detect SOP’ or SOP’’ Packets and Discards
them.
 During PD Connection (Explicit Contract - PE_SRC_Ready State):
o The Source processes and responds (if a response is required) to all Messages received and sends appropriate
Messages whenever its Local Policy requires:
 The Source informs the Sink whenever its capabilities change, by sending a Source_Capabilities Message.
 The Source will always have Rp asserted on its CC wire.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 53

  When this Port is a DRP the Source can initiate or receive a request for the exchange of power roles. After
the Power Role Swap this Port will be a Sink and an Implicit Contract will be in place until an Explicit
Contract is negotiated immediately afterwards.
 When this Port is a DRD the Source can initiate or receive a request for an exchange of data roles. After a
Data Role Swap the DFP (Host) becomes a UFP (Device). The Port remains a Source and the VCONN
Source role (or not) remains unchanged.
 The Source can initiate or receive a request for an exchange of VCONN Source. During a VCONN Swap
VCONN is applied by both ends (make before break). The Port remains a Source and DFP/UFP roles
remain unchanged.
o The Source when it is the VCONN Source can communicate with a Cable Plug using SOP’ or SOP’’
Communication at any time it is not engaged in any other SOP Communications:
 If SOP Packets are received by the Source, during SOP’ or SOP’’ Communication, the SOP’ or SOP’’
Communication is immediately terminated (the Cable Plug times out and does not retry)
 If the Source needs to initiate an SOP Communication during an ongoing SOP’ or SOP’’ Communication
(e.g. for a Capabilities change) then the SOP’ or SOP’’ Communications will be interrupted.
o When the Source Port is also a DFP:
 The Source can control the entry and exiting of modes in the Cable Plug(s) and control Modal Operation.
 The Source can initiate Unstructured or Structured VDMs.
 The Source can control the entry and exiting of modes in the Sink and control Modal Operation using
Structured VDMs.
o When the Source Port is part of a multi-port system:
 Will issue GotoMin requests when the Power Reserve is needed.
 Detach or Communications Failure:
o A Source detects plug Detach and takes VBUS down to vSafe5V within tSafe5V and vSafe0V within tSafe0V (i.e.
using USB Type-C Detach detection via CC).
o When the Source detects the failure to receive a GoodCRC Message in response to a Message within tReceive:
 Leads to a Soft Reset, within tSoftReset of the CRCReceiveTimer expiring.
 If the soft reset process cannot be completed a Hard Reset will be issued within tHardReset of the
CRCReceiveTimer to restore VBUS to USB Default Operation within ~1-1.5s:
 When the Source is also the VCONN Source, VCONN will also be power cycled during the Hard Reset.
o Receiving no response to further attempts at communication is interpreted by the Source as an error (see
Error handling).
o Errors during power transitions will automatically lead to a Hard Reset in order to restore power to default
levels.
 Error handling:
o Protocol Errors are handled by a Soft_Reset Message issued by either Port Partner, that resets counters,
timers and states, but does not change the negotiated voltage and current or the Port’s role (e.g. Source,
DFP/UFP, VCONN Source) and does not cause an exit from Modal Operation.
o Serious errors are handled by Hard Reset Signaling issued by either Port Partner. A Hard Reset:
 Resets protocol as for a Soft Reset but also returns the power supply to USB Default Operation (vSafe0V
or vSafe5V output) in order to protect the Sink.
 Restores the Port’s data role to DFP.
 When the Sink is the VCONN Source it removes VCONN then the Source Port is restored as the VCONN
Source.
 Causes all Active Modes to be exited such that the Source is no longer in Modal Operation.
o After a Hard Reset it is expected that the Port Partner will respond within tNoResponse. If this does not
occur then nHardResetCount further Hard Resets are carried out before the Source performs additional
Error Recovery steps, as defined in [USB Type-C 1.2] , by entering the ErrorRecovery state.

Page 54 USB Power Delivery Specification Revision 3.0, Version 1.1

 2.6.2 Sink Operation
 At Attach (no PD Connection or Contract):
o Sink detects Source Attachment through the presence of vSafe5V.
o For a DRP that toggles the Port becomes a Sink Port on Attachment of a Source.
o Once the Sink detects the presence of vSafe5V on VBUS it waits for a Source_Capabilities Message indicating
the presence of a PD capable Source.
o If the Sink does not receive a Source_Capabilities Message within tTypeCSinkWaitCap then it issues Hard
Reset Signaling in order to cause the Source Port to send a Source_Capabilities Message if the Source Port is
PD capable.
o The Sink does not generate SOP’ or SOP’’ Packets, is not required to detect SOP’ or SOP’’ Packets and does not
recognize them.
 Establishing PD Connection (no PD Connection or Contract):
o The Sink receives a Source_Capabilities Message and responds with a GoodCRC Message.
o The Sink does not generate SOP’ or SOP’’ Packets, is not required to detect SOP’ or SOP’’ Packets and Discards
them.
 Establishing Explicit Contract (PD Connection but no Explicit Contract or Implicit Contract after a Power Role
Swap or Fast Role Swap):
o The Sink receives a Source_Capabilities Message from the Source and responds with a Request Message. If
this is a Valid request the Sink receives an Accept Message followed by a PS_RDY Message when the Source’s
power supply is ready to source power at the agreed level. At this point the Source and Sink have entered
into an Explicit Contract:
 The Sink Port may request one of the capabilities offered by the Source, even if this is the vSafe5V output
offered by [USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2], in order to enable future power
negotiation:
 A Sink not requesting any capability with a Request Message results in an error.
 A Sink unable to fully operate at the offered capabilities requests the default capability but indicates that
it would prefer another power level and provide a physical indication of the failure to the end user (e.g.
using an LED).
 A Sink does not generate SOP’ or SOP’’ Packets, is not required to detect SOP’ or SOP’’ Packets and
Discards them.
 During PD Connection (Explicit Contract – PE_SNK_Ready state):
o The Sink processes and responds (if a response is required) to all Messages received and sends appropriate
Messages whenever its Local Policy requires.
o A Sink whose power needs have changed indicates this to the Source with a new Request Message. The Sink
Port can request one of the capabilities previously offered by the Source, even if this is the vSafe5V output
offered by [USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2], in order to enable future power negotiation:
 Not requesting any capability with a Request Message results in an error.
 A Sink unable to fully operate at the offered capabilities requests an offered capability but indicates a
capability mismatch i.e. that it would prefer another power level also providing a physical indication of
the failure to the End User (e.g. using an LED).
o The Sink will always have Rd asserted on its CC wire.
o When this Port is a DRP the Sink can initiate or receive a request for the exchange of power roles. After the
Power Role Swap this Port will be a Source and an Implicit Contract will be in place until an Explicit Contract
is negotiated immediately afterwards.
o When this Port is a DRD the Sink can initiate or receive a request for an exchange of data roles. After a Data
Role Swap the DFP (Host) becomes a UFP (Device). The Port remains a Sink and V CONN Source role (or not)
remains unchanged.
o The Sink can initiate or receive a request for an exchange of VCONN Source. During a VCONN Swap VCONN is
applied by both ends (make before break). The Port remains a Sink and DFP/UFP roles remain unchanged.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 55

 o The Sink when it is the VCONN Source can communicate with a Cable Plug using SOP’ or SOP’’ Communication
at any time it is not engaged in any other SOP Communications:
 If SOP Packets are received by the Sink, during SOP’ or SOP’’ Communication, the SOP’ or SOP’’
Communication is immediately terminated (the Cable Plug times out and does not retry)
 If the Sink needs to initiate an SOP Communication during an ongoing SOP’ or SOP’’ Communication (e.g.
for a Capabilities change) then the SOP’ or SOP’’ Communications will be interrupted.
 When the Sink Port is also a DFP the Sink can control the entry and exiting of modes in the Cable Plug(s)
and control Modal Operation.
o When the Sink Port is also a DFP:
 The Sink can initiate Unstructured or Structured VDMs.
 The Sink can control the entry and exiting of modes in the Source and control Modal Operation using
Structured VDMs.
 Detach or Communications Failure:
o A Sink detects the removal of VBUS and interprets this as the end of the PD Connection:
 This is unless the vSafe0V is due to either a Hard Rest, Power Role Swap or Fast Role Swap.
o A Sink detects plug removal and discharges VBUS.
o When the Sink detects the failure to receive a GoodCRC Message in response to a Message within tReceive:
 Leads to a Soft Reset, within tSoftReset of the CRCReceiveTimer expiring.
 If the soft reset process cannot be completed a Hard Reset will be issued within tHardReset of the
CRCReceiveTimer to restore VBUS to USB Default Operation within ~1-1.5s.
 Receiving no response to further attempts at communication is interpreted by the Sink as an error (see
Error handling).
o Errors during power transitions will automatically lead to a Hard Reset in order to restore power to default
levels.
 Error handling:
o Protocol Errors are handled by a Soft_Reset Message issued by either Port Partner, that resets counters,
timers and states, but does not change the negotiated voltage and current or the Port’s role (e.g. Sink,
DFP/UFP, VCONN Source) and does not cause an exit from Modal Operation.
o Serious errors are handled by Hard Reset Signaling issued by either Port Partner. A Hard Reset:
 resets protocol as for a Soft Reset but also returns the power supply to USB Default Operation (vSafe0V
or vSafe5V output) in order to protect the Sink.
 restores the Port’s data role to UFP.
 when the Sink is the VCONN Source it removes VCONN then the Source Port is restored as the VCONN Source.
 causes all Active Modes to be exited such that the Source is no longer in Modal Operation.
 After a Hard Reset it is expected that the Port Partner will respond within tTypeCSinkWaitCap. If this does not
occur then 2 further Hard Resets are carried out before the UFP stays in the PE_SNK_Wait_for_Capabilities state.

2.6.3 Cable Plugs

 Cable Plugs are powered when Vconn is present but are not aware of the status of the Contract.
 Cable Plugs do not initiate message sequences and only respond to messages sent to them.
 Detach or Communications Failure:
o Communications can be interrupted at any time.
o There is no communication timeout scheme between the DFP/UFP and Cable Plug.
o The Cable Plug is ready to respond to potentially repeated requests.
 Error handling:
o The Cable Plug detects Hard Reset Signaling to determine that the Source and Sink have been reset and will
need to reset itself (equivalent to a power cycle).
 The Cable Plug cannot generate Hard Reset Signaling itself.

Page 56 USB Power Delivery Specification Revision 3.0, Version 1.1

  The Hard Reset process power cycles both VBUS and Vconn so this is expected to reset the Cable
Plugs by itself.
o A Cable Plug detects Cable Reset Signaling to determine that it will need to reset itself (equivalent to a power
cycle).

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 57

 2.7 Architectural Overview
This logical architecture is not intended to be taken as an implementation architecture. An implementation architecture
is, by definition, a part of product definition and is therefore outside of the scope of this specification.
This section outlines the high level logical architecture of USB Power Delivery referenced throughout this
specification. In practice various implementation options are possible based on many different possible types of PD
device. PD devices can have many different configurations e.g. USB or non-USB communication, single versus multiple
ports, dedicated power supplies versus supplies shared on multiple ports, hardware versus software based
implementations etc. The architecture outlined in this section is therefore provided only for reference in order to
indicate the high level logical model used by the PD specification. This architecture is used to identify the key
concepts and also to indicate logical blocks and possible links between them.
The USB Power Delivery architecture in each USB Power Delivery capable Device is made up of a number of major
components.
The communications stack seen in Figure 2-3 consists of:
 A Device Policy Manager (see Section 8.2) that exists in all devices and manages USB Power Delivery resources
within the device across one or more ports based on the Device’s Local Policy.
 A Policy Engine (see Section 8.3) that exists in each USB Power Delivery Port implements the Local Policy for
that Port.
 A Protocol Layer (see Chapter 6) that enables Messages to be exchanged between a Source Port and a Sink Port.
 A Physical Layer (see Chapter 5) that handles transmission and reception of bits on the wire and handles data
transmission.

Figure 2-3 USB Power Delivery Communications Stack

Provider Consumer
Device Policy Device Policy
Manager Manager

Policy Engine Policy Engine

Protocol Protocol

Physical Layer Physical Layer

CC

Additionally USB Power Delivery devices which can operate as USB devices can communicate over USB (see Figure
2-4). An Optional System Policy Manager (see Chapter 9) that resides in the USB Host communicates with the PD
Device over USB, via the root Port and potentially over a tree of USB Hubs. The Device Policy Manager interacts with
the USB interface in each device in order to provide and update PD related information in the USB domain. Note that a
PD device is not required to have a USB device interface.

Page 58 USB Power Delivery Specification Revision 3.0, Version 1.1

 Figure 2-4 USB Power Delivery Communication Over USB

USB Host

System Policy
Manager

USB hub tree

(optional)

PD USB
Device
USB Interface
(optional)

Device Policy
Manager

Policy Engine

Protocol

Physical Layer

CC

Figure 2-5 shows the logical blocks between two Attached PD ports. In addition to the communication stack
described above there are also:
 For a Provider or Dual-Role Power Device: one or more Sources providing power to one or more ports.
 For a Consumer or Dual-Role Power Device: a Sink consuming power.
 A USB-C Port Control module (see Section4.4) that detects cable Attach/Detach as defined in [USB Type-C 1.2].
 USB Power Delivery uses standard cabling as defined in [USB Type-C 1.2].
The Device Policy Manager talks to the communication stack, Source/Sink and the USB-C Port Control block in order
to manage the resources in the Provider or Consumer.
Figure 2-5 illustrates a Provider and a Consumer. Dual-Role Power Devices can be constructed by combining the
elements of both Provider and Consumer into a single device. Providers can also contain multiple Source Ports each
with their own communications stack and USB-C Port Control.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 59

 Figure 2-5 High Level Architecture View

Provider Consumer

Device Policy Manager Device Policy Manager

Source Port Sink Port

Policy Engine Policy Engine

Protocol Power Power Protocol

Source(s) Sink

USB-C Port USB-C Port

Control Physical Layer Physical Layer Control

BMC BMC

USB Port USB Port

CC VBUS VBUS CC

VBUS

CC

2.7.1 Policy
There are two possible levels of Policy:
1) System Policy applied system wide by the System Policy Manager across multiple Providers or Consumers.
2) Local Policy enforced on a Provider or Consumer by the Device Policy Manager.
Policy comprises several logical blocks:
 System Policy Manager (system wide).
 Device Policy Manager (one per Provider or Consumer).
 Policy Engine (one per Source or Sink Port).

2.7.1.1 System Policy Manager

Since the USB Power Delivery protocol is essentially point to point, implementation of a System Policy requires
communication by an additional data communication mechanism i.e. USB. The System Policy Manager monitors and
controls System Policy between various Providers and Consumers connected via USB. The System Policy Manager
resides in the USB Host and communicates via USB with the Device Policy Manager in each connected Device. Devices
without USB data communication capability or are not data connected, will not be able to participate in System Policy.
The System Policy Manager is Optional in any given system so USB Power Delivery Providers and Consumers can
operate without it being present. This includes systems where the USB Host does not provide a System Policy
Manager and can also include “headless” systems without any USB Host. In those cases where a Host is not present,
USB Power Delivery is useful for charging purposes, or the powering of devices since useful USB functionality is not
possible. Where there is a USB Host but no System Policy Manager, Providers and Consumers can negotiate power
between themselves, independently of USB power rules, but are more limited in terms of the options available for
managing power.

Page 60 USB Power Delivery Specification Revision 3.0, Version 1.1

 2.7.1.2 Device Policy Manager
The Device Policy Manager provides mechanisms to monitor and control the USB Power Delivery system within a
particular Consumer or Provider. The Device Policy Manager enables Local Policies to be enforced across the system
by communication with the System Policy Manager. Local Policies are enacted on a per Port basis by the Device Policy
Manager’s control of the Source/Sink Ports and by communication with the Policy Engine and USB-C Port Control for
that Port.

2.7.1.3 Policy Engine

Providers and Consumers are free to implement their own Local Policies on their directly connected Source or Sink
Ports. These will be supported by negotiation and status mechanisms implemented by the Policy Engine for that Port.
The Policy Engine interacts directly with the Device Policy Manager in order to determine the present Local Policy to
be enforced. The Policy Engine will also be informed by the Device Policy Manager whenever there is a change in
Local Policy (e.g. a capabilities change).

2.7.2 Message Formation and Transmission

2.7.2.1 Protocol Layer
The Protocol Layer forms the Messages used to communicate information between a pair of ports. It is responsible
for forming Capabilities Messages, requests and acknowledgements. Additionally it forms Messages used to swap
roles and maintain presence. It receives inputs from the Policy Engine indicating which Messages to send and
indicates the responses back to the Policy Engine.
The basic protocol uses a push model where the Provider pushes it capabilities to the Consumer that in turn responds
with a request based on the offering. However, the Consumer can asynchronously request the Provider’s present
capabilities and can select another voltage/current.
Extended Messages of up to a Data Size of MaxExtendedMsgLen can be sent and received provided the Protocol Layer
determines that both Port Partners support this capability. When one of both Port Partners do not support Extended
Messages of Data Size greater than MaxExtendedMsgLegacyLen then the Protocol Layer supports a Chunking
mechanism to break larger Messages into smaller Chunks of size MaxExtendedMsgChunkLen.

2.7.2.2 PHY Layer

The PHY Layer is responsible for sending and receiving Messages across the USB Type-C CC wire and for managing
data. It tries to avoid collisions on the wire, recovering from them when they occur. It also detects errors in the
Messages using a CRC.

2.7.3 Collision Avoidance

2.7.3.1 Policy Engine
The Policy Engine in a Source will indicate to the Protocol Layer the start and end of each Atomic Message Sequence
(AMS) that the Source initiates. The Policy Engine in a Sink will indicate to the Protocol Layer the start of each AMS
the Sink initiates. This enables co-ordination of AMS initiation between the Port Partners.

2.7.3.2 Protocol Layer

The Protocol Layer in the Source will request the PHY to set the Rp value to SinkTxOk to indicate that the Sink can
initiate an AMS by sending the first Message in the sequence. The Protocol Layer in the Source will request the PHY to
set the Rp value to SinkTxNG to indicate that the Sink cannot initiate an AMS since the Source is about to initiate an
AMS.
The Protocol Layer in the Sink, when the Policy Engine indicates that an AMS is being initiated, will wait for the Rp
value to be set to SinkTxOk before initiating the AMS by sending the first Message in the sequence.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 61

 2.7.3.3 PHY Layer
The PHY Layer in the Source will set the Rp value to either SinkTxOk or SinkTxNG as directed by the Protocol Layer.
The PHY Layer in the Sink will detect the present Rp value and inform the Protocol Layer.

2.7.4 Power supply

2.7.4.1 Source
Each Provider will contain one or more Sources that are shared between one or more ports. These Sources are
controlled by the Local Policy. Sources start up in USB Default Operation where the Port applies vSafe0V or vSafe5V
on VBUS and return to this state on Detach or after a Hard Reset. If the Source applies vSafe0V as their default, it
detects Attach events and transitions its output to vSafe5V upon detecting an Attach.

2.7.4.2 Sink
Consumers are assumed to have one Sink connected to a Port. This Sink is controlled by Local Policy. Sinks start up in
USB Default Operation where the Port can operate at vSafe5V with USB default specified current levels and return to
this state on Detach or after a Hard Reset.

2.7.4.3 Dual-Role Power Ports

Dual-Role Power Ports have the ability to operate as either a Source or a Sink and to swap between the two roles
using Power Role Swap or Fast Role Swap.

2.7.4.4 Dead Battery or Lost Power Detection

[USB Type-C 1.2] defines mechanisms intended to communicate with and charge a Sink or DRP with a Dead Battery.

2.7.5 DFP/UFP
2.7.5.1 Downstream Facing Port (DFP)
The Downstream Facing Port or DFP is equivalent in the USB topology to the USB A-Port. The DFP will also
correspond to the USB Host but only if USB Communication is supported while acting as a DFP. Products such as Wall
Warts can be a DFP while not having USB Communication capability. The DFP also acts as the bus master when
controlling alternate mode operation.

2.7.5.2 Upstream Facing Port (UFP)

The Upstream Facing Port or UFP is equivalent in the USB topology to the USB B-Port. The UFP will also correspond
to the USB Device but only if USB Communication is supported while acting as a UFP. Products which charge can be a
UFP while not having USB Communication capability.

2.7.5.3 Dual-Role Data Ports

Dual-Role Data Ports have the ability to operate as either a DFP or a UFP and to swap between the two roles using
Data Role Swap. Note that products can be Dual-Role Data Ports without being Dual-Role Power ports i.e. they can
switch logically between DFP and UFP roles even if they are Source-only or Sink-only Ports.

2.7.6 VCONN Source

One Port, initially the Source Port, is the VCONN Source. The Cable Plugs use this supply to determine which Cable Plug
is SOP’. The responsibility for sourcing VCONN can be swapped between the Source and Sink Ports in a make before
break fashion to ensure that the Cable Plugs continue to be powered. To ensure reliable communication with the
Cable Plugs only the VCONN Source is permitted to communicate with the Cable Plugs. Prior to a Power Role Swap,
Data Role Swap or Fast Role Swap each Port needs to ensure that it is the V CONN Source if it needs to communicate
with the Cable Plugs after the swap.

Page 62 USB Power Delivery Specification Revision 3.0, Version 1.1

 2.7.7 Cable and Connectors
2.7.7.1 USB-C Port Control
The USB-C Port Control block provides mechanisms to inform the Device Policy Manager of cable Attach/Detach
events.
The USB Power Delivery specification assumes certified USB cables and associated detection mechanisms as defined
in the [USB Type-C 1.2] specification.

2.7.8 Interactions between Non-PD, BC and PD devices

USB Power Delivery only operates when two USB Power Delivery devices are directly connected. When a Device finds
itself a mixed environment, where the other device does not support the USB Power Delivery Specification, the
existing rules on supplying vSafe5V as defined in the [USB 2.0], [USB 3.1], [USBBC 1.2] or [USB Type-C 1.2]
specifications are applied.
There are two primary cases to consider:
 The Host (DFP/Source) is non-PD and as such will not send any advertisements. An Attached PD capable Device
will not see any advertisements and operates using the rules defined in the [USB 2.0], [USB 3.1], [USBBC 1.2] or
[USB Type-C 1.2] specifications.
 The Device (UFP/Sink) is non-PD and as such will not see any advertisements and therefore will not respond. The
Host (DFP/Source) will continue to supply vSafe5V to VBUS as specified in the [USB 2.0], [USB 3.1], [USBBC 1.2] or
[USB Type-C 1.2] specifications.

2.7.9 Power Rules

Power Rules define voltages and current ranges that are offered by USB Power Delivery Sources and used by a USB
Power Delivery Sink for a given value of PD Power. See Section 10 for further details.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 63

3. USB Type-A and USB Type-B Cable Assemblies and Connectors
This section has been Deprecated. Please refer to [USBPD 2.0] for details of cables and connectors used in scenarios
utilizing the BFSK Signaling scheme in conjunction with USB Type-A or USB Type-B connectors.

Page 64 USB Power Delivery Specification Revision 3.0, Version 1.1

4. Electrical Requirements
This chapter covers the platform’s electrical requirements for implementing USB Power Delivery.

4.1 Interoperability with other USB Specifications

USB Power Delivery May be implemented alongside the [USB 2.0], [USB 3.1], [USBBC 1.2] and [USB Type-C 1.2]
specifications. In the case where a Device requests power via the Battery Charging Specification and then the USB
Power Delivery Specification, it Shall follow the USB Power Delivery Specification until the Port Pair is Detached or
there is a Hard Reset. If the USB Power Delivery connection is lost, the Port Shall return to its default state, see
Section 6.8.2.

4.2 Dead Battery Detection / Unpowered Port Detection

Dead Battery/Unpowered operation is when a USB Device needs to provide power to a USB Host under the
circumstances where the USB Host:
 Has a Dead Battery that requires charging or
 Has lost its power source or
 Does not have a power source or
 Does not want to provide power.
Dead Battery charging operation for connections between USB Type-C connectors is defined in [USB Type-C 1.2].

4.3 Cable IR Ground Drop (IR Drop)

Every PD Sink Port capable of USB communications can be susceptible to unreliable USB communication if the voltage
drop across ground falls outside of the acceptable common mode range for the USB Hi-Speed transceivers data lines
due to excessive current draw. Certified USB cabling is specified such that such errors don’t typically occur (See [USB
Type-C 1.2]).

4.4 Cable Type Detection

Standard USB Type-C cable assemblies are rated for PD voltages higher than vSafe5V and current levels of at least 3A
(See [USB Type-C 1.2]). The Source Shall limit maximum capabilities it offers so as not to exceed the capabilities of
the type of cabling detected.
Sources Shall detect the type of Attached cable and limit the Capabilities they offer based on the current carrying
capability of the cable determined by the Cable capabilities determined using the Discover Identity Command (see
Section 6.4.4.2) sent using SOP’ Communication (see Section 2.5) to the Cable Plug. The Cable VDO returned as part of
the Discover Identity Command details the maximum current and voltage values that Shall be negotiated for a given
cable as part of an Explicit Contract.
The cable detection process is usually run when the Source is powered up, after a Power Role Swap or Fast Role Swap
or when power is applied to a Sink. The exact method used to detect these events is up to the manufacturer and Shall
meet the following requirements:
 Sources Shall run the cable detection process prior to the Source sending Source_Capabilities Messages offering
currents in excess of 3A and/or voltages in excess of 20V.
 Sinks with USB Type-C connectors Shall select Capabilities from the offered Source Capabilities assuming that the
Source has already determined the Capabilities of the cable.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 65

5. Physical Layer
5.1 Physical Layer Overview
The Physical Layer (PHY Layer) defines the signaling technology for USB Power Delivery. This chapter defines the
electrical requirements and parameters of the PD Physical Layer required for interoperability between USB PD
devices.

5.2 Physical Layer Functions

The USB PD Physical Layer consists of a pair of transmitters and receivers that communicate across a single signal
wire (CC). All communication is half duplex. The PHY Layer practices collision avoidance to minimize communication
errors on the channel.
The transmitter performs the following functions:
 Receive packet data from the protocol layer.
 Calculate and append a CRC.
 Encode the packet data including the CRC (i.e. the payload).
 Transmit the Packet (Preamble, SOP*, payload, CRC and EOP) across the channel using Biphase Mark Coding
(BMC) over CC.
The receiver performs the following functions:
 Recover the clock and lock onto the Packet from the Preamble.
 Detect the SOP*.
 Decode the received data including the CRC.
 Detect the EOP and validate the CRC:
o If the CRC is Valid, deliver the packet data to the protocol layer.
o If the CRC is Invalid, flush the received data.

Page 66 USB Power Delivery Specification Revision 3.0, Version 1.1

 5.3 Symbol Encoding
Except for the Preamble, all communications on the line Shall be encoded with a line code to ensure a reasonable level
of DC-balance and a suitable number of transitions. This encoding makes receiver design less complicated and allows
for more variations in the receiver design.
4b5b line code Shall be used. This encodes 4-bit data to 5-bit symbols for transmission and decodes 5-bit symbols to
4-bit data for consumption by the receiver.
The 4b5b code provides data encoding along with special symbols. Special symbols are used to signal Hard Reset,
and delineate packet boundaries.

Table 5-1 4b5b Symbol Encoding Table

Name 4b 5b Symbol Description

0 0000 11110 hex data 0
1 0001 01001 hex data 1
2 0010 10100 hex data 2
3 0011 10101 hex data 3
4 0100 01010 hex data 4
5 0101 01011 hex data 5
6 0110 01110 hex data 6
7 0111 01111 hex data 7
8 1000 10010 hex data 8
9 1001 10011 hex data 9
A 1010 10110 hex data A
B 1011 10111 hex data B
C 1100 11010 hex data C
D 1101 11011 hex data D
E 1110 11100 hex data E
F 1111 11101 hex data F
Sync-1 K-code 11000 Startsynch #1
Sync-2 K-code 10001 Startsynch #2
RST-1 K-code 00111 Hard Reset #1
RST-2 K-code 11001 Hard Reset #2
EOP K-code 01101 EOP End Of Packet
Reserved Error 00000 Shall Not be used
Reserved Error 00001 Shall Not be used
Reserved Error 00010 Shall Not be used
Reserved Error 00011 Shall Not be used
Reserved Error 00100 Shall Not be used
Reserved Error 00101 Shall Not be used
Sync-3 K-code 00110 Startsynch #3
Reserved Error 01000 Shall Not be used
Reserved Error 01100 Shall Not be used
Reserved Error 10000 Shall Not be used
Reserved Error 11111 Shall Not be used

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 67

 5.4 Ordered Sets
Ordered sets Shall be interpreted according to Figure 5-1.
An ordered set consists of 4 K-codes sent as shown in Figure 5-1.

Figure 5-1 Interpretation of ordered sets

A list of the ordered sets used by USB Power Delivery can be seen in Table 5-2. SOP* is a generic term used in place of
SOP/SOP’/SOP’’.

Table 5-2 Ordered Sets

Ordered Set Reference

Cable Reset Section 5.6.5
Hard Reset Section 5.6.4
SOP Section 5.6.1.2.1
SOP’ Section 5.6.1.2.2
SOP’_Debug Section 5.6.1.2.4
SOP’’ Section 5.6.1.2.3
SOP’’_Debug Section 5.6.1.2.5

The receiver Shall search for all four K-codes and when it finds either three out of four or all four in the correct place,
it May interpret it as a Valid ordered set (see Table 5-3).

Table 5-3 Validation of Ordered Sets

1st code 2nd code 3rd code 4th code

Valid Corrupt K-code K-code K-code
Valid K-code Corrupt K-code K-code
Valid K-code K-code Corrupt K-code
Valid K-code K-code K-code Corrupt
Valid (perfect) K-code K-code K-code K-code
Invalid (example) K-code Corrupt K-code Corrupt

Page 68 USB Power Delivery Specification Revision 3.0, Version 1.1

 5.5 Transmitted Bit Ordering
This section describes the order of bits on the wire that Shall be used when transmitting data of varying sizes. Table
5-4 shows the different data sizes that are possible.
Figure 5-2 shows the transmission order that Shall be followed.

Table 5-4 Data Size

Unencoded Encoded
Byte 8-bits 10-bits
Word 16-bits 20- bits
DWord 32-bits 40-bits

Figure 5-2 Transmit Order for Various Sizes of Data

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 69

 5.6 Packet Format
The packet format Shall consist of a Preamble, an SOP*, (see Section 5.6.1.2), packet data including the Message
Header, a CRC and an EOP (see Section 5.6.1.5). The packet format is shown in Figure 5-3 and indicates which parts of
the packet Shall be 4b/5b encoded. Once 4b/5b encoded, the entire Packet Shall be transmitted using BMC over CC.
Note that all the bits in the Packet, including the Preamble, are BMC encoded. See Section 6.2.1 for more details of the
Packet construction for Control, Data and Extended Messages.

Figure 5-3 USB Power Delivery Packet Format

Preamble(training for receiver)

SOP* (Start
Of Packet)
Message
Header
Byte 0 Byte 1 ...

... Byte n-1 Byte n CRC

EOP (End Of
Packet)

LEGEND:
Training sequence provided by the Provided by the Physical Provided by the Protocol
Physical layer, not encoded with 4b5b layer, encoded with 4b5b layer, encoded with 4b5b

5.6.1 Packet Framing

The transmission starts with a Preamble that is used to allow the receiver to lock onto the carrier. It is followed by a
SOP* (Start of Packet). The packet is terminated with an EOP (End of Packet) K-code.

5.6.1.1 Preamble
The Preamble is used to achieve lock in the receiver by presenting an alternating series of "0s" and "1s", so the
average frequency is the carrier frequency. Unlike the rest of the packet, the Preamble Shall Not be 4b/5b encoded.
The Preamble Shall consist of a 64-bit sequence of alternating 0s and 1s. The Preamble Shall start with a "0" and
Shall end with a "1".

5.6.1.2 Start of Packet Sequences

5.6.1.2.1 Start of Packet Sequence (SOP)

SOP is an ordered set. The SOP ordered set is defined as: three Sync-1 K-codes followed by one Sync-2 K-code (see
Table 5-5).

Table 5-5 SOP ordered set

K-code number K-code in code table

1 Sync-1
2 Sync-1
3 Sync-1
4 Sync-2

A Power Delivery Capable Source or Sink Shall be able to detect and communicate with packets using SOP. If a Valid
SOP is not detected (see Table 5-3) then the whole transmission Shall be Discarded.
Sending and receiving of SOP Packets Shall be limited to PD Capable Ports on PDUSB Hosts and PDUSB Devices. Cable
Plugs Shall neither send nor receive SOP Packets. Note that PDUSB Devices, even if they have the physical form of a
cable (e.g. AMAs), are still required to respond to SOP Packets.

Page 70 USB Power Delivery Specification Revision 3.0, Version 1.1

 5.6.1.2.2 Start of Packet Sequence Prime (SOP’)
The SOP’ ordered set is defined as: two Sync-1 K-codes followed by two Sync-3 K-codes (see Table 5-6).

Table 5-6 SOP’ ordered set

K-code number K-code in code table

1 Sync-1
2 Sync-1
3 Sync-3
4 Sync-3

A Cable Plug capable of SOP’ Communications Shall only detect and communicate with packets starting with SOP’.
A Port needing to communicate with a Cable Plug capable of SOP’ Communications, Attached between a Port Pair will
be able to communicate using both packets starting with SOP’ to communicate with the Cable Plug and starting with
SOP to communicate with its Port Partner.
For a Cable Plug supporting SOP’ Communications, if a Valid SOP’ is not detected (see Table 5-3) then the whole
transmission Shall be Discarded. For a Port supporting SOP’ Communications if a Valid SOP or SOP’ is not detected
(see Table 5-3) then the whole transmission Shall be Discarded. When there is no Explicit Contract or an Implicit
Contract in place a Sink Shall Not send SOP’ Packets and Shall Discard all packets starting with SOP’.

5.6.1.2.3 Start of Packet Sequence Double Prime (SOP’’)

The SOP’’ ordered set is defined as the following sequence of K-codes: Sync-1, Sync-3, Sync-1, Sync-3 (see Table 5-7).

Table 5-7 SOP’’ ordered set

K-code number K-code in code table

1 Sync-1
2 Sync-3
3 Sync-1
4 Sync-3

A Cable Plug capable of SOP’’ Communication, Shall have a SOP’ Communication capability in the other Cable Plug. No
cable Shall only support SOP’’ Communication. A Cable Plug to which SOP’’ Communication is assigned Shall only
detect and communicate with packets starting with SOP’’ and Shall Discard any other packets.
A Port needing to communicate with such a Cable Plug, Attached between a Port Pair will be able to communicate
using packets starting with SOP’ and SOP’’ to communicate with the Cable Plugs and packets starting with SOP to
communicate with its Port Partner. A Port which supports SOP’’ Communication Shall also support SOP’
Communication and Shall co-ordinate SOP* Communication so as to avoid collisions.
For the Cable Plug supporting SOP’’ Communication, if a Valid SOP’’ is not detected (see Table 5-3) then the whole
transmission Shall be Discarded. For the Port if a Valid SOP* is not detected (see Table 5-3) then the whole
transmission Shall be Discarded.

5.6.1.2.4 Start of Packet Sequence Prime Debug (SOP’_Debug)

The SOP’_Debug ordered set is defined as the following sequence of K-codes: Sync-1, RST-2, RST-2, Sync-3 (see Table
5-8). The usage of this Ordered Set is presently undefined.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 71

 Table 5-8 SOP’_Debug ordered set

K-code number K-code in code table

1 Sync-1
2 RST-2
3 RST-2
4 Sync-3

5.6.1.2.5 Start of Packet Sequence Double Prime Debug (SOP’’_Debug)

The SOP’’_Debug ordered set is defined as the following sequence of K-codes: Sync-1, RST-2, Sync-3, Sync-2 (see
Table 5-9). The usage of this Ordered Set is presently undefined.

Table 5-9 SOP’’_Debug ordered set

K-code number K-code in code table

1 Sync-1
2 RST-2
3 Sync-3
4 Sync-2

5.6.1.3 Packet Payload

The packet payload is delivered from the protocol layer (Section 6.2) and Shall be encoded with the hex data codes
from Table 5-1.

5.6.1.4 CRC
The CRC Shall be inserted just after the payload. It is described in Section 5.6.2.

5.6.1.5 End of Packet (EOP)

The end of packet marker Shall be a single EOP K-code as defined in Table 5-1. This Shall mark the end of the CRC.
After the EOP, the CRC-residual Shall be checked. If the CRC is not good, the whole transmission Shall be Discarded,
if it is good, the packet Shall be delivered to the Protocol Layer. Note an EOP May be used to prematurely terminate a
Packet e.g. before sending Hard Reset Signaling.

5.6.2 CRC
The Message Header and data Shall be protected by a 32-bit CRC.
CRC-32 protects the data integrity of the data payload. CRC-32 is defined as follows:
 The CRC-32 polynomial Shall be = 04C1 1DB7h.
 The CRC-32 Initial value Shall be = FFFF FFFFh.
 CRC-32 Shall be calculated for all bytes of the payload not inclusive of any packet framing symbols (i.e. excludes
the Preamble, SOP*, EOP).
 CRC-32 calculation Shall begin at byte 0 bit 0 and continue to bit 7 of each of the bytes of the packet.
 The remainder of CRC-32 Shall be complemented.
 The residual of CRC-32 Shall be C704 DD7Bh.
Note: This inversion of the CRC-32 remainder adds an offset of FFFF FFFFh that will create a constant CRC-32
residual of C704 DD7Bh at the receiver side.
Note: The CRC implementation is identical to the one used in [USB 3.1].

Page 72 USB Power Delivery Specification Revision 3.0, Version 1.1

Figure 5-4 is an illustration of CRC-32 generation. The output bit ordering Shall be as detailed in Table 5-10.

Figure 5-4 CRC 32 generation

Table 5-10 CRC-32 Mapping

CRC-32 Result bit Position in CRC-32 Field

0 31
1 30
2 29
3 28
4 27
5 26
6 25
7 24
8 23
9 22
10 21
11 20
12 19
13 18
14 17
15 16
16 15
17 14
18 13
19 12
20 11
21 10
22 9

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 73

 CRC-32 Result bit Position in CRC-32 Field
23 8
24 7
25 6
26 5
27 4
28 3
29 2
30 1
31 0

The CRC-32 Shall be encoded before transmission.

5.6.3 Packet Detection Errors

CRC errors, or errors detected while decoding encoded symbols using the code table, Shall be treated the same way;
the Message Shall be Discarded and a GoodCRC Message Shall Not be returned.
While the receiver is processing a packet, if at any time VBUS becomes idle the receiver Shall stop processing the
packet and Discard it (no GoodCRC Message is returned). See Section 5.8.6.1 for the definition of BMC idle.

5.6.4 Hard Reset

Hard Reset Signaling is an ordered set of bytes sent with the purpose to be recognized by the PHY Layer. The Hard
Reset Signaling ordered set is defined as: three RST-1 K-codes followed by one RST-2 K-code (see Table 5-11).

Table 5-11 Hard Reset ordered set

K-code number K-code in code table

1 RST-1
2 RST-1
3 RST-1
4 RST-2

A device Shall perform a Hard Reset when it receives Hard Reset Signaling. After receiving the Hard Reset Signaling,
the device Shall reset as described in Section 6.8.2. If a Valid Hard Reset is not detected (see Table 5-3) then the
whole transmission Shall be Discarded.
A Cable Plug Shall perform a Hard Reset when it detects Hard Reset Signaling being sent between the Port Partners.
After receiving the Hard Reset Signaling, the device Shall reset as described in Section 6.8.2.
The procedure for sending Hard Reset Signaling Shall be as follows:
1. If the PHY Layer is currently sending a Message, the Message Shall be interrupted by sending an EOP K-code and
the rest of the Message Discarded.
2. If CC is not idle, wait for it to become idle (see Section 5.8.6.1).
3. Wait tInterFrameGap.
4. If CC is still idle send the Preamble followed by the 4 K-codes for Hard Reset Signaling.
5. Disable the channel (i.e. stop sending and receiving), reset the PHY Layer and inform the Protocol Layer that the
PHY Layer has been reset.
6. Re-enable the channel when requested by the Protocol Layer.
Figure 5-5 shows the line format of Hard Reset Signaling which is a Preamble followed by the Hard Reset Ordered
Set.

Page 74 USB Power Delivery Specification Revision 3.0, Version 1.1

 Figure 5-5 Line format of Hard Reset

Preamble(training for receiver) RST-1 RST-1 RST-1 RST-2

LEGEND:
Preamble provided by the Physical layer, Provided by the Physical
not encoded with 4b5b layer, encoded with 4b5b

5.6.5 Cable Reset

Cable Reset Signaling is an ordered set of bytes sent with the purpose to be recognized by the PHY Layer. The Cable
Reset Signaling ordered set is defined as the following sequence of K-codes: RST-1, Sync-1, RST-1, Sync-3 (see Table
5-12).

Table 5-12 Cable Reset ordered set

K-code number K-code in code table

1 RST-1
2 Sync-1
3 RST-1
4 Sync-3

Cable Reset Signaling Shall only be sent by the DFP. The Cable Reset Ordered Set is used to reset the Cable Plugs
without the need to Hard Reset the Port Partners. The state of the Cable Plug after the Cable Reset Signaling Shall be
equivalent to power cycling the Cable Plug.
Figure 5-6 shows the line format of Cable Reset Signaling which is a Preamble followed by the Cable Reset Ordered
Set.

Figure 5-6 Line format of Cable Reset

Preamble(training for receiver) RST-1 Sync-1 RST-1 Sync-3

LEGEND:
Preamble provided by the Physical layer, Provided by the Physical
not encoded with 4b5b layer, encoded with 4b5b

5.7 Collision Avoidance

The PHY Layer Shall monitor the channel for data transmission and only initiate transmissions when CC is idle. If the
bus idle condition is present, it Shall be considered safe to start a transmission provided the conditions detailed in
Section 5.8.5.4 are met. The bus idle condition Shall be checked immediately prior to transmission. If transmission
cannot be initiated then the packet Shall be Discarded. If the packet is Discarded because CC is not idle, the PHY
Layer Shall signal to the protocol layer that it has Discarded the Message as soon as CC becomes idle. See Section
5.8.6.1 for the definition of idle CC.
In addition the PHY Layer Shall control the Rp resistor value to avoid collisions between Source and Sink
transmissions. The Source Shall set an Rp value corresponding to a current of 3A to indicate to the Sink that it May
initiate an AMS. The Source Shall set an Rp value corresponding to a current of 1.5A this Shall indicate to the Sink

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 75

that it Shall Not initiate an AMS and Shall only respond to Messages as part of an AMS. See [USB Type-C 1.2] for details of
the corresponding Rp values.
Table 5-13 details the Rp values that Shall be used by the Source to control Sink initiation of an AMS.

Table 5-13 Rp values used for Collision Avoidance

Source Rp Parameter Description Sink operation Source operation

Sink Transmit “No Go”, Sink cannot initiate an AMS. Source can initiate an AMS
1.5A@5V SinkTxNG Sink can only respond to Messages tSinkTx after setting Rp to this
as part of an AMS value.
Sink Transmit “Ok” Sink can initiate an AMS. Source cannot initiate an AMS
3A@5V SinkTxOk
while it has this value set.

See also Section 6.6.15 and Section 6.11.2.1.

5.8 Biphase Mark Coding (BMC) Signaling Scheme

Biphase Mark Coding (BMC) is the physical layer Signaling Scheme for carrying USB Power Delivery Messages. This
encoding assumes a dedicated DC connection, identified as the CC wire, which is used for sending PD Messages.
Biphase Mark Coding is a version of Manchester coding (see [IEC 60958-1]). In BMC, there is a transition at the start
of every bit time (UI) and there is a second transition in the middle of the UI when a 1 is transmitted. BMC is
effectively DC balanced, (each 1 is DC balanced and two successive zeroes are DC balanced, regardless of the number
of intervening 1’s). It has bounded disparity (limited to 1 bit over an arbitrary packet, so a very low DC level).
Figure 5-7 illustrates Biphase Mark Coding. This example shows the transition from a Preamble to the Sync-1 K-codes
of the SOP Ordered Set at the start of a Message. Note that other K-codes can occur after the Preamble for Signaling
such as Hard Reset and Cable Reset.

Figure 5-7 BMC Example

5.8.1 Encoding and signaling

BMC uses DC coupled baseband signaling on CC. Figure 5-8 shows a block diagram for a Transmitter and Figure 5-9
shows a block diagram for the corresponding Receiver.

Page 76 USB Power Delivery Specification Revision 3.0, Version 1.1

 Figure 5-8 BMC Transmitter Block Diagram

Data 4b5b BMC

Encoder Encoder to CC

CRC

Figure 5-9 BMC Receiver Block Diagram

from CC BMC SOP 5b4b Data

Decoder Detect Decoder

CRC

The USB PD baseband signal Shall be driven on the CC wire with a tristate driver that Shall cause a vSwing swing on
CC. The tristate driver is slew rate limited (see min rise/fall time in Section 5.8.5) to limit coupling to D+/D- and to
other signal lines in the USB Type-C fully featured cables (see [USB Type-C 1.2]). This slew rate limiting can be
performed either with driver design or an RC filter on the driver output.
When sending the Preamble, the transmitter Shall start by transmitting a low level. The receiver Shall tolerate the
loss of the first edge. The transmitter May vary the start of the Preamble by tStartDrive min (see Figure 5-10).

Figure 5-10 BMC Encoded Start of Preamble

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 77

The transmitter Shall terminate the final bit of the Frame by an edge (the “trailing edge”) to help ensure that the
receiver clocks the final bit. If the trailing edge results in the transmitter driving CC low (i.e. the final half-UI of the
frame is high), then the transmitter:
1. Shall continue to drive CC low for tHoldLowBMC.
2. Then Shall continue to drive CC low for tEndDriveBMC measured from the trailing edge of the final bit of the Frame.
3. Then Shall release CC to high impedance.
Figure 5-11 illustrates the end of a BMC encoded Frame with an encoded zero for which the final bit of the Frame is
terminated by a high to low transition. Figure 5-12 illustrates the end of a BMC Encoded frame with an encoded one
for which the final bit of the Frame is terminated by a high to low transition. Both figures also illustrate the
tInterFrameGap timing requirement before the start of the next Frame when the Port has either been transmitting or
receiving the previous Frame (see Section 5.8.5.4).

Figure 5-11 Transmitting or Receiving BMC Encoded Frame Terminated by Zero with High-to-Low Last Transition

Figure 5-12 Transmitting or Receiving BMC Encoded Frame Terminated by One with High-to-Low Last Transition

If the trailing edge results in the transmitter driving CC high (i.e. the final half-UI of the frame is low), then the
transmitter:
1. Shall continue to drive CC high for 1 UI.
2. Then Shall drive CC low for tHoldLowBMC.
3. Then Shall continue to drive CC low for tEndDriveBMC measured from the final edge of the final bit of the Frame.
4. Then Shall release CC to high impedance.
Figure 5-13 illustrates the ending of a BMC encoded Frame that ends with an encoded zero for which the final bit of
the Frame is terminated by a low to high transition. Figure 5-14 illustrates the ending of a BMC encoded Frame that
ends with an encoded one for which the final bit of the Frame is terminated by a low to high transition. Both figures
also illustrate the tInterFrameGap timing requirement before the start of the next Frame when the Port has either
been transmitting or receiving the previous Frame (see Section 5.8.5.4).

Page 78 USB Power Delivery Specification Revision 3.0, Version 1.1

 Figure 5-13 Transmitting or Receiving BMC Encoded Frame Terminated by Zero with Low to High Last Transition

Figure 5-14 Transmitting or Receiving BMC Encoded Frame Terminated by One with Low to High Last Transition

Note: There is no requirement to maintain a timing phase relationship between back-to-back packets.

5.8.2 Transmit and Receive Masks

5.8.2.1 Transmit Masks
The transmitted signal Shall Not violate the masks defined in Figure 5-15, Figure 5-16, Table 5-14 and Table 5-15 at
the output of a load equivalent to the cable model and receiver load model described in Section 5.8.3. The masks
apply to the full range of Rp/Rd values as defined in [USB Type-C 1.2]. Note: the measurement of the transmitter does
not need to accommodate a change in signal offset due to the ground offset when current is flowing in the cable.
The transmitted signal Shall have a rise time no faster than tRise. The transmitted signal Shall have a fall time no
faster than tFall. The maximum limits on the rise and fall times are enforced by the Tx inner masks.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 79

 Figure 5-15 BMC Tx ‘ONE’ Mask

Figure 5-16 BMC Tx ‘ZERO’ Mask

Page 80 USB Power Delivery Specification Revision 3.0, Version 1.1

 Table 5-14 BMC Tx Mask Definition, X Values

Name Description Value Units

X1Tx Left Edge of Mask 0.015 UI
X2Tx see figure 0.07 UI
X3Tx see figure 0.15 UI
X4Tx see figure 0.25 UI
X5Tx see figure 0.35 UI
X6Tx see figure 0.43 UI
X7Tx see figure 0.485 UI
X8Tx see figure 0.515 UI
X9Tx see figure 0.57 UI
X10Tx see figure 0.65 UI
X11Tx see figure 0.75 UI
X12Tx see figure 0.85 UI
X13Tx see figure 0.93 UI
X14Tx Right Edge of Mask 0.985 UI

Table 5-15 BMC Tx Mask Definition, Y Values

Name Description Value Units

Y1Tx Lower bound of Outer mask -0.075 V
Y2Tx Lower bound of inner mask 0.075 V
Y3Tx see figure 0.15 V
Y4Tx see figure 0.325 V
Y5Tx Inner mask vertical midpoint 0.5625 V
Y6Tx see figure 0.8 V
Y7Tx see figure 0.975 V
Y8Tx see figure 1.04 V
Y9Tx Upper Bound of Outer mask 1.2 V

5.8.2.2 Receive Masks

A Source using the BMC Signaling Scheme Shall be capable of receiving a signal that complies with the mask when
sourcing power as defined in Figure 5-17, Figure 5-18 and Table 5-16. The Source Rx mask is bounded by sweeping a
Tx mask compliant signal, with added vNoiseActive between power neutral and Source offsets.
A Consumer using the BMC Signaling Scheme Shall be capable of receiving a signal that complies with the mask when
sinking power as defined in Figure 5-21, Figure 5-22 and Table 5-16. The Consumer Rx mask is bounded by sweeping
a Tx mask compliant signal, with added vNoiseActive between power neutral and Consumer offsets.
Every product using the BMC Signaling Scheme Shall be capable of receiving a signal that complies with the mask
when power neutral as defined in Figure 5-19, Figure 5-20 and Table 5-16.
Dual-Role Power Devices Shall meet the receiver requirements for a Source when providing power during any
transmission using the BMC Signaling Scheme or a Sink when consuming power during any transmission using the
BMC Signaling Scheme.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 81

Cable Plugs Shall meet the receiver requirements for both a Source and a Sink during any transmission using the BMC
Signaling Scheme.
The parameters used in the masks are specified to be appropriate to either edge triggered or oversampling receiver
implementations.
The masks are defined for ‘ONE’ and ‘ZERO’ separately as BMC enforces a transition at the midpoint of the unit
interval while a ‘ONE’ is transmitted.
The Rx masks are defined to bound the Rx noise after the Rx bandwidth limiting filter with the time constant tRxFilter
has been applied.
The boundaries of Rx outer mask, Y1Rx and Y5Rx, are specified according to vSwing max and accommodate half of
vNoiseActive from cable noise coupling and the signal offset vIRDropGNDC due to the ground offset when current is
flowing in the cable.
The vertical dimension of the Rx inner mask, Y4Rx - Y2Rx, for power neutral is derived by reducing the vertical
dimension of the Tx inner mask, Y7Tx - Y3Tx, at time location X3Tx by vNoiseActive to account for cable noise
coupling. The received signal is composed of a waveform compliant to the Tx mask plus vNoiseActive.
The vertical dimension of the Rx inner mask for sourcing power is derived by reducing the vertical dimension of the
Tx inner mask by vNoiseActive and vIRDropGNDC to account for both cable noise coupling and signal DC offset. The
received signal is composed of a waveform compliant to the Tx mask plus the maximum value of vNoiseActive plus
vIRDropGNDC where the vIRDropGNDC value transitions between the minimum and the maximum values as allowed
in this spec.
The vertical dimension of the Rx inner mask for sinking power is derived by reducing the vertical dimension of the Tx
inner mask by vNoiseActive max and vIRDropGNDC max for account for both cable noise coupling and signal DC
offset. The received signal is composed of a waveform compliant to the Tx mask plus the maximum value of
vNoiseActive plus vIRDropGNDC where the vIRDropGNDC value transitions between the minimum and the maximum
values as allowed in this spec.
The center line of the Rx inner mask, Y3Rx, is at half of the nominal vSwing for power neutral, and is shifted up by half
of vIRDropGNDC max for sourcing power and is shifted down by half of vIRDropGNDC max for sinking power.
The receiver sensitivity Shall be set such that the receiver does not treat noise on an undriven signal path as an
incoming signal. Signal amplitudes below vNoiseIdle max Shall be treated as noise when BMC is idle.

Page 82 USB Power Delivery Specification Revision 3.0, Version 1.1

 Figure 5-17 BMC Rx ‘ONE’ Mask when Sourcing Power

Figure 5-18 BMC Rx ‘ZERO’ Mask when Sourcing Power

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 83

 Figure 5-19 BMC Rx ‘ONE’ Mask when Power neutral

Figure 5-20 BMC Rx ‘ZERO’ Mask when Power neutral

Page 84 USB Power Delivery Specification Revision 3.0, Version 1.1

 Figure 5-21 BMC Rx ‘ONE’ Mask when Sinking Power

Figure 5-22 BMC Rx ‘ZERO’ Mask when Sinking Power

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 85

 Table 5-16 BMC Rx Mask Definition

Name Description Value Units

X1Rx Left Edge of Mask 0.07 UI

X2Rx Top Edge of Mask 0.15 UI

X3Rx See figure 0.35 UI

X4Rx See figure 0.43 UI

X5Rx See figure 0.57 UI

X6Rx See figure 0.65 UI

X7Rx See figure 0.85 UI

X8Rx See figure 0.93 UI

Y1Rx Lower bound of Outer Mask -0.3325 V

Y2Rx Lower Bound of Inner Mask Y3Rx – 0.205 when sourcing power1
or sinking power1 V
Y3Rx – 0.33 when power neutral1
Y3Rx Center line of Inner Mask 0.6875 Sourcing Power1 V
0.5625 Power Neutral1
0.4375 Sinking Power1
Y4Rx Upper bound of Inner mask Y3Rx + 0.205 when sourcing power1 or sinking power1 V
Y3Rx + 0.33 when power neutral1
Y5Rx Upper bound of the Outer mask 1.5325 V
Note 1: The position of the center line of the Inner Mask is dependent on whether the receiver is Sourcing or Sinking power or
is Power Neutral (see earlier in this section).

5.8.3 Transmitter Load Model

The transmitter load model Shall be equivalent to the circuit outlined in Figure 5-23 for a Source and Figure 5-24 for a
Sink. It is formed by the concatenation of a cable load model and a receiver load model. See [USB Type-C 1.2] for
details of the Rp and Rd resistors. Note the parameters zCable_CC, tCableDelay_CC and cCablePlug_CC are defined in
[USB Type-C 1.2].

Figure 5-23 Transmitter Load Model for BMC Tx from a Source

Transmitter Load
Model Output
Cable Model Receiver
Rp Load Model
rOutput Connector La
cCablePlug_CC

cCablePlug_CC

cShunt ca ca Rd cReceiver
2 2

Page 86 USB Power Delivery Specification Revision 3.0, Version 1.1

 Figure 5-24 Transmitter Load Model for BMC Tx from a Sink

Transmitter Load
Model Output
Cable Model Receiver
Rp Load Model
rOutput Connector La

cCablePlug_CC
cCablePlug_CC
Rd cShunt ca ca cReceiver
2 2

The transmitter system components rOutput and cShunt are illustrated for informative purposes, and do not form part
of the transmitter load model. See Section 5.8.5 for a description of the transmitter system design.
The value of the modeled cable inductance, La, (in nH) Shall be calculated from the following formula:
𝐿𝑎 = 𝑡𝐶𝑎𝑏𝑙𝑒𝐷𝑒𝑙𝑎𝑦_𝐶𝐶𝑚𝑎𝑥 ∗ 𝑧𝐶𝑎𝑏𝑙𝑒_𝐶𝐶𝑚𝑖𝑛
tCableDelay_CC is the modeled signal propagation delay through the cable, and zCable_CC is the modeled cable
impedance.
The modeled cable inductance is 640 nH for a cable with zCable_CCmin = 32 Ω and tCableDelay_CCmax = 20 nS.
The value of the modeled cable capacitance, Ca, (in pF) Shall be calculated from the following formula:
𝑡𝐶𝑎𝑏𝑙𝑒𝐷𝑒𝑙𝑎𝑦_𝐶𝐶𝑚𝑎𝑥
𝐶𝑎 =
𝑧𝐶𝑎𝑏𝑙𝑒_𝐶𝐶𝑚𝑖𝑛
The modeled cable capacitance is Ca = 625 pF for a cable with zCable_CCmin = 32 Ω and tCableDelay_CCmax = 20 nS.
Therefore, Ca/2 = 312.5 pF.
cCablePlug_CC models the capacitance of the plug at each end of the cable. cReceiver models the capacitance of the
receiver. The maximum values Shall be used in each case.
Note: the transmitter load model assumes that there are no other return currents on the ground path.

5.8.4 BMC Common specifications

This section defines the common receiver and transmitter requirements.

5.8.4.1 BMC Common Parameters

The electrical requirements specified in Table 5-17 Shall apply to both the transmitter and receiver.

Table 5-17 BMC Common Normative Requirements

Name Description Min Nom Max Units Comment

fBitRate Bit rate 270 300 330 Kbps
tUnitInterval1 Unit Interval 3.03 3.70 µs 1/fBitRate
Note 1: tUnitInterval denotes the time to transmit an unencoded data bit, not the shortest high or low times on the wire after
encoding with BMC. A single data bit cell has duration of 1UI, but a data bit cell with value 1 will contain a centrally placed 01 or
10 transition in addition to the transition at the start of the cell.

5.8.5 BMC Transmitter Specifications

The transmitter Shall meet the specifications defined in Table 5-18.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 87

 Table 5-18 BMC Transmitter Normative Requirements

Name Description Min Nom Max Units Comment

pBitRate Maximum difference between 0.25 % The reference bit rate is the
the bit-rate during the part of average bit rate of the last 32
the packet following the bits of the Preamble.
Preamble and the reference
bit-rate.
Maximum driver resistance of
a Fast Role Swap request
transmitter. Assumes a
Fast Role Swap worst case cable resistance of
request transmit 15Ω as defined in [USB Type-
rFRSwapTx 5 Ω
driver resistance (excluding C 1.2]. Note: based on this
cable resistance) value the maximum combined
driver and cable resistance of
a Fast Role Swap request
transmitter is 20Ω.
Time to cease driving the line
Min value is limited by
tEndDriveBMC after the end of the last bit of 23 µs
tHoldLowBMC.
the Frame.
10 % and 90 % amplitude
tFall Fall Time 300 ns points, minimum is under an
unloaded condition.
Time to cease driving the line
Max value is limited by
tHoldLowBMC after the final high-to-low 1 µs
tEndDriveBMC.
transition.
tInterFrameGap Time from the end of last bit 25 µs
of a Frame until the start of
the first bit of the next
Preamble.
tFRSwapTx Fast Role Swap request 60 120 µs Fast Role Swap request is
transmit duration indicated from the initial
Source to the initial Sink by
driving CC low for this time.
10 % and 90 % amplitude
tRise Rise time 300 ns points, minimum is under an
unloaded condition.
tStartDrive Time before the start of the -1 1 µs
first bit of the Preamble when
the transmitter Shall start
driving the line.
Applies to both no load
condition and under the load
vSwing Voltage Swing 1.05 1.125 1.2 V
condition specified in Section
5.8.3.
Source output impedance at
the Nyquist frequency of [USB
Transmitter output
zDriver 33 75 Ω 2.0] low speed (750 kHz)
impedance
while the source is driving the
CC line.

5.8.5.1 Capacitance when not transmitting

cReceiver is the capacitance that a DFP or UFP Shall present on the CC line when the DFP or UFP’s receiver is not
transmitting on the line. The transmitter May have more capacitance than cReceiver while driving the CC line, but

Page 88 USB Power Delivery Specification Revision 3.0, Version 1.1

Shall meet the waveform mask requirements. Once transmission is complete, the transmitter Shall disengage
capacitance in excess of cReceiver from the CC wire within tInterFrameGap.

5.8.5.2 Source Output Impedance

Source output impedance zDriver is determined by the driver resistance and the shunt capacitance of the source and
is hence a frequency dependent term. zDriver impacts the noise ingression in the cable. It is specified such that the
noise at the Receiver is bounded.
zDriver is defined by the following equation:
𝑟𝑂𝑢𝑡𝑝𝑢𝑡
𝑧𝐷𝑟𝑖𝑣𝑒𝑟 =
1 + 𝑠 ∗ 𝑟𝑂𝑢𝑡𝑝𝑢𝑡 ∗ 𝑐𝑆ℎ𝑢𝑛𝑡

Figure 5-25 Transmitter diagram illustrating zDriver

rOutput

cShunt zDriver

cShunt Shall Not cause a violation of cReceiver when not transmitting.

5.8.5.3 Bit Rate Drift

Limits on the drift in fBitRate are set in order to help low-complexity receiver implementations.
fBitRate is the reciprocal of the average bit duration from the previous 32 bits at a given portion of the packet. The
change in fBitRate during a packet Shall be less than pBitRate. The reference bit rate (refBitRate) is the average
fBitRate over the last 32 bits of the Preamble. fBitRate throughout the packet, including the EOP, Shall be within
pBitRate of refBitRate. pBitRate is expressed as a percentage:

pBitRate = | fBitRate – refBitRate | / refBitRate x 100%

The transmitter Shall have the same pBitRate for all packet types. The BIST Carrier Mode and Bit Stream signals are
continuous signals without a payload. When checking pBitRate any set of 1044 bits (20 bit SOP followed by 1024
PRBS bits) within a continuous signal May be considered as the part of the packet following the Preamble and the 32
preceding bits considered to be the last 32 bits of the Preamble used to compute refBitRate .

5.8.5.4 Inter-Frame Gap

Figure 5-26 illustrates the inter-Frame gap timings.

Figure 5-26 Inter-Frame Gap Timings

Bus driven after end Bus driven before

End of Frame of Frame Preamble Preamble

tInterFrameGap

tEndDriveBMC tStartDrive

The transmitter Shall drive the bus for no longer than tEndDriveBMC after transmitting the final bit of the Frame.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 89

Before starting to transmit the next Frame’s Preamble the transmitter of the next Frame Shall ensure that it waits for
tInterFrameGap after either:
1. Transmitting the previous frame, for example sending the next Message in an AMS immediately after having sent a
GoodCRC Message, or
2. Receiving the previous frame, for example when responding to a received Message with a GoodCRC Message, or
3. Observing an idle condition on CC (see Section 5.7). In this case the Port is waiting to initiate an AMS observes idle (see
Section 5.8.6.1) and then waits tInterFrameGap before transmitting the Frame. See also Section 5.7 for details on when
an AMS can be initiated.
Note: the transmitter is also required to verify a bus idle condition immediately prior to starting transmission of the
next Frame (see Section 5.8.6.1).
The transmitter of the next Frame May vary the start of the Preamble by tStartDrive (see Section 5.8.1).
See also Section 5.8.1 for figures detailing the timings relating to transmitting, receiving and observing idle in relating
to Frames.

5.8.5.5 Shorting of Transmitter Output

A Transmitter in a Port or Cable Plug Shall tolerate having its output be shorted to ground for tFRSwapTx max. This
is due to the potential for Fast Role Swap to be signaled while the Transmitter is in the process of transmitting (see
Section 5.8.5.6).

5.8.5.6 Fast Role Swap Transmission

The Fast Role Swap process is intended for use by a PDUSB HUB that presently has an external wall supply, and is
providing power both through its downstream Ports to USB Devices and upstream to a USB Host such as a notebook.
On removal of the external wall supply Fast Role Swap enables a VBUS supply to be maintained by allowing the USB
Host to apply vSafe5V when it sees VBUS droop below vSafe5V after having detected Fast Role Swap signaling. The
Fast Role Swap AMS is then used to correctly assign Source/Sink roles and configure the Rp/Rd resistors (see Section
8.3.2.7).
The initial Source Shall signal a Fast Role Swap request by driving CC to ground with a resistance of less than
rFRSwapTx for tFRSwapTx. The initial Source Shall only signal a Fast Role Swap when it has an Explicit Contract. On
transmission of the Fast Role Swap signal any pending Messages Shall be Discarded (see Section 6.11.2.2.1).
The Fast Role Swap signal May override any active transmissions.
Since the initial Sink’s response to the Fast Role Swap signal is to send an FR_Swap Message, the initial Source Shall
ensure Rp is set to SinkTxOk once the Fast Role Swap signal is complete.

5.8.6 BMC Receiver Specifications

The receiver Shall meet the specifications defined in Table 5-19.

Table 5-19 BMC Receiver Normative Requirements

Name Description Min Nom Max Units Comment

The DFP or UFP system Shall
have capacitance within this
cReceiver CC receiver capacitance 200 600 pF
range when not transmitting
on the line.
nBER Bit error rate, S/N = 25 dB 10-6
Number of transitions to be
Transitions for signal
nTransitionCount 3 detected to declare bus non-
detect
idle.

Page 90 USB Power Delivery Specification Revision 3.0, Version 1.1

Name Description Min Nom Max Units Comment
A Fast Role Swap request
Fast Role Swap request results in the receiver
tFRSwapRx 30 50 µs
detection time detecting a signal low for at
least this amount of time.
Time constant of a single pole
Rx bandwidth limiting
tRxFilter 100 ns filter to limit broad-band
filter (digital or analog)
noise ingression1.
Time window for
tTransitionWindow 12 20 µs
detecting non-idle
Fast Role Swap request The Fast Role Swap request
vFRSwapCableTx voltage detection 490 520 550 mV has to be below this voltage
threshold threshold to be detected.
As specified in [USB Type-C
vIRDropGNDC Cable Ground IR Drop 250 mV
1.2]
Peak-to-peak noise from VBUS,
USB 2.0 and SBU lines after
Noise amplitude when
vNoiseActive 165 mV the Rx bandwidth limiting
BMC is active.
filter with the time constant
tRxFilter has been applied.
Peak-to-peak noise from VBUS,
USB 2.0 and SBU lines after
Noise amplitude when
vNoiseIdle 300 mV the Rx bandwidth limiting
BMC is idle.
filter with the time constant
tRxFilter has been applied.
zBmcRx Receiver Input Impedance 1 MΩ
Note 1: Broad-band noise ingression is due to coupling in the cable interconnect.

5.8.6.1 Definition of Idle

BMC packet collision is avoided by the detection of signal transitions at the receiver. This is the equivalent of squelch
for FSK modulation. Detection is active when nTransitionCount transitions occur at the receiver within a time
window of tTransitionWindow. After waiting tTransitionWindow without detecting nTransitionCount transitions
the bus Shall be declared idle.
Refer to Section 5.8.5.4 for details of when transmissions May start.

5.8.6.2 Multi-Drop
The BMC Signaling Scheme is suitable for use in Multi-Drop configurations containing one or two BMC Multi-Drop
transceivers connected to the CC wire, for example where one or both ends of a cable contains a Multi-Drop
transceiver. In this specification the location of the Multi-Drop transceiver is referred to as the Cable Plug.
Figure 5-27 below illustrates a typical Multi Drop configuration with two DRPs.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 91

 Figure 5-27 Example Multi-Drop Configuration showing two DRPs

The Multi-Drop transceiver Shall obey all the electrical characteristics specified in this section except for those
relating to capacitance. The maximum capacitance allowed for the Multi-Drop node when not driving the line is
cCablePlug_CC defined in [USB Type-C 1.2] . There are no constraints as to the distance of the Multi-Drop transceiver
from the end of the plug. The Multi-Drop transceiver(s) May be located anywhere along the cable including the plugs.
The Multi-Drop transceiver suffers less from ground offset compared to the transceivers in the host or device and
contributes no significant reflections.
It is possible to have a configuration at Attach where one Port is able to be a Vconn Source and the other Port is not
able to be a Vconn Source, such that there is no switch in the second Port. An example of a DFP with a switch Attached
to a UFP without a switch is outlined in Figure 5-28. The capacitance on the CC line for a Port not able to be a VCONN
Source Shall still be within cReceiver except when transmitting.

Figure 5-28 Example Multi-Drop Configuration showing a DFP and UFP

5.8.6.3 Fast Role Swap Detection

An initial Sink prepares for a Fast Role Swap by ensuring that once it has detected the Fast Role Swap signal its power
supply is ready to respond by applying vSafe5V according to the timing detailed in Section 7.1.13. The initial Sink
Shall only respond to the Fast Role Swap signal when it has an Explicit Contract. On detection of the Fast Role Swap
signal any pending Messages Shall be Discarded (see Section 6.11.2.2.1).
When the initial Sink is prepared for a Fast Role Swap and the bus is idle the CC voltage averaged over tFRSwapRx
min remains above 0.7V (see [USB Type-C 1.2]) since the Source Rp is either 1.5A or 3.0A. However vNoiseIdle noise
May cause the CC line voltage to reach 0.7V-vNoiseIdle/2 for short durations. When the initial Sink is prepared for a
Fast Role swap while it is transmitting and the initial Source is signaling a Fast Role swap request, the transmission
will be attenuated such that the peak CC voltage will not exceed vFRSwapCableTx min. Therefore, when the initial

Page 92 USB Power Delivery Specification Revision 3.0, Version 1.1

Sink is prepared for a Fast Role Swap, it Shall Not detect a Fast Swap signal when the CC voltage, averaged over
tFRSwapRx min, is above 0.7V. When the initial Sink is prepared for a Fast Role Swap, it Shall detect a CC voltage
lower than vFRSwapCableTx min for tFRSwapRx as a Fast Role Swap request. Note: the initial Sink is not required to
average the CC voltage to meet these requirements.
The initial Sink Shall initiate the Fast Role Swap AMS within tFRSwapInit of detecting the Fast Role Swap request in
order to assign the Rp/Rd resistors to the correct Ports and to re-synchronize the state machines (see Section 6.3.17).
The initial Sink Shall become the new Source and Shall start supplying vSafe5V at USB Type-C Current (see [USB
Type-C 1.2]) no later than tSrcFRSwap after VBUS has dropped below vSafe5V. An initial Sink Shall disable its VBUS
Disconnect Threshold detection circuitry while Fast Role Swap detection is active.
Note: while power is transitioning the VCONN Source to the Cable Plug(s) cannot be guaranteed.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 93

 5.9 Built in Self-Test (BIST)
The following sections define BIST functionality which Shall be supported.

5.9.1 BIST Carrier Mode

In BIST Carrier Mode, the Physical Layer Shall send out a BMC encoded continuous string of alternating "1"s and “0”s.
This enables the measurement of power supply noise and frequency drift.
Note that this transmission is a purely a sequence of alternating bits and Shall Not be formatted as a Packet.
See also Section 6.4.3.

5.9.2 BIST Test Data

A BIST Test Data Message is used by the Tester to send various Tester generated test patterns to the UUT in order to
test the UUT’s receiver. See also Section 6.4.3.
Figure 5-29 shows the Test Data Frame which Shall be sent by the Tester to the UUT. The BIST Message, with a BIST
Test Data BIST Data Object consists of a Preamble, followed by SOP*, followed by the Message Header with a data
length of 7 Data Objects, followed a BIST Test Data BIST Data Object, followed by 6 Data Objects containing Test data,
followed by the CRC and then an EOP.

Figure 5-29 Test Data Frame

SOP* (Start Header BIST Test Data
Preamble(training for receiver)
Of Packet) Data Objects = 7 BDO Test Data 192 bits ...

... CRC
EOP (End Of
Packet)

LEGEND:

Preamble, not encoded Provided by the Physical Provided by the Protocol

with 4b5b layer, encoded with 4b5b layer, encoded with 4b5b

Page 94 USB Power Delivery Specification Revision 3.0, Version 1.1

6. Protocol Layer
6.1 Overview
This chapter describes the requirements of the USB Power Delivery Specification’s protocol layer including:
 Details of how Messages are constructed and used.
 Use of timers and timeout values.
 Use of Message and retry counters.
 Reset operation.
 Error handling.
 State behavior.
Refer to Section 2.6 for an overview of the theory of operation of USB Power Delivery.

6.2 Messages
This specification defines three types of Messages:
 Control Messages that are short and used to manage the Message flow between Port Partners or to exchange
Messages that require no additional data. Control Messages are 16 bits in length.
 Data Messages that are used to exchange information between a pair of Port Partners. Data Messages range from
48 to 240 bits in length.
o There are three types of Data Messages:
 Those used to expose capabilities and negotiate power
 Those used for the BIST
 Those that are Vendor Defined
 Extended Messages that are used to exchange information between a pair of Port Partners. Extended Messages
are up to MaxExtendedMsgLen bytes.
o There are several types of Extended Messages:
 Those used for Source and Battery information
 Those used for Security
 Those used for Firmware Update
 Those that are vendor defined

6.2.1 Message Construction

All Messages Shall be composed of a Message Header and a variable length (including zero) data portion. A Message
either originates in the Protocol Layer and is passed to the Physical Layer, or it is received by the Physical Layer and is
passed to the Protocol Layer.
Figure 6-1 illustrates a Control Message as part of a Packet showing the parts are provided by the Protocol and PHY
Layers.

Figure 6-1 USB Power Delivery Packet Format including Control Message Payload
SOP* (Start Message Header EOP (End Of
Preamble CRC
Of Packet) (16 bit) Packet)

Legend:

PHY Layer Protocol Layer

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 95

Figure 6-2 illustrates a Data Message as part of a Packet showing the parts are provided by the Protocol and PHY
Layers.

Figure 6-2 USB Power Delivery Packet Format including Data Message Payload
SOP* (Start Message Header EOP (End Of
Preamble 0..7 Data Object(s) CRC
Of Packet) (16 bit) Packet)

Legend:

PHY Layer Protocol Layer

Figure 6-3 illustrates an Extended Message as part of a Packet showing the parts are provided by the Protocol and
PHY Layers.

Figure 6-3 USB Power Delivery Packet Format including an Extended Message Header and Payload
SOP* (Start Message Header Extended Message Header EOP (End Of
Preamble Data (0..260 bytes) CRC
Of Packet) (16 bit) (16 bit) Packet)

Legend:

PHY Layer Protocol Layer

6.2.1.1 Message Header

Every Message Shall start with a Message Header as shown in Figure 6-1, Figure 6-2 and Figure 6-3 and as defined in
Table 6 1. The Message Header contains basic information about the Message and the PD Port Capabilities.
The Message Header May be used standalone as a Control Message when the Number of Data Objects field is zero or
as the first part of a Data Message when the Number of Data Objects field is non-zero.

Table 6-1 Message Header

Bit(s) Start of Packet Field Name Reference

15 SOP* Extended Section 6.2.1.1.1
14…12 SOP* Number of Data Objects Section 6.2.1.1.2
11…9 SOP* MessageID Section 6.2.1.1.3
SOP only Port Power Role Section 6.2.1.1.4
8
SOP’/SOP’’ Cable Plug Section 6.2.1.1.7
7…6 SOP* Specification Revision Section 6.2.1.1.5
SOP only Port Data Role Section 6.2.1.1.6
5
SOP’/SOP’’ Reserved Section 1.4.2.10
4…0 SOP* Message Type Section 6.2.1.1.8

6.2.1.1.1 Extended
The 1-bit Extended field Shall be set to zero to indicate a Control Message or Data Message and set to one to indicate
an Extended Message.
The Extended field Shall apply to all SOP* Packet types.

Page 96 USB Power Delivery Specification Revision 3.0, Version 1.1

 6.2.1.1.2 Number of Data Objects
When the Extended field is set to zero the 3-bit Number of Data Objects field Shall indicate the number of 32-bit
Data Objects that follow the Message Header. When this field is zero the Message is a Control Message and when it is
non-zero, the Message is a Data Message.
The Number of Data Objects field Shall apply to all SOP* Packet types.
When both the Extended bit and Chunked bit are set to one, the Number of Data Objects field Shall indicate the
number of Data Objects in the Message padded to the 4-byte boundary including the Extended Header as part of the
first Data Object.
When the Extended bit is set to one and Chunked bit is set to zero, the Number of Data Objects field Shall be
Reserved. Note that in this case, the message length is determined solely by the Data Size field in the Extended
Message Header.

6.2.1.1.3 MessageID
The 3-bit MessageID field is the value generated by a rolling counter maintained by the originator of the Message.
The MessageIDCounter Shall be initialized to zero at power-on as a result of a Soft Reset, or a Hard Reset. The
MessageIDCounter Shall be incremented when a Message is successfully received as indicated by receipt of a
GoodCRC Message. Note: the usage of MessageID during testing with BIST Messages is defined in
[USBPDCompliance].
The MessageID field Shall apply to all SOP* Packet types.

6.2.1.1.4 Port Power Role

The 1-bit Port Power Role field Shall indicate the Port’s present power role:
 0b Sink
 1b Source
Messages, such as Ping, and GotoMin, that are only ever sent by a Source, Shall always have the Port Power Role field
set to Source. Similarly Messages such as the Request Message that are only ever sent by a Sink Shall always have the
Port Power Role field set to Sink.
During the Power Role Swap Sequence, for the initial Source Port, the Port Power Role field Shall be set to Sink in the
PS_RDY Message indicating that the initial Source’s power supply is turned off (see Figure 8-6 and Figure 8-7).
During the Power Role Swap Sequence, for the initial Sink Port, the Port Power Role field Shall be set to Source for
Messages initiated by the Policy Engine after receiving the PS_RDY Message from the initial Source (see Figure 8-6 and
Figure 8-7).
During the Fast Role Swap Sequence, for the initial Source Port, the Port Power Role field Shall be set to Sink in the
PS_RDY Message indicating that VBUS is not being driven by the initial Source and is within vSafe5V (see Figure 8-13).
During the Fast Role Swap Sequence, for the initial Sink Port, the Port Power Role field Shall be set to Source for
Messages initiated by the Policy Engine after receiving the PS_RDY Message from the initial Source (see Figure 8-13).
Note that the GoodCRC Message sent by the initial Sink in response to the PS_RDY Message from the initial Source will
have its Port Power Role field set to Sink since this is initiated by the Protocol Layer. Subsequent Messages initiated
by the Policy Engine, such as the PS_RDY Message sent to indicate that VBUS is ready, will have the Port Power Role
field set to Source.
The Port Power Role field of a received Message Shall Not be verified by the receiver and Shall Not lead to Soft Reset,
Hard Reset or Error Recovery if it is incorrect.
The Port Power Role field Shall only be defined for SOP Packets.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 97

 6.2.1.1.5 Specification Revision
The Specification Revision field Shall be one of the following values (except 11b):
 00b –Revision 1.0
 01b –Revision 2.0
 10b – Revision 3.0
 11b – Reserved, Shall Not be used
To ensure interoperability with existing USBPD Products, USBPD Products Shall support every PD Specification
Revision starting from [USBPD 2.0].
The 2-bit Specification Revision field of a GoodCRC Message does not carry any meaning and Shall be considered as
don’t care by the recipient of the Message. The sender of a GoodCRC Message Should set the Specification Revision
field to 00b.
The Specification Revision field Shall apply to all SOP* Packet types.
When the Source Port first communicates with the Sink Port the Specification Revision field Shall be used as
described by the following steps:
1. The Source Port sends a Source_Capabilities Message to the Sink Port setting the Specification Revision field to the
highest Revision of the Power Delivery Specification the Source Port supports.
2. The Sink Port responds with a Request Message setting the Specification Revision field to the highest Revision of the
Power Delivery Specification the Sink Port supports that is equal to or lower than the Specification Revision received
from the Source Port.
3. The Source and Sink Ports Shall use the Specification Revision in the Request Message from the Sink in step 2 in all
subsequent communications until they are Detached.
When a VCONN Source first communicates with a Cable Plug the Specification Revision field Shall be used as
described by the following steps:
1. The VCONN Source sends a Discover Identity REQ to the Cable Plug (SOP') setting the Specification Revision field
in the Message to the highest Revision of the Power Delivery Specification the VCONN Source supports. After a VCONN
Swap the required Soft_Reset / Accept message exchange is used for the same purpose (see Section 6.3.13).
2. The Cable Plug responds with a Discover Identity ACK setting the Specification Revision field in the Message to the
highest Revision of the Power Delivery Specification the VCONN Source supports that is equal to or lower than the
Specification Revision it received from the Source Port.
3. The Cable Plug and VCONN Source Shall communicate using the lower of the two revisions until an Explicit Contract
has been established.
4. Table 6-2 shows the Specification Revision that Shall be used between the Port Partners and the Cable Plugs when the
Specification Revision has been discovered and an Explicit Contract is in place.
Note: when a Cable Plug does not respond to a Revision 3.0 Discover Identity REQ with a Discover Identity ACK or
BUSY the VCONN Source May repeat steps 1-4 using a Revision 2.0 Discover Identity REQ in step 1 before establishing
that there is no Cable Plug to communicate with.
A VCONN Source that supports Revision 3.0 of the Power Delivery Specification May communicate with a Cable Plug
also supporting Revision 3.0 using Revision 3.0 Compliant Communications regardless of the Specification Revision
of its Port Partner until it enters an Explicit Contract. After the Explicit Contract has been established the Port
Partners and Cable Plug(s) Shall use Table 6-2 to determine the Revision to be used.
All data in all Messages Shall be consistent with the Specification Revision field in the Message Header for that
particular Message.
A Cable Plug Shall Not save the state of the agreed Specification Revision. A Cable Plug Shall respond with the
highest Specification Revision it supports that is equal to or lower than the Specification Revision contained in the
Message received from the VCONN Source.

Page 98 USB Power Delivery Specification Revision 3.0, Version 1.1

Cable Plugs Shall operate using the same Specification Revision for both SOP’ and SOP’’. Cable assemblies with two
Cable Plugs Shall operate using the same Specification Revision for both Cable Plugs.
See Table 6-2 for details of how various Revisions Shall interoperate.

Table 6-2 Revision Interoperability during an Explicit Contract

Port 1 Cable Plug Port 2 Port to Port Port to Cable Plug

Revision Revision Revision operating operating
Revision Revision
2 2 2 2 2
2 2 3 2 2
3 2 3 3 2
2 3 2 2 2
2 3 3 2 2
3 3 2 2 2
3 3 3 3 3

6.2.1.1.6 Port Data Role

The 1-bit Port Data Role field Shall indicate the Port’s present data role:
 0b UFP
 1b DFP
The Port Data Role field Shall only be defined for SOP Packets. For all other SOP* Packets the Port Data Role field is
Reserved and Shall be set to zero.
Should a USB Type-C Port receive a Message with the Port Data Role field set to the same Data Role as its current
Data Role, except for the GoodCRC Message, USB Type-C Error Recovery actions as defined in [USB Type-C 1.2] Shall
be performed.
For a USB Type-C Port the Port Data Role field Shall be set to the default value at Attachment after a Hard Reset: 0b
for a Port with Rd asserted and 1b for a Port with Rp asserted.
In the case that a Port is not USB Communications Capable, at Attachment a Source Port Shall default to DFP and a
Sink Port Shall default to UFP.

6.2.1.1.7 Cable Plug

The 1-bit Cable Plug field Shall indicate whether this Message originated from a Cable Plug:
 0b Message originated from a DFP or UFP
 1b Message originated from a Cable Plug
The Cable Plug field Shall only apply to SOP’ and SOP’’ Packet types.

6.2.1.1.8 Message Type

The 5-bit Message Type field Shall indicate the type of Message being sent. To fully decode the Message Type, the
Number of Data Objects field is first examined to determine whether the Message is a Control Message or a Data
Message. Then the specific Message Type can be found in Table 6-5 (Control Message) or Table 6-6 (Data Message).
The Message Type field Shall apply to all SOP* Packet types.

6.2.1.2 Extended Message Header

Every Extended Message (indicated by the Extended field being set in the Message Header) Shall contain an Extended
Message Header following the Message Header as shown in Figure 6-3 and defined in Table 6-3.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 99

The Extended Message Header is used to support Extended Messages containing Data Blocks of Data Size either sent
in a single Message or as a series of Chunks. When the Data Block is sent as a series of Chunks, each Chunk in the
series, except for the last Chunk, Shall contain MaxExtendedMsgChunkLen bytes. The last Chunk in the series Shall
contain the remainder of the Data Block and so could be less than MaxExtendedMsgChunkLen bytes and Shall be
padded to the next 4-byte Data Object boundary.

Table 6-3 Extended Message Header

Bit(s) Start of Packet Field Name Reference

15 SOP* Chunked Section 6.2.1.2.1
14…11 SOP* Chunk Number Section 6.2.1.2.2
10 SOP* Request Chunk Section 6.2.1.2.3
9 SOP* Reserved Section 1.4.2.10
8…0 SOP* Data Size Section 6.2.1.2.4

6.2.1.2.1 Chunked
The Port Partners Shall use the Unchunked Extended Messages Supported fields in the Source_Capabilities Message
and the Request Message to determine whether to send Messages of Data Size > MaxExtendedMsgLegacyLen bytes in
a single Unchunked Extended Message (see Section 6.4.1.2.2.6 and Section 6.4.2.6).
When either Port Partner only supports Chunked Extended Messages:
1. The Chunked bit in every Extended Message Shall be set to one
2. Every Extended Message of Data Size > MaxExtendedMsgLegacyLen Shall be transmitted between the Port
Partners in Chunks
3. The Number of Data Objects in the Message Header Shall indicate the number of Data Objects in the Message
padded to the 4-byte boundary including the Extended Header as part of the first Data Object.
4. Point 1, Point 2 and Point 3 above Shall apply until the Port Pair is Detached, there is a Hard Reset or the Source
removes power (except during a Power Role Swap or Fast Role Swap when the initial Source removes power in
order to for the new Source to apply power).
When both Port Partners support Unchunked Extended Messages:
1. The Chunked bit in every Extended Message Shall be set to zero.
2. Every Extended Message Shall be transmitted between the Port Partners Unchunked
3. The Number of Data Objects in the Message Header is Reserved.
4. Point 1, Point 2 and Point 3 above Shall apply until the Port Pair is Detached, there is a Hard Reset or the Source
removes power (except during a Power Role Swap or Fast Role Swap when the initial Source removes power in
order to for the new Source to apply power).
When sending Extended Messages to the Cable Plug the VCONN Source Shall only send Chunked Messages. Cable Plugs
Shall always send Extended Messages of Data Size > MaxExtendedMsgLegacyLen Chunked and Shall set the
Chunked bit in every Extended Message to one.
When Extended Messages are supported Chunking Shall be supported.

6.2.1.2.2 Chunk Number

The Chunk Number field Shall only be Valid in a Message if the Chunked flag is set to one. if the Chunked flag is set
to zero the Chunk Number field Shall also be set to zero.
The Chunk Number field is used differently depending on whether the Message is a request for Data or a requested
Data Block being returned:

Page 100 USB Power Delivery Specification Revision 3.0, Version 1.1
In a request for data the Chunk Number field indicates the number of the Chunk being requested. The requestor
Shall only set this field to one of the following values:
 Zero to request the first Chunk in the series
 The number of the last received Chunk in the series
 The number of the next Chunk in the series (the next Chunk after the last received Chunk)
In the requested Data Block the Chunk Number field indicates the number of the Chunk being returned. The Chunk
number for each Chunk in the series Shall start at zero and Shall increment for each Chunk by one up to a maximum
of 9 corresponding to 10 Chunks in total.

6.2.1.2.3 Request Chunk

The Request Chunk bit Shall only be used for the Chunked transfer of an Extended Message when the Chunked bit is
set to 1 (see Figure 6-7). For Unchunked Extended Message transfers Messages Shall be sent and received without
the request/response mechanism (see Figure 6-4).
The Request Chunk bit Shall be set to one to indicate that this is a request for a Chunk of a Data Block and Shall be set
to zero to indicate that this is a Chunk response containing a Chunk. Except for Chunk zero, a requested Chunk of a
Data Block Shall only be returned as a Chunk response to a corresponding request for that Chunk. Both the Chunk
request and the Chunk response Shall contain the same value in the Message Type field. When the Request Chunk
bit is set to one the Data Size field Shall be zero.

6.2.1.2.4 Data Size

The Data Size field Shall indicate how many bytes of data in total are in Data Block being returned. The total number
of data bytes in the Message Shall Not exceed MaxExtendedMsgLen.
If the Data Size field is less than MaxExtendedMsgLegacyLen and the Chunked bit is set then the Packet payload
Shall be padded to the next 4-byte Data Object boundary with zeros (0x00).
If the Data Size field is greater than expected for a given Extended Message but less than or equal to
MaxExtendedMsgLen then the expected fields in the Message Shall be processed appropriately and the additional
fields Shall be Ignored.

6.2.1.2.5 Extended Message Examples

The following examples illustrate the transmission of Extended Messages both Chunked (Chunked bit is one) and
Unchunked (Chunked bit is zero). The examples use a Security_Request Message of Data Size 7 bytes which is
responded to by a Security_Response Message of Data Size 30 bytes. The sizes of these Messages are arbitrary and
are used to illustrate Message transmission; they are not intended to correspond to genuine security related
Messages.
During negotiation of the Explicit Contract after connection, the Port Partners use the Unchunked Extended Messages
Supported fields in the Source_Capabilities Message and the Request Message to determine the value of the Chunked
bit (see Table 6-4). When both Port Partners support Unchunked Messages then the Chunked bit is zero otherwise
the Chunked bit is one.
The Chunked bit is used to determine whether or not:
 The Chunk request/response mechanism is used
 Extended Messages are Chunked
 Padding is applied
 The Number of Data Objects field is used
The following examples illustrate the expected usage in each case.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 101
 Table 6-4 Use of Unchunked Message Supported bit

Source: Source_Capabilities Message

Unchunked Message Unchunked Message

Supported bit = 0 Supported bit = 1

Sink: Unchunked Message Chunked bit = 1 Chunked bit = 1

Request Supported bit = 0
Message
Unchunked Message Chunked bit = 1 Chunked bit = 0
Supported bit = 1

6.2.1.2.5.1 Security_Request/Security_Response Unchunked Example

Figure 6-4 illustrates a typical sequence for a Security_Request Message responded to by a Security_Response
Message using Unchunked Extended Messages (Chunked bit is zero) between a USB Host and a power brick. The
entire Data Block is returned in one Message. The Chunk request/response mechanism is not used.

Figure 6-4 Example Security_Request sequence Unchunked (Chunked bit = 0)

Host Power Brick

Security_R
(Data Size equest
= 7, Chunke
d = 0)

GoodCRC
esponse
Security_R ked = 0)
= 30 Chun
,
(Data Size
GoodCRC

Figure 6-5 details the Security_Request Message shown in Figure 6-4. The figure shows the byte ordering on the bus
as well as the fact that there is no padding in this case. The Number of Data Objects field has a value of 0 since it is
Reserved when the Chunked bit is zero. The Data Size field indicates the length of the Extended Message when the
Chunked bit is set to 0, which in this case is 7 bytes.

Figure 6-5 Example byte transmission for Security_Request Message of Data Size 7 (Chunked bit is set to 0)

Message Header Extended Message

(16 bit) Header
Message Type =
(16 bit) Data (7 bytes)
Security_Request
Number of Data Chunked = 0
Objects = 0 (Reserved) Data Size = 7

Message Message Message Message

Header Header Header Header B0 B1 B2 B3 B4 B5 B6
LSB MSB LSB MSB

Figure 6-6 details the Security_Response Message shown in Figure 6-4. The figure shows the byte ordering on the
bus as well as the fact that there is no padding in this case. The Number of Data Objects field has a value of 0 since it
is Reserved when the Chunked bit is zero. The Data Size field indicates the length of the Extended Message when the
Chunked bit is set to 0, which in this case is 30 bytes.

Page 102 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 6-6 Example byte transmission for Security_Response Message of Data Size 7 (Chunked bit is set to 0)

Message Header Extended Message

(16 bit) Header
Message Type =
(16 bit) Data (30 bytes)
Security_Response
Number of Data Chunked = 0
Objects = 0 (Reserved) Data Size = 30

Message Message Message Message

Header Header Header Header B0 B1 B28 B29
LSB MSB LSB MSB

6.2.1.2.5.2 Security_Request/Security_Response Chunked Example

Figure 6-7 illustrates a typical sequence for a Security_Request Message responded to by a Security_Response
Message using Chunked Extended Messages (Chunked bit is one) between a USB Host and a power brick. Note that
Chunk Number zero in every Extended Message is sent without the need for a Chunk Request, but Chunk Number
one and following need to be requested with a Chunk request.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 103
 Figure 6-7 Example Security_Request sequence Chunked (Chunked bit = 1)

Host Power Brick

Security_Request Chunk
Security
(Number of _Request
Chunked = Data Objec
1, ts = 3,
Request Ch Chunk Number = 0,
unk = 0, D
ata Size =
7)

GoodCRC

Security_Response
esponse
Security_R bjects = 7,
r of D ataO
(Numbe un k Number
= 0,
1, Ch
Chunked = = 0, D ata Size =
30)
un k
Request Ch

GoodCRC

Security_R
espons
(Number of e “Chunk request”
Chunked = Data Objec
1, ts = 1,
Request Ch Chunk Number = 1,
unk = 1, D
ata Size =
0)

GoodCRC
esponse
Security_R bjects = 2,
of D ataO
(Number umber = 1,
d = 1, Chunk N )
Ch un ke
0, D ata Size = 30
unk =
Request Ch

GoodCRC

Figure 6-8 shows the Security_Request Message shown in Figure 6-7 in more detail including the byte ordering on the
bus and padding. Three bytes of padding have been added to the Message so that the total number of bytes is a
multiple of 32-bits, corresponding to 3 Data Objects. The Number of Data Objects field is set to 3 to indicate the
length of this Chunk. The Chunk Number is set to zero and the Data Size field is set to 7 to indicate the length of the
whole Extended Message.

Page 104 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 6-8 Example Security_Request Message of Data Size 7 (Chunked bit set to 1)
Extended Message
Message Header
Header
(16 bit)
Message Type =
(16 bit)
Chunked = 1 Data (7 bytes) Padding (3 bytes)
Security_Request
Number of Data Chunk Number = 0
Request Chunk = 0
Objects = 3
Data Size = 7

Message Message Message Message

P0 P1 P2
Header Header Header Header B0 B1 B2 B3 B4 B5 B6
(0x00) (0x00) (0x00)
LSB MSB LSB MSB

Data Object 0 Data Object 1 Data Object 2

Figure 6-9 shows Chunk Number zero of the Security_Response Message shown in Figure 6-7 in more detail
including the byte ordering on the bus and padding. No padding is need for this Chunk since the full 26-byte payload
plus 2-byte Extended Message Header is a multiple of 32-bits, corresponding to 7 Data Objects. The Number of Data
Objects field is set to 7 to indicate the length of this Chunk and the Data Size field is set to 30 to indicate the length of
the whole Extended Message.

Figure 6-9 Example Chunk 0 of Security_Response Message of Data Size 30 (Chunked bit set to 1)
Extended Message
Message Header
Header
(16 bit)
Message Type =
(16 bit)
Chunked = 1 Data (26 bytes)
Security_Response
Number of Data Chunk Number = 0
Request Chunk = 0
Objects = 7
Data Size = 30

Message Message Message Message

Header Header Header Header B0 B1 B22 B23 B24 B25
LSB MSB LSB MSB

Data Object 0 Data Object 6

Figure 6-10 shows an example of the Message format, byte ordering and padding for the Security_Response Message
Chunk request for Chunk Number one shown in Figure 6-7. In the Chunk request the Number of Data Objects field in
the Message is set to 1 to indicate that the payload is 32 bits equivalent to 1 data object. Since the Chunked bit is set
to 1 the Chunk request/Chunk response mechanism is used. The Message is a Chunk request so the Request Chunk
bit is set to one, and in this case Chunk one is being requested so Chunk Number is set to one. Data Size is set to 0
indicating the length of the Data Block being transferred. Two bytes of padding are added to ensure that the payload
is a multiple of 32 bits.

Figure 6-10 Example byte transmission for a Security_Request Message Chunk request (Chunked bit is set to 1)
Extended Message
Message Header
Header
(16 bit)
Message Type =
(16 bit)
Chunked = 1 Padding (2 bytes)
Security_Response
Number of Data Chunk Number = 1
Request Chunk = 1
Objects = 1
Data Size = 0

Message Message Message Message

P0 P1
Header Header Header Header
(0x00) (0x00)
LSB MSB LSB MSB

Data Object 0

Figure 6-11 shows Chunk Number one of the Security_Response Message shown in Figure 6-7 in more detail
including the byte ordering on the bus and padding. Two bytes of padding are added to ensure that the payload is a
multiple of 32 bits, corresponding to 2 Data Objects. The Number of Data Objects field is set to 2 to indicate the
length of this Chunk and the Data Size field is set to 30 to indicate the length of the whole Extended Message.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 105
 Figure 6-11 Example Chunk 1 of Security_Response Message of Data Size 30 (Chunked bit set to 1)
Extended Message
Message Header
Header
(16 bit)
Message Type =
(16 bit)
Chunked = 1 Data (4 bytes) Padding (2 bytes)
Security_Request
Number of Data Chunk Number = 1
Request Chunk = 0
Objects = 2
Data Size = 30

Message Message Message Message

P0 P1
Header Header Header Header B0 B1 B2 B3
(0x00) (0x00)
LSB MSB LSB MSB

Data Object 0 Data Object 1

6.3 Control Message

A Message is defined as a Control Message when the Number of Data Objects field in the Message Header is set to 0.
The Control Message consists only of a Message Header and a CRC. The Protocol Layer originates the Control
Messages (i.e. Accept Message, Reject Message etc.).
The Control Message types are specified in the Message Header’s Message Type field (bits 4…0) and are summarized
in Table 6-5. The Sent by column indicates entities which May send the given Message (Source, Sink or Cable Plug);
entities not listed Shall Not issue the corresponding Message. The “Valid Start of Packet” column indicates the
Messages which Shall only be issued in SOP Packets and the Messages which May be issued in SOP* Packets.

Table 6-5 Control Message Types

Bits Message Type Sent by Description Valid Start

4…0 of Packet
0 0000 N/A All values not explicitly defined
Reserved are Reserved and Shall Not be
used.
0 0001 GoodCRC Source, Sink or Cable Plug See Section 6.3.1. SOP*
0 0010 GotoMin Source only See Section 6.3.2. SOP only
0 0011 Accept Source, Sink or Cable Plug See Section 6.3.3. SOP*
0 0100 Reject Source or Sink See Section 6.3.4. SOP only
0 0101 Ping Source only See Section 6.3.5. SOP only
0 0110 PS_RDY Source or Sink See Section 6.3.6. SOP only
0 0111 Get_Source_Cap Sink or DRP See Section 6.3.7. SOP only
0 1000 Get_Sink_Cap Source or DRP See Section 6.3.8. SOP only
0 1001 DR_Swap Source or Sink See Section 6.3.9 SOP only
0 1010 PR_Swap Source or Sink See Section 6.3.10 SOP only
0 1011 VCONN_Swap Source or Sink See Section 6.3.11 SOP only
0 1100 Wait Source or Sink See Section 6.3.12 SOP only
0 1101 Soft_Reset Source or Sink See Section 6.3.13 SOP*
0 1110- Reserved N/A All values not explicitly defined
0 1111 are Reserved and Shall Not be
used.
1 0000 Not_Supported Source, Sink or Cable Plug See Section 6.3.14 SOP*
1 0001 Get_Source_Cap_Extended Sink or DRP See Section 6.3.15 SOP only
1 0010 Get_Status Source or Sink See Section 6.3.16 SOP only

Page 106 USB Power Delivery Specification Revision 3.0, Version 1.1
 Bits Message Type Sent by Description Valid Start
4…0 of Packet
1 0011 FR_Swap Sink1 See Section 6.3.17 SOP only
1 0100
Get_PPS_Status Sink See Section 6.3.18 SOP only

1 0101 Get_Country_Codes Source or Sink See Section 6.3.19 SOP*

1 0110- Reserved N/A All values not explicitly defined
1 1111 are Reserved and Shall Not be
used.
Note 1: In this case the Port is providing vSafe5V however it will have Rd asserted rather than Rp and sets the Port
Power Role field to Sink, until the Fast Role Swap AMS has completed.

6.3.1 GoodCRC Message

The GoodCRC Message Shall be sent by the receiver to acknowledge that the previous Message was correctly received
(i.e. had a good CRC). The GoodCRC Message Shall return the Message’s MessageID so the transmitter can determine
that the correct Message is being acknowledged. The first bit of the GoodCRC Message Shall be returned within
tTransmit after receipt of the last bit of the previous Message.
BIST does not send the GoodCRC Message while in a Continuous BIST Mode (see Section 6.4.3).

6.3.2 GotoMin Message

The GotoMin Message applies only to those Sinks that have requested power with the GiveBack capable flag set in the
Sink Request Data Object.
It is a directive to the Sink Port to reduce its operating power level to the amount specified in the Minimum Operating
Current field of its latest Sink Request Data Object.
The GotoMin process is designed to allow the Source to temporarily reallocate power to meet a short term
requirement. For example, a Source can reduce a Sink’s power consumption for 10-20 seconds to allow another Sink
(e.g. an HDD to spin up).
The Source sends this Message as a means to harvest power in order to meet a request for power that it cannot
otherwise meet. The Device Policy Manager determines which Port or ports will receive the Message.
The Sink Shall respond to a GotoMin Message by reducing its power consumption to less than or equal to the pre-
negotiated value (Minimum Operating Current) within tSnkNewPower time.
The Source sends a GotoMin Message as a shortcut in the power negotiation process since the Source and Sink have
already made a Contract with respect to the power to be returned. In essence, the Source does not have to advertise
its Capabilities and the Sink does not have to make a Request based on them. The Source simply sends the GotoMin
Message in place of the Accept Message normally sent during the power negotiation process (see step 19 in Figure
8-5). The power negotiation process then completes from this point in the normal manner with the Source sending a
PS_RDY Message once the power supply transition is complete. The steps of the GotoMin process are fully described
in Figure 8-6.
The Source Shall return power to the Sink(s) it has ‘borrowed’ from using the GotoMin mechanism before it can
allocate any ‘new’ power to other devices.

6.3.3 Accept Message

The Accept Message is a Valid response in the following cases:
 It Shall be sent by the Source to signal the Sink that the Source is willing to meet the Request Message.
 It Shall be sent by the recipient of the PR_Swap Message to signal that it is willing to do a Power Role Swap and
has begun the Power Role Swap sequence.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 107
 It Shall be sent by the recipient of the DR_Swap Message to signal that it is willing to do a Data Role Swap and has
begun the Data Role Swap sequence.
 It Shall be sent by the recipient of the VCONN_Swap Message to signal that it is willing to do a VCONN Swap and
has begun the VCONN Swap sequence.
 It Shall be sent by the recipient of the FR_Swap Message to indicate that it has begun the Fast Role Swap
sequence.
 It Shall be sent by the recipient of the Soft_Reset Message to indicate that it has completed its Soft Reset.
The Accept Message Shall be sent within tReceiverResponse of the receipt of the last bit of the Message (see Section
6.6.2).

6.3.4 Reject Message

The Reject Message is a Valid response in the following cases:
 It Shall be sent to signal the Sink that the Source is unable to meet the Request Message. This May be due an
Invalid request or because the Source can no longer provide what it previously advertised.
 It Shall be sent by the recipient of a PR_Swap Message to indicate it is unable to do a Power Role Swap.
 It Shall be sent by the recipient of a DR_Swap Message to indicate it is unable to do a Data Role Swap.
 It Shall be sent by the recipient of a VCONN_Swap Message that is not presently the VCONN Source, to indicate it is
unable to do a VCONN Swap.
The Reject Message Shall be sent within tReceiverResponse of the receipt of the last bit of Message (see Section
6.6.2).
Note: the Reject Message is not a Valid response when a Message is not supported. In this case the Not_Supported
Message is returned (see Section 6.3.14).

6.3.5 Ping Message

The Ping Message was previously used on USB Type-A and USB Type-B connectors to determine the continued
presence of the Sink when no other messaging was taking place. USB Type-C connectors have a mechanism to
determine Sink presence so when the Port Partners are both connected using USB Type-C connectors the Ping
Message is not necessary but May be sent by a Source if desired. A Sink using a USB Type-C connector Shall Not
expect to receive Ping Messages but Shall Not treat Ping Messages as an error if they are received.

6.3.6 PS_RDY Message

The PS_RDY Message Shall be sent by the Source (or by both the new Sink and new Source during the Power Role
Swap sequence or Fast Role Swap sequence) to indicate its power supply has reached the desired operating condition
(see Section 8.3.2.2).

6.3.7 Get_Source_Cap Message

The Get_Source_Cap (Get Source Capabilities) Message May be sent by a Port to request the Source Capabilities and
Dual-Role Power capability of its Port Partner (e.g. Dual-Role Power capable). The Port Shall respond by returning a
Source_Capabilities Message (see Section 6.4.1.1.1).

6.3.8 Get_Sink_Cap Message

The Get_Sink_Cap (Get Sink Capabilities) Message May be sent by a Port to request the Sink Capabilities and Dual-
Role Power capability of its Port Partner (e.g. Dual-Role Power capable). The Port Shall respond by returning a
Sink_Capabilities Message (see Section 6.4.1.1.2).

Page 108 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.3.9 DR_Swap Message
The DR_Swap Message is used to exchange DFP and UFP operation between Port Partners while maintaining the
direction of power flow over VBUS. The DR_Swap process can be used by Port Partners whether or not they support
USB Communications capability. A DFP that supports USB Communication Capability starts as the USB Host on
Attachment. A UFP that supports USB Communication Capability starts as the USB Device on Attachment.
[USB Type-C 1.2] DRPs Shall have the capability to perform a Data Role Swap from the PE_SRC_Ready or
PE_SNK_Ready states. DFPs and UFPs May have the capability to perform a Data Role Swap from the PE_SRC_Ready
or PE_SNK_Ready states. A Data Role Swap Shall be regarded in the same way as a cable Detach/re-Attach in relation
to any USB communication which is ongoing between the Port Partners. If there are any Active Modes between the
Port Partners when a DR_Swap Message is a received then a Hard Reset Shall be performed (see Section 6.4.4.3.4). If
the Cable Plug has any Active Modes then the DFP Shall Not issue a DR_Swap Message and Shall cause all Active
Modes in the Cable Plug to be exited before accepting a DR Swap request.
The Source of VBUS and VCONN Source Shall remain unchanged as well as the Rp/Rd resistors on the CC wire during the
Data Role Swap process.
The DR_Swap Message May be sent by either Port Partner. The recipient of the DR_Swap Message Shall respond by
sending an Accept Message, Reject Message or Wait Message.
 If an Accept Message is sent, the Source and Sink Shall exchange operational roles.
 If a Reject Message is sent, the requester is informed that the recipient is unable, or unwilling, to do a Data Role
Swap and no action Shall be taken.
 If a Wait Message is sent, the requester is informed that a Data Role Swap might be possible in the future but that
no immediate action Shall be taken.
Before a Data Role Swap the initial DFP Shall have its Port Data Role bit set to DFP, and the initial UFP Shall have its
Port Data Role bit set to UFP.
After a successful Data Role Swap the DFP/Host Shall become the UFP/Device and vice-versa; the new DFP Shall have
its Port Data Role bit set to DFP, and the new UFP Shall have its Port Data Role bit set to UFP. Where USB
Communication is supported by both Port Partners a USB data connection Should be established according to the new
data roles.
If the Data Role Swap, after having been accepted by the Port Partner, is subsequently not successful, in order to
attempt a re-establishment of the connection on the CC Wire, USB Type-C Error Recovery actions, such as disconnect,
as defined in [USB Type-C 1.2] will be necessary.
See Section 8.3.2.6, Section 8.3.3.16.1 and Section 8.3.3.16.2 for further details.

6.3.10 PR_Swap Message

The PR_Swap Message May be sent by either Port Partner to request an exchange of power roles. The recipient of the
Message Shall respond by sending an Accept Message, Reject Message or Wait Message.
 If an Accept Message is sent, the Source and Sink Shall do a Power Role Swap.
 If a Reject Message is sent, the requester is informed that the recipient is unable, or unwilling, to do a Power Role
Swap and no action Shall be taken.
 If a Wait Message is sent, the requester is informed that a Power Role Swap might be possible in the future but
that no immediate action Shall be taken.
After a successful Power Role Swap the Port Partners Shall reset their respective Protocol Layers (equivalent to a Soft
Reset): resetting their MessageIDCounter, RetryCounter and Protocol Layer state machines before attempting to
establish an Explicit Contract. At this point the Source Shall also reset its CapsCounter.
Since a UFP Source can attempt to send a Discover Identity Command using SOP’ to a Cable Plug prior to the
establishment of an Explicit Contract, a DFP Sink Shall disable the receiving of SOP’ Messages until an Explicit

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 109
Contract has been established. This ensures that only the Cable Plug responds with a GoodCRC Message to the
Discover Identity Command.
The Source Shall have Rp asserted on the CC wire and the Sink Shall have Rd asserted on the CC wire as defined in
[USB Type-C 1.2]. When performing a Power Role Swap from Source to Sink, the Port Shall change its CC Wire
resistor from Rp to Rd. When performing a Power Role Swap from Sink to Source, the Port Shall change its CC Wire
resistor from Rd to Rp. The DFP (Host), UFP (Device) roles and VCONN Source Shall remain unchanged during the
Power Role Swap process.
Note: during the Power Role Swap process the initial Sink does not disconnect even though V BUS drops below vSafe5V.
For more information regarding the Power Role Swap, refer to Section 7.3.9 and Section 7.3.10 in the Power Supply
chapter, Section 8.3.2.6, Section 8.3.3.16.3 and Section 8.3.3.16.4 in the Device Policy chapter and Section 9.1.2 for VBUS
mapping to USB states.

6.3.11 VCONN_Swap Message

The VCONN_Swap Message Shall be supported by any Port that can operate as a VCONN Source.
The VCONN_Swap Message May be sent by either Port Partner to request an exchange of VCONN Source. The recipient
of the Message Shall respond by sending an Accept Message, Reject Message or Wait Message.
 If an Accept Message is sent, the Port Partners Shall perform a VCONN Swap. The new VCONN Source Shall send a
PS_RDY Message within tVCONNSourceOn to indicate that it is now sourcing VCONN. The initial VCONN Source
Shall cease sourcing VCONN within tVCONNSourceOff of receipt of the last bit of the EOP of the PS_RDY Message.
 If a Reject Message is sent, the requester is informed that the recipient is unable, or unwilling, to do a V CONN Swap
and no action Shall be taken. A Reject Message Shall only be sent by the Port that is not presently the Vconn
Source in response to a VCONN_Swap Message. The Port that is presently the Vconn Source Shall Not send a
Reject Message in response to VCONN_Swap Message.
 If a Wait Message is sent, the requester is informed that a VCONN Swap might be possible in the future but that no
immediate action Shall be taken. A Wait Message Shall only be sent by the Port that is not presently the Vconn
Source in response to a VCONN_Swap Message. The Port that is presently the Vconn Source Shall Not send a
Wait Message in response to VCONN_Swap Message.
The DFP (Host), UFP (Device) roles and Source of VBUS Shall remain unchanged as well as the Rp/Rd resistors on the
CC wire during the VCONN Swap process.
Note: VCONN Shall be continually sourced during the VCONN Swap process in order to maintain power to the Cable
Plug(s) i.e. make before break.
Before communicating with a Cable Plug a Port Shall ensure that it is the VCONN Source and that the Cable Plugs are
powered, by performing a VCONN swap if necessary. Since it cannot be guaranteed that the present VCONN Source is
supplying VCONN, the only means to ensure that the Cable Plugs are powered is for a Port wishing to communicate
with a Cable Plug to become the VCONN Source. If a Not_Supported Message is returned in response to the
VCONN_Swap Message then the Port is allowed to become the VCONN Source until a Hard Reset or Detach.
Note: even when it is presently the VCONN Source, the Sink is not permitted to initiate an AMS with a Cable Plug unless
Rp is set to SinkTxOk (see Section 6.9).

6.3.12 Wait Message

The Wait Message is a Valid response to a Request, a PR_Swap, DR_Swap or VCONN_Swap Message.
 It Shall be sent to signal the Sink that the Source is unable to meet the request at this time.
 It Shall be sent by the recipient of a PR_Swap Message to indicate it is unable to do a Power Role Swap at this
time.
 It Shall be sent by the recipient of a DR_Swap Message to indicate it is unable to do a Data Role Swap at this time.

Page 110 USB Power Delivery Specification Revision 3.0, Version 1.1
 It Shall be sent by the recipient of a VCONN_Swap Message that is not presently the VCONN Source to indicate it is
unable to do a VCONN Swap at this time.
The Wait Message Shall be sent within tReceiverResponse of the receipt of the last bit of the Message (see Section
6.6.2).

6.3.12.1 Wait in response to a Request Message

The Wait Message is used by the Source when a Sink that has reserved power, requests it. The Wait Message allows
the Source time to recover the power it requires to meet the request through the GotoMin process. A Source Shall
only send a Wait Message in response to a Request Message when an Explicit Contract exists between the Port
Partners.
The Sink is allowed to repeat the Request Message using the SinkRequestTimer and Shall ensure that there is
tSinkRequest after receiving the Wait Message before sending another Request Message.

6.3.12.2 Wait in response to a PR_Swap Message

The Wait Message is used when responding to a PR_Swap Message to indicate that a Power Role Swap might be
possible in the future. This can occur in any case where the device receiving the PR_Swap Message needs to evaluate
the request further e.g. by requesting Capabilities from the originator of the PR_Swap Message. Once it has completed
this evaluation one of the Port Partners Should initiate the Power Role Swap process again by sending a PR_Swap
Message.
The Wait Message is also used where a Hub is operating in hybrid mode when a request cannot be satisfied (see
[USBTypeCBridge 1.0]).
A Port that receives a Wait Message in response to a PR_Swap Message Shall wait tPRSwapWait after receiving the
Wait Message before sending another PR_Swap Message.

6.3.12.3 Wait in response to a DR_Swap Message

The Wait Message is used when responding to a DR_Swap Message to indicate that a Date Role Swap might be
possible in the future. This can occur in any case where the device receiving the DR_Swap Message needs to evaluate
the request further. Once it has completed this evaluation one of the Port Partners Should initiate the Data Role Swap
process again by sending a DR_Swap Message.
A Port that receives a Wait Message in response to a DR_Swap Message Shall wait tDRSwapWait after receiving the
Wait Message before sending another DR_Swap Message.

6.3.12.4 Wait in response to a VCONN_Swap Message

The Wait Message is used when responding to a VCONN_Swap Message to indicate that a VCONN_Swap might be
possible in the future. This can occur in any case where the device receiving the VCONN_Swap Message needs to
evaluate the request further. A Wait Message Shall only be sent by the Port that is not presently the Vconn Source in
response to a VCONN_Swap Message. The Port that is presently the Vconn Source Shall Not send a Wait Message in
response to VCONN_Swap Message. Once it has completed this evaluation one of the Port Partners Should initiate the
VCONN Swap process again by sending a VCONN_Swap Message.
A Port that receives a Wait Message in response to a VCONN_Swap Message Shall wait tVCONNSwapWait after
receiving the Wait Message before sending another VCONN_Swap Message.

6.3.13 Soft Reset Message

A Soft_Reset Message May be initiated by either the Source or Sink to its Port Partner requesting a Soft Reset. The
Soft_Reset Message Shall cause a Soft Reset of the connected Port Pair (see Section 6.8.1). If the Soft_Reset Message
fails a Hard Reset Shall be initiated within tHardReset of the last CRCReceiveTimer expiring after nRetryCount
retries have been completed.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 111
A Soft_Reset Message is used to recover from Protocol Layer errors; putting the Message counters to a known state in
order to regain Message synchronization. The Soft_Reset Message has no effect on the Source or Sink; that is the
previously negotiated direction. Voltage and current remain unchanged. Modal Operation is unaffected by Soft Reset.
However after a Soft Reset has completed, an Explicit Contract negotiation occurs, in order to re-establish PD
Communication and to bring state operation for both Port Partners back to either the PE_SNK_Ready or
PE_SRC_Ready states as appropriate (see Section 8.3.3.4).
A Soft_Reset Message May be sent by either the Source or Sink when there is a Message synchronization error. If the
error is not corrected by the Soft Reset, Hard Reset Signaling Shall be issued (see Section 6.8).
A Soft_Reset Message Shall be targeted at a specific entity depending on the type of SOP* Packet used. Soft_Reset
Messages sent using SOP Packets Shall Soft Reset the Port Partner only. Soft_Reset Messages sent using SOP’/SOP’’
Packets Shall Soft Reset the corresponding Cable Plug only.
After a VCONN Swap the VCONN Source needs to reset the Cable Plug’s Protocol Layer in order to ensure MessageID
synchronization. If after a VCONN Swap the VCONN Source wants to communicate with a Cable Plug using SOP’ Packets
it Shall issue a Soft_Reset Message using a SOP’ Packet in order to reset the Cable Plug’s Protocol Layer. If the VCONN
Source wants to communicate with a Cable Plug using SOP’’ Packets it Shall issue a Soft_Reset Message using a SOP’’
Packet in order to reset the Cable Plug’s Protocol Layer.

6.3.14 Not_Supported Message

The Not_Supported Message Shall be sent by a Port in response to any Message it does not support. Returning a
Not_Supported Message is assumed in this specification and has not been called out explicitly except in Section 6.12
which defines cases where the Not_Supported Message is returned.

6.3.15 Get_Source_Cap_Extended Message

The Get_Source_Cap_Extended (Get Source Capabilities Extended) Message is sent by a Port to request additional
information about a Port’s Source Capabilities. The Port Should respond by returning a
Source_Capabilities_Extended Message (see Section 6.5.1).

6.3.16 Get_Status Message

The Get_Status Message is sent by a Port to request the Port Partner’s present status. The Source or Sink Shall
respond by returning a Status Message (see Section 6.5.2). A Port that receives an Alert Message (see Section 6.4.6)
indicates that the Source or Sink’s Status has changed and Should be re-read using a Get_Status Message.

6.3.17 FR_Swap Message

The FR_Swap Message Shall be sent by the new Source within tFRSwapInit after it has detected a Fast Role Swap
signal (see Section 5.8.6.3 and Section 6.6.16). The Fast Role Swap AMS is necessary to apply Rp to the new Source
and Rd to the new Sink and to re-synchronize the state machines.
The recipient of the FR_Swap Message Shall respond by sending an Accept Message.
After a successful Fast Role Swap the Port Partners Shall reset their respective Protocol Layers (equivalent to a Soft
Reset): resetting their MessageIDCounter, RetryCounter and Protocol Layer state machines before attempting to
establish an Explicit Contract. At this point the Source Shall also reset its CapsCounter.
Since a UFP Source can attempt to send a Discover Identity Command using SOP’ to a Cable Plug prior to the
establishment of an Explicit Contract, a DFP Sink Shall disable the receiving of SOP’ Messages until an Explicit
Contract has been established. This ensures that only the Cable Plug responds with a GoodCRC Message to the
Discover Identity Command.
Prior to the Fast Role Swap AMS the new Source Shall have Rd asserted on the CC wire and the new Sink Shall have
Rp asserted on the CC wire. Note that this is an incorrect assignment of Rp/Rd (since Rp follows the Source and Rd
follows the Sink as defined in [USB Type-C 1.2]) that is corrected by the Fast Role Swap AMS.

Page 112 USB Power Delivery Specification Revision 3.0, Version 1.1
During the Fast Role Swap AMS the new Source Shall change its CC Wire resistor from Rd to Rp and the new Sink
Shall change its CC Wire resistor from Rp to Rd. The DFP (Host), UFP (Device) roles and VCONN Source Shall remain
unchanged during the Fast Role Swap process.
The initial Source Should avoid being the VCONN source (by using the VCONN Swap process) whenever not actively
communicating with the cable, since it is difficult for the initial Source to maintain VCONN power during the Fast Role
Swap process.
Note: a Fast Role Swap is a “best effort” solution to a situation where a PDUSB Device has lost its external power. This
process can occur at any time, even during a Non-interruptible AMS in which case error handling such as Hard Reset
or [USB Type-C 1.2] Error Recovery will be triggered.
Note: during the Fast Role Swap process the initial Sink does not disconnect even though V BUS drops below vSafe5V.
For more information regarding the Fast Role Swap process, refer to Section 7.1.13 and Section 7.2.9.2 in the Power
Supply chapter, Section 8.3.3.16.5 and Section 8.3.3.16.6 in the Device Policy chapter and Section 9.1.2 for VBUS
mapping to USB states.

6.3.18 Get_PPS_Status
The Get_PPS_Status Message is sent by the Sink to request additional information about a Source’s status. The Port
Shall respond by returning a PPS_Status Message (see Section 6.5.10).

6.3.19 Get_Country_Codes
The Get_Country_Codes Message is sent by a Port to request the alpha-2 country codes its Port Partner supports as
defined in [ISO 3166]. The Port Partner Shall respond by returning a Country_Codes Message (see Section 6.5.11).

6.4 Data Message

A Data Message Shall consist of a Message Header and be followed by one or more Data Objects. Data Messages are
easily identifiable because the Number of Data Objects field in the Message Header is a non-zero value.
There are several types of Data Objects:
 BIST Data Object (BDO) used for PHY Layer compliance testing.
 Power Data Object (PDO) used to expose a Source Port’s power capabilities or a Sink’s power requirements.
 Request Data Object (RDO) used by a Sink Port to negotiate a Contract.
 Vendor Defined Data Object (VDO) used to convey vendor specific information.
 Battery Status Data Object (BSDO) used to convey Battery status information.
 Alert Data Object (ADO) used to indicates events occurring on the Source or Sink.
The type of Data Object being used in a Data Message is defined by the Message Header’s Message Type field and is
summarized in Table 6-6. The Sent by column indicates entities which May send the given Message (Source, Sink or
Cable Plug); entities not listed Shall Not issue the corresponding Message. The Valid Start of Packet column indicates
the Messages which Shall only be issued in SOP Packets and the Messages which May be issued in SOP* Packets.

Table 6-6 Data Message Types

Bits 4…0 Type Sent by Description Valid Start

of Packet
0 0000 Reserved All values not explicitly defined are
Reserved and Shall Not be used.
0 0001 Source_Capabilities Source or Dual-Role See Section 6.4.1.2 SOP only
Power
0 0010 Request Sink only See Section 6.4.2 SOP only
0 0011 BIST Tester, Source or See Section 6.4.3 SOP*
Sink

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 113
 Bits 4…0 Type Sent by Description Valid Start
of Packet
0 0100 Sink_Capabilities Sink or Dual-Role See Section 6.4.1.3 SOP only
Power

0 0101 Battery_Status Source or Sink See Section 6.4.5 SOP only

0 0110 Alert Source or Sink See Section 6.4.6 SOP only
0 0111 Get_Country_Info Source or Sink See Section 6.4.7 SOP only
0 1000 -0 1110 Reserved All values not explicitly defined are
Reserved and Shall Not be used.
0 1111 Vendor_Defined Source, Sink or See Section 6.4.4 SOP*
Cable Plug
1 0000-1 1111 Reserved All values not explicitly defined are
Reserved and Shall Not be used.

6.4.1 Capabilities Message

A Capabilities Message (Source_Capabilities Message or Sink_Capabilities Message) Shall have at least one Power
Data Object for vSafe5V. The Capabilities Message Shall also contain the sending Port’s information followed by up to
6 additional Power Data Objects. Power Data Objects in a Capabilities Message Shall be sent in the following order:
1. The vSafe5V Fixed Supply Object Shall always be the first object.
2. The remaining Fixed Supply Objects, if present, Shall be sent in voltage order; lowest to highest.
3. The Battery Supply Objects, if present Shall be sent in Minimum Voltage order; lowest to highest.
4. The Variable Supply (non-Battery) Objects, if present, Shall be sent in Minimum Voltage order; lowest to highest.
5. The Programmable Power Supply Objects, if present, Shall be sent in Maximum Voltage order, lowest to highest.

Figure 6-12 Example Capabilities Message with 2 Power Data Objects

Header
Object1 Object2
No. of Data Objects = 2

In Figure 6-12, the Number of Data Objects field is 2: vSafe5V plus one other voltage.
Power Data Objects (PDO) and Augmented Power Data Objects (APDO) are identified by the Message Header’s Type
field. They are used to form Source_Capabilities Messages and Sink_Capabilities Messages.
There are three types of Power Data Objects. They contain additional information beyond that encoded in the
Message Header to identify each of the three types of Power Data Objects:
 Fixed Supply is the most commonly used to expose well-regulated fixed voltage power supplies.
 Variable power supply is used to expose very poorly regulated power supplies.
 Battery is used to expose batteries than can be directly connected to VBUS.
There is one type of Augmented Power Data Object:
 Programmable Power Supply is used to expose a power supply whose output voltage can be programmatically
adjusted over the advertised voltage range.
Power Data Objects are also used to expose additional capabilities that May be utilized; such as in the case of a Power
Role Swap.
A list of one or more Power Data Objects Shall be sent by the Source in order to convey its capabilities. The Sink May
then request one of these capabilities by returning a Request Data Object that contains an index to a Power Data
Object, in order to negotiate a mutually agreeable Contract.

Page 114 USB Power Delivery Specification Revision 3.0, Version 1.1
Where Maximum and Minimum Voltage and Current values are given in PDOs these Shall be taken to be absolute
values.
The Source and Sink Shall Not negotiate a power level that would allow the current to exceed the maximum current
supported by their receptacles or the Attached plug (see [USB Type-C 1.2]). The Source Shall limit its offered
capabilities to the maximum current supported by its receptacle and Attached plug. A Sink Shall only make a request
from any of the capabilities offered by the Source. For further details see Section 4.4.
Sources expose their power capabilities by sending a Source_Capabilities Message. Sinks expose their power
requirements by sending a Sink_Capabilities Message. Both are composed of a number of 32-bit Power Data Objects
(see Table 6-7).

Table 6-7 Power Data Object

Bit(s) Description
B31…30 Value Parameter
00b Fixed supply (Vmin = Vmax)
01b Battery
10b Variable Supply (non-Battery)
11b Augmented Power Data Object (APDO)
B29…0 Specific Power Capabilities are described by the PDOs in the following sections.

The Augmented Power Data Object (APDO) is defined to allow support for more than the four PDO types by extending
the Power Data Object field from 2 to 4 bits when the B31…B30 are 11b. The generic APDO structure is shown in
Table 6-8.

Table 6-8 Augmented Power Data Object

Bit(s) Description
B31…30 11b – Augmented Power Datat Object (APDO)
B29…28 00b – Programmable Power Supply
01b-11b - Reserved
B27…0 Specific Power Capabilities are described by the APDOs in the following sections.

6.4.1.1 Use of the Capabilities Message

6.4.1.1.1 Use by Sources

Sources send a Source_Capabilities Message (see Section 6.4.1) either as part of advertising Port capabilities, or in
response to a Get_Source_Cap Message.
Following a Hard Reset, a power-on event or plug insertion event, a Source Port Shall send a Source_Capabilities
Message after every SourceCapabilityTimer timeout as an advertisement that Shall be interpreted by the Sink Port
on Attachment. The Source Shall continue sending a minimum of nCapsCount Source_Capabilities Messages until a
GoodCRC Message is received.
Additionally, a Source_Capabilities Message Shall only be sent in the following cases:
 By the Source Port from the PE_SRC_Ready state upon a change in its ability to supply power.
 By a Source Port or Dual-Role Power Port in response to a Get_Source_Cap Message.

6.4.1.1.2 Use by Sinks

Sinks send a Sink_Capabilities Message (see Section 6.4.1.3) in response to a Get_Sink_Cap Message.
A USB Power Delivery capable Sink, upon detecting vSafe5V on VBUS and after a SinkWaitCapTimer timeout without
seeing a Source_Capabilities Message, Shall send a Hard Reset. If the Attached Source is USB Power Delivery capable,
it responds by sending Source_Capabilities Messages thus allowing power negotiations to begin.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 115
 6.4.1.1.3 Use by Dual-Role Power devices
Dual-Role Power devices send a Source_Capabilities Message (see Section 6.4.1) as part of advertising Port
capabilities when operating in Source role. Dual-Role Power devices send a Source_Capabilities Message (see Section
6.4.1) in response to a Get_Source_Cap Message regardless of their present operating role. Similarly Dual-Role Power
devices send a Sink_Capabilities Message (see Section 6.4.1.3) in response to a Get_Sink_Cap Message regardless of
their present operating role.

6.4.1.2 Source_Capabilities Message

A Source Port Shall report its capabilities in a series of 32-bit Power Data Objects (see Table 6-7) as part of a
Source_Capabilities Message (see Figure 6-12). Power Data Objects are used to convey a Source Port’s capabilities to
provide power including Dual-Role Power ports presently operating as a Sink.
Each Power Data Object Shall describe a specific Source capability such as a Battery (e.g. 2.8-4.1V) or a fixed power
supply (e.g. 12V) at a maximum allowable current. The Number of Data Objects field in the Message Header Shall
define the number of Power Data Objects that follow the Message Header in a Data Message. All Sources Shall
minimally offer one Power Data Object that reports vSafe5V. A Source Shall Not offer multiple Power Data Objects of
the same type (fixed, variable, Battery) and the same voltage but Shall instead offer one Power Data Object with the
highest available current for that Source capability and voltage. Sinks with Accessory Support do not source VBUS (see
[USB Type-C 1.2]) however when sourcing VCONN they Shall advertise vSafe5V with the Maximum Current set to 0mA
in the first Power Data Object.
A Sink Shall evaluate every Source_Capabilities Message it receives and Shall respond with a Request Message. If its
power consumption exceeds the Source’s capabilities it Shall re-negotiate so as not to exceed the Source’s most
recently advertised capabilities.
A Sink that evaluates the Source_Capabilities Message it receives and identifies a PPS APDO Shall periodically re-
request the PPS APDO at least every tPPSRequest until either:
 The Sink requests something other than PPS APDO.
 There is a Power Role Swap.
 There is a Hard Reset.
A Source that has accepted a Request Message with a Programmable RDO Shall issue Hard Reset Signaling if it has
not received a Request Message with a Programmable RDO within tPPSTimeout. The Source Shall discontinue this
behavior after:
 Receiving a Request Message with a Fixed, Variable or Battery RDO.
 There is a Power Role Swap.
 There is a Hard Reset.

6.4.1.2.1 Management of the Power Reserve

A Power Reserve May be allocated to a Sink when it makes a request from Source Capabilities which includes a
Maximum Operating Current/Power. The size of the Power Reserve for a particular Sink is calculated as the
difference between its Maximum Operating Current/Power field and its Operating Current/Power field. For a Hub
with multiple ports this same Power Reserve May be shared between several Sinks. The Power Reserve May also be
temporarily used by a Sink which has indicated it can give back power by setting the GiveBack flag.
Where a Power Reserve has been allocated to a Sink the Source Shall indicate the Power Reserve as part of every
Source_Capabilities Message it sends. When the same Power Reserve is shared between several Sinks the Source
Shall indicate the Power Reserve as part of every Source_Capabilities Message it sends to every Sink. Every time a
Source sends capabilities including the Power Reserve capability and then accepts a request from a Sink including the
Power Reserve indicated by its Maximum operating Current/Power it is confirming that the Power Reserve is part of
the Explicit Contract with the Sink.
When the Reserve is being temporarily used by a giveback capable Sink the Source Shall indicate the Power Reserve
as available in every Source_Capabilities Message it sends. However in this situation, when the Power Reserve is

Page 116 USB Power Delivery Specification Revision 3.0, Version 1.1
requested by a Sink, the Source Shall return a Wait Message while it retrieves this power using a GotoMin Message.
Once the additional power has been retrieved the Source Shall send a new Source_Capabilities Message in order to
trigger a new request from the Sink requesting the Power Reserve.
The Power Reserve May be de-allocated by the Source at any time, but the de-allocation Shall be indicated to the Sink
or Sinks using the Power Reserve by sending a new Source_Capabilities Message.

6.4.1.2.2 Fixed Supply Power Data Object

Table 6-9 describes the Fixed Supply (00b) PDO. See Section 7.1.3 for the electrical requirements of the power supply.
Since all USB Providers support vSafe5V, the required vSafe5V Fixed Supply Power Data Object is also used to convey
additional information that is returned in bits 29 through 25. All other Fixed Supply Power Data Objects Shall set bits
29…22 to zero.
For a Source offering no capabilities, the Voltage (B19…10) Shall be set to 5V and the Maximum Current Shall be set
to 0mA. This is used in cases such as a Dual-Role Power device which offers no capabilities in its default role or when
external power is required in order to offer power.
When a Source wants a Sink, consuming power from VBUS, to go to its lowest power state, the Voltage (B19…10) Shall
be set to 5V and the Maximum Current Shall be set to 0mA. This is used in cases where the Source wants the Sink to
draw pSnkSusp.

Table 6-9 Fixed Supply PDO - Source

Bit(s) Description
B31…30 Fixed supply
B29 Dual-Role Power
B28 USB Suspend Supported
B27 Unconstrained Power
B26 USB Communications Capable
B25 Dual-Role Data
B24 Unchunked Extended Messages Supported
B23…22 Reserved – Shall be set to zero.
B21…20 Peak Current
B19…10 Voltage in 50mV units
B9…0 Maximum Current in 10mA units

6.4.1.2.2.1 Dual-Role Power

The Dual-Role Power bit Shall be set when the Port is Dual-Role Power capable i.e. supports the PR_Swap Message.
This is a static capability which Shall remain fixed for a given device regardless of the device’s present power role. If
the Dual-Role Power bit is set to one in the Source_Capabilities Message the Dual-Role Power bit in the
Sink_Capabilities Message Shall also be set to one. If the Dual-Role Power bit is set to zero in the Source_Capabilities
Message the Dual-Role Power bit in the Sink_Capabilities Message Shall also be set to zero.

6.4.1.2.2.2 USB Suspend Supported

Prior to a Contract or when the USB Communications Capable bit is set to zero, this flag is undefined and Sinks Shall
follow the rules for suspend as defined in [USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2]. After a Contract has
been negotiated:
 If the USB Suspend Supported flag is set, then the Sink Shall follow the [USB 2.0] or [USB 3.1] rules for suspend
and resume. A PDUSB Peripheral May draw up to pSnkSusp during suspend; a PDUSB Hub May draw up to
pHubSusp during suspend (see Section 7.2.3).

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 117
 If the USB Suspend Supported flag is cleared, then the Sink Shall Not apply the [USB 2.0] or [USB 3.1] rules for
suspend and May continue to draw the negotiated power. Note that when USB is suspended, the USB device state
is also suspended.
Sinks May indicate to the Source that they would prefer to have the USB Suspend Supported flag cleared by setting the
No USB Suspend flag in a Request Message (see Section 6.4.2.5).

6.4.1.2.2.3 Unconstrained Power

The Unconstrained Power bit Shall be set when an external source of power is available that is sufficient to
adequately power the system while charging external devices, or when the device’s primary function is to charge
external devices.
To set the Unconstrained Power bit as a result of an external source, the external source of power Should be either:
 An AC supply, e.g. a wall wart, directly connected to the Sink.
 Or, in the case of a PDUSB Hub:
o A PD Source with its Unconstrained Power bit set.
o Multiple PD Sources all with their Unconstrained Power bits set.

6.4.1.2.2.4 USB Communications Capable

The USB Communications Capable bit Shall only be set for Sources capable of communication over the USB data lines
(e.g. D+/- or SS Tx/Rx).

6.4.1.2.2.5 Dual-Role Data

The Dual-Role Data bit Shall be set when the Port is Dual-Role data capable i.e. it supports the DR_Swap Message.
This is a static capability which Shall remain fixed for a given device regardless of the device’s present power role or
data role. If the Dual-Role Data bit is set to one in the Source_Capabilities Message the Dual-Role Data bit in the
Sink_Capabilities Message Shall also be set to one. If the Dual-Role Data bit is set to zero in the Source_Capabilities
Message the Dual-Role Data bit in the Sink_Capabilities Message Shall also be set to zero.

6.4.1.2.2.6 Unchunked Extended Messages Supported

The Unchunked Extended Messages Supported bit Shall be set when the Port can send and receive Extended
Messages with Data Size > MaxExtendedMsgLegacyLen bytes in a single, Unchunked Message.

6.4.1.2.2.7 Peak Current

The USB Power Delivery Fixed Supply is only required to deliver the amount of current requested in the Operating
Current (IOC) field of an RDO. In some usages however, for example computer systems, where there are short bursts
of activity, it might be desirable to overload the power source for short periods.
For example when a computer system tries to maintain average power consumption, the higher the peak current, the
longer the low current (see Section 7.2.8) period needed to maintain such average power. The Peak Current field
allows a power source to advertise this additional capability. This capability is intended for direct Port to Port
connections only and Shall Not be offered to downstream Sinks via a Hub.
Every Fixed Supply PDO Shall contain a Peak Current field. Supplies that want to offer a set of overload capabilities
Shall advertise this through the Peak Current field in the corresponding Fixed Supply PDO (see Table 6-10). Supplies
that do not support an overload capability Shall set these bits to 00b in the corresponding Fixed Supply PDO. Supplies
that support an extended overload capability specified in the PeakCurrent1…3 fields of the
Source_Capabilities_Extended Message (see Section 6.5.1) Shall also set these bits to 00b. Sinks wishing to utilize
these extended capabilities Shall first send the Get_Source_Cap_Extended Message to determine what capabilities, if
any are supported by the Source.

Page 118 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 6-10 Fixed Power Source Peak Current Capability

Bits 21…20 Description

00 Peak current equals IOC (default)
or look at extended Source capabilities (send Get_Source_Cap_Extended Message)
01 Overload Capabilities:
1. Peak current equals 150% IOC for 1ms @ 5% duty cycle (low current equals 97% I OC for 19ms)
2. Peak current equals 125% IOC for 2ms @ 10% duty cycle (low current equals 97% I OC for 18ms)
3. Peak current equals 110% IOC for 10ms @ 50% duty cycle (low current equals 90% IOC for 10ms)
10 Overload Capabilities:
1. Peak current equals 200% IOC for 1ms @ 5% duty cycle (low current equals 95% IOC for 19ms)
2. Peak current equals 150% IOC for 2ms @ 10% duty cycle (low current equals 94% I OC for 18ms)
3. Peak current equals 125% IOC for 10ms @ 50% duty cycle (low current equals 75% IOC for 10ms)
11 Overload Capabilities:
1. Peak current equals 200% IOC for 1ms @ 5% duty cycle (low current equals 95% I OC for 19ms)
2. Peak current equals 175% IOC for 2ms @ 10% duty cycle (low current equals 92% I OC for 18ms)
3. Peak current equals 150% IOC for 10ms @ 50% duty cycle (low current equals 50% IOC for 10ms)

6.4.1.2.3 Variable Supply (non-Battery) Power Data Object

Table 6-11 describes a Variable Supply (non-Battery) (10b) PDO for a Source. See Section 7.1.3 for the electrical
requirements of the power supply.
The voltage fields Shall define the range that output voltage Shall fall within. This does not indicate the voltage that
will actually be supplied, except it Shall fall within that range. The absolute voltage, including any voltage variation,
Shall Not fall below the Minimum Voltage and Shall Not exceed the Maximum Voltage.

Table 6-11 Variable Supply (non-Battery) PDO - Source

Bit(s) Description
B31…30 Variable Supply (non-Battery)
B29…20 Maximum Voltage in 50mV units
B19…10 Minimum Voltage in 50mV units
B9…0 Maximum Current in 10mA units

6.4.1.2.4 Battery Supply Power Data Object

Table 6-12 describes a Battery (01b) PDO for a Source. See Section 7.1.3 for the electrical requirements of the power
supply.
The voltage fields Shall represent the Battery’s voltage range. The Battery Shall be capable of supplying the Power
value over the entire voltage range. The absolute voltage, including any voltage variation, Shall Not fall below the
Minimum Voltage and Shall Not exceed the Maximum Voltage. Note, only the Battery PDO uses power instead of
current.
The Sink May monitor the Battery voltage.

Table 6-12 Battery Supply PDO - Source

Bit(s) Description
B31…30 Battery
B29…20 Maximum Voltage in 50mV units
B19…10 Minimum Voltage in 50mV units
B9…0 Maximum Allowable Power in 250mW units

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 119
 6.4.1.2.5 Programmable Power Supply Augmented Power Data Object
Table 6-13 below describes a Programmable Power Supply (1100b) APDO for a Source. See Section 7.1.3 for the
electrical requirements of the power supply. This APDO is used primarily for Sink Directed Charge of a Battery in the
Sink. When applying a current to the Battery greater than the cable supports, a high efficiency fixed scaler May be
used in the Sink to reduce the cable current.
The voltage fields define the output voltage range over which the power supply Shall be adjustable in 20mV steps.
The Maximum Current field contains the current the Programmable Power Supply Shall be capable of delivering over
the advertised voltage range.

Table 6-13 Programmable Power Supply APDO - Source

Bit(s) Description
B31…30 11b – Augmented Power Data Object (APDO)
B29…28 00b – Programmable Power Supply
01b…11b - Reserved, Shall Not be used
B27…25 Reserved – Shall be set to zero
B24…17 Maximum Voltage in 100mV increments
B16 Reserved – Shall be set to zero
B15…8 Minimum Voltage in 100mV increments
B7 Reserved – Shall be set to zero
B6…0 Maximum Current in 50mA increments

6.4.1.3 Sink Capabilities Message

A Sink Port Shall report power levels it is able to operate at in a series of 32-bit Power Data Objects (see Table 6-7).
These are returned as part of a Sink_Capabilities Message in response to a Get_Sink_Cap Message (see Figure 6-12).
This is similar to that used for Source Port capabilities with equivalent Power Data Objects for Fixed, Variable and
Battery Supplies as defined in this section. Power Data Objects are used to convey the Sink Port’s operational power
requirements including Dual-Role Power Ports presently operating as a Source.
Each Power Data Object Shall describe a specific Sink operational power level, such as a Battery (e.g. 2.8-4.1V) or a
fixed power supply (e.g. 12V). The Number of Data Objects field in the Message Header Shall define the number of
Power Data Objects that follow the Message Header in a Data Message.
All Sinks Shall minimally offer one Power Data Object with a power level at which the Sink can operate. A Sink Shall
Not offer multiple Power Data Objects of the same type (fixed, variable, Battery) and the same voltage but Shall
instead offer one Power Data Object with the highest available current for that Sink capability and voltage.
All Sinks Shall include one Power Data Object that reports vSafe5V even if they require additional power to operate
fully. In the case where additional power is required for full operation the Higher Capability bit Shall be set.

6.4.1.3.1 Sink Fixed Supply Power Data Object

Table 6-14 describes the Sink Fixed Supply (00b) PDO. See Section 7.1.3 for the electrical requirements of the power
supply. The Sink Shall set Voltage to its required voltage and Operational Current to its required operating current.
Required operating current is defined as the amount of current a given device needs to be functional. This value could
be the maximum current the Sink will ever require or could be sufficient to operate the Sink in one of its modes of
operation.
Since all USB Consumers support vSafe5V, the required vSafe5V Fixed Supply Power Data Object is also used to
convey additional information that is returned in bits 29 through 20. All other Fixed Supply Power Data Objects Shall
set bits 29…20 to zero.
For a Sink requiring no power from the Source, the Voltage (B19…10) Shall be set to 5V and the Operational Current
Shall be set to 0mA.

Page 120 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 6-14 Fixed Supply PDO - Sink

Bit(s) Description
B31…30 Fixed supply
B29 Dual-Role Power
B28 Higher Capability
B27 Unconstrained Power
B26 USB Communications Capable
B25 Dual-Role Data
B24…23 Fast Role Swap required USB Type-C Current (see also [USB Type-C 1.2]):

Value Description
00b Fast Swap not supported (default)
01b Default USB Power
10b 1.5A @ 5V
11b 3.0A @ 5V
B22…20 Reserved – Shall be set to zero.
B19…10 Voltage in 50mV units
B9…0 Operational Current in 10mA units

6.4.1.3.1.1 Dual-Role Power

The Dual-Role Power bit Shall be set when the Port is Dual-Role Power capable i.e. supports the PR_Swap Message.
This is a static capability which Shall remain fixed for a given device regardless of the device’s present power role. If
the Dual-Role Power bit is set to one in the Source_Capabilities Message the Dual-Role Power bit in the
Sink_Capabilities Message Shall also be set to one. If the Dual-Role Power bit is set to zero in the Sink_Capabilities
Message the Dual-Role Power bit in the Sink_Capabilities Message Shall also be set to zero.

6.4.1.3.1.2 Higher Capability

In the case that the Sink needs more than vSafe5V (e.g. 12V) to provide full functionality, then the Higher Capability
bit Shall be set.

6.4.1.3.1.3 Unconstrained Power

The Unconstrained Power bit Shall be set when an external source of power is available that is sufficient to
adequately power the system while charging external devices, or when the device’s primary function is to charge
external devices.
To set the Unconstrained Power bit as a result of an external source, the external source of power Should be either:
 An AC supply, e.g. a wall wart, directly connected to the Sink.
 Or, in the case of a PDUSB Hub:
o A PD Source with its Unconstrained Power bit set.
o Multiple PD Sources all with their Unconstrained Power bits set.

6.4.1.3.1.4 USB Communications Capable

The USB Communications Capable bit Shall only be set for Sinks capable of communication over the USB data lines
(e.g. D+/- or SS Tx/Rx).

6.4.1.3.1.5 Dual-Role Data

The Dual-Role Data bit Shall be set when the Port is Dual-Role data capable i.e. it supports the DR_Swap Message.
This is a static capability which Shall remain fixed for a given device regardless of the device’s present power role or
data role. If the Dual-Role Data bit is set to one in the Source_Capabilities Message the Dual-Role Data bit in the

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 121
Sink_Capabilities Message Shall also be set to one. If the Dual-Role Data bit is set to zero in the Source_Capabilities
Message the Dual-Role Data bit in the Sink_Capabilities Message Shall also be set to zero.

6.4.1.3.1.6 Fast Role Swap USB Type-C Current

The Fast Role Swap USB Type-C Current field Shall indicate the current level the Sink will require after a Fast Role
Swap has been performed.
Initially when the new Source applies vSafe5V it will have Rd asserted but Shall provide the USB Type-C Current
indicated by the new Sink in this field. If the new Source is not able to supply this level of current it Shall Not perform
a Fast Role Swap. When Rp is asserted by the new Source during the Fast Role Swap AMS (see Section 6.3.17), the
value of USB Type-C Current indicated by Rp Shall be the same or greater than that indicated in the Fast Role Swap
USB Type-C Current field.

6.4.1.3.2 Variable Supply (non-Battery) Power Data Object

Table 6-15 describes a Variable Supply (non-Battery) (10b) PDO used by a Sink. See Section 7.1.3 for the electrical
requirements of the power supply.
The voltage fields Shall be set to the output voltage range that the Sink requires to operate. The Operational Current
field Shall be set to the operational current that the Sink requires at the given voltage range. The absolute voltage,
including any voltage variation, Shall Not fall below the Minimum Voltage and Shall Not exceed the Maximum
Voltage. Required operating current is defined as the amount of current a given device needs to be functional. This
value could be the maximum current the Sink will ever require or could be sufficient to operate the Sink in one of its
modes of operation.

Table 6-15 Variable Supply (non-Battery) PDO - Sink

Bit(s) Description
B31…30 Variable Supply (non-Battery)
B29…20 Maximum Voltage in 50mV units
B19…10 Minimum Voltage in 50mV units
B9…0 Operational Current in 10mA units

6.4.1.3.3 Battery Supply Power Data Object

Table 6-16 describes a Battery (01b) PDO used by a Sink. See Section 7.1.3 for the electrical requirements of the
power supply.
The voltage fields Shall be set to the output voltage range that the Sink requires to operate. The Operational Power
field Shall be set to the operational power that the Sink requires at the given voltage range. The absolute voltage,
including any voltage variation, Shall Not fall below the Minimum Voltage and Shall Not exceed the Maximum
Voltage. Note, only the Battery PDO uses power instead of current. Required operating power is defined as the
amount of power a given device needs to be functional. This value could be the maximum power the Sink will ever
require or could be sufficient to operate the Sink in one of its modes of operation.

Table 6-16 Battery Supply PDO - Sink

Bit(s) Description
B31…30 Battery
B29…20 Maximum Voltage in 50mV units
B19…10 Minimum Voltage in 50mV units
B9…0 Operational Power in 250mW units

6.4.1.3.4 Programmable Power Supply Augmented Power Data Object

Table 6-17 below describes a Programmable Power Supply (1100b) APDO used by a Sink. See Section 7.1.3 for the
electrical requirements of the power supply.

Page 122 USB Power Delivery Specification Revision 3.0, Version 1.1
The Maximum and Minimum Voltage fields Shall be set to the output voltage range that the Sink requires to operate.
The Operational Current field Shall be set to the maximum current the Sink requires over the voltage range. The
Operating Current is defined as the maximum amount of current the device needs to fully support its function (e.g.,
Sink Directed Charge).

Table 6-17 Programmable Power Supply APDO - Sink

Bit(s) Description
B31…30 11b – Augmented Power Data Object (APDO)
B29…28 00b – Programmable Power Supply
B27…25 Reserved – Shall be set to zero
B24…17 Maximum Voltage in 100mV increments
B16 Reserved – Shall be set to zero
B15…8 Minimum Voltage in 100mV increments
B7 Reserved – Shall be set to zero
B6…0 Maximum Current in 50mA increments

6.4.2 Request Message

A Request Message Shall be sent by a Sink to request power, typically during the request phase of a power
negotiation. The Request Data Object Shall be returned by the Sink making a request for power. It Shall be sent in
response to the most recent Source_Capabilities Message (see Section 8.3.2.2). A Request Message Shall return one
and only one Sink Request Data Object that Shall identify the Power Data Object being requested.
The Request Message includes the requested power level. For example, if the Source_Capabilities Message includes a
Fixed Supply PDO that offers 12V @ 1.5A and if the Sink only wants 12V @ 0.5A, it will set the Operating Current field
to 50 (i.e. 10mA * 50 = 0.5A). The Request Message requests the highest current the Sink will ever require in the
Maximum Operating Current Field (in this example it would be 100 (100 * 10mA = 1.0A)).
The request takes a different form depending on the kind of power requested. The Fixed Power Data Object and
Variable Power Data Object share a common format shown in Table 6-18 and Table 6-19. The Battery Power Data
Object uses the format shown in Table 6-20 and Table 6-21. The Programmable Request Object the format shown in
Table 6-22.

Table 6-18 Fixed and Variable Request Data Object

Bits Description
B31 Reserved – Shall be set to zero
B30…28 Object position (000b is Reserved and Shall Not be used)
B27 GiveBack flag = 0
B26 Capability Mismatch
B25 USB Communications Capable
B24 No USB Suspend
B23 Unchunked Extended Messages Supported
B22…20 Reserved - Shall be set to zero.
B19…10 Operating current in 10mA units
B9…0 Maximum Operating Current 10mA units

Table 6-19 Fixed and Variable Request Data Object with GiveBack Support

Bits Description
B31 Reserved – Shall be set to zero
B30…28 Object position (000b is Reserved and Shall Not be used)
B27 GiveBack flag =1
B26 Capability Mismatch

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 123
 Bits Description
B25 USB Communications Capable
B24 No USB Suspend
B23 Unchunked Extended Messages Supported
B22…20 Reserved - Shall be set to zero.
B19…10 Operating Current in 10mA units
B9…0 Minimum Operating Current 10mA units

Table 6-20 Battery Request Data Object

Bits Description
B31 Reserved – Shall be set to zero
B30…28 Object position (000b is Reserved and Shall Not be used)
B27 GiveBackFlag = 0
B26 Capability Mismatch
B25 USB Communications Capable
B24 No USB Suspend
B23 Unchunked Extended Messages Supported
B22…20 Reserved - Shall be set to zero.
B19…10 Operating Power in 250mW units
B9…0 Maximum Operating Power in 250mW units

Page 124 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 6-21 Battery Request Data Object with GiveBack Support

Bits Description
B31 Reserved – Shall be set to zero
B30…28 Object position (000b is Reserved and Shall Not be used)
B27 GiveBackFlag = 1
B26 Capability Mismatch
B25 USB Communications Capable
B24 No USB Suspend
B23 Unchunked Extended Messages Supported
B22…20 Reserved - Shall be set to zero.
B19…10 Operating Power in 250mW units
B9…0 Minimum Operating Power in 250mW units

Table 6-22 Programmable Request Data Object

Bits Description
B31 Reserved – Shall be set to zero
B30…28 Object position (000b is Reserved and Shall Not be used)
B27 Reserved – Shall be set to zero
B26 Capability Mismatch
B25 USB Communications Capable
B24 No USB Suspend
B23 Unchunked Extended Messages Supported
B22…20 Reserved - Shall be set to zero.
B19…9 Output Voltage in 20mV units
B8…7 Reserved - Shall be set to zero.
B6…0 Operating Current 50mA units

6.4.2.1 Object Position

The value in the Object Position field Shall indicate which object in the Source_Capabilities Message the RDO refers.
The value 1 always indicates the 5V Fixed Supply PDO as it is the first object following the Source_Capabilities
Message Header. The number 2 refers to the next PDO and so forth.

6.4.2.2 GiveBack Flag

The GiveBack flag Shall be set to indicate that the Sink will respond to a GotoMin Message by reducing its load to the
Minimum Operating Current. It will typically be used by a USB Device while charging its Battery because a short
interruption of the charge will have minimal impact on the user and will allow the Source to manage its load better.

6.4.2.3 Capability Mismatch

A Capability Mismatch occurs when the Sink cannot satisfy its power requirements from the capabilities offered by
the Source. In this case the Sink Shall make a Valid request from the offered capabilities and Shall set the Capability
Mismatch bit (see Section 8.2.5.2).
When a Sink returns a Request Data Object in response to advertised capabilities with this bit set, it indicates that the
Sink wants power that the Source cannot provide. This can be due to either a voltage that is not available or the
amount of available current. At this point the Source can use the information in the Request Message combined with
the contents of the Sink_Capabilities Message to ascertain the Voltage and Current required by the Sink for full
operation.
In this context a Valid Request Message means the following:
 The Object position field Shall contain a reference to an object in the last received Source_Capabilities Message.
USB Power Delivery Specification Revision 3.0, Version 1.1 Page 125
 The Operating Current/Power field Shall contain a value which is less than or equal to the maximum
current/power offered in the Source_Capabilities Message.
 If the GiveBack flag is set to zero i.e. there is a Maximum Operating Current/Power field:
o If the Capability Mismatch bit is set to one:
 The Maximum Operating Current/Power field May contain a value larger than the maximum
current/power offered in the Source_Capabilities Message’s PDO as referenced by the Object position
field. This enables the Sink to indicate that it requires more current/power than is being offered. If the
Sink requires a different voltage this will be indicated by its Sink_Capabilities Message.
o Else if the Capability Mismatch bit is set to zero:
 The Maximum Operating Current/Power field Shall contain a value less than or equal to the maximum
current/power offered in the Source_Capabilities Message’s PDO as referenced by the Object position
field.
 Else if the GiveBack flag is set to one i.e. there is a Minimum Operating Current/Power field:
o The Minimum Operating Current/Power field Shall contain a value less than the Operating Current/Power
field.

6.4.2.4 USB Communications Capable

The USB Communications Capable flag Shall be set to one when the Sink has USB data lines and is capable of
communicating using either [USB 2.0] or [USB 3.1] protocols. The USB Communications Capable flag Shall be set to
zero when the Sink does not have USB data lines or is otherwise incapable of communicating using either [USB 2.0] or
[USB 3.1] protocols. This is used by the Source to determine operation in certain cases such as USB suspend. If the
USB Communications Capable flag has been set to zero by a Sink then the Source needs to be aware that USB Suspend
rules cannot be observed by the Sink.

6.4.2.5 No USB Suspend

The No USB Suspend flag May be set by the Sink to indicate to the Source that this device is requesting to continue its
Contract during USB Suspend. Sinks setting this flag typically have functionality that can use power for purposes
other than USB communication e.g. for charging a Battery.
The Source uses this flag to evaluate whether it Should re-issue the Source_Capabilities Message with the USB
Suspend flag cleared.

6.4.2.6 Unchunked Extended Messages Supported

The Unchunked Extended Messages Supported bit Shall be set when the Port can send and receive Extended
Messages with Data Size > MaxExtendedMsgLegacyLen bytes in a single, Unchunked Message.

6.4.2.7 Operating Current

The Operating Current field in the Request Data Object Shall be set to the actual amount of current the Sink needs to
operate at a given time. A new Request Message, with an updated Operating Current value, Shall be issued whenever
the Sink’s power needs change e.g. from Maximum Operating Current down to a lower current level. In conjunction
with the Maximum Operating Current field or Minimum Operating Current field, it provides the Source with additional
information that allows it to better manage the distribution of its power.
The Operating Current field in the Programmable Request Data Object is used in addition by the Sink to request the
Source for the Current Foldback level it needs. When the request is accepted the Source’s output current supplied into
any load Shall be less than or equal to the Operating Current. When the Sink attempts to consume more current, the
Source Shall reduce the output voltage so as not to exceed the Operating Current value.
The value in the Operating Current field Shall Not exceed the value in the Maximum Current field.
This field Shall apply to the Fixed, Variable and Programmable RDO.

Page 126 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.4.2.8 Maximum Operating Current
The Maximum Operating Current field in the Request Message Shall be set to the highest current the Sink will ever
require. The difference between the Operating Current and Maximum Operating Current fields (when the GiveBack
Flag is cleared) is used by the Device Policy Manager in the Source to calculate the size of the Power Reserve to be
maintained (see Section 8.2.5.1). The Operating Current value Shall be less than or equal to the Maximum Operating
Current value.
When the Capabilities Mismatch bit is set to zero the requested Maximum Operating Current Shall be less than or
equal to the current in the offered Source Capabilities since the Source will need to reserve this power for future use.
The Maximum Operating Current field Shall continue to be set to the highest current needed in order to maintain the
allocation of the Power Reserve. If Maximum Operating Current is requested when the Power Reserve is being used
by a GotoMin capable device then the resulting Message will be a Wait Message to enable the Source to reclaim the
additional current (see Section 6.3.12.1 and Section 8.2.5.1).
When the Capabilities Mismatch bit is set to one the requested Maximum Operating Current May be greater than the
current in the offered Source Capabilities since the Source will need this information to ascertain the Sink’s actual
needs.
See Section 6.4.2.3 for more details of the usage of the Capabilities Mismatch bit.
This field Shall apply to the Fixed and Variable RDO.

6.4.2.9 Minimum Operating Current

The Minimum Operating Current field in the Request Message Shall be set to the lowest current the Sink requires to
maintain operation. The difference between the Operating Current and Minimum Operating Current fields (when the
GiveBack Flag is set) is used by the Device Policy Manager to calculate the amount of power which can be reclaimed
using a GotoMin Message. The Operating Current value Shall be greater than the Minimum Operating Current value.
This field Shall apply to the Fixed and Variable RDO.

6.4.2.10 Operating Power

The Operating Power field in the Request Data Object Shall be set to the actual amount of power the Sink wants at this
time. In conjunction with the Maximum Operating Power field, it provides the Source with additional information that
allows it to better manage the distribution of its power.
This field Shall apply to the Battery RDO.

6.4.2.11 Maximum Operating Power

The Maximum Operating Power field in the Request Message Shall be set to the highest power the Sink will ever
require. This allows a Source with a power supply shared amongst multiple ports to intelligently distribute power.
When the Capabilities Mismatch bit is set to zero the requested Maximum Operating Power Shall be less than or equal
to the power in the offered Source Capabilities since the Source will need to reserve this power for future use. The
Maximum Operating Power field Shall continue to be set to the highest power needed in order to maintain the
allocation of the Power Reserve. If Maximum Operating Power is requested when the Power Reserve is being used by
a GotoMin capable device then the resulting Message will be a Wait Message to enable the Source to reclaim the
additional power (see Section 6.3.12.1 and Section 8.2.5.1).
When the Capabilities Mismatch bit is set to one the requested Maximum Operating Power May be greater than the
current in the offered Source Capabilities since the Source will need this information to ascertain the Sink’s actual
needs
See Section 6.4.2.3 for more details of the usage of the Capabilities Mismatch bit.
This field Shall apply to the Battery RDO.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 127
 6.4.2.12 Minimum Operating Power
The Minimum Operating Power field in the Request Message Shall be set to the lowest current the Sink requires to
maintain operation. When combined with the Operating Power, it gives a Source with a power supply shared amongst
multiple ports information about how much power it can temporarily get back so it can to intelligently distribute
power.
This field Shall apply to the Battery RDO.

6.4.2.13 Output Voltage

The Output Voltage field in the Programmable Request Data Object Shall be set by the Sink to the voltage the Sink
requires as measured at the Source’s output connector. The Output Voltage field Shall be greater than or equal to the
Minimum Voltage field and less than or equal to the Maximum Voltage field in the Programmable Power Supply APDO.
This field Shall apply to the Programmable RDO.

6.4.3 BIST Message

The BIST Message is sent to request the Port to enter a Physical Layer test mode (see Section 5.9) that performs one of
the following functions:
 Enter a Continuous BIST Mode to send a continuous stream of test data to the Tester.
 Send BIST test data to the UUT.
The Message format is as follows:

Figure 6-13 BIST Message

Header
BIST Data Object
No. of Data Objects = 1 or 7

All ports Shall be able to be a Unit Under Test (UUT) only when operating at vSafe5V. All of the following BIST Modes
Shall be supported:
 Process reception of a BIST Carrier Mode BIST Data Object that Shall result in the generation of the appropriate
carrier signal.
 Process reception of a BIST Test Data BIST Data Object that Shall result in the Message being Ignored.
It is Optional for a Port to take on the role of a Tester.
When a Port receives a BIST Message BIST Data Object for a BIST Mode when Power Role swapped or not operating at
vSafe5V, the BIST Message Shall be Ignored.
When a Port receives a BIST Message BIST Data Object for a BIST Mode it does not support the BIST Message Shall be
Ignored.
When a Port or Cable Plug receives a BIST Message BIST Data Object for a Continuous BIST Mode that it supports, the
Port or Cable Plug enters the requested BIST Mode and Shall remain in that BIST Mode for tBISTContMode and then
Shall return to normal operation (see Section 6.6.7.2).
The usage model of the PHY Layer BIST modes generally assumes that some controlling agent will request a test of its
Port Partner. A UUT Port minimally has to process a request to enter test mode and return error counters. A Tester
Port Shall have a means to place the UUT Port into receiver test mode and retrieve the error counters from the UUT.
A Port, that is not part of a Tester, is not expected to be the initiator of a receiver test operation, but is not precluded
from doing so.
In Section 8.3.2.14 there is a sequence description of the test sequences used for compliance testing.
The fields in the BIST Data Object are defined in the Table 6-23.

Page 128 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 6-23 BIST Data Object

Bit(s) Value Parameter Description Reference

B31…28 0000b…0100b Shall Not be used
Reserved Section 1.4.2.10

0101b BIST Carrier Mode Request Transmitter to enter BIST Section 6.4.3.1
Carrier Mode
0110b…0111b Shall Not be used Section 1.4.2.10
Reserved

1000b BIST Test Data Sends a Test Data Frame. Section 6.4.3.2
1001b…1111b Shall Not be used Section 1.4.2.10
Reserved

B27…0 Shall be set to zero. Section 1.4.2.10

Reserved

6.4.3.1 BIST Carrier Mode

Upon receipt of a BIST Message, with a BIST Carrier Mode BIST Data Object, the UUT Shall send out a continuous
string of alternating "1"s and “0”s. Note: that in the case that the BMC Signaling Scheme is used the “1”s and “0”s will
in addition be BMC encoded.
The UUT Shall exit the Continuous BIST Mode within tBISTContMode of this Continuous BIST Mode being enabled
(see Section 6.6.7.2).

6.4.3.2 BIST Test Data

Upon receipt of a BIST Message, with a BIST Test Data BIST Data Object, the UUT Shall return a GoodCRC Message
and Shall enter a test mode in which it sends no further Messages except for GoodCRC Messages in response to
received Messages. See Section 5.9.2 for the definition of the Test Data Frame.
The test Shall be ended by sending Hard Reset Signaling to reset the UUT.

6.4.4 Vendor Defined Message

The Vendor_Defined Message (VDM) is provided to allow vendors to exchange information outside of that defined by
this specification.
A Vendor_Defined Message Shall consist of at least one Vendor Data Object, the VDM Header, and May contain up to a
maximum of six additional VDM Objects (VDO).
To ensure vendor uniqueness of Vendor_Defined Messages, all Vendor_Defined Messages Shall contain a Valid USB
Standard or Vendor ID (SVID) allocated by USB-IF in the VDM Header.
Two types of Vendor_Defined Messages are defined: Structured VDMs and Unstructured VDMs. A Structured VDM
defines an extensible structure designed to support Modal Operation. An Unstructured VDM does not define any
structure and Messages May be created in any manner that the vendor chooses.
Vendor_Defined Messages Shall Not be used for direct power negotiation. They May however be used to alter Local
Policy, affecting what is offered or consumed via the normal PD Messages. For example a Vendor_Defined Message
could be used to enable the Source to offer additional power via a Source_Capabilities Message.
The Message format Shall be as shown in Figure 6-14.

Figure 6-14 Vendor Defined Message

Header
VDM Header 0-6 VDOs
No. of Data Objects = 1-7

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 129
The VDM Header Shall be the first 4-byte object in a Vendor Defined Message. The VDM Header provides command
space to allow vendors to customize Messages for their own purposes. Additionally vendors May make use of the
Commands in a Structured VDM.
The fields in the VDM Header for an Unstructured VDM, when the VDM Type Bit is set to zero, Shall be as defined in
Table 6-24. The fields in the VDM Header for a Structured VDM, when the VDM Type Bit is set to one Shall be as
defined in Table 6-25.
Both Unstructured and Structured VDMs Shall only be sent and received after an Explicit Contract has been
established. The only exception to this is the Discover Identity Command which May be sent by Source when no
Contract or an Implicit Contract (in place after a Power Role Swap or Fast Role Swap) is in place in order to discover
Cable capabilities (see Section 8.3.3.22.3). A VDM Message sequence Shall Not interrupt any other PD Message
Sequence. A VDM Message sequence Shall be interruptible by any other PD Message Sequence.

6.4.4.1 Unstructured VDM

The Unstructured VDM does not define the contents of bits B14…0 in the VDM Header. Their definition and use are
the sole responsibility of the vendor indicated by the VID. The Port Partners and Cable Plugs Shall exit any states
entered using an Unstructured VDM when a Hard Reset appears on PD.
The following rules apply to the use of Unstructured VDM Messages:
 Unstructured VDMs Shall only be used when an Explicit Contract is in place.
 Prior to establishing an Explicit Contract Unstructured VDMs Shall Not be sent and Shall be Ignored if received.
 Only the DFP Shall be an Initiator of Unstructured VDMs.
 Only the UFP or a Cable Plug Shall be a Responder to Unstructured VDM.
 Unstructured VDMs Shall Not be initiated or responded to under any other circumstances.
 A “command” sequence Shall be interruptible e.g. due to the need for a power related AMS.
 Unstructured VDMs Shall only be used during Modal Operation in the context of an Active Mode.
 Unstructured VDMs May be used with SOP* Packets.
 When a DFP or UFP does not support Unstructured VDMs or does not recognize the VID it Shall return a
Not_Supported Message.
Table 6-24 illustrates the VDM Header bits.

Table 6-24 Unstructured VDM Header

Bit(s) Parameter Description

B31…16 Vendor ID (VID) Unique 16-bit unsigned integer. Assigned by the USB-IF to the
Vendor.
B15 VDM Type 0 = Unstructured VDM
B14…0 Available for Vendor Use Content of this field is defined by the vendor.

6.4.4.1.1 USB Vendor ID

The Vendor ID field Shall contain the 16-bit Vendor ID value assigned to the vendor by the USB-IF (VID). No other
value Shall be present in this field.

6.4.4.1.2 VDM Type

The VDM Type field Shall be set to zero indicating that this is an Unstructured VDM.

6.4.4.2 Structured VDM

Setting the VDM Type field to 1 (Structured VDM) defines the use of bits B14…0 in the Structured VDM Header. The
fields in the Structured VDM Header are defined in Table 6-25.
The following rules apply to the use of Structured VDM Messages:

Page 130 USB Power Delivery Specification Revision 3.0, Version 1.1
 Structured VDMs Shall only be used when an Explicit Contract is in place with the following exception:
o Prior to establishing an Explicit Contract a Source May issue Discover Identity Messages, to a Cable Plug
using SOP’ Packets, as an Initiator (see Section 8.3.3.22.3).
 Either Port May be an Initiator of Structured VDMs except for the Enter Mode and Exit Mode Commands which
Shall only be initiated by the DFP.
 A Cable Plug Shall only be a Responder to Structured VDMs.
 Enter Mode and Exit Mode Commands Shall only be responded to by a UFP or Cable Plug.
 Structured VDMs Shall Not be initiated or responded to under any other circumstances.
 When a DFP or UFP does not support Structured VDMs any Structured VDMs received Shall return a
Not_Supported Message.
 When a Cable Plug does not support Structured VDMs any Structured VDMs received Shall be Ignored.
 A DFP, UFP or Cable Plug which supports Structured VDMs and receiving a Structured VDM for a SVID that it does
not recognize Shall reply with a NAK Command.
 A Structured VDM Command sequence Shall be interruptible e.g. due to the need for a power related AMS.

Table 6-25 Structured VDM Header

Bit(s) Field Description

B31…16 Standard or Vendor ID Unique 16 bit unsigned integer, assigned by the USB-IF
(SVID)
B15 VDM Type 1 = Structured VDM
B14…13 Structured VDM Version Version Number of the Structured VDM (not this specification Version):
 Version 1.0 = 00b (Shall Not be used)
 Version 2.0 = 01b
 Values 2-3 are Reserved and Shall Not be used
B12…11 Reserved For Commands 0…15 Shall be set to 0 and Shall be Ignored
SVID Specific Commands (16…31) defined by the SVID.
B10…8 Object Position For the Enter Mode, Exit Mode and Attention Commands
(Requests/Responses):
 000b = Reserved and Shall Not be used.
 001b…110b = Index into the list of VDOs to identify the desired Mode VDO
 111b = Exit all Active Modes (equivalent of a power on reset). Shall only be
used with the Exit Mode Command.
Commands 0…3, 7…15:
 000b
 001b…111b = Reserved and Shall Not be used.
SVID Specific Commands (16…31) defined by the SVID.
B7…6 Command Type 00b = REQ (Request from Initiator Port)
01b = ACK (Acknowledge Response from Responder Port)
10b = NAK (Negative Acknowledge Response from Responder Port)
11b = BUSY (Busy Response from Responder Port)
B5 Reserved Shall be set to 0 and Shall be Ignored
B4…0 Command1 0 = Reserved, Shall Not be used
1 = Discover Identity
2 = Discover SVIDs
3 = Discover Modes
4 = Enter Mode
5 = Exit Mode
6 = Attention
7-15 = Reserved, Shall Not be used
16…31 = SVID Specific Commands

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 131
Bit(s) Field Description
Note 1: In the case where a SID is used the modes are defined by a standard. When a VID is used the modes are defined by the
Vendor.

Table 6-26 shows the Commands, which SVID to use with each Command and the SOP* values which Shall be used.

Table 6-26 Structured VDM Commands

Command VDM Header SVID Field SOP* used

Discover Identity Shall only use the PD SID. Shall only use SOP/SOP’.

Discover SVIDs Shall only use the PD SID. Shall only use SOP/SOP’.

Discover Modes Valid with any SVID. Shall only use SOP/SOP’.

Enter Mode Valid with any SVID. Valid with SOP*.

Exit Mode Valid with any SVID. Valid with SOP*.

Attention Valid with any SVID. Valid with SOP.

SVID Specific Valid with any SVID. Valid with SOP* (defined by SVID).
Commands

6.4.4.2.1 SVID
The SVID field Shall contain either a 16-bit USB Standard ID value (SID) or the 16-bit assigned to the vendor by the
USB-IF (VID). No other value Shall be present in this field.
Table 6-27 lists specific SVID values referenced by this specification.

Table 6-27 SVID Values

Parameter Value Description

PD SID 0xFF00 Standard ID allocated to this specification.

6.4.4.2.2 VDM Type

The VDM Type field Shall be set to one indicating that this is a Structured VDM.

6.4.4.2.3 Structured VDM Version

The Structured VDM Version field indicates the level of functionality supported in the Structured VDM part of the
specification. This is not the same version as the version of this specification. This field Shall be set to 01b to indicate
Version 2.0.
To ensure interoperability with existing USBPD Products, USBPD Products Shall support every Structured VDM
Version number starting from Version 1.0.
On receipt of a VDM Header with a higher Version number than that supported, a Port Shall respond using the highest
Version number it supports.
The Structured VDM Version field of the Discover Identity Command sent and received during VDM discovery Shall
be used to determine the lowest common Structured VDM Version supported by the Port Partners or Cable Plug and
Shall continue to operate using this Specification Revision until they are Detached. After discovering the Structure
VDM Version, the Structured VDM Version field Shall match the agreed common Structured VDM Version.

6.4.4.2.4 Object Position

The Object Position field Shall be used by the Enter Mode and Exit Mode Commands. The Discover Modes Command
returns a list of zero to six VDOs, each of which describes a Mode. The value in Object Position field is an index into
that list that indicates which VDO (e.g. Mode) in the list the Enter Mode and Exit Mode Command refers to. The Object
Position Shall start with one for the first Mode in the list. If the SVID is a VID, the content of the VDO for the Mode

Page 132 USB Power Delivery Specification Revision 3.0, Version 1.1
Shall be defined by the vendor. If the SVID is a SID, the content Shall be defined by the Standard. The VDO’s content
May be as simple as a numeric value or as complex as bit mapped description of capabilities of the Mode. In all cases,
the Responder is responsible for deciphering the contents to know whether or not it supports the Mode at the Object
Position.
This field Shall be set to zero in the Request or Response (REQ, ACK, NAK or BUSY) when not required by the
specification of the individual Command.

6.4.4.2.5 Command Type

6.4.4.2.5.1 Commands other than Attention

This Command Type field Shall be used to indicate the type of Command request/response being sent.
An Initiator Shall set the field to REQ to indicate that this is a Command request from an Initiator.
If Structured VDMs are supported, then the responses are as follows:
 “Responder ACK” is the normal return and Shall be sent to indicate that the Command request was received and
handled normally.
 “Responder NAK” Shall be returned when the Command request:
 Has an Invalid parameter (e.g. Invalid SVID or Mode).
 Cannot not be acted upon because the configuration is not correct (e.g. a Mode which has a dependency on
another Mode or a request to exit a Mode which is not Active).
 Is Unrecognized.
 The handling of “Responder NAK” is left up to the Initiator.
 “Responder BUSY” Shall be sent in the response to a VDM when the Responder is unable to respond to the
Command request immediately, but the Command request May be retried. The Initiator Shall wait tVDMBusy
after a “Responder BUSY” response is received before retrying the Command request.

6.4.4.2.5.2 Attention Command

This Command Type field Shall be used to indicate the type of Command request being sent. An Initiator Shall set the
field to REQ to indicate that this is a Command request from an Initiator. If Structured VDMs are supported, then no
response Shall be made to an Attention Command.

6.4.4.2.6 Command

6.4.4.2.6.1 Commands other than Attention

This field contains the value for the VDM Command being sent. The Commands explicitly listed in this field are used
to identify devices and manage their operational Modes. There is a further range of Command values left for the
vendor to use to manage additional extensions.
A Structured VDM Command consists of a Command request and a Command response (ACK, NAK or BUSY). A
Structured VDM Command is deemed to be completed (and if applicable, the transition to the requested functionality
is made) when the GoodCRC Message has been successfully received by the Responder in reply to its Command
response.
If Structured VDMs are supported, but the Structured VDM Command request is not recognized it Shall be NAKed (see
Table 6-28).

6.4.4.2.6.2 Attention Command

This field contains the value for the VDM Command being sent (Attention). The Attention Command May be used by
the Initiator to notify the Responder that it requires service.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 133
A Structured VDM Attention Command consists of a Command request but no Command response. A Structured VDM
Attention Command is deemed to be completed when the GoodCRC Message has been successfully received by the
Initiator in reply to its Attention Command request.
If Structured VDMs are supported, but the Structured VDM Attention Command request is not recognized it Shall be
Ignored (see Table 6-28).

6.4.4.3 Use of Commands

The VDM Header for a Structured VDM Message defines Commands used to retrieve a list of SVIDs the device
supports, to discover the Modes associated with each SVID, and to enter/exit the Modes. The Commands include:
 Discover Identity.
 Discover SVIDs.
 Discover Modes.
 Enter Mode.
 Exit Mode.
 Attention.
Additional Command space is also reserved for Standard and Vendor use and for future extensions.
The Command sequences use the terms Initiator and Responder to identify messaging roles the ports are taking on
relative to each other. This role is independent of the Port’s power capability (Provider, Consumer etc.) or its present
power role (Source or Sink). The Initiator is the Port sending the initial Command request and the Responder is the
Port replying with the Command response. See Section 6.4.4.3.6.
All Ports that support Modes Shall support the Discover Identity, Discover SVIDs, the Discover Modes, the Enter
Mode and Exit Mode Commands.
Table 6-28 details the responses a Responder May issue to each Command request. Responses not listed for a given
Command Shall Not be sent by a Responder. A NAK response Should be taken as an indication not to retry that
particular Command.

Table 6-28 Commands and Responses

Command Allowed Response Reference

Discover Identity ACK, NAK, BUSY Section 6.4.4.3.1
Discover SVIDs ACK, NAK, BUSY Section 6.4.4.3.2
Discover Modes ACK, NAK, BUSY Section 6.4.4.3.3
Enter Mode ACK, NAK Section 6.4.4.3.4
Exit Mode ACK, NAK Section 6.4.4.3.5
Attention None Section 6.4.4.3.6

Examples of Command usage can be found in Appendix G.

6.4.4.3.1 Discover Identity

The Discover Identity Command is provided to enable an Initiator to identify its Port Partner and for an Initiator
(VCONN Source) to identify the Responder (Cable Plug). The Discover Identity Command is also used to determine
whether a Cable Plug is PD-Capable by looking for a GoodCRC Message Response.
The Discover Identity Command Shall be used to determine whether a given Cable Plug is PD Capable (see Section
8.3.3.18.1 and Section 8.3.3.22.3). In this case a Discover Identity Command request sent to SOP' Shall Not cause a
Soft Reset if a GoodCRC Message response is not returned since this can indicate a non-PD Capable cable. Note that a
Cable Plug will not be ready for PD Communication until tVCONNStable after VCONN has been applied (see [USB Type-C
1.2]). During Cable Plug discovery, when there is an Explicit Contract, Discover Identity Commands are sent at a rate
defined by the DiscoverIdentityTimer (see Section 6.6.14) up to a maximum of nDiscoverIdentityCount times (see
Section 6.7.5).

Page 134 USB Power Delivery Specification Revision 3.0, Version 1.1
A PD-Capable Cable Plug Shall return a Discover Identity Command ACK in response to a Discover Identity
Command request sent to SOP’.
A PD-Capable UFP that supports Modal Operation Shall return a Discover Identity Command ACK in response to a
Discover Identity Command request sent to SOP.
The SVID in the Discover Identity Command request Shall be set to the PD SID (see Table 6-27).
The Number of Data Objects field in the Message Header in the Discover Identity Command request Shall be set to 1
since the Discover Identity Command request Shall Not contain any VDOs.
The Discover Identity Command ACK sent back by the Responder Shall contain an ID Header VDO, a Cert Stat VDO, a
Product VDO and the Product Type VDOs defined by the Product Type as shown in Figure 6-15. This specification
defines the following Product Type VDOs:
 Cable VDO (see Section 6.4.4.3.1.4).
 Alternate Mode Adapter VDO (see Section 6.4.4.3.1.5).
No VDOs other than those defined in this specification Shall be sent as part of the Discover Identity Command
response. Where there is no Product Type VDO defined for a specific Product Type, no VDOs Shall be sent as part of
the Discover Identity Command response. Any additional VDOs received by the initiator Shall be Ignored.

Figure 6-15 Discover Identity Command response

Header
VDM Header ID Header VDO Cert Stat VDO Product VDO 0..32 Product Type VDO(s)
No. of Data Objects = 4-71

1 Only Data objects defined in this specification can be sent as part of the Discover Identity Command.
2 The following sections define the number and content of the VDOs for each Product Type.
The Number of Data Objects field in the Message Header in the Discover Identity Command NAK and BUSY
responses Shall be set to 1 since they Shall Not contain any VDOs.

6.4.4.3.1.1 ID Header VDO

The ID Header VDO contains information corresponding to the Power Delivery Product. The fields in the ID Header
VDO Shall be as defined in Table 6-29.

Table 6-29 ID Header VDO

Bit(s) Description Reference

B31 USB Communications Capable as USB Host: Section 6.4.4.3.1.1.1
 Shall be set to one if the product is capable of enumerating USB Devices.
 Shall be set to zero otherwise
B30 USB Communications Capable as a USB Device: Section 6.4.4.3.1.1.2
 Shall be set to one if the product is capable of being enumerated as a USB
Device.
 Shall be set to zero otherwise
B29…27 Product Type (UFP): Section 6.4.4.3.1.1.3
 000b – Undefined
 001b – PDUSB Hub
 010b – PDUSB Peripheral
 011b…100b – Reserved, Shall Not be used.
 101b – Alternate Mode Adapter (AMA)
 110b…111b – Reserved, Shall Not be used.

Product Type (Cable Plug):

 000b – Undefined
 001b…010b – Reserved, Shall Not be used.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 135
Bit(s) Description Reference
 011b – Passive Cable
 100b – Active Cable
 101b…111b – Reserved, Shall Not be used.
B26 Modal Operation Supported: Section 6.4.4.3.1.1.4
 Shall be set to one if the product supports Modal Operation.
 Shall be set to zero otherwise
B25…23 Product Type (DFP):
 000b – Undefined
 001b – PDUSB Hub
 010b – PDUSB Host
 011b – Power Brick
 100b - Alternate Mode Controller (AMC)
 101b…111b – Reserved, Shall Not be used.
B22…16 Reserved. Shall be set to zero.
B15…0 16-bit unsigned integer. USB Vendor ID [USB 2.0]/[USB 3.1]

6.4.4.3.1.1.1 Data Capable as a USB Host

The Data Capable as a USB Host field is used to indicate whether or not the Port has a USB Host Capability.
6.4.4.3.1.1.2 Data Capable as a USB Device
The Data Capable as a USB Device field is used to indicate whether or not the Port has a USB Device Capability.
6.4.4.3.1.1.3 Product Type (UFP)
The Product Type (UFP) field indicates the type of Product when in UFP Data Role, whether a VDO will be returned
and if so the type of VDO to be returned. For DRD Products this field Shall indicate the capability regardless of the
present Data Role. Table 6-30 defines the Product Type VDOs which Shall be returned.

Table 6-30 Product Types (UFP)

Product Type Description Product Type VDO Reference

Undefined Shall be used where no other Product Type None
value is appropriate.
PDUSB Hub Shall be used when the Product is a PDUSB None
Hub.
PDUSB Peripheral Shall be used when the Product is a PDUSB None
Device other than a PDUSB Hub.
Alternate Mode Shall be used when the Product is a PDUSB AMA VDO
Adapter Device that supports one or more Alternate Section 6.4.4.3.1.5
Modes.

6.4.4.3.1.1.4 Product Type (Cable Plug)

The Product Type (Cable Plug) field indicates the type of Product when the Product is a Cable Plug, whether a VDO
will be returned and if so the type of VDO to be returned. Table 6-31 defines the Product Type VDOs which Shall be
returned.

Page 136 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 6-31 Product Types (Cable Plug)

Product Type Description Product Type VDO Reference

Undefined Shall be used where no other Product Type None
value is appropriate.
Active Cable Shall be used when the Product is a cable that Active Cable VDO
Section 6.4.4.3.1.4.2
incorporates signal conditioning circuits.
Passive Cable Shall be used when the Product is a cable that Passive Cable VDO
does not incorporate signal conditioning Section 6.4.4.3.1.4.1
circuits.

6.4.4.3.1.1.5 Modal Operation Supported

The Modal Operation Supported bit is used to indicate whether or the not the Product supports Modes.
6.4.4.3.1.1.6 Product Type (DFP)
The Product Type (DFP) field indicates the type of Product when in DFP Data Role, whether a VDO will be returned
and if so the type of VDO to be returned. For DRD Products this field Shall indicate the capability regardless of the
present Data Role. Table 6-32 defines the Product Type VDOs which Shall be returned.

Table 6-32 Product Types (DFP)

Product Type Description Product Type VDO Reference

Undefined Shall be used where no other Product Type None
value is appropriate.
PDUSB Hub Shall be used when the Product is a PDUSB None
Hub.
PDUSB Host Shall be used when the Product is a PDUSB None
Host.
Power Brick Shall be used when the Product is a Power None
Brick/Wall Wart.
Alternate Mode Shall be used when the Product is a PDUSB AMA VDO
Controller Host or DFP that supports one or more Section 6.4.4.3.1.5
Alternate Modes.

6.4.4.3.1.1.7 Vendor ID
Manufacturers Shall set the Vendor ID field to the value of the Vendor ID assigned to them by USB-IF. For USB
Devices or Hubs which support USB communications the Vendor ID field Shall be identical to the Vendor ID field
defined in the product’s USB Device Descriptor (see [USB 2.0] and [USB 3.1]).

6.4.4.3.1.2 Cert Stat VDO

The Cert Stat VDO Shall contain the XID assigned by USB-IF to the product before certification in binary format. The
fields in the Cert Stat VDO Shall be as defined in Table 6-33.

Table 6-33 Cert Stat VDO

Bit(s) Description Reference

B31…0 32-bit unsigned integer, XID Assigned by USB-IF

6.4.4.3.1.3 Product VDO

The Product VDO contains identity information relating to the product. The fields in the Product VDO Shall be as
defined in Table 6-34.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 137
 Table 6-34 Product VDO

Bit(s) Description Reference

B31…16 16-bit unsigned integer. USB Product ID [USB 2.0]/[USB 3.1]
B15…0 16-bit unsigned integer. bcdDevice [USB 2.0]/[USB 3.1]

Manufacturers Should set the USB Product ID field to a unique value identifying the product and Should set the
bcdDevice field to a version number relevant to the release version of the product.

6.4.4.3.1.4 Cable VDO

The Cable VDO defined in this section Shall be sent when the Product Type is given as Passive or Active Cable. Table
6-35 and Table 6-36 define the Cable VDOs which Shall be sent in each case.
6.4.4.3.1.4.1 Passive Cable VDO
A Passive Cable has a USB Plug on each end at least one of which is a Cable Plug supporting SOP’ Communication. A
Passive Cable Shall Not incorporate data bus signal conditioning circuits and hence has no concept of Super Speed
Directionality. A Passive Cable Shall include a VBUS wire and Shall only respond to SOP’ Communication. Passive
Cables Shall support the Structured VDM Discover Identity Command and Shall return the Passive Cable VDO in a
Discover Identity Command ACK as shown in Table 6-35.

Table 6-35 Passive Cable VDO

Bit(s) Field Description

B31…28 HW Version 0000b…1111b assigned by the VID owner
B27…24 Firmware Version 0000b…1111b assigned by the VID owner
B23…21 VDO Version Version Number of the VDO (not this specification Version):
 Version 1.0 = 000b
Values 001b…111b are Reserved and Shall Not be used
B20 Reserved Shall be set to zero.
B19…18 USB Type-C plug to USB Type- 00b = Reserved, Shall Not be used
C/Captive 01b = Reserved, Shall Not be used
10b = USB Type-C
11b = Captive
B17 Reserved Shall be set to zero.
B16…13 Cable Latency 0000b – Reserved, Shall Not be used
0001b – <10ns (~1m)
0010b – 10ns to 20ns (~2m)
0011b – 20ns to 30ns (~3m)
0100b – 30ns to 40ns (~4m)
0101b – 40ns to 50ns (~5m)
0110b – 50ns to 60ns (~6m)
0111b – 60ns to 70ns (~7m)
1000b – > 70ns (>~7m)
1001b ….1111b Reserved, Shall Not be used
Includes latency of electronics in Active Cable
B12…11 Cable Termination Type 00b = VCONN not required. Cable Plugs that only support Discover Identity
Commands Shall set these bits to 00b.
01b = VCONN required
10b…11b = Reserved, Shall Not be used

Page 138 USB Power Delivery Specification Revision 3.0, Version 1.1
Bit(s) Field Description
B10…9 Maximum VBUS Voltage Maximum Cable VBUS Voltage:

00b – 20V
01b – 30V
10b – 40V
11b – 50V
B8…7 Reserved Shall be set to zero.
B6…5 VBUS Current Handling Capability 00b = Reserved, Shall Not be used.
01b = 3A
10b = 5A
11b = Reserved, Shall Not be used.
B4…3 Reserved Shall be set to zero.
B2…0 USB SuperSpeed Signaling 000b = USB 2.0 only, no SuperSpeed support
Support 001b = [USB 3.1] Gen1
010b = [USB 3.1] Gen1 and Gen2
011b…111b = Reserved, Shall Not be used
See [USB Type-C 1.2] for definitions.

The HW Version field (B31…28) contains a HW Version assigned by the VID owner.
The FW Version field (B27…24) contains a FW Version assigned by the VID owner.
The VDO Version field (B23…20) contains a VDO version for this VDM version number. This field indicates the
expected content for this VDO.
The Connector Type field (B19…18) Shall contain a value corresponding to the connector type on the opposite end
from the USB Type-C connector.
The Cable Latency field (B16…13) Shall contain a value corresponding to the signal latency through the cable which
can be used as an approximation for its length.
The Cable Termination Type field (B12…11) Shall contain a value indicating whether the Passive Cable needs VCONN
only initially in order to support the Discover Identity Command, after which it can be removed, or the Passive Cable
needs VCONN to be continuously applied in order to power some feature of the Cable Plug.
The Maximum VBUS Voltage field (B10…9) Shall contain the maximum voltage that Shall be negotiated using a Fixed
Supply over the cable as part of an Explicit Contract where the maximum voltage that Shall be applied to the cable is
vSrcNew max + vSrcValid max. For example when the Maximum VBUS Voltage field is 20V, a Fixed Supply of 20V can
be negotiated as part of an Explicit Contract where the absolute maximum voltage that can be applied to the cable is
21.5V.
The VBUS Current Handling Capability field (B6…5) Shall indicate whether the cable is capable of carrying 3A or 5A.
The USB SuperSpeed Signaling Support field (B2…0) Shall indicate whether the cable supports only [USB 2.0] , or in
addition Supports [USB 3.1] Gen1, or Gen1 and Gen2.
6.4.4.3.1.4.2 Active Cable VDO
An Active Cable has a USB Plug on each end at least one of which is a Cable Plug supporting SOP’ Communication. An
Active Cable Shall incorporate data bus signal conditioning circuits and May have a concept of Super Speed
Directionality on its Super Speed wires. An Active Cable May include a VBUS wire. An Active Cable Shall respond to
SOP’ Communication and May respond to SOP’’ Communication. Active Cables Shall support the Structured VDM
Discover Identity Command and Shall return the Active Cable VDO in a Discover Identity Command ACK as shown in
Table 6-36.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 139
 Table 6-36 Active Cable VDO

Bit(s) Field Description

B31…28 HW Version 0000b…1111b assigned by the VID owner
B27…24 Firmware Version 0000b…1111b assigned by the VID owner
B23…21 VDO Version Version Number of the VDO (not this specification Version):
 Version 1.0 = 000b
Values 001b…111b are Reserved and Shall Not be used
B20 Reserved Shall be set to zero.
B19…18 USB Type-C plug to USB Type- 00b = Reserved, Shall Not be used
C/Captive 01b = Reserved, Shall Not be used
10b = USB Type-C
11b = Captive
B17 Reserved Shall be set to zero.
B16…13 Cable Latency 0000b – Reserved, Shall Not be used
0001b – <10ns (~1m)
0010b – 10ns to 20ns (~2m)
0011b – 20ns to 30ns (~3m)
0100b – 30ns to 40ns (~4m)
0101b – 40ns to 50ns (~5m)
0110b – 50ns to 60ns (~6m)
0111b – 60ns to 70ns (~7m)
1000b –1000ns (~100m)
1001b –2000ns (~200m)
1010b – 3000ns (~300m)
1011b ….1111b Reserved, Shall Not be used
Includes latency of electronics in Active Cable
B12…11 Cable Termination Type 00b…01b = Reserved, Shall Not be used
10b = One end Active, one end passive, VCONN required
11b = Both ends Active, VCONN required

B10…9 Maximum VBUS Voltage Maximum Cable VBUS Voltage:

00b – 20V
01b – 30V
10b – 40V
11b – 50V
B8…7 Reserved Shall be set to zero.
B6…5 VBUS Current Handling When VBUS Through Cable is “No”, Reserved, Shall Not be used.
Capability
When VBUS Though Cable is “Yes”:

00b = Reserved, Shall Not be used.

01b = 3A
10b = 5A
11b = Reserved, Shall Not be used.
B4 VBUS Through Cable 0 = No
1 = Yes
B3 SOP” Controller Present 0 = No SOP” controller present
1 = SOP” controller present

Page 140 USB Power Delivery Specification Revision 3.0, Version 1.1
Bit(s) Field Description
B2…0 USB SuperSpeed Signaling 000b = [USB 2.0] only
Support 001b = [USB 3.1] Gen1
010b = [USB 3.1] Gen1 and Gen2
011b…111b = Reserved, Shall Not be used

The HW Version field (B31…28) contains a HW Version assigned by the VID owner.
The FW Version field (B27…24) contains a FW Version assigned by the VID owner.
The VDO Version field (B23…20) contains a VDO version for this VDM version number. This field indicates the
expected content for this VDO.
The Connector Type field (B19…18) Shall contain a value corresponding to the connector type on the opposite end
from the USB Type-C connector.
The Cable Latency field (B16…13) Shall contain a value corresponding to the signal latency through the cable which
can be used as an approximation for its length.
The Cable Termination Type field (B12…11) Shall contain a value corresponding to whether the Active Cable has one
or two Cable Plugs requiring power from VCONN.
The Maximum VBUS Voltage field (B10…9) Shall contain the maximum voltage that Shall be negotiated using a Fixed
Supply over the cable as part of an Explicit Contract where the maximum voltage that Shall be applied to the cable is
vSrcNew max + vSrcValid max. For example when the Maximum VBUS Voltage field is 20V, a Fixed Supply of 20V can
be negotiated as part of an Explicit Contract where the absolute maximum voltage that can be applied to the cable is
21.5V.
The VBUS Current Handling Capability field (B6…5) Shall indicate whether the cable is capable of carrying 3A or 5A.
The VBUS Current Handling Capability Shall only be Valid when the VBUS Through Cable field indicates an end to end
VBUS wire.
The VBUS Through Cable field (B4) Shall indicate whether the cable contains an end to end VBUS wire.
The SOP’’ Controller Present field (B3) Shall indicate whether one of the Cable Plugs is capable of SOP’’
Communication in addition to the Normative SOP’ Communication.
The USB SuperSpeed Signaling Support field (B2…0) Shall indicate whether the cable supports only [USB 2.0] , or in
addition Supports [USB 3.1] Gen1, or Gen1 and Gen2.

6.4.4.3.1.5 Alternate Mode Adapter VDO

The Alternate Mode Adapter (AMA) VDO defined in this section Shall be sent when the Product Type is given as
Alternate Mode Adapter. Table 6-37 defines the AMA VDO which Shall be sent.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 141
 Table 6-37 AMA VDO

Bit(s) Field Description

B31…28 HW Version 0000b…1111b assigned by the VID owner
B27…24 Firmware Version 0000b…1111b assigned by the VID owner
B23…21 VDO Version Version Number of the VDO (not this specification Version):
 Version 1.0 = 000b
Values 001b…111b are Reserved and Shall Not be used
B20…8 Reserved. Shall be set to zero.
B7…5 VCONN power When the VCONN required field is set to “Yes” VCONN power needed by adapter for
full functionality
000b = 1W
001b = 1.5W
010b = 2W
011b = 3W
100b = 4W
101b = 5W
110b = 6W
111b = Reserved, Shall Not be used

When the VCONN required field is set to “No” Reserved, Shall be set to zero.
B4 VCONN required 0 = No
1 = Yes
B3 VBUS required 0 = No
1 = Yes
B2…0 USB SuperSpeed Signaling 000b = [USB 2.0] only
Support 001b = [USB 3.1] Gen1 and USB 2.0
010b = [USB 3.1] Gen1, Gen2 and USB 2.0
011b = [USB 2.0] billboard only
100b…111b = Reserved, Shall Not be used

The HW Version field (B31…28) contains a HW Version assigned by the VID owner.
The FW Version field (B27…24) contains a FW Version assigned by the VID owner.
The VDO Version field (B23…20) contains a VDO version for this VDM version number. This field indicates the
expected content for this VDO.
When the VCONN required field indicates that VCONN is required the VCONN power field Shall indicate how much power
the AMA needs in order to fully operate.
The VCONN required field Shall indicate whether VCONN is needed for the AMA to operate.
The VBUS required field Shall indicate whether VBUS is needed for the AMA to operate.
The USB SuperSpeed Signaling Support field (B2…0) Shall indicate whether the cable supports only [USB 2.0] , or in
addition Supports [USB 3.1] Gen1, or Gen1 and Gen2 or [USB 2.0] billboard only.

6.4.4.3.2 Discover SVIDs

The Discover SVIDs Command is used by an Initiator to determine the SVIDs for which a Responder has Modes. The
Discover SVIDs Command is used in conjunction with the Discover Modes Command in the Discovery Process to
determine which Modes a device supports. The list of SVIDs is always terminated with one or two 0x0000 SVIDs.
The SVID in the Discover SVIDs Command Shall be set to the PD SID (see Table 6-27) by both the Initiator and the
Responder for this Command.
The Number of Data Objects field in the Message Header in the Discover SVIDs Command request Shall be set to 1
since the Discover SVIDs Command request Shall Not contain any VDOs.

Page 142 USB Power Delivery Specification Revision 3.0, Version 1.1
The Discover SVIDs Command ACK sent back by the Responder Shall contain one or more SVIDs. The SVIDs are
returned 2 per VDO (see Table 6-38). If there are an odd number of supported SVIDs, the Discover SVIDs Command is
returned ending with a SVID value of 0x0000 in the last part of the last VDO. If there are an even number of supported
SVIDs, the Discover SVIDs Command is returned ending with an additional VDO containing two SVIDs with values of
0x0000. A Responder Shall only return SVIDs for which a Discover Modes Command request for that SVID will return
at least one Mode.
A Responder that does not support any SVIDs Shall return a NAK.
The Number of Data Objects field in the Message Header in the Discover SVIDs Command NAK and BUSY responses
Shall be set to 1 since they Shall Not contain any VDOs.
If the Responder supports 12 or more SVIDs then the Discover SVIDs Command Shall be executed multiple times
until a Discover SVIDs VDO is returned ending either with a SVID value of 0x0000 in the last part of the last VDO or
with a VDO containing two SVIDs with values of 0x0000. Each Discover SVID ACK Message, other than the one
containing the terminating 0x0000 SVID, Shall convey 12 SVIDs. The Responder Shall restart the list of SVIDs each
time a Discover Identity Command request is received from the Initiator.
Note: that since a Cable Plug does not retry Messages if the GoodCRC Message from the Initiator becomes corrupted
the Cable Plug will consider the Discover SVIDs Command ACK unsent and will send the same list of SVIDs again.
Figure 6-16 shows an example response to the Discover SVIDs Command request with two VDOs containing three
SVIDs. Figure 6-17 shows an example response with two VDOs containing four SVIDs followed by an empty VDO to
terminate the response. Figure 6-18 shows an example response with six VDOs containing twelve SVIDs followed by
an additional request that returns an empty VDO indicating there are no more SVIDs to return.

Table 6-38 Discover SVIDs Responder VDO

Bit(s) Field Description

B31…16 SVID n 16 bit unsigned integer, assigned by the USB-IF or
0x0000 if this is the last VDO and the Responder supports an even number of SVIDs.
B15…0 SVID n+1 16 bit unsigned integer, assigned by the USB-IF or
0x0000 if this is the last VDO and the Responder supports an odd or even number of SVIDs.

Figure 6-16 Example Discover SVIDs response with 3 SVIDs

VDO 1 VDO 2
Header
VDM Header
No. of Data Objects = 3 SVID 0 SVID 1 SVID 2 0x0000
(B31..16) (B15..0) (B31..16) (B15..0)

Figure 6-17 Example Discover SVIDs response with 4 SVIDs

VDO 1 VDO 2 VDO 3

Header
VDM Header
No. of Data Objects = 4 SVID 0 SVID 1 SVID 2 SVID 3 0x0000 0x0000
(B31..16) (B15..0) (B31..16) (B15..0) (B31..16) (B15..0)

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 143
 Figure 6-18 Example Discover SVIDs response with 12 SVIDs followed by an empty response

VDO 1 VDO 2 VDO 3 VDO 4 VDO 5 VDO 6

Header
VDM Header
No. of Data Objects = 7 SVID 0 SVID 1 SVID 2 SVID 3 SVID 4 SVID 5 SVID 6 SVID 7 SVID 8 SVID 9 SVID 10 SVID 11
(B31..16) (B15..0) (B31..16) (B15..0) (B31..16) (B15..0) (B31..16) (B15..0) (B31..16) (B15..0) (B31..16) (B15..0)

VDO 1
Header
VDM Header
No. of Data Objects = 2 0x0000 0x0000
(B31..16) (B15..0)

6.4.4.3.3 Discover Modes

The Discover Modes Command is used by an Initiator to determine the Modes a Responder supports for a given SVID.
The SVID in the Discover Modes Command Shall be set to the SVID for which Modes are being requested by both the
Initiator and the Responder for this Command.
The Number of Data Objects field in the Message Header in the Discover Modes Command request Shall be set to 1
since the Discover Modes Command request Shall Not contain any VDOs.
The Discover Modes Command ACK sent back by the Responder Shall contain one or more Modes. The Discover
Modes Command ACK Shall contain a Message Header with the Number of Data Objects field set to a value of 1 to 7
(the actual value is the number of Mode objects plus one). If the ID is a VID, the structure and content of the VDO is
left to the Vendor. If the ID is a SID, the structure and content of the VDO is defined by the relevant Standard.
A Responder that does not support any Modes Shall return a NAK.
The Number of Data Objects field in the Message Header in the Discover Modes Command NAK and BUSY responses
Shall be set to 1 since they Shall Not contain any VDOs.
Figure 6-19 shows an example of a Discover Modes Command response from a Responder which supports three
Modes for a given SVID.

Figure 6-19 Example Discover Modes response for a given SVID with 3 Modes

Header
VDM Header Mode 1 Mode 2 Mode 3
No. of Data Objects = 4

6.4.4.3.4 Enter Mode Command

The Enter Mode Command is used by an Initiator (DFP) to command a Responder (UFP or Cable Plug) to enter a
specified Mode of operation. Only a DFP is allowed to initiate the Enter Mode Process which it starts after it has
successfully completed the Discovery Process.
The value in the Object Position field in the VDM Header Shall indicate to which Mode in the Discover Modes
Command the VDO refers (see Figure 6-19). The value 1 always indicates the first Mode as it is the first object
following the VDM Header. The value 2 refers to the next Mode and so forth.
The Number of Data Objects field in the Message Header in the Command request Shall be set to either 1 or 2 since
the Enter Mode Command request Shall Not contain more than 1 VDO. When a VDO is included in an Enter Mode
Command request the contents of the 32 bit VDO is defined by the Mode.
The Number of Data Objects field in the Command response Shall be set to 1 since an Enter Mode Command
response (ACK, NAK, BUSY) Shall Not contain any VDOs.

Page 144 USB Power Delivery Specification Revision 3.0, Version 1.1
Before entering a Mode, by sending the Enter Mode Command request, that requires the reconfiguring of any pins on
entry to that Mode, the Initiator Shall ensure that those pins being reconfigured are placed into the USB Safe State.
Before entering a Mode that requires the reconfiguring of any pins, the Responder Shall ensure that those pins being
reconfigured are placed into either USB operation or the USB Safe State.
A device May support multiple Modes with one or more active at any point in time. Any interactions between them
are the responsibility of the Standard or Vendor. Where there are multiple Active Modes at the same time Modal
Operation Shall start on entry to the first Mode.
On receiving an Enter Mode Command request the Responder Shall respond with either an ACK or a NAK response.
The Responder is not allowed to return a BUSY response. The value in the Object Position field of the Enter Mode
Command response Shall contain the same value as the received Enter Mode Command request.
If the Responder responds to the Enter Mode Command request with an ACK, the Responder Shall enter the Mode
before sending the ACK. The Initiator Shall enter the Mode on reception of the ACK. Receipt of the GoodCRC Message
corresponding to the ACK confirms to the Responder that the Initiator is in an Active Mode and is ready to operate.
If the Responder responds to the Enter Mode Command request with a NAK, the Mode is not entered. If not presently
in Modal Operation the Initiator Shall return to USB operation. If not presently in Modal Operation the Responder
Shall remain in either USB operation or the USB Safe State.
If the Initiator fails to receive a response within tVDMWaitModeEntry it Shall Not enter the Mode but return to USB
operation.
Figure 6-20 shows the sequence of events during the transition between USB operation and entering a Mode. It
illustrates when the Responder’s Mode changes and when the Initiator’s Mode changes. Figure 6-21 shows a
sequence that is Interrupted by a Source_Capabilities Message, that completes a Contract Negotiation, and then the
sequence is Re-run. Figure 6-22 illustrates that when the Responder returns a NAK the transition to a Mode do not
take place and the Responder and Initiator remain in their default USB roles.

Figure 6-20 Successful Enter Mode sequence

DFP (Initiator) UFP (Responder)

USB
USB or USB Safe State
Enter Mod
e

GoodCRC
USB Safe State

ACK
New
Mode
New GoodCRC
Mode

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 145
 Figure 6-21 Enter Mode sequence Interrupted by Source Capabilities and then Re-run

DFP (Initiator) UFP (Responder)

USB
USB or USB Safe State
Enter Mode

USB Safe State

GoodCRC
Source
interrupts
Source_Cap
AMS abilites

USB
GoodCRC

Contract
negotiation
completed
Enter Mode
Enter Mode
Re-tried

GoodCRC
USB Safe State

ACK
New Mode

GoodCRC
New Mode

Figure 6-22 Unsuccessful Enter Mode sequence due to NAK

DFP (Initiator) UFP (Responder)

USB
USB or USB Safe State
Enter Mod
e

GoodCRC
USB Safe State

NAK

GoodCRC
USB

Page 146 USB Power Delivery Specification Revision 3.0, Version 1.1
Once the Mode is entered, the device Shall remain in that Active Mode until the Exit Mode Command is successful (see
Section 6.4.4.3.5).
The following events Shall also cause the Port Partners and Cable Plug(s) to exit all Active Modes:
 A PD Hard Reset.
 The Port Partners or Cable Plug(s) are Detached.
 A Cable Reset (only exits the Cable Plug’s Active Modes).
The Initiator Shall return to USB Operation within tVDMExitMode of a disconnect or of Hard Reset Signaling being
detected.
The Responder Shall return to either USB operation or USB Safe State within tVDMExitMode of a disconnect or of
Hard Reset Signaling being detected.
A DR_Swap Message Shall Not be sent during Modal Operation between the Port Partners (see Section 6.3.9).

6.4.4.3.5 Exit Mode Command

The Exit Mode Command is used by an Initiator (DFP) to command a Responder (UFP or Cable Plug) to exit its Active
Mode and return to normal USB operation. Only the DFP is allowed to initiate the Exit Mode Process.
The value in the Object Position field Shall indicate to which Mode in the Discover Modes Command the VDO refers
(see Figure 6-19) and Shall have been used previously in an Enter Mode Command request for an Active Mode. The
value 1 always indicates the first Mode as it is the first object following the VDM Header. The value 2 refers to the
next Mode and so forth. A value of 111b in the Object Position field Shall indicate that all Active Modes Shall be
exited.
The Number of Data Objects field in both the Command request and Command response (ACK, NAK, BUSY) Shall be
set to 1 since an Exit Mode Command Shall Not contain any VDOs.
The Responder Shall exit its Active Mode before sending the response Message. The Initiator Shall exit its Active
Mode before sending GoodCRC Message in response to the ACK. Receipt of the GoodCRC Message confirms to the
Responder that the Initiator has exited the Mode. The Responder Shall Not return a BUSY acknowledgement and
Shall only return a NAK acknowledgement to a request not containing an Active Mode (i.e. Invalid object position).
An Initiator which fails to receive an ACK within tVDMWaitModeExit or receives a NAK or BUSY response Shall exit
its Active Mode.
Figure 6-23 shows the sequence of events during the transition between exiting an Active Mode and USB operation. It
illustrates when the Responder’s Mode changes and when the Initiator’s Mode changes.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 147
 Figure 6-23 Exit Mode sequence

DFP (Initiator) UFP (Responder)

Mode

Mode
Exit Mode

GoodCRC
USB Safe State

ACK
USB or USB Safe
State
GoodCRC
USB

6.4.4.3.6 Attention
The Attention Command May be used by the Initiator to notify the Responder that it requires service.
The value in the Object Position field Shall indicate to which Mode in the Discover Modes Command the VDO refers
(see Figure 6-19) and Shall have been used previously in an Enter Mode Command request for an Active Mode. The
value 1 always indicates the first Mode as it is the first object following the VDM Header. The value 2 refers to the
next Mode and so forth. A value of 000b or 111b in the Object Position field Shall Not be used by the Attention
Command.
The Number of Data Objects field in the Message Header Shall be set to 1 or 2 since the Attention Command Shall
Not contain more than 1 VDO. When a VDO is included in an Attention Command the contents of the 32 bit VDO is
defined by the Mode.

Figure 6-24 Attention Command request/response sequence

Responder Initiator
)
(Attention
Command

GoodCRC

Command Complete

6.4.4.4 Command Processes

The Message flow of Commands during a Process is a query followed by a response. Every Command request sent has
to be responded to with a GoodCRC Message. The GoodCRC Message only indicates the Command request was
received correctly; it does not mean that the Responder understood or even supports a particular SVID. Figure 6-25
shows the request/response sequence including the GoodCRC Messages.

Page 148 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 6-25 Command request/response sequence

Initiator Responder
Command
(request)

GoodCRC

(response)
Command

GoodCRC

Command Complete

In order for the Initiator to know that the Command request was actually consumed, it needs an acknowledgement
from the Responder. There are three responses that indicate the Responder received and processed the Command
request:
 ACK.
 NAK.
 BUSY.
The Responder Shall complete:
 Enter Mode requests within tVDMEnterMode.
 Exit Mode requests within tVDMExitMode.
 Other requests within tVDMReceiverResponse.
An Initiator not receiving a response within the following times Shall timeout and return to either the PE_SRC_Ready
or PE_SNK_Ready state (as appropriate):
 Enter Mode requests within tVDMWaitModeEntry.
 Exit Mode requests within tVDMWaitModeExit.
 Other requests within tVDMSenderResponse.
The Responder Shall respond with:
 ACK if it recognizes the SVID and can process it at this time
 NAK:
o if it recognizes the SVID but cannot process the Command request
o or if it does not recognize the SVID
o or if it does not support the Command
o or if a VDO has been supplied which is Invalid.
 BUSY if it recognizes the SVID and the Command but cannot process the Command request at this time.
The ACK, NAK or BUSY response Shall contain the same SVID as the Command request.

6.4.4.4.1 Discovery Process

The Initiator (usually the DFP) always begins the Discovery Process. The Discovery Process has two phases. In the
first phase, the Discover SVIDs Command request is sent by the Initiator to get the list of SVIDs the Responder
supports. In the second phase, the Initiator sends a Discover Modes Command request for each SVID supported by
both the Initiator and Responder.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 149
 6.4.4.4.2 Enter Vendor Mode / Exit Vendor Mode Processes
The result of the Discovery Process is that both the Initiator and Responder identify the Modes they mutually support.
The Initiator (DFP), upon finding a suitable Mode, uses the Enter Mode Command to enable the Mode.
The Responder (UFP or Cable Plug) and Initiator continue using the Active Mode until the Active Mode is exited. In a
managed termination, using the Exit Mode Command, the Active Mode Shall be exited in a controlled manner as
described in Section 6.4.4.3.5. In an unmanaged termination, triggered by a Power Delivery Hard Reset (i.e. Hard
Reset Signaling sent by either Port Partner) or by cable Detach (device unplugged), the Active Mode Shall still be
exited but there Shall Not be a transition through the USB Safe State. In both the managed and unmanaged
terminations the Initiator and Responder return to USB operation as defined in [USB Type-C 1.2] following an exit
from a Mode.
The overall Message flow is illustrated in Figure 6-26.

Page 150 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 6-26 Enter/Exit Mode Process
Initiator (DFP) Responder (UFP or Cable Plug)
Establish PD Contract

Discover SVID
s

USB
s
List of SVID
For every DFP supported SVID
Discover Mod
es (SVID )
USB or USB Safe
State
r SV ID
Modes fo

Stay in USB mode N Modes Supported?

USB or USB Safe Y

State

Enter Mode
USB Safe State
ode)
ched to M
nder swit
ACK (Respo
Alternate Mode

Initiator and Responder operate using Mode

N
Alternate Mode

Exit Mode or PD Hard Reset or cable

unplugged or power removed?

USB
USB
Y

Return to USB mode

6.4.4.5 VDM Message Timing and Normal PD Messages

Any Command Process or other VDM sequence May be interrupted by any other USB PD Message. The Vendor or
Standards defined state operation Shall comprehend this and continue to operate as expected when processing any
other USB PD Messages.
The timing and interspersing of VDMs between regular PD Messages Shall be done without perturbing the PD
Message sequences. This requirement Shall apply to both Unstructured VDMs and Structured VDMs.
The use of Structured VDMs by an Initiator Shall Not interfere with the normal PD Message timing requirements nor
Shall either the Initiator or Responder interrupt a PD Message sequence (e.g. Power Negotiation, Power Role Swap,
Data Role Swap etc.). The use of Unstructured VDMs Shall Not interfere with normal PD Message timing.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 151
VDM sequences Shall be interruptible after the return of a GoodCRC Message has been completed. In the case where
there is an error in transmission of the Vendor_Defined Message, as for any other PD Message, the Vendor_Defined
Message will not be retried, but instead the incoming Message will be processed by the Policy Engine. This means that
the Vendor_Defined Message sequence will need to be Re-run after the USB PD Message sequence has completed.

6.4.5 Battery_Status Message

The Battery_Status Message Shall be sent in response to a Get_Battery_Status Message. The Battery_Status Message
contains one Battery Status Data Object (BSDO) for one of the Batteries it supports as reported by Battery field in the
Source_Capabilities_Extended Message. The returned BSDO Shall correspond to the Battery requested in the
Battery Status Ref field contained in the Get_Battery_Status Message.
The Battery_Status Message returns a BSDO whose format Shall be as shown in Figure 6-27 and Table 6-39. The
Number of Data Objects field in the Battery_Status Message Shall be set to 1.

Figure 6-27 Battery_Status Message

Header
BSDO
No. of Data Objects = 1

Table 6-39 Battery Status Data Object (BSDO)

Bit(s) Field Size Value Description

B31…16 Battery Present Capacity 2 1/10 WH Battery’s State of Charge (SoC)
Note:
0xFFFF = Battery’s SOC unknown

B15…8 Battery Info 1 Bit Field

Bit Description
0 Invalid Battery reference
1 Battery is present when set
3…2 When Battery is present Shall contain the
Battery charging status:
00b: Battery is Charging
01b: Battery is Discharging
10b: Battery is Idle
11b: Reserved, Shall Not be used

When Battery is not present:

11b…00b: Reserved, Shall Not be used
7…4 Reserved and Shall be set to zero
B7…0 Reserved 2 Numeric Shall be set to zero

6.4.5.1 Battery Present Capacity

The Battery Present Capacity field Shall return either the Battery’s State of Charge (SoC) in tenths of WH or indicate
that the Battery’s present State of Charge (SOC) is unknown.

6.4.5.2 Battery Info

The Battery Info field Shall be used to report additional information about the Battery’s present status. The Battery
Info field’s bits Shall reflect the present conditions under which the Battery is operating in the systems.

Page 152 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.4.5.2.1 Invalid Battery Reference
The Invalid Battery Reference bit Shall be set when the Get_Battery_Status Message contains a reference to a Battery
that does not exist.

6.4.5.2.2 Battery is Present

The Battery is Present bit Shall be set whenever the Battery is present. It Shall always be set for Batteries that are not
Hot Swappable Batteries. For Hot Swappable Batteries, Battery is Present bit Shall indicate whether the Battery is
Attached or Detached.

6.4.5.2.3 Battery Charging Status

The Battery charging status bits indicate whether the Battery is being charged, discharged or is idle (neither charging
nor discharging). These bits Shall be set when the Battery is present bit is set. Otherwise when the Battery is present
bit is zero the Battery charging status bits Shall also be zero.

6.4.6 Alert Message

The Alert Message is provided to allow Port Partners to inform each other when there is a status change event. Some
of the events are critical such as OCP, OVP and OTP, while others are informative such as change in a Battery’s status
from charging to neither charging nor discharging.
The Alert Message Shall only be sent when the Source or Sink detects a status change.
The Alert Message Shall contain exactly one Alert Data Object (ADO) and the format Shall be as shown in Figure 6-28
and Table 6-40.

Figure 6-28 Alert Message

Header
ADO
No. of Data Objects = 1

Table 6-40 Alert Data Object

Bit(s) Field Value Description

B31…24 Type of Alert Bit Field
Bit Description
0 Reserved and Shall be set to zero
1 Battery Status Change
Event(Attach/Detach/charging/discharging/idle)
2 OCP event when set (Source only, for Sink
Reserved and Shall be set to zero)
3 OTP event when set
4 Operating Condition Change when set
5 Source Input Change Event when set
6 OVP event when set (Sink only, for Source
Reserved and Shall be set to zero)
7 Reserved and Shall be set to zero
B23…20 Fixed Batteries Bit Field When Battery Status Change bit set indicates which Fixed Batteries have had a status
change. B20 corresponds to Battery 0 and B23 corresponds to Battery 3.
B19…16 Hot Swappable Bit Field When Battery Status Change bit set indicates which Hot Swappable Batteries have
Batteries had a status change. B16 corresponds to Battery 4 and B19 corresponds to Battery 7.
B15…0 Reserved n/a Shall be set to zero

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 153
 6.4.6.1 Type of Alert
The Type of Alert field Shall be used to report Source or Sink status changes. Only one Alert Message Shall be
generated for each Event or Change; however multiple Type of Alert bits May be set in one Alert Message. Once the
Alert Message has been sent the Type of Alert field Shall be cleared.
A Get_Battery_Status Message Should be sent in response to a Battery status change in an Alert Message to get the
details of the change.
A Get_Status Message Should be sent in response to a non-Battery status change in an Alert Message from to get the
details of the change.

6.4.6.1.1 Battery Status Change

The Battery Status Change bit Shall be set when any Battery’s power state changes between charging, discharging,
neither. For Hot Swappable Batteries, it Shall also be set when a Battery is Attached or Detached.

6.4.6.1.2 Over-Current Protection Event

The Over-Current Protection Event bit Shall be set when a Source detects its output current exceeds its limits
triggering its protection circuitry. This bit is Reserved for a Sink.

6.4.6.1.3 Over-Temperature Protection Event

The Over-Temperature Protection Event bit Shall be set when a Source or Sink shuts down due to over-temperature
triggering its protection circuitry.

6.4.6.1.4 Operating Condition Change

The Operating Condition Change bit Shall be set when a Source or Sink detects its Operating Condition enters or exits
either the ‘warning’ or ‘over temperature’ temperature states.
The Operating Condition Change bit Shall be set when the Source operating in the Programmable Power Supply mode
detects it has changed its operating condition between Constant Voltage (CV) and Current Foldback (CF).

6.4.6.1.5 Source Input Change Event

The Source Input Event bit Shall be set when the Source/Sink’s input changes. For example when the AC input is
removed and the Source/Sink continues to be powered from one or more of its batteries or when AC returns and the
Source/Sink transitions from Battery to AC operation or when the Source/Sink changes operation from one (or more)
Battery to another (or more) Battery.

6.4.6.1.6 Over-Voltage Protection Event

The Over-Voltage Protection Event bit Shall be set when the Sink detects its output voltage exceeds its limits
triggering its protection circuitry. This bit is Reserved for a Source.

6.4.6.2 Fixed Batteries

The Fixed Batteries field indicates which Fixed Batteries have had a status change. B20 corresponds to Battery 0 and
B23 corresponds to Battery 3.
Once the Alert Message has been sent the Fixed Batteries field Shall be cleared.

6.4.6.3 Hot Swappable Batteries

The Hot Swappable Batteries field indicates which Hot Swappable Batteries have had a status change. B16
corresponds to Battery 0 and B19 corresponds to Battery 3.
Once the Alert Message has been sent the Hot Swappable Batteries field Shall be cleared.

Page 154 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.4.7 Get_Country_Info Message
The Get_Country_Info Message Shall be sent by a port to get country specific information from its port partner using
the country’s Alpha-2 Country Code defined by [ISO 3166]. The port partner responds with a Country_Info Message
that contains the country specific information. The Get_Country_Info Message Shall be as shown in Figure 6-29 and
Table 6-41.
For example, if the request is for China information, then the Country Code Data Object would be CCDO[31:0] =
434E0000h for “CN” country code.

Figure 6-29 Get_Country_Info Message

Header Country Code

No. of Data Objects = 1 Data Object

Table 6-41 Country Code Data Object

Bit(s) Value Parameter Description

B31…24 Byte First character of the Alpha-2 Country
Code defined by [ISO 3166]
B23…16 Byte Second character of the Alpha-2 Country
Code defined by [ISO 3166]
B15…0 Shall be set to zero.
Reserved

6.5 Extended Message

An Extended Message Shall contain an Extended Message Header (indicated by the Extended field in the Message
Header being set) and be followed by zero or more data bytes.
The format of the Extended Message is defined by the Message Header’s Message Type field and is summarized in
Table 6-42. The Sent by column indicates entities which May send the given Message (Source, Sink or Cable Plug);
entities not listed Shall Not issue the corresponding Message. The Valid Start of Packet column indicates the
Messages which Shall only be issued in SOP Packets and the Messages which May be issued in SOP* Packets.

Table 6-42 Extended Message Types

Bits Type Sent by Description Valid Start

4…0 of Packet
0 0000 Reserved All values not explicitly defined
are Reserved and Shall Not be
used.
0 0001 Source_Capabilities_Extended Source or Dual- SOP only
See Section 6.5.1
Role Power
0 0010 Status Source or Sink See Section 6.5.2 SOP only
0 0011 Get_Battery_Cap Source or Sink See Section 6.5.3 SOP only
0 0100 Get_Battery_Status Source or Sink See Section 6.5.4
0 0101 Battery_Capabilities Source or Sink See Section 6.5.5 SOP only
0 0110 Get_Manufacturer_Info Source or Sink See Section6.5.6 SOP*
0 0111 Manufacturer_Info Source, Sink or See Section 6.5.7 SOP*
Cable Plug
0 1000 Security_Request Source or Sink See Section 6.5.8.1 SOP*
0 1001 Security_Response Source, Sink or See Section 6.5.8.2 SOP*
Cable Plug

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 155
 Bits Type Sent by Description Valid Start
4…0 of Packet
0 1010 Firmware_Update_Request Source or Sink See Section 6.5.9.1 SOP*
0 1011 Firmware_Update_Response Source, Sink or See Section 6.5.9.2 SOP*
Cable Plug
0 1100 PPS_Status Source See Section 6.5.10 SOP only
0 1101 Country_Info Source, Sink or See Section 6.5.12 SOP*
Cable Plug
0 1110 Country_Codes Source, Sink or See Section 6.5.11 SOP*
Cable Plug
0 1111 - Reserved All values not explicitly defined
1 1111 are Reserved and Shall Not be
used.

6.5.1 Source_Capabilities_Extended Message

The Source_Capabilities_Extended Message Should be sent in response to a Get_Source_Cap_Extended Message. The
Source_Capabilities_Extended Message enables a Source or a DRP to inform the Sink about its capabilities as a
Source.
The Source_Capabilities_Extended Message Shall return a 24-byte Source Capabilities Extended Data Block (SCEDB)
whose format Shall be as shown in Figure 6-30 and Table 6-43.

Figure 6-30 Source_Capabilities_Extended Message

Extended Header SCEDB

Data Size = 24 (24-byte Data Block)

Table 6-43 Source Capabilities Extended Data Block (SCEDB)

Offset Field Size Value Description

0 VID 2 Numeric Vendor ID (assigned by the USB-IF)
2 PID 2 Numeric Product ID (assigned by the manufacturer)
4 XID 4 Numeric Value provided by the USB-IF assigned to the product
8 FW Version 1 Numeric Firmware version number
9 HW Version 1 Numeric Hardware version number
10 Voltage Regulation 1 Bit Field
Bit Description
1…0 00b: 150mA/µs Load Step (default)
01b: 500mA/µs Load Step
11b…10b: Reserved and Shall Not be used
2 0b: 25% IoC (default)
1b: 90% IoC
3…7 Reserved and Shall be set to zero

11 Holdup Time 1 Numeric Output will stay with regulated limits for this number of
milliseconds after removal of the AC from the input.
0x00 = feature not supported
Note: a value of 3ms Should be used

Page 156 USB Power Delivery Specification Revision 3.0, Version 1.1
Offset Field Size Value Description
12 Compliance 1 Bit Field
Bit Description
0 LPS compliant when set
1 PS1 compliant when set
2 PS2 compliant when set
3…7 Reserved and Shall be set to zero

13 Touch Current 1 Bit Field

Bit Description
0 Low touch Current EPS when set
1 Ground pin supported
when set
2 Ground pin intended for protective earth
when set
3…7 Reserved and Shall be set to zero

14 Peak Current1 2 Bit field

Bit Description
0…4 Percent overload in 10% increments
Values higher than 25 (11001b) are clipped to
250%.
5…10 Overload period in 20ms
11.14 Duty cycle in 5% increments
15 VBUS Voltage droop

16 Peak Current2 2 Bit field

Bit Description
0…4 Percent overload in 10% increments
Values higher than 25 (11001b) are clipped to
250%.
5…10 Overload period in 20ms
11.14 Duty cycle in 5% increments
15 VBUS Voltage droop

18 Peak Current3 2 Bit field

Bit Description
0…4 Percent overload in 10% increments
Values higher than 25 (11001b) are clipped to
250%.
5…10 Overload period in 20ms
11.14 Duty cycle in 5% increments
15 VBUS Voltage droop

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 157
Offset Field Size Value Description
20 Touch Temp 1 Value Temperature conforms to:
0 = [IEC 60950-1] (default)
1 = [IEC 62368-1] TS1
2 = [IEC 62368-1] TS2
Note: All other values Reserved
21 Source Inputs 1 Bit field
Bit Description
0 0b: No external supply
1b: External supply present
1 If bit 0 is set:

0b: External supply is constrained

1b: External supply is unconstrained

If bit 0 is not set Reserved and Shall be set to

zero
2 0b: No internal Battery
1b: Internal Battery present
3…7 Reserved and Shall be set to zero

22 Batteries 1 Byte Upper Nibble = Number of Hot Swappable Batteries (0…4)

Lower Nibble = Number of Fixed Batteries (0…4)
23 Source PDP 1 Byte 0…6: Source’s rated PDP
7: Reserved and Shall be set to zero

6.5.1.1 Vendor ID (VID) Field

The Vendor ID field Shall contain the 16-bit Vendor ID (VID) assigned to the Source’s vendor by the USB-IF. If the
vendor does not have a VID, the Vendor ID field Shall be set to zero. Devices that have a USB data interface Shall
report the same VID as the idVendor in the Standard Device Descriptor (see [USB 2.0] and [USB 3.1]).

6.5.1.2 Product ID (PID) Field

The Product ID field Shall contain the 16-bit Product ID (PID) assigned by the Source’s vendor. Devices that have a
USB data interface Shall report the same PID as the idProduct in the Standard Device Descriptor (see [USB 2.0] and
[USB 3.1]).

6.5.1.1 XID Field

The XID field Shall contain the 32-bit XID provided by the USB-IF to the vendor who in turns assigns it to a product. If
the vendor does not have an XID, then it Shall return zero in this field (see [USB 2.0] and [USB 3.1]).

6.5.1.2 Firmware Version Field

The Firmware Version field Shall contain an 8-bit firmware version number assigned to the device by the vendor.

6.5.1.3 Hardware Version Field

The Hardware Version field Shall contain an 8-bit hardware version number assigned to the device by the vendor.

6.5.1.4 Voltage Regulation Field

The Voltage Regulation field contains bits covering Load Step Slew Rate and Magnitude.
See Section 7.1.12.1 for further details.

Page 158 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.5.1.4.1 Load Step Slew Rate
The Source Shall report its load step response capability in bits 0…1 of the Voltage Regulation bit field.

6.5.1.4.2 Load Step Magnitude

The Source Shall report its load step magnitude rate as a percentage of IoC in bit 2 of the Voltage Regulation field.

6.5.1.5 Holdup Time Field

The Holdup Time field Shall contain the Source’s holdup time (see Section 7.1.12.2).

6.5.1.6 Compliance Field

The Compliance field Shall contain the standards the Source is compliant with (see Section 7.1.12.3).

6.5.1.7 Touch Current

The Touch Current field reports whether the Source meets certain leakage current levels and if it has a ground pin.
A Source Shall set the Touch Current bit (bit-0) when their leakage current is less than 65µA rms when Source’s
maximum capability is less than or equal to 30W, or when their leakage current is less than 100 µA rms when its
power capability is between 30W and 100W. The total combined leakage current Shall be measured in accordance
with [IEC 60950-1] when tested at 250VAC rms at 50 Hz.
A Source with a ground pin Shall set the Ground pin bit (bit-1).
A Source whose Ground pin is intended to be connected to a protective earth Shall set both bit1 and bit 2.

6.5.1.8 Peak Current

The Peak Current field Shall contain the combinations of Peak Current that the Source supports (see Section 7.1.12.4).
Peak Current provides a means for Source report its ability to provide current in excess of the negotiated amount for
short periods. The Peak Current descriptor defines up to three combinations of % overload, duration and duty cycle
defined as PeakCurrent1, PeakCurrent2 and PeakCurrent3 that the Source supports. A Source May offer no Peak
Current capability. A Source Shall populate unused Peak Current bit fields with zero.
The Bit Fields within Peak Current1, Peak Current2, and Peak Current3 contain the following subfields:
 Percentage Overload Shall be the maximum peak current reported in 10% increments as a percentage of the
negotiated operating current (IoC) offered by the Source. Values higher than 25 (11001b) are clipped to 250%.
 Overload Period Shall be the minimum rolling average time window in 20ms increments, where a value of 20ms
is recommended.
 Duty Cycle Shall be the maximum percentage of overload period reported in 5% increments. The values Should
be 5%, 10% and 50% for PeakCurrent1, PeakCurrent2 and PeakCurrent3 respectively.
 VBUS Droop Shall be set to one to indicate there is an additional 5% voltage droop on VBUS when the overload
conditions occur. However, it is recommended that the Source Should provide VBUS in the range of vSrcNew when
overload conditions occur and set this bit to zero.

6.5.1.9 Touch Temp

The Touch Temp field Shall report the IEC standard used to determine the surface temperature of the Source’s
enclosure. Safety limits for the Source’s touch temperature are set in applicable product safety standards (e.g. [IEC
60950-1] or [IEC 62368-1]). The Source May report when its touch temperature performance conforms to the TS1 or
TS2 limits described in [IEC 62368-1].

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 159
 6.5.1.10 Source Inputs
The Source Inputs field Shall identify the possible inputs that provide power to the Source. Note some Sources are
only powered by a Battery (e.g. an automobile) rather than the more common mains.
 When bit 0 is set, the Source can be sourced by an external power supply.
 When bits 0 and 1 are set, the Source can be sourced by an external power supply which is assumed to be
effectively “infinite” i.e. it won’t run down over time.
 When bit 2 is set the Source can be sourced by an internal Battery.
Bit 2 May be set independently of bits 0 and 1.

6.5.1.11 Batteries
The Batteries field Shall report the number of batteries the source supports. It Shall independently report the
number of Hot Swappable Batteries and the number of Fixed batteries. The maximum number of each type of Battery
Shall be no more than 4.

6.5.1.12 Source PDP

The Source PDP field Shall report the Source’s rated PDP as defined in Table 10-2.

6.5.2 Status Message

The Status Message Shall be sent in response to a Get_Status Message. The Status Message enables a Port to inform
its Port Partner about the present status of the Source or Sink. Typically a Get_Status Message will be sent by the Port
after receipt of an Alert Message. Some of the reported events are critical such as OCP, OVP and OTP, while others are
informative such as change in a Battery’s status from charging to neither charging nor discharging.
The Status Message returns a 5-byte Status Data Block (SDB) whose format Shall be as shown in Figure 6-31 and
Table 6-44.

Figure 6-31 Status Message

Extended Header SDB

Data Size = 5 (5-byte block)

Table 6-44 Status Data Block (SDB)

Offset Field Size Value Description

(Byte)
0 Internal Temp 1 Numeric Source or Sink’s internal temperature in degrees centigrade.
0 = feature not supported
1 = temperature is less than 2°C.
2-255 = temperature in °C.
1 Present Input 1 Bit field
Bit Description
0 Reserved and Shall be set to zero
1 External Power when set
2 External Power AC/DC (Valid when Bit 1 set)
0: DC
1: AC
Reserved when Bit 1 is zero
3 Internal Power from Battery when set
4 Internal Power from non-Battery power
source when set
5…7 Reserved and Shall be set to zero

Page 160 USB Power Delivery Specification Revision 3.0, Version 1.1
Offset Field Size Value Description
(Byte)
2 Present Battery Input 1 Bit field When Present Input field bit 3 set Shall contain the bit
corresponding to the Battery or Batteries providing power:

Upper nibble = Hot Swappable Battery (b7…4)

Lower nibble = Fixed Battery (b3…0)

When Present Source Input field bit 3 is not set this field is
Reserved and Shall be set to zero.
3 Event Flags 1 Bit field Bit Description
0 Reserved and Shall be set to zero
1 OCP event when set
2 OTP event when set
3 OVP event when set (Sink only, for Source
Reserved and Shall be set to zero)
4 CF mode when set, CV mode when cleared
5…7 Reserved and Shall be set to zero
4 Temperature Status 1 Bit field Bit Description
0 Reserved and Shall be set to zero
1…2 00 – Not Supported
01 – Normal
10 – Warning
11 – Over temperature
3…7 Reserved and Shall be set to zero

6.5.2.1 Internal Temp

The Internal Temp field reports the instantaneous temperature of a portion of the Source or Sink.

6.5.2.2 Present Input

The Present Input field indicates which supplies are presently powering the Source or Sink.
The following bits are defined:
 Bit 1 indicates that an external Source is present.
 Bit 2 indicates whether the external unconstrained Source is AC or DC.
 Bit 3 indicates that power is being provided from Battery.
 Bit4 indicates an alternative internal source of power that is not a Battery.

6.5.2.3 Present Battery Input

The Present Battery Input field indicates which Battery or Batteries are presently supplying power to the Source or
Sink. The Present Battery Input field is only Valid when the Present Input field indicates that there is Internal Power
from Battery.
The upper nibble of the field indicates which Hot Swappable Battery/Batteries are supplying power with bit 4 in
upper nibble corresponding to Battery 4 and bit 7 in the upper nibble corresponding to Battery 7 (see Section 6.5.3
and Section 6.5.4).
The lower nibble of the field indicates which Fixed Battery/Batteries are supplying power with bit 0 in lower nibble
corresponding to Battery 0 and bit 3 in the lower nibble corresponding to Battery 3 (see Section 6.5.3 and Section
6.5.4).

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 161
 6.5.2.4 Event Flags Field
The Event Flags field returns event flags. The OTP, OVP and OCP event flags Shall be set when there is an event and
Shall only be cleared when read with the Get_PPS_Status Message.
When the OTP event flag is set the Temperature Status field Shall also be set to over temperature.
The CF/CV mode bit is only Valid when operating as a Programmable Power Supply and Shall be Ignored otherwise.
When the Source is operating as a Programmable Power Supply the CF/CV mode bit Shall be set when operating in
Current Foldback mode (CF mode) and Shall be cleared when operating in Constant Voltage mode (CV mode).

6.5.2.5 Temperature Status

The Temperature Status field returns the current temperature status of the device either: normal, warning and over
temperature. When the Temperature Status field is set to over temperature the OTP event flag Shall also be set.

6.5.3 Get_Battery_Cap Message

The Get_Battery_Cap (Get Battery Capabilities) Message is used to request the capability of a Battery present in its
Port Partner. The Port Shall respond by returning a Battery_Capabilities Message (see Section 6.5.5) containing a
Battery Capabilities Data Block (BCDB) for the targeted Battery.
The Get_Battery_Cap Message contains a 1 byte Get Battery Cap Data Block (GBCDB), whose format Shall be as shown
in Figure 6-32 and Table 6-45. This block defines for which Battery the request is being made.
The Data Size field in the Get_Battery_Cap Message Shall be set to 1.

Figure 6-32 Get_Battery_Cap Message

Extended Header
GBCDB
Data Size = 1

Table 6-45 Get Battery Cap Data Block (GBCDB)

Offset Field Size Value Description

0 Battery Cap Ref 1 Value Number of the Battery indexed from zero:
 Values 0…3 represent the Fixed Batteries.
 Values 4…7 represent the Hot Swappable Batteries.
 Values 8…255 are Reserved and Shall Not be used.

6.5.4 Get_Battery_Status Message

The Get_Battery_Status (Get Battery Status) Message is used to request the status of a Battery present in its Port
Partner. The port Shall respond by returning a Battery_Status Message (see Section 6.4.5) containing a Battery
Status Data Object (BSDO) for the targeted Battery.
The Get_Battery_Status Message contains a 1 byte Get Battery Status Data Block (GBSDB) whose format Shall be as
shown in Figure 6-33 and Table 6-46. This block contains details of the requested Battery. The Data Size field in the
Get_Battery_Status Message Shall be set to 1.

Figure 6-33 Get_Battery_Status Message

Extended Header
GBSDB
Data Size = 1

Page 162 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 6-46 Get Battery Status Data Block (GBSDB)

Offset Field Size Value Description

0 Battery Status Ref 1 Value Number of the Battery indexed from zero:
 Values 0…3 represent the Fixed Batteries.
 Values 4…7 represent the Hot Swappable Batteries.
 Values 8…255 are Reserved and Shall Not be used.

6.5.5 Battery_Capabilities Message

The Battery_Capabilities Message is sent in response to a Get_Battery_Cap Message. The Battery_Capabilities
Message contains one Battery Capability Data Block (BCDB) for one of the Batteries its supports as reported by
Battery field in the Source_Capabilities_Extended Message. The returned BCDB Shall correspond to the Battery
requested in the Battery Cap Ref field contained in the Get_Battery_Cap Message.
The Battery_Capabilities Message returns a 9-byte BCDB whose format Shall be as shown in Figure 6-34 and Table
6-44.

Figure 6-34 Battery_Capabilities Message

Extended Header
BCDB
Data Size = 9

Table 6-47 Battery Capability Data Block (BCDB)

Offset Field Size Value Description

(Byte)
0 VID 2 Numeric Vendor ID (assigned by the USB-IF)
2 PID 2 Numeric Product ID (assigned by the manufacturer)
4 Battery Design Capacity 2 1/10 WH Battery’s design capacity
Note:
0x0000 = Battery not present
0xFFFF = design capacity unknown
6 Battery Last Full Charge 2 1/10 WH Battery’s last full charge capacity
Capacity Note:
0x0000 = Battery not present
0xFFFF = last full charge capacity unknown
8 Battery Type 1 Bit Field
Bit Description
0 Invalid Battery reference
1-7 Reserved

6.5.5.1 Battery Design Capacity Field

The Battery Design Capacity field Shall return the Battery’s design capacity in tenths of WH. If the Battery is Hot
Swappable and is not present, the Battery Design Capacity field Shall be set to 0. If the Battery is unable to report its
Design Capacity, it Shall return 0xFFFF.

6.5.5.2 Battery Last Full Charge Capacity Field

The Battery Last Full Charge Capacity field Shall return the Battery’s last full charge capacity in tenths of WH. If the
Battery is Hot Swappable and is not present, the Battery Last Full Charge Capacity field Shall be set to 0. If the Battery
is unable to report its Design Capacity, the Battery Last Full Charge Capacity field Shall be set to 0xFFFF.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 163
 6.5.5.3 Battery Type Field
The Battery Type Field is used to report additional information about the Battery’s capabilities.

6.5.5.3.1 Invalid Battery Reference

The Invalid Battery Reference bit Shall be set when the Get_Battery_Cap Message contains a reference to a Battery
that does not exist.

6.5.6 Get_Manufacturer_Info Message

The Get_Manufacturer_Info (Get Manufacturer Info) Message is sent by a Port to request manufacturer specific
information relating to its Port Partner or Cable Plug or of a Battery behind a Port. The Port or Cable Plug Shall
respond by returning a Manufacturer_Info Message (Section 6.5.7) containing a Manufacturer Info Data Block
(MIDB).
The Get_Manufacturer_Info Message contains a 2-byte Get Manufacturer Info Data Block (GMIDB). This block defines
whether it is the Device or Battery manufacturer information being requested and for which Battery the request is
being made.
The Get_Manufacturer_Info Message returns a GMIDB whose format Shall be as shown in Figure 6-33 and Table
6-48.

Figure 6-35 Get_Manufacturer_Info Message

Extended Header
GMIDB
Data Size = 2

Table 6-48 Get Manufacturer Info Data Block (GMIDB)

Offset Field Size Value Description

0 Manufacturer Info Target 1 Value 0: Port/Cable Plug
1: Battery
255…2: Reserved Shall Not be used.
1 Manufacturer Info Ref 1 Value If Manufacturer Info Target subfield is Battery (01b) the
Manufacturer Info Ref field Shall contain the Battery number
reference which is the number of the Battery indexed from zero:
 Values 0…3 represent the Fixed Batteries.
 Values 4…7 represent the Hot Swappable Batteries.

Otherwise this field is Reserved and Shall be set to zero.

6.5.7 Manufacturer_Info Message

The Manufacturer_Info Message Shall be sent in response to a Get_Manufacturer_Info Message. The
Manufacturer_Info Message contains the USB VID and the Vendor’s PID to identify the device or Battery and the
device or Battery’s manufacturer byte array in a variable length Data Block of up to MaxExtendedMsgLegacyLen .
The Manufacturer_Info Message returns a Manufacturer Info Data Block (MIDB) whose format Shall be as shown in
Figure 6-34 and Table 6-44.

Figure 6-36 Manufacturer_Info Message

Extended Header
MIDB
Data Size = 4..26

Page 164 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 6-49 Manufacturer Info Data Block (MIDB)

Offset Field Size Value Description

0 VID 2 Numeric Vendor ID (assigned by the USB-IF)
2 PID 2 Numeric Product ID (assigned by the manufacturer)
4 Manufacturer String 0…22 String Vendor defined byte array
If the Manufacturer Info Target field or Manufacturer Info Ref
field in the Get_Manufacturer_Info Message is unrecognized
return zero bytes.

6.5.7.1 Vendor ID (VID)

This field Shall contain the device’s or Battery’s16-bit vendor ID assigned by the USB.

6.5.7.2 Product ID (PID)

This field Shall contain the device’s or Battery’s 16-bit product identifier designated by the vendor.

6.5.7.3 Manufacturer String

This field Shall contain the device’s or Battery’s manufacturer string as defined by the vendor. If the Manufacturer
Info Target field or Manufacturer Info Ref field in the Get_Manufacturer_Info Message is unrecognized the field
Shall return zero bytes.

6.5.8 Security Messages

The authentication process between Port Partners or a Port and Cable Plug is fully described in
[USBTypeCAuthentication 1.0]. This specification describes two Extended Messages used by the authentication
process when applied to PD.
In the authentication process described in [USBTypeCAuthentication 1.0] there are three basic exchanges that serve
to:
 Get the Port or Cable Plug’s certificates.
 Get the Port or Cable Plug’s digest.
 Challenge the Port Partner or Cable Plug.
Certificates are used to convey information, attested to by a signer, which attests to the Port Partner’s or Cable Plug’s
authenticity. The Port’s or Cable Plug’s certificates are needed when a Port encounters a Port Partner or Cable Plug it
has not been Attached to before. To minimize calculations after the initial Attachment, a Port can also use a digest
consisting of hashes of the certificates rather than the certificates themselves. Once the port has the certificates and
has calculated the hashes, it stores the hashes and uses the digest in future exchanges. After the port gets the
certificates or digest, it challenges its Port Partner or the Cable Plug to detect replay attacks.
For further details refer to [USBTypeCAuthentication 1.0].

6.5.8.1 Security_Request
The Security_Request Message is used by a Port to pass a security data structure to its Port Partner or a Cable Plug.
The Security_Request Message contains a Security Request Data Block (SRQDB) whose format Shall be as shown in
Figure 6-37. The contents of the SRQDB and its use are defined in [USBTypeCAuthentication 1.0].

Figure 6-37 Security_Request Message

Extended Header
SRQDB
Data Size = 4..260

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 165
 6.5.8.2 Security_Response
The Security_Response Message is used by a Port or Cable Plug to pass a security data structure to the Port that sent
the Security_Request Message.
The Security_Response Message contains a Security Response Data Block (SRPDB) whose format Shall be as shown in
Figure 6-38. The contents of the SRPDB and its use are defined in [USBTypeCAuthentication 1.0].

Figure 6-38 Security_Response Message

Extended Header
SRPDB
Data Size = 4..260

6.5.9 Firmware Update Messages

The firmware update process between Port Partners or a Port and Cable Plug is fully described in
[USBPDFirmwareUpdate 1.0]. This specification describes two Extended Messages used by the firmware update
process when applied to PD.

6.5.9.1 Firmware_Update_Request
The Firmware_Update_Request Message is used by a Port to pass a firmware update data structure to its Port
Partner or a Cable Plug.
The Firmware_Update_Request Message contains a Firmware Update Request Data Block (FRQDB) whose format
Shall be as shown in Figure 6-39. The contents of the FRQDB and its use are defined in [USBPDFirmwareUpdate
1.0].

Figure 6-39 Firmware_Update_Request Message

Extended Header
FRQDB
Data Size = 4..260

6.5.9.2 Firmware_Update_Response
The Firmware_Update_Response Message is used by a Port or Cable Plug to pass a firmware update data structure to
the Port that sent the Firmware_Update_Request Message.
The Firmware_Update_Response Message contains a Firmware Update Response Data Block (FRPDB) whose format
Shall be as shown in Figure 6-40. The contents of the FRPDB and its use are defined in [USBPDFirmwareUpdate 1.0].

Figure 6-40 Firmware_Update_Response Message

Extended Header
FRPDB
Data Size = 4..260

6.5.10 PPS_Status Message

The PPS_Status Message Shall be sent in response to a Get_PPS_Status Message. The PPS_Status Message enables a
Sink to query the Source to get additional information about its operational state. The Get_PPS_Status Message and
the PPS_Status Message Shall only be supported when the Alert Message is also supported.
The PPS_Status Message Shall return a 4-byte PPS Status Data Block (PPSSDB) whose format Shall be as shown in
Figure 6-41 and Table 6-50.

Page 166 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 6-41 PPS_Status Message

Extended Header PPSSDB

Data Size = 4 (4-byte Data Block)

Table 6-50 PPS Status Data Block (PPSSDB)

Offset Field Size Value Description

0 Output Voltage 1 Word Source’s output voltage in 20mV units.
When set to 0xFFFF, the Source does not support this
field.
2 Output Current 1 Byte Source’s output current in 50mA units.
When set to 0xFF, the Source does not support this
field.
3 Real Time Flags 1 Bit Field Bit Description
0 Reserved and Shall be set to zero
1…2 PTF: 00 – Not Supported
PTF: 01 – Normal
PTF: 10 – Warning
PTF: 11 – Over temperature
3 OMF set when operating in Current Foldback
mode, and cleared when operating in
Constant Voltage mode.
4…7 Reserved and Shall be set to zero

6.5.10.1 Output Voltage Field

The Output Voltage field Shall return the Source’s output voltage at the time of the request. It is measured at the
Source’s receptacle or if the Source has a captive cable, it measured where the voltage is applied to the cable. If the
Source does not support this field, it Shall be set to 0xFFFF.

6.5.10.2 Output Current Field

The Output Current field Shall return the Source’s output current at the time of the request. If the Source does not
support this field, it Shall be set to 0xFF.

6.5.10.3 Real Time Flags Field

Real Time flags provide a real time indication of the Source’s operating state.
 The PTF (Present Temperature Flag) Shall provide a real time indication of the Source’s internal thermal status.
If the PTF is not supported, it will be set to zero.
o Normal indicates that that the Source is operating within its normal thermal envelope.
o Warning indicates that the Source is over-heating, but is not in imminent danger of shutting down.
o Over Temperature indicates that the Source is over heated and will shut down soon or has already shutdown
and has sent an OTP in an Alert Message.
 The OMF (Operating Mode Flag) Shall provide a real time indication of the Source’s operating mode. When set,
the Source is operating in Current Foldback mode; when cleared it is operating Constant Voltage mode.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 167
 6.5.11 Country_Codes Message
The Country_Codes Message Shall be sent in response to a Get_Country_Codes Message. The Country_Codes Message
enables a Port to query its Port partner to get a list of alpha-2 country codes as defined in [ISO 3166] for which the
Port Partner has country specific information.
The Country_Codes Message Shall contain a 4-260 byte Country Code Data Block (CCDB) whose format Shall be as
shown in Figure 6-42 and Table 6-51.

Figure 6-42 Country_Codes Message

Extended Header CCDB

Data Size = 4-260 (4-260 byte Data Block)

Table 6-51 Country Codes Data Block (CCDB)

Offset Field Size Value Description

0 Length 1 Word Number of country codes in the message
2 1st Country Code 2 Bytes First character of the Alpha-2 Country Code defined by
[ISO 3166]
Second character of the Alpha-2 Country Code defined
by [ISO 3166]
4 2nd Country Code 2 Bytes
…
Length * 2n nth Country Code 2 Bytes

6.5.11.1 Country Code Field

The Country Code field Shall contain the Alpha-2 Country Code defined by [ISO 3166].

6.5.12 Country_Info Message

The Country_Info Message Shall be sent in response to a Get_Country_Info Message. The Country_Info Message
enables a Port to get additional country specific information from its Port Partner.
The Country_Info Message Shall contain a 4-260 byte Country Info Data Block (CIDB) whose format Shall be as
shown in Figure 6-43 and Table 6-52.

Figure 6-43 Country_Info Message

Extended Header CIDB

Data Size = 4-260 (4-260 byte Data Block)

Table 6-52 Country Info Data Block (CIDB)

Offset Field Size Value Description

0 Country Code 2 Bytes First character of the Alpha-2 Country Code defined by
[ISO 3166]
Second character of the Alpha-2 Country Code defined
by [ISO 3166]

Page 168 USB Power Delivery Specification Revision 3.0, Version 1.1
Offset Field Size Value Description
2 Reserved 1 Word Shall be set to 0.
4 Country Specific Data 0-256 Byte Content defined by the country’s authority.

6.5.12.1 Country Code Field

The Country Code field Shall contain the Alpha-2 Country Code defined by [ISO 3166].

6.5.12.2 Country Specific Data Field

The Country Specific Data field Shall contain content defined by and formatted in a manner determined by an official
agency of the country indicated in the Country Code field.

6.6 Timers
All the following timers are defined in terms of bits on the bus regardless of where they are implemented in terms of
the logical architecture. This is to ensure a fixed reference for the starting and stopping of timers. It is left to the
implementer to ensure that this timing is observed in a real system.

6.6.1 CRCReceiveTimer
The CRCReceiveTimer Shall be used by the sender’s Protocol Layer to ensure that a Message has not been lost.
Failure to receive an acknowledgement of a Message (a GoodCRC Message) whether caused by a bad CRC on the
receiving end or by a garbled Message within tReceive is detected when the CRCReceiveTimer expires.
The sender’s Protocol Layer response when a CRCReceiveTimer expires Shall be to retry nRetryCount times. Note:
that Cable Plugs do not retry Messages and large Extended Messages that are not Chunked are not retried (see Section
6.7.2). Sending of the Preamble corresponding to the retried Message Shall start within tRetry of the
CRCReceiveTimer expiring.
The CRCReceiveTimer Shall be started when the last bit of the Message EOP has been transmitted by the Physical
Layer. The CRCReceiveTimer Shall be stopped when the last bit of the EOP corresponding to the GoodCRC Message
has been received by the Physical Layer.
The Protocol Layer receiving a Message Shall respond with a GoodCRC Message within tTransmit in order to ensure
that the sender’s CRCReceiveTimer does not expire. The tTransmit Shall be measured from when the last bit of the
Message EOP has been received by the Physical Layer until the first bit of the Preamble of the GoodCRC Message has
been transmitted by the Physical Layer.

6.6.2 SenderResponseTimer
The SenderResponseTimer Shall be used by the sender’s Policy Engine to ensure that a Message requesting a
response (e.g. Get_Source_Cap Message) is responded to within a bounded time of tSenderResponse. Failure to
receive the expected response is detected when the SenderResponseTimer expires.
The Policy Engine’s response when the SenderResponseTimer expires Shall be dependent on the Message sent (see
Section 8.3).
The SenderResponseTimer Shall be started from the time the last bit of the GoodCRC Message EOP (i.e. the GoodCRC
Message corresponding to the Message requesting a response) has been received by the Physical Layer. The
SenderResponseTimer Shall be stopped when the last bit of the expected response Message EOP has been received
by the Physical Layer.
The receiver of a Message requiring a response Shall respond within tReceiverResponse in order to ensure that the
sender’s SenderResponseTimer does not expire.
The tReceiverResponse time Shall be measured from the time the last bit of the Message EOP has been received by
the Physical Layer until the first bit of the response Message Preamble has been transmitted by the Physical Layer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 169
 6.6.3 Capability Timers
Sources and Sinks use Capability Timers to determine Attachment of a PD Capable device. By periodically sending or
requesting capabilities it is possible to determine PD device Attachment when a response is received.

6.6.3.1 SourceCapabilityTimer
Prior to a successful negotiation a Source Shall use the SourceCapabilityTimer to periodically send out a
Source_Capabilities Message every tTypeCSendSourceCap while:
 The Port is Attached.
 The Source is not in an active connection with a PD Sink Port.
Whenever there is a SourceCapabilityTimer timeout the Source Shall send a Source_Capabilities Message. It Shall
then re-initialize and restart the SourceCapabilityTimer. The SourceCapabilityTimer Shall be stopped when the
last bit of the EOP corresponding to the GoodCRC Message has been received by the Physical Layer since a PD
connection has been established. At this point the Source waits for a Request Message or a response timeout.
See Section 8.3.3.2 more details of when Source_Capabilities Messages are transmitted.

6.6.3.2 SinkWaitCapTimer
The Sink Shall support the SinkWaitCapTimer. When a Sink observes an absence of Source_Capabilities Messages,
after VBUS is present, for a duration of tTypeCSinkWaitCap the Sink Shall issue Hard Reset Signaling in order to
restart the sending of Source_Capabilities Messages by the Source (see Section 6.7.4).
See Section 8.3.3.3 for more details of when the SinkWaitCapTimer are run.

6.6.3.3 tFirstSourceCap
After Port Partners are Attached or after a Hard Reset or after a Power Role Swap or after a Fast Role Swap a Source
Shall send its first Source_Capabilities Message within tFirstSourceCap of VBUS reaching vSafe5V. This ensures that
the Sink receives a Source_Capabilities Message before the Sink’s SinkWaitCapTimer expires.

6.6.4 Wait Timers and Times

6.6.4.1 SinkRequestTimer
The SinkRequestTimer is used to ensure that the time before the next Sink Request Message, after a Wait Message
has been received from the Source in response to a Sink Request Message, is a minimum of tSinkRequest min (see
Section 6.3.12).
The SinkRequestTimer Shall be started when the EOP of a Wait Message has been received and Shall be stopped if
any other Message is received or during a Hard Reset.
The Sink Shall wait at least tSinkRequest, after receiving the EOP of a Wait Message sent in response to a Sink
Request Message, before sending a new Request Message. Whenever there is a SinkRequestTimer timeout the Sink
May send a Request Message. It Shall then re-initialize and restart the SinkRequestTimer.

6.6.4.2 tPRSwapWait
The time before the next PR_Swap Message, after a Wait Message has been received in response to a PR_Swap
Message is a minimum of tPRSwapWait min (see Section 6.3.12). The Port Shall wait at least tPRSwapWait after
receiving the EOP of a Wait Message sent in response to a PR_Swap Message, before sending a new PR_Swap
Message.

6.6.4.3 tDRSwapWait
The time before the next DR_Swap Message, after a Wait Message has been received in response to a DR_Swap
Message is a minimum of tDRSwapWait min (see Section 6.3.12). The Port Shall wait at least tDRSwapWait after

Page 170 USB Power Delivery Specification Revision 3.0, Version 1.1
receiving the EOP of a Wait Message sent in response to a DR_Swap Message, before sending a new DR_Swap
Message.

6.6.4.4 tVconnSwapWait
The time before the next VCONN_Swap Message, after a Wait Message has been received in response to a
VCONN_Swap Message is a minimum of tVCONNSwapWait min (see Section 6.3.12). The Port Shall wait at least
tVCONNSwapWait after receiving the EOP of a Wait Message sent in response to a VCONN_Swap Message, before
sending a new VCONN_Swap Message.

6.6.5 Power Supply Timers

6.6.5.1 PSTransitionTimer
The PSTransitionTimer is used by the Policy Engine to timeout on a PS_RDY Message. It is started when a request for
a new Capability has been accepted and will timeout after tPSTransition if a PS_RDY Message has not been received.
This condition leads to a Hard Reset and a return to USB Default Operation. The PSTransitionTimer relates to the
time taken for the Source to transition from one voltage, or current level, to another (see Section 7.1).
The PSTransitionTimer Shall be started when the last bit of an Accept or GotoMin Message EOP has been received
by the Physical Layer. The PSTransitionTimer Shall be stopped when the last bit of the PS_RDY Message EOP has
been received by the Physical Layer.

6.6.5.2 PSSourceOffTimer

6.6.5.2.1 Use during Power Role Swap

The PSSourceOffTimer is used by the Policy Engine in Dual-Role Power Device that is currently acting as a Sink to
timeout on a PS_RDY Message during a Power Role Swap sequence. This condition leads to USB Type-C Error
Recovery.
If a PR_Swap Message request has been sent by the Dual-Role Power Device currently acting as a Source the Sink can
respond with an Accept Message. When the last bit of the EOP of the GoodCRC Message corresponding to this Accept
Message is received by the Sink, then the PSSourceOffTimer Shall be started.
If a PR_Swap Message request has been sent by the Dual-Role Power Device currently acting as a Sink the Source can
respond with an Accept Message. When the last bit of the EOP of this Accept Message is received by the Sink then the
PSSourceOffTimer Shall be started.
The PSSourceOffTimer Shall be stopped when:
 The last bit of the EOP of the PS_RDY Message is received.
The PSSourceOffTimer relates to the time taken for the remote Dual-Role Power Device to stop supplying power (see
also Section 7.3.9 and Section 7.3.10). The timer Shall time out if a PS_RDY Message has not been received from the
remote Dual-Role Power Device within tPSSourceOff indicating this has occurred.

6.6.5.2.2 Use during Fast Role Swap

The PSSourceOffTimer is used by the Policy Engine in Dual-Role Power Device that is the initial Sink (currently
providing vSafe5V) to timeout on a PS_RDY Message during a Fast Role Swap sequence. This condition leads to USB
Type-C Error Recovery.
When the FR_Swap Message request has been sent by the initial Sink, the initial Source Shall respond with an Accept
Message. When the last bit of the EOP of the GoodCRC Message corresponding to this Accept Message is received by
the initial Sink, then the PSSourceOffTimer Shall be started.
The PSSourceOffTimer Shall be stopped when:
 The last bit of the EOP of the PS_RDY Message is received.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 171
The PSSourceOffTimer relates to the time taken for the initial Source to stop supplying power and for VBUS to revert
to vSafe5V (see also Section 7.2.10 and Section 7.3.15). The timer Shall time out if a PS_RDY Message has not been
received from the initial Source within tPSSourceOff indicating this has occurred.

6.6.5.3 PSSourceOnTimer

6.6.5.3.1 Use during Power Role Swap

The PSSourceOnTimer is used by the Policy Engine in Dual-Role Power Device that has just stopped sourcing power
and is waiting to start sinking power to timeout on a PS_RDY Message during a Power Role Swap. This condition leads
to USB Type-C Error Recovery.
The PSSourceOnTimer Shall be started when:
 The last bit of the EOP of the GoodCRC Message corresponding to the transmitted PS_RDY Message is received by
the Physical Layer.
The PSSourceOnTimer Shall be stopped when:
 The last bit of the EOP of the PS_RDY Message is received by the Physical Layer.
The PSSourceOnTimer relates to the time taken for the remote Dual-Role Power Device to start sourcing power (see
also Section 7.3.9 and Section 7.3.10) and will time out if a PS_RDY Message indicating this has not been received
within tPSSourceOn.

6.6.5.3.2 Use during Fast Role Swap

The PSSourceOnTimer is used by the Policy Engine in Dual-Role Power Device that has just stopped sourcing power
and is waiting to start sinking power to timeout on a PS_RDY Message during a Fast Role Swap. This condition leads
to USB Type-C Error Recovery.
The PSSourceOnTimer Shall be started when:
 The last bit of the EOP of the GoodCRC Message corresponding to the transmitted PS_RDY Message is received by
the Physical Layer.
The PSSourceOnTimer Shall be stopped when:
 The last bit of the EOP of the PS_RDY Message is received by the Physical Layer.
The PSSourceOnTimer relates to the time taken for the remote Dual-Role Power Device to start sourcing power (see
also Section 7.2.10 and Section 7.3.15) and will time out if a PS_RDY Message indicating this has not been received
within tPSSourceOn.

6.6.6 NoResponseTimer
The NoResponseTimer is used by the Policy Engine in a Source or Sink to determine that its Port Partner is not
responding after a Hard Reset. When the NoResponseTimer times out, the Policy Engine Shall issue up to
nHardResetCount additional Hard Resets before determining that the Port Partner is non-responsive to USB Power
Delivery messaging.
If the Source fails to receive a GoodCRC Message in response to a Source_Capabilities Message within tNoResponse
of:
 The last bit of a Hard Reset Signaling being sent by the PHY Layer if the Hard Reset Signaling was initiated by the
Sink.
 The last bit of a Hard Reset Signaling being received by the PHY Layer if the Hard Reset Signaling was initiated by
the Source.
Then the Source Shall issue additional Hard Resets up to nHardResetCount times (see Section 6.8.2).

Page 172 USB Power Delivery Specification Revision 3.0, Version 1.1
For a non-responsive device, the Policy Engine in a Source May either decide to continue sending Source_Capabilities
Messages or to go to non-USB Power Delivery operation and cease sending Source_Capabilities Messages.

6.6.7 BIST Timers

6.6.7.1 tBISTMode
tBISTMode is used to define the maximum time that a UUT has to enter a BIST mode when requested by a Tester.
A UUT Shall enter the appropriate BIST mode within tBISTMode of the last bit of the EOP of the BIST Message used to
initiate the test is received by the Physical Layer. In BIST Carrier Mode when transmitting a continuous carrier signal
transmission Shall start as soon as the UUT enters BIST mode.

6.6.7.2 BISTContModeTimer
The BISTContModeTimer is used by a UUT to ensure that a Continuous BIST Mode (i.e. BIST Carrier Mode) is exited
in a timely fashion. A UUT that has been put into a Continuous BIST Mode Shall return to normal operation (either
PE_SRC_Transition_to_default, PE_SNK_Transition_to_default, or PE_CBL_Ready) within tBISTContMode of the last
bit of the bit of the EOP of GoodCRC Message sent in response to the BIST Message used to enable the Continuous
BIST Mode.

6.6.8 Power Role Swap Timers

6.6.8.1 SwapSourceStartTimer
The SwapSourceStartTimer Shall be used by the new Source, after a Power Role Swap or Fast Role Swap, to ensure
that it does not send Source_Capabilities Message before the new Sink is ready to receive the Source_Capabilities
Message. The new Source Shall Not send the Source_Capabilities Message earlier than tSwapSourceStart after the
last bit of the EOP of GoodCRC Message sent in response to the PS_RDY Message sent by the new Source indicating
that its power supply is ready. The Sink Shall be ready to receive a Source_Capabilities Message tSwapSinkReady
after having sent the last bit of the EOP of GoodCRC Message sent in response to the PS_RDY Message sent by the new
Source indicating that its power supply is ready.

6.6.9 Soft Reset Timers

6.6.9.1 tSoftReset
A failure to see a GoodCRC Message in response to any Message within tReceive (after nRetryCount retries), when a
Port Pair is Connected, is indicative of a communications failure. This Shall cause the Source or Sink to send a
Soft_Reset Message, transmission of which Shall be completed within tSoftReset of the CRCReceiveTimer expiring.

6.6.9.2 tProtErrSoftReset
If the Protocol Error occurs that causes the Source or Sink to send a Soft_Reset Message, the transmission of the
Soft_Reset Message Shall be completed within tProtErrSoftReset of the EOP of the GoodCRC sent in response to the
Message that caused the Protocol Error.

6.6.10 Hard Reset Timers

6.6.10.1 HardResetCompleteTimer
The HardResetCompleteTimer is used by the Protocol Layer in the case where it has asked the PHY Layer to send
Hard Reset Signaling and the PHY Layer is unable to send the Signaling within a reasonable time due to a non-idle
channel. If the PHY Layer does not indicate that the Hard Reset Signaling has been sent within tHardResetComplete
of the Protocol Layer requesting transmission, then the Protocol Layer Shall inform the Policy Engine that the Hard
Reset Signaling has been sent in order to ensure the power supply is reset in a timely fashion.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 173
 6.6.10.2 PSHardResetTimer
The PSHardResetTimer is used by the Policy Engine in a Source to ensure that the Sink has had sufficient time to
process Hard Reset Signaling before turning off its power supply to VBUS.
When a Hard Reset occurs the Source stops driving VCONN, removes Rp from the VCONN pin and starts to transition the
VBUS voltage to vSafe0V either:
 tPSHardReset after the last bit of the Hard Reset Signaling has been received from the Sink or
 tPSHardReset after the last bit of the Hard Reset Signaling has been sent by the Source.
See Section 7.1.5.

6.6.10.3 tDRSwapHardReset
If a DR_Swap Message is received during Modal Operation then a Hard Reset Shall be initiated by the recipient of the
unexpected DR_Swap Message; Hard Reset Signaling Shall be generated within tDRSwapHardReset of the EOP of the
GoodCRC sent in response to the DR_Swap Message.

6.6.10.4 tProtErrHardReset
If a Protocol Error occurs that directly leads to a Hard Reset, the transmission of the Hard Reset Signaling Shall be
completed within tProtErrHardReset of the EOP of the GoodCRC sent in response to the Message that caused the
Protocol Error.

6.6.11 Structured VDM Timers

6.6.11.1 VDMResponseTimer
The VDMResponseTimer Shall be used by the Initiator’s Policy Engine to ensure that a Structured VDM Command
request needing a response (e.g. Discover Identity Command request) is responded to within a bounded time of
tVDMSenderResponse. The VDMResponseTimer Shall be applied to all Structured VDM Commands except the Enter
Mode and Exit Mode Commands which have their own timers (VDMModeEntryTimer and VDMModeExitTimer
respectively). Failure to receive the expected response is detected when the VDMResponseTimer expires.
The Policy Engine’s response when the VDMResponseTimer expires Shall be dependent on the Message sent (see
Section 8.3).
The VDMResponseTimer Shall be started from the time the last bit of the GoodCRC Message EOP (i.e. the GoodCRC
Message corresponding to the VDM Command requesting a response) has been received by the Physical Layer. The
VDMResponseTimer Shall be stopped when the last bit of the expected VDM Command response EOP has been
received by the Physical Layer.
The receiver of a Message requiring a response Shall respond within tVDMReceiverResponse in order to ensure that
the sender’s VDMResponseTimer does not expire.
The tVDMReceiverResponse time Shall be measured from the time the last bit of the Message EOP has been received
by the Physical Layer until the first bit of the response Message Preamble has been transmitted by the Physical Layer.

6.6.11.2 VDMModeEntryTimer
The VDMModeEntryTimer Shall be used by the Initiator’s Policy Engine to ensure that the response to a Structured
VDM Enter Mode Command request (ACK or NAK with ACK indicating that the requested Mode has been entered)
arrives within a bounded time of tVDMWaitModeEntry. Failure to receive the expected response is detected when
the VDMModeEntryTimer expires.
The Policy Engine’s response when the VDMModeEntryTimer expires is to inform the Device Policy Manager (see
Section 8.3.3.20.1).

Page 174 USB Power Delivery Specification Revision 3.0, Version 1.1
The VDMModeEntryTimer Shall be started from the time the last bit of the GoodCRC Message EOP (i.e. the GoodCRC
Message corresponding to the VDM Command request) has been received by the Physical Layer. The
VDMModeEntryTimer Shall be stopped when the last bit of the expected Structured VDM Command response (ACK,
NAK or BUSY) EOP has been received by the Physical Layer.
The receiver of a Message requiring a response Shall respond within tVDMEnterMode in order to ensure that the
sender’s VDMModeEntryTimer does not expire.
The tVDMEnterMode time Shall be measured from the time the last bit of the Message EOP has been received by the
Physical Layer until the first bit of the response Message Preamble has been transmitted by the Physical Layer.

6.6.11.3 VDMModeExitTimer
The VDMModeExitTimer Shall be used by the Initiator’s Policy Engine to ensure that the ACK response to a
Structured VDM Exit Mode Command, indicating that the requested Mode has been exited, arrives within a bounded
time of tVDMWaitModeExit. Failure to receive the expected response is detected when the VDMModeExitTimer
expires.
The Policy Engine’s response when the VDMModeExitTimer expires is to inform the Device Policy Manager (see
Section 8.3.3.20.2).
The VDMModeExitTimer Shall be started from the time the last bit of the GoodCRC Message EOP (i.e. the GoodCRC
Message corresponding to the VDM Command requesting a response) has been received by the Physical Layer. The
VDMModeExitTimer Shall be stopped when the last bit of the expected Structured VDM Command response ACK EOP
has been received by the Physical Layer.
The receiver of a Message requiring a response Shall respond within tVDMExitMode in order to ensure that the
sender’s VDMModeExitTimer does not expire.
The tVDMExitMode time Shall be measured from the time the last bit of the Message EOP has been received by the
Physical Layer until the first bit of the response Message Preamble has been transmitted by the Physical Layer.

6.6.11.4 tVDMBusy
The Initiator Shall wait at least tVDMBusy, after receiving a BUSY Command response, before repeating the
Structured VDM request again.

6.6.12 VCONN Timers

6.6.12.1 VCONNOnTimer
The VCONNOnTimer is used during a VCONN Swap.
The VCONNOnTimer Shall be started when:
 The last bit of the EOP of the Accept Message is received.
 The last bit of the EOP of GoodCRC Message corresponding to the Accept Message is received.
The VCONNOnTimer Shall be stopped when:
 The last bit of the EOP of the PS_RDY Message is received.
Prior to sending the PS_RDY Message, the Port Shall have turned VCONN On.

6.6.12.2 tVCONNSourceOff
The tVCONNSourceOff time applies during a Vconn Swap. The initial VCONN Source Shall cease sourcing VCONN within
tVCONNSourceOff of receipt of the last bit of the EOP of the PS_RDY Message.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 175
 6.6.13 tCableMessage
Ports compliant with this Revision of the specification Shall Not wait tCableMessage before sending an SOP’ or SOP’’
Packet even when communicating using [USBPD 2.0] with a Cable Plug. This specification defines collision avoidance
mechanisms that obviate the need for this time.
Cable Plugs Shall only wait tCableMessage before sending an SOP’ or SOP’’ Packet when operating at [USBPD 2.0].
When operating at Revisions higher than [USBPD 2.0] Cable Plugs Shall Not wait tCableMessage before sending an
SOP’ or SOP’’ Packet.

6.6.14 DiscoverIdentityTimer
The DiscoverIdentityTimer is used during an Explicit Contract when discovering whether a Cable Plug is PD Capable
using SOP’. When performing cable discovery during an Explicit Contract the Discover Identity Command request
Shall be sent every tDiscoverIdentity. No more than nDiscoverIdentityCount Discover Identity Messages without a
GoodCRC Message response Shall be sent. If no GoodCRC Message response is received after nDiscoverIdentityCount
Discover Identity Command requests have been sent by a Port, the Port Shall Not send any further SOP’/SOP’’
Messages.

6.6.15 Collision Avoidance Timers

The SinkTxTimer is used by the Protocol Layer in a Source to allow the Sink to complete its transmission before
initiating an AMS.
The Source Shall wait a minimum of tSinkTx after changing Rp from SinkTxOk to SinkTxNG before initiating an AMS
by sending a Message.
A Sink Shall only initiate an AMS when it has determined that Rp is set to SinkTxOk.

6.6.16 tFRSwapInit
That last bit of the EOP of the FR_Swap Message Shall be transmitted by the new Source no later than tFRSwapInit
after the Fast Role Swap request has been detected (see Section 5.8.6.3).

6.6.17 Chunking Timers

6.6.17.1 ChunkingNotSupportedTimer
The ChunkingNotSupportedTimer is used by a Source or Sink which does not support multi-chunk Chunking but has
received a Message Chunk.
The ChunkingNotSupportedTimer Shall be started when:
 The last bit of the EOP of a Message Chunk of a multi-chunk Message is received. The Policy Engine Shall Not
send its Not_Supported Message before the ChunkingNotSupportedTimer expires.

6.6.17.2 ChunkSenderRequestTimer
The ChunkSenderRequestTimer is used during a Chunked Message transmission.
The ChunkSenderRequestTimer Shall be used by the sender’s Chunking state machine to ensure that a Chunk
Response is responded to within a bounded time of tChunkSenderRequest. Failure to receive the expected response
is detected when the ChunkSenderRequestTimer expires.
The ChunkSenderRequestTimer Shall be started when:
 The last bit of the EOP of the GoodCRC Message corresponding to the Chunk Response Message is received.
The ChunkSenderRequestTimer Shall be stopped when:
 The last bit of the EOP of the Chunk Request Message is received.

Page 176 USB Power Delivery Specification Revision 3.0, Version 1.1
 A Message other than a Chunk Request is received from the Protocol Layer Rx.
The receiver of a Chunk Response requiring a Chunk Request Shall respond with a Chunk Request within
tChunkReceiverRequest in order to ensure that the sender’s ChunkSenderRequestTimer does not expire.
The tChunkReceiverRequest time Shall be measured from the time the last bit of the Message EOP has been received
by the Physical Layer until the first bit of the response Message Preamble has been transmitted by the Physical Layer.

6.6.17.3 ChunkSenderResponseTimer
The ChunkSenderResponseTimer is used during a Chunked Message transmission.
The ChunkSenderResponseTimer Shall be used by the sender’s Chunking state machine to ensure that a Chunk
Request is responded to within a bounded time of tChunkSenderResponse. Failure to receive the expected response
is detected when the ChunkSenderResponseTimer expires.
The ChunkSenderResponseTimer Shall be started when:
 The last bit of the EOP of GoodCRC Message corresponding to the Chunk Request Message is received.
The ChunkSenderResponseTimer Shall be stopped when:
 The last bit of the EOP of the Chunk Response Message is received.
 A Message other than a Chunk is received from the Protocol Layer.
The receiver of a Chunk Request requiring a Chunk Response Shall respond with a Chunk Response within
tChunkReceiverResponse in order to ensure that the sender’s ChunkSenderResponseTimer does not expire.
The tChunkReceiverResponse time Shall be measured from the time the last bit of the Message EOP has been
received by the Physical Layer until the first bit of the response Message Preamble has been transmitted by the
Physical Layer.

6.6.18 Programmable Power Supply Timers

6.6.18.1 SinkPPSPeriodicTimer
The SinkPPSPeriodicTimer Shall be used by the Sink’s Policy Engine to ensure that a Request Message requesting a
PPS APDO is sent periodically within a bounded time of tPPSRequest.
The tPPSRequest time Shall be measured from the time the last bit of the EOP of the GoodCRC Message sent by the
Source in response to the previous Request Message. SinkPPSPeriodicTimer Shall be re-initialized and restarted
when the last bit of the EOP of the GoodCRC Message sent in response to a Request Message for a PPS APDO has been
received by the Physical Layer.
The Sink Shall stop the SinkPPSPeriodicTimer when:
 The Sink requests something other than PPS APDO.
 There is a Power Role Swap.
 There is a Hard Reset.

6.6.18.2 SourcePPSCommTimer
The SourcePPSCommTimer Shall be used by the Source’s Policy Engine to ensure that a Request Message requesting
a PPS APDO is received periodically within a bounded time of tPPSTimeout.
The tPPSTimeout time Shall be measured from the time the last bit of the EOP of the GoodCRC Message sent in
response to the previous Request Message for a PPS APDO has been sent by the Physical Layer.
The SourcePPSCommTimer Shall be re-initialized and restarted when the last bit of the EOP of the GoodCRC Message
sent in response to a Request Message for a PPS APDO has been sent by the Physical Layer.
The Source Shall stop the SourcePPSCommTimer when:

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 177
 A Request Message has been received.
 There is a Power Role Swap.
 There is a Hard Reset.
When the SourcePPSCommTimer times out the Source Shall issue Hard Reset Signaling.

6.6.19 Time Values and Timers

Table 6-53 summarizes the values for the timers listed in this section. For each Timer Value, a given implementation
Shall pick a fixed value within the range specified. Table 6-54 lists the timers.

Page 178 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 6-53 Time Values

Parameter Value (min) Value (max) Units Reference

tBISTContMode 30 60 ms Section 6.6.7.2

tBISTMode 300 ms Section 6.6.7.1

tCableMessage 750 µs Section 6.6.13

tChunkingNotSupported 40 50 ms Section 6.6.17.1

tChunkSenderRequest 24 30 ms Section 6.6.17.2

tChunkSenderResponse 24 30 ms Section 6.6.17.3

tChunkReceiverRequest 15 ms Section 6.6.17.2

tChunkReceiverResponse 15 ms Section 6.6.17.3

tDiscoverIdentity 40 50 ms Section 6.6.13

tDRSwapHardReset 15 ms Section 6.6.10.3

tDRSwapWait 100 ms Section 6.6.4.3

tFirstSourceCap 250 ms Section 6.6.3.3

tFRSwapInit 15 ms Section 6.3.17

tHardReset 5 ms Section 6.3.13

tHardResetComplete 4 5 ms Section 6.6.9

tNoResponse 4.5 5.5 s Section 6.6.6

tPPSRequest 10 s Section 6.6.18.1

tPPSTimeout 15 s Section 6.6.18.2

tProtErrHardReset 15 ms Section 6.6.10.4

tProtErrSoftReset 15 ms Section 6.6.9.2

tPRSwapWait 100 ms Section 6.6.4.2

tPSHardReset 25 35 ms Section 6.6.10.2

tPSSourceOff 750 920 ms Section 6.6.5.2

tPSSourceOn 390 480 ms Section 6.6.5.3

tPSTransition 450 550 ms Section 6.6.5.1

tReceive 0.9 1.1 ms Section 6.6.1

tReceiverResponse 15 ms Section 6.6.2

tRetry 75 µs Section 6.6.1

tSenderResponse 24 30 ms Section 6.6.2

tSinkRequest 100 ms Section 6.6.4.1

tSinkTx 16 20 ms Section 6.6.15

tSoftReset 15 ms Section 6.8.1

tSwapSinkReady 15 ms Section 6.6.8.1

tSwapSourceStart 20 ms Section 6.6.8.1

tTransmit 195 µs Section 6.6.1

tTypeCSendSourceCap 100 200 ms Section 6.6.3.1

tTypeCSinkWaitCap 310 620 ms Section 6.6.3.2

tVCONNSourceOff 25 ms Section 6.6.12

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 179
 Parameter Value (min) Value (max) Units Reference
tVCONNSourceOn 100 ms Section 6.6.12

tVCONNSwapWait 100 ms Section 6.6.4.4

tVDMBusy 50 ms Section 6.6.11.4

tVDMEnterMode 25 ms Section 6.6.11.2

tVDMExitMode 25 ms Section 6.6.11.3

tVDMReceiverResponse 15 ms Section 6.6.11.1

tVDMSenderResponse 24 30 ms Section 6.6.11.1

tVDMWaitModeEntry 40 50 ms Section 6.6.11.2

tVDMWaitModeExit 40 50 ms Section 6.6.11.3

Table 6-54 Timers

Timer Parameter Used By Reference

BISTContModeTimer tBISTContMode Policy Engine Section 6.6.7.2
ChunkingNotSupportedTimer tChunkingNotSupported Policy Engine Section 6.6.17.1

ChunkSenderRequestTimer tChunkSenderRequest Protocol Section 6.6.17.2

ChunkSenderResponseTimer tChunkSenderResponse Protocol Section 6.6.17.3

CRCReceiveTimer tReceive Protocol Section 6.6.1

DiscoverIdentityTimer tDiscoverIdentity Policy Engine Section 6.6.14

HardResetCompleteTimer tHardResetComplete Protocol Section 6.6.9

NoResponseTimer tNoResponse Policy Engine Section 6.6.6

PSHardResetTimer tPSHardReset Policy Engine Section 6.6.10.2

PSSourceOffTimer tPSSourceOff Policy Engine Section 6.6.5.2

PSSourceOnTimer tPSSourceOn Policy Engine Section 6.6.5.3

PSTransitionTimer tPSTransition Policy Engine Section 6.6.5.1

SenderResponseTimer tSenderResponse Policy Engine Section 6.6.2

SinkPPSPeriodicTimer tPPSRequest Policy Engine Section 6.6.18.1

SinkRequestTimer tSinkRequest Policy Engine Section 6.6.4

SinkWaitCapTimer tTypeCSinkWaitCap Policy Engine Section 6.6.3.2

SourceCapabilityTimer tTypeCSendSourceCap Policy Engine Section 6.6.3.1

SourcePPSCommTimer tPPSTimeout Policy Engine Section 6.6.18.2

SinkTxTimer tSinkTx Protocol Layer Section 6.6.15

SwapSourceStartTimer tSwapSourceStart Policy Engine Section 6.6.8.1

VCONNOnTimer tVCONNSourceOn Policy Engine Section 6.6.12.1

VDMModeEntryTimer tVDMWaitModeEntry Policy Engine Section 6.6.11.2

VDMModeExitTimer tVDMWaitModeExit Policy Engine Section 6.6.11.3

VDMResponseTimer tVDMSenderResponse Policy Engine Section 6.6.11.1

Page 180 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.7 Counters
6.7.1 MessageID Counter
The MessageIDCounter is a rolling counter, ranging from 0 to nMessageIDCount, used to detect duplicate Messages.
This value is used for the MessageID field in the Message Header of each transmitted Message.
Each Port Shall maintain a copy of the last MessageID value received from its Port Partner. Devices that support
multiple ports, such as Hubs, Shall maintain copies of the last MessageID on a per Port basis. A Port which
communicates using SOP* Packets Shall maintain copies of the last MessageID for each type of SOP* it uses.
The transmitter Shall use the MessageID in a GoodCRC Message to verify that a particular Message was received
correctly. The receiver Shall use the MessageID to detect duplicate Messages.

6.7.1.1 Transmitter Usage

The Transmitter Shall use the MessageID as follows:
 Upon receiving either Hard Reset Signaling, or a Soft_Reset Message, the transmitter Shall set its
MessageIDCounter to zero and re-initialize its retry mechanism.
 If a GoodCRC Message with a MessageID matching the MessageIDCounter is not received before the
CRCReceiveTimer expires, it Shall retry the same packet up to nRetryCount times using the same MessageID.
 If a GoodCRC Message is received with a MessageID matching the current MessageIDCounter before the
CRCReceiveTimer expires, the transmitter Shall re-initialize its retry mechanism and increment its
MessageIDCounter.
 If the Message is aborted by the Policy Engine, the transmitter Shall delete the Message from its transmit buffer,
re-initialize its retry mechanism and increment its MessageIDCounter.
 The MessageID is incremented if a GoodCRC Message is not received and the RetryCounter has reached
nRetryCount.

6.7.1.2 Receiver Usage

The Receiver Shall use the MessageID as follows:
 When the first good packet is received after a reset, the receiver Shall store a copy of the received MessageID
value.
 For subsequent Messages, if MessageID value in a received Message is the same as the stored value, the receiver
Shall return a GoodCRC Message with that MessageID value and drop the Message (this is a retry of an already
received Message). Note: this Shall Not apply to the Soft_Reset Message which always has a MessageID value of
zero.
 If MessageID value in the received Message is different than the stored value, the receiver Shall return a
GoodCRC Message with the new MessageID value, store a copy of the new MessageID value and process the
Message.

6.7.2 Retry Counter

The RetryCounter is used by a Port whenever there is a Message transmission failure (timeout of CRCReceiveTimer).
If the nRetryCount retry fails, then the link Shall be reset using the Soft Reset mechanism.
The following rules apply to retries when there is a Message transmission failure (see also Section 6.11.2.1):
 Cable Plugs Shall Not retry Messages.
 Extended Messages of Data Size > MaxExtendedMsgLegacyLen that are not Chunked (Chunked flag set to zero)
Shall Not be retried .
 Extended Messages of Data Size ≤ MaxExtendedMsgLegacyLen (Chunked flag set to zero or one) Shall be
retried.
USB Power Delivery Specification Revision 3.0, Version 1.1 Page 181
 Extended Messages of Data Size > MaxExtendedMsgLegacyLen that are Chunked (Chunked flag set to one)
individual Chunks Shall be retried.
When messages are not retried, then the RetryCounter is not used. Higher layer protocols are expected to
accommodate message delivery failure or failure to receive a GoodCRC Message.

6.7.3 Hard Reset Counter

The HardResetCounter is used to retry the Hard Reset whenever there is no response from the remote device (see
Section 6.6.6). Once the Hard Reset has been retried nHardResetCount times then it Shall be assumed that the
remote device is non-responsive.

6.7.4 Capabilities Counter

The CapsCounter is used to count the number of Source_Capabilities Messages which have been sent by a Source at
power up or after a Hard Reset. Implementation of the CapsCounter is Optional but May be used by any Source
which wishes to preserve power by not sending Source_Capabilities Messages after a period of time.
When the CapsCounter is implemented and the Source detects that a Sink is Attached then after nCapsCount
Source_Capabilities Messages have been sent the Source Shall decide that the Sink is non-responsive, stop sending
Source_Capabilities Messages and disable PD.
A Sink Shall use the SinkWaitCapTimer to trigger the resending of Source_Capabilities Messages by a USB Power
Delivery capable Source which has previously stopped sending Source_Capabilities Messages. Any Sink which is
Attached and does not detect a Source_Capabilities Message, Shall issue Hard Reset Signaling when the
SinkWaitCapTimer times out in order to reset the Source. Resetting the Source Shall also reset the CapsCounter and
restart the sending of Source_Capabilities Messages.

6.7.5 Discover Identity Counter

When sending Discover Identity Messages to a Cable Plug a Port Shall maintain a count of Messages sent
(DiscoverIdentityCounter). No more than nDiscoverIdentityCount Discover Identity Messages Shall be sent by the
Port receiving a GoodCRC Message response. A Data Role Swap Shall reset the DiscoverIdentityCounter to zero.

6.7.6 VDMBusyCounter
When sending Responder Busy responses to a Structured Vendor_Defined Message a UFP or Cable Plug Shall
maintain a count of Messages sent (VDMBusyCounter). No more than nBusyCount Responder Busy responses Shall
be sent. The VDMBusyCounter Shall be reset on sending a non-Busy response. Products wishing to meet [USB Type-
C 1.2] requirements for Mode entry Should use an nBusyCount of 1.

6.7.7 Counter Values and Counters

Table 6-56 lists the counters used in this section and Table 6-55 shows the corresponding parameters.

Table 6-55 Counter parameters

Parameter Value Reference

nBusyCount 5 Section 6.7.6

nCapsCount 50 Section 6.7.4

nDiscoverIdentityCount 20 Section 6.7.5

nHardResetCount 2 Section 6.7.3

nMessageIDCount 7 Section 6.7.1

nRetryCount 2 Section 6.7.2

Page 182 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 6-56 Counters

Counter Max Reference

CapsCounter nCapsCount Section 6.7.4

DiscoverIdentityCounter nDiscoverIdentityCount Section 6.7.5

HardResetCounter nHardResetCount Section 6.7.3

MessageIDCounter nMessageIDCount Section 6.7.1

RetryCounter nRetryCount Section 6.7.2

VDMBusyCounter nBusyCount Section 6.7.6

6.8 Reset
Resets are a necessary response to protocol or other error conditions. USB Power Delivery defines two different types
of reset; a Soft Reset, that resets protocol, and a Hard Reset which resets both the power supplies and protocol.

6.8.1 Soft Reset and Protocol Error

A Soft_Reset Message is used to cause a Soft Reset of protocol communication when this has broken down in some
way. It Shall Not have any impact on power supply operation, but is used to correct a Protocol Error occurring during
an Atomic Message Sequence (AMS). The Soft Reset May be triggered by either Port Partner in response to the
Protocol Error.
Protocol Errors are any unexpected Message during an AMS. If the first Message in an AMS has been passed to the
Protocol Layer by the Policy Engine but has not yet been sent (GoodCRC Message not received) when the Protocol
Error occurs, the Policy Engine Shall Not issue a Soft Reset but Shall return to the PE_SNK_Ready or PE_SRC_Ready
state and then process the incoming Message. If the Protocol Error occurs during an Interruptible AMS then the Policy
Engine Shall Not issue a Soft Reset but Shall return to the PE_SNK_Ready or PE_SRC_Ready state and then process the
incoming Message. If the incoming Message is an Unexpected Message received in the PE_SNK_Ready or
PE_SRC_Ready state the Policy Engine Shall issue a Soft Reset. If the Protocol Error occurs during a Non-interruptible
AMS this Shall lead to a Soft Reset in order to re-synchronize the Policy Engine state machines (see Section 8.3.3.4)
except when the voltage is transition when a Protocol Error Shall lead to a Hard Reset (see Section 6.6.10.4 and
Section 8.3.3.2). Details of Interruptible and Non-interruptible AMS’s can be found in Section 8.3.2.1.3.
An unrecognized or unsupported Message received in the PE_SNK_Ready or PE_SRC_Ready states, Shall Not cause a
Soft_Reset Message to be generated but instead a Not_Supported Message Shall be generated.
A Soft_Reset Message Shall be sent regardless of the Rp value either SinkTxOk or SinkTxNG if it is the correct
response in that state,
Table 6-57 and Table 6-58 summarize the responses that Shall be made to an incoming Message including VDMs.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 183
 Table 6-57 Response to an incoming Message (except VDM)

Incoming Message

Recognized
Recipient's
Recipient's state
Power Role
Supported Unrecognized
Unsupported
Expected Unexpected

Not_Supported Message (except

Process Soft_Reset for VDM)
PE_SRC_Ready Not_Supported Message
Message Message See 6.4.4.1 for UVDM, 6.12.4 for
SVDM

During Process
return to PE_SRC_Ready state and process Message
Interruptible AMS Message

Source During Non-

interruptible AMS Process
Soft_Reset Message
(not power Message
transitioned)
During Non-
interruptible AMS Process
Hard Reset Signaling
(power Message
transitioned)

Not_Supported Message (except for

Process Soft_Reset Not_Supported
PE_SNK_Ready VDM)
Message Message Message
See 6.4.4.1 for UVDM, 6.12.4 for SVDM

During Process
return to PE_SNK_Ready state and process Message
Interruptible AMS Message

Sink During Non-

interruptible AMS Process
Soft_Reset Message
(not power Message
transitioned)

During Non-
interruptible AMS Process
Hard Reset Signaling
(power Message
transitioned)

Table 6-58 Response to an incoming VDM

Recipient's Supported Unsupported Unrecognized Unsupported Unrecognized

Supported SVDM
Role UVDM UVDM UVDM SVDM SVDM

Defined by Not_Supported Not_Supported Not_Supported

DFP or UFP See 6.12.4 NAK Command
vendor Message Message Message

Defined by
Cable Plug Message Ignored Message Ignored See 6.12.4 Message Ignored NAK Command
vendor

A failure to see a GoodCRC Message in response to any Message within tReceive (after nRetryCount retries), when a
Port Pair is Connected, is indicative of a communications failure resulting in a Soft Reset (see Section 6.6.9.1).
A Soft Reset Shall impact the USB Power Delivery layers in the following ways:
 Physical Layer: Reset not required since the Physical Layer resets on each packet transmission/reception.

Page 184 USB Power Delivery Specification Revision 3.0, Version 1.1
 Protocol Layer: Reset MessageIDCounter, RetryCounter and state machines.
 Policy Engine: Reset state dependent behavior by performing an Explicit Contract negotiation.
 Power supply: Shall Not change.
A Soft Reset is performed using a sequence of protocol Messages (see Table 8-7). Message numbers Shall be set to
zero prior to sending the Soft_Reset/Accept Message since the issue might be with the counters. The sender of a
Soft_Reset Message Shall reset its MessageIDCounter and RetryCounter, the receiver of the Message Shall reset its
MessageIDCounter and RetryCounter before sending the Accept Message response. Any failure in the Soft Reset
process will trigger a Hard Reset when SOP Packets are being used or Cable Reset for any other SOP* Packets; for
example a GoodCRC Message is not received during the Soft Reset process (see Section 6.8.2 and Section 6.8.3).

6.8.2 Hard Reset

Hard Resets are signaled by an ordered set as defined in Section 5.6.4. Both the sender and recipient Shall cause their
power supplies to return to their default states (see Section 7.3.12 and Section 7.3.13 for details of voltage
transitions). In addition their respective Protocol Layers Shall be reset as for the Soft Reset. This allows the Attached
devices to be in a state where they can re-establish USB PD communication. Hard Reset is retried up to
nHardResetCount times (see also Section 6.6.6 and Section 6.7.3). Note: that even though VBUS drops to vSafe0V
during a Hard Reset a Sink will not see this as a disconnect since this is expected behavior.
A Hard Reset Shall Not cause any change to either the Rp/Rd resistor being asserted.
If there has been a Data Role Swap the Hard Reset Shall cause the Port Data Role to be changed back to DFP for a Port
with the Rp resistor asserted and UFP for a Port with the Rd resistor asserted.
When VCONN is supported (see [USB Type-C 1.2]) the Hard Reset Shall cause the Port with the Rp resistor asserted to
supply VCONN and the Port with the Rd resistor asserted to turn off VCONN.
In effect the Hard Reset will revert the Ports to their default state based on their CC line resistors. Removing and
reapplying VCONN from the Cable Plugs also ensures that they re-establish their configuration as either SOP’ or SOP’’
based on the location of VCONN (see [USB Type-C 1.2]).
If the Hard Reset is insufficient to clear the error condition then the Port Should use Error Recovery mechanisms as
defined in [USB Type-C 1.2].
A Sink Shall be able to send Hard Reset signaling regardless of the value of Rp (see Section 5.7).

6.8.2.1 Cable Plugs and Hard Reset

Cable Plugs Shall Not generate Hard Reset Signaling but Shall monitor for Hard Reset Signaling between the Port
Partners and Shall reset when this is detected (see Section 8.3.3.22.2.2). The Cable Plugs Shall perform the
equivalent of a power cycle returning to their initial power up state. This allows the Attached products to be in a state
where they can re-establish USB PD communication.

6.8.2.2 Modal Operation and Hard Reset

A Hard Reset Shall cause all Active Modes to be exited by both Port Partners and any Cable Plugs (see Section
6.4.4.3.4).

6.8.3 Cable Reset

Cable Resets are signaled by an ordered set as defined in Section 5.6.5. Both the sender and recipient of Cable Reset
Signaling Shall reset their respective Protocol Layers. The Cable Plugs Shall perform the equivalent of a power cycle
returning to their initial power up state. This allows the Attached products to be in a state where they can re-establish
USB PD communication.
The DFP has to be supplying VCONN prior to a Cable Reset to ensure that the Cable Plugs correctly configure SOP’ and
SOP’’ after the Cable Reset is complete. If VCONN has been turned off the DFP Shall turn on VCONN prior to generating

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 185
Cable Reset Signaling. If there has been a VCONN Swap and the UFP is currently supplying VCONN, the DFP Shall
perform a VCONN Swap such that it is supplying VCONN prior to generating Cable Reset Signaling.
Only a DFP Shall generate Cable Reset Signaling. A DFP Shall only generate Cable Reset Signaling within an Explicit
Contract.
A Cable Reset Shall cause all Active Modes in the Cable Plugs to be exited (see Section 6.4.4.3.4).

6.9 Collision Avoidance

In order to avoid message collisions due to asynchronous Messaging sent from the Sink, the Source sets Rp to
SinkTxOk to indicate to the Sink that it is ok to initiate an AMS. When the Source wishes to initiate an AMS it sets Rp
to SinkTxNG. When the Sink detects that Rp is set to SinkTxOk it May initiate an AMS. When the Sink detects that Rp
is set to SinkTxNG it Shall Not initiate an AMS and Shall only send Messages that are part of an AMS the Source has
initiated. Note that this restriction applies to SOP* AMS’s i.e. for both Port to Port and Port to Cable Plug
communications.
Note: a Sink can still send Hard Reset signaling at any time.

6.10 Message Discarding

On receiving a received Message on SOP, the Protocol Layer Shall Discard any pending SOP* Messages. A received
Message on SOP’/SOP’’ Shall Not cause any pending SOP* Messages to be Discarded.
It is assumed that Messages using SOP’/SOP’’ constitute a simple request/response AMS, with the Cable Plug
providing the response so there is no reason for a pending SOP* Message to be Discarded. There can only be one AMS
between the Port Partners and these also take priority over Cable Plug communications so a Message received on SOP
will always cause a Message pending on SOP* to be Discarded.
See Table 6-59 for details of the Messages that Shall/ Shall Not be Discarded.

Table 6-59 Message discarding

Message pending Message received Discard pending transmission?

transmission
SOP SOP Yes
SOP SOP’/SOP’’ No
SOP’ SOP Yes
SOP’ SOP’ No
SOP’ SOP’’ No
SOP’’ SOP Yes
SOP’’ SOP’ No
SOP’’ SOP’’ No

Page 186 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.11 State behavior
6.11.1 Introduction to state diagrams used in Chapter 6
The state diagrams defined in Section 6.11 are Normative and Shall define the operation of the Power Delivery
protocol layer. Note that these state diagrams are not intended to replace a well written and robust design.
Figure 6-44 shows an outline of the states defined in the following sections. At the top there is the name of the state.
This is followed by “Actions on entry” a list of actions carried out on entering the state and in some states “Actions on
exit” a list of actions carried out on exiting the state.

Figure 6-44 Outline of States

<Name of State>
Actions on entry:
“List of actions to carry out on entering the
state”
Actions on exit:
“List of actions to carry out on exiting the
state”

Transitions from one state to another are indicated by arrows with the conditions listed on the arrow. Where there
are multiple conditions these are connected using either a logical OR “|” or a logical AND “&”. The inverse of a
condition is shown with a “NOT” in front of the condition.
In some cases there are transitions which can occur from any state to a particular state. These are indicated by an
arrow which is unconnected to a state at one end, but with the other end (the point) connected to the final state.
In some state diagrams it is necessary to enter or exit from states in other diagrams. Figure 6-45 indicates how such
references are made. The reference is indicated with a hatched box. The box contains the name of the referenced
state.

Figure 6-45 References to states

<Name of reference state>

Timers are included in many of the states. Timers are initialized (set to their starting condition) and run (timer is
counting) in the particular state it is referenced. As soon as the state is exited then the timer is no longer active.
Timeouts of the timers are listed as conditions on state transitions.
Conditions listed on state transitions will come from one of three sources:
 Messages received from the PHY Layer
 Events triggered within the Protocol Layer e.g. timer timeouts
 Message and related indications passed up to the Policy Engine from the Protocol Layer (Message sent, Message
received etc.)

6.11.2 State Operation

The following section details Protocol Layer State Operation when sending and receiving SOP* Packets.
For each SOP* Communication being sent and received there Shall be separate Protocol Layer Transmission and
Protocol Layer Reception and Hard Reset State Machine instances, with their own counter and timer instances. When
Chunking is supported there Shall be separate Chunked Tx, Chunked Tx and Chunked Message Router State Machine
instances.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 187
Soft Reset Shall only apply to the State Machine instances it is targeted at based on the type of SOP* Packet used to
send the Soft_Reset Message. The Hard Reset State Machine (including Cable Reset) Shall apply simultaneously to all
Protocol Layer State Machine instances active in the DFP, UFP and Cable Plug (if present).

6.11.2.1 Protocol Layer Chunking

6.11.2.1.1 Architecture of Device Including Chunking Layer

The Chunking component resides in the Protocol Layer between the Policy Engine and Protocol Tx/Rx. Figure 6-46
illustrates the relationship between components.
The Chunking Layer comprises three related state machines:
 Chunked Rx.
 Chunked Tx.
 Chunked Message Router.
Note that the consequence of this architecture is that the Policy Engine deals entirely in un-chunked messages. It will
not receive (and might not respond to) a message until all the related chunks have been collated.
If a PD Device or Cable Marker has no requirement to handle any message requiring more than one Chunk of any
Extended Message, it May omit the Chunking Layer. In this case it Shall implement the
ChunkingNotSupportedTimer to ensure compatible operation with partners which support Chunking (see Section
6.6.17.1 and Section 8.3.3.5).

Figure 6-46 Chunking architecture Showing Message and Control Flow

Policy Engine

Protocol Layer AMS Notification

Chunked Rx Chunked Tx

Chunked Message Router

Chunking

Protocol Layer Rx Hard Reset Protocol Layer Tx

Rp Control or
PHY Layer
Detection

Page 188 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.11.2.1.1.1 Optional Abort Mechanism
Long Chunked Messages bring with them the potential problem that they could prevent urgent messages from being
transmitted in a timely manner. An optional Abort mechanism is provided to remedy this problem.
The Abort Flag referred to in the diagrams below May be set and examined by the Policy Engine. The specific means
are left to the implementer.

6.11.2.1.1.2 Aborting Sending a Long Chunked Message

A long Chunked Message being sent May be aborted by setting the Optional Abort Flag. The message Shall be
considered aborted when the Abort Flag is again cleared by the Chunked Tx state machine.

6.11.2.1.1.3 Aborting Receiving a Long Chunked Message

If the optional Abort mechanism has been implemented, any message sent while a Chunked Message receive is in
progress will result in an error report being received by the Policy Engine, to indicate that the message request has
been Discarded. If the message was urgent the Policy Engine might set the Abort Flag, which will result in the
incoming Chunked Message being aborted. The Abort Flag being cleared by the Chunked Rx state machine indicates
that the urgent message can now be sent.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 189
 6.11.2.1.2 Chunked Rx State Diagram
Figure 6-47 shows the state behavior for the Chunked Rx State Machine. This recognizes whether chunked received
messages are involved, and deals with requesting chunks when they are. It also performs validity checks on all
messages related to chunking.

Figure 6-47 Chunked Rx State Diagram

Soft Reset occured | Start

Exit from Hard Reset
Any Message Received and
RCH_Wait_For_ RCH_Report_Error not in state RCH_Waiting_Chunk
Message_From_ or RCH_Wait_For_Message_From_
Protocol_Layer Actions on entry: Protocol_Layer
Reported Report Error to Policy Engine.
Message Passed Actions on entry: If a Message was received, pass it to
Clear Extended Rx Buffer the Policy Engine.
Clear Abort Flag Chunked !=
Chunking
Other Message Received
from Protocol Layer |
Received Non-Extended Message |
ChunkSenderResponseTimer timeout
(Received Extended Message &
(Chunking = 0 & Chunked = 0) )
Abort Flag Set Transmission Error
RCH_Pass_Up_Message from Protocol Layer |
Unexpected
Actions on entry:
Received Chunk Number Message Received
Pass Message to Policy Engine Extended Message & from Protocol Layer
(Chunking = 1 &
Chunked = 1)
Message is Complete
(Num bytes received
>= specified Data Size)2
RCH_Processing_ RCH_Requesting_Chunk RCH_Waiting_Chunk
Extended_Message
Actions on entry: Message Actions on entry:
Actions on entry: Message Send Chunk Request to Protocol Transmitted Start ChunkSenderResponseTimer
If first chunk: set not Layer with Chunk Number = received from
Chunk_Number_Expected = 0 and Complete Chunk_Number_Expected
Num bytes received = 0
Protocol Layer

If expected Chunk Number: Append

data to Extended_Message_Buffer;
Increment Chunk_Number_Expected
and adjust Num bytes received.

Chunk Response Received

from Protocol Layer

1Chunking is an internal state that is set to 1 if the ‘Unchunked Extended Messages Supported’ bit in either Source
Capabilities or Request is 0. It defaults to 1 and is set after the first exchange of Source Capabilities and Request. It is
also set to 1 for SOP’ or SOP’’ communication.
2 Additional bytes received over specified Data Size will be as a result of padding in the last chunk.

6.11.2.1.2.1 RCH_Wait_For_Message_From_Protocol_Layer State

The Chunked Rx State Machine Shall enter the RCH_Wait_For_Message_From_Protocol_Layer state:
 At startup.
 As a result of a Soft Reset occurring.
 On exit from a Hard Reset.
On entry to the RCH_Wait_For_Message_From_Protocol_Layer state the Chunked Rx state machine clears the
Extended Rx Buffer, and clears the optional Abort Flag.
In the RCH_Wait_For_Message_From_Protocol_Layer state the Chunked Rx state machine waits until the Chunked
Message Router passes up a received message.
The Chunked Rx State Machine Shall transition to the RCH_Pass_Up_Message state when:
 A non-Extended Message is passed up from the Chunked Message Router.
 An Extended Message is passed up from the Chunked Message Router, and the Policy Engine has determined that
we are not doing Chunking, and the Message has its Chunked bit set to 0b.

Page 190 USB Power Delivery Specification Revision 3.0, Version 1.1
The Chunked Rx State Machine Shall transition to the RCH_Processing_Extended_Message state when:
 An Extended Message is passed up from the Chunked Message Router, and the Policy Engine has determined that
we are doing Chunking, and the Message has its Chunked bit set to 1b.

6.11.2.1.2.2 RCH_Pass_Up_Message State

On entry to the RCH_Pass_Up_Message state the Chunked Rx state machine Shall pass the received message to the
Policy Engine.
The Chunked Rx State Machine Shall transition to the RCH_Wait_For_Message_From_Protocol_Layer state when:
 The Message has been passed.

6.11.2.1.2.3 RCH_Processing_Extended_Message State

On entry to the RCH_Processing_Extended_Message state the Chunked Rx state machine Shall:
 If this is the first chunk:
o Set Chunk_Number_Expected = 0.
o Set Num bytes received = 0.
 If chunk contains the expected Chunk Number:
o Append its data to the Extended_Message_Buffer.
o Increment Chunk_Number_Expected.
o Adjust Num bytes received.
The Chunked Rx State Machine Shall transition to the RCH_Pass_Up_Message state when:
 The message is complete (i.e. Num bytes received >= specified Data Size. Note that the inequality allows for
padding bytes in the last chunk, which are not actually part of the extended message).
The Chunked Rx State Machine Shall transition to the RCH_Requesting_Chunk state when:
 The Message is not yet complete.
The Chunked Rx State Machine Shall transition to the RCH_Report_Error state when:
 An unexpected Chunk Number is received.
The Chunked Rx State Machine Shall transition to the RCH_Wait_For_Message_From_Protocol_Layer state when:
 The optional Abort Flag is set.

6.11.2.1.2.4 RCH_Requesting_Chunk State

On entry to the RCH_Requesting_Chunk state the Chunked Rx state machine Shall:
 Send Chunk Request to Protocol Layer with Chunk Number = Chunk_Number_Expected.
The Chunked Rx State Machine Shall transition to the RCH_Waiting_Chunk state when:
 Message Transmitted is received from the Protocol Layer.
The Chunked Rx State Machine Shall transition to the RCH_Report_Error state when:
 Transmission Error is received from the Protocol Layer, or
 A Message is received from the Protocol Layer.

6.11.2.1.2.5 RCH_Waiting_Chunk State

On entry to the RCH_Waiting_Chunk state the Chunked Rx state machine Shall:
 Start the ChunkSenderResponseTimer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 191
The Chunked Rx State Machine Shall transition to the RCH_Processing_Extended_Message state when:
 A Chunk is received from the Protocol Layer.
The Chunked Rx State Machine Shall transition to the RCH_Report_Error state when:
 A Message, other than a Chunk, is received from the Protocol Layer, or
 The ChunkSenderResponseTimer expires.

6.11.2.1.2.6 RCH_Report_Error State

The Chunked Rx State Machine Shall enter the RCH_Report_Error state:
 When any Message is received and the Chunked Rx State Machine is not in one of the states RCH_Waiting_Chunk
or RCH_Wait_For_Message_From_Protocol_Layer.
On entry to the RCH_Report_Error state the Chunked Rx state machine Shall:
 Report the error to the Policy Engine.
 If the state was entered because a Message was received, this Message Shall be passed to the Policy Engine.
The Chunked Rx State Machine Shall transition to the RCH_Wait_For_Message_From_Protocol_Layer state when:
 The error has been reported.
 Any message received was passed to the Policy Engine.

Page 192 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.11.2.1.3 Chunked Tx State Diagram
Figure 6-48 shows the state behavior for the Chunked Tx State Machine. This recognizes whether chunked
transmitted messages are involved, and deals with sending chunks and waiting for chunk requests when they are. It
also performs validity checks on all related messages related to chunking.

Figure 6-48 Chunked Tx State Diagram

Soft Reset occured |

Exit from Hard Reset

Start

TCH_ Wait_ For_Message_Request_From_Policy_Engine

Actions on entry:
Clear Abort Flag

Chunking &
Non-Extended Message Request | Message passed
Extended Message Request
Informed Not Chunking to Chunked Rx
(Rx Chunking Abort Flag Set
State != (Rx Chunking
RCH_Wait_For_ State !=
TCH_Pass_Down_Message Message_From_ TCH_Prepare_To_Send_ RCH_Wait_For_ TCH_Message_Received
Reported
Protocol_Layer) & Chunked_Message Message_From_
Actions on entry: Protocol_Layer) & Actions on entry:
Pass Message to Protocol Layer Abort Supported Actions on entry: Clear Extended Message Buffers
Abort Not Supported Pass Message to Chunked Rx
'Chunk Number To Send' = 0

Message
Passed

TCH_Wait_For_ Tx Error from TCH_Report_Error

Chunk Number Set
Transmision_Complete Protocol Layer
Actions on entry:
Actions on entry: Report Error to Policy Engine
Any Message Received and
not in state
TCH_Wait_Chunk_Request
TCH_Construct_
(Chunk Request Rcvd &
Chunked_Message
Message Transmitted Chunk Number != Actions on entry: Other
Transmission Construct Message Chunk and pass
received from Chunk Number to Send) Message
Error to Protocol Layer
Protocol Layer Received

TCH_Message_Sent
Chunk
Actions on entry: Passed
Inform Policy Engine of Message
Sent
Chunk Request Rcvd &
Chunk Number =
TCH_Sending_ Chunk Number to Send
Message Transmitted
Chunked_Message
Actions on entry:
received from Protocol Layer &
Last Chunk

ChunkSenderRequestTimer
timeout
Message Transmitted
from Protocol Layer &
Not Last Chunk

TCH_Wait_Chunk_Request
Actions on entry:
Increment Chunk Number to Send
Start ChunkSenderRequestTimer

6.11.2.1.3.1 TCH_Wait_For_Message_Request_From_Policy_Engine State

The Chunked Tx State Machine Shall enter the TCH_Wait_For_Message_Request_From_Policy_Engine state:
 At startup.
 As a result of a Soft Reset occurring.
 On exit from a Hard Reset.
On entry to the TCH_Wait_For_Message_Request_From_Policy_Engine state the Chunked Tx state machine clears the
optional Abort Flag.
In the TCH_Wait_For_Message_Request_From_Policy_Engine state the Chunked Tx State Machine waits until the
Policy Engine sends it a Message Request.
The Chunked Tx State Machine Shall transition to the TCH_Pass_Down_Message state when:

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 193
 A non-Extended Message Request is received from the Policy Engine, or
 A Message Request is received from the Policy Engine and the link is not Chunking.
The Chunked Tx State Machine Shall transition to the TCH_Prepare_To_Send_Chunked_Message state when:
 An Extended Message Request is received from the Policy Engine, and the link is Chunking.
The Chunked Tx State Machine Shall Discard the Message Request and remain in the
TCH_Wait_For_Message_Request_From_Policy_Engine state when:
 The Chunked Rx state is any other than TCH_Wait_For_Message_Request_From_Policy_Engine, and the optional
Abort Flag has not been implemented.
The Chunked Tx State Machine Shall Discard the Message Request and enter the TCH_Report_Error state when:
 The Chunked Rx state is any other than TCH_Wait_For_Message_Request_From_Policy_Engine, and the optional
Abort Flag has been implemented.

6.11.2.1.3.2 TCH_Pass_Down_Message State

On entry to the TCH_Pass_Down_Message state the Chunked Tx State Machine Shall pass the message to the Protocol
Layer.
The Chunked Tx State Machine Shall transition to the TCH_Wait_For_Transmision_Complete state when:
 The message has been passed to the Protocol Layer.

6.11.2.1.3.3 TCH_Wait_For_Transmision_Complete State

The Chunked Tx State Machine Shall transition to the TCH_Message_Sent state when:
 Message Transmitted has been received from the Protocol Layer.
The Chunked Tx State Machine Shall transition to the TCH_Report_Error state when:
 Transmission Error has been received from the Protocol Layer.

6.11.2.1.3.4 TCH_Message_Sent State

On entry to the TCH_Message_Sent state the Chunked Tx State Machine Shall:
 Inform the Policy Engine that the Message has been sent.
The Chunked Tx State Machine Shall transition to the TCH_Wait_For_Message_Request_From_Policy_Engine state
when:
 The Policy Engine has been informed.

6.11.2.1.3.5 TCH_Prepare_To_Send_Chunked_Message State

On entry to the TCH_Prepare_To_Send_Chunked_Message state the Chunked Tx State Machine Shall:
 Set 'Chunk Number To Send' to zero.
The Chunked Tx State Machine Shall transition to the TCH_Construct_Chunked_Message state when:
 'Chunk Number To Send' has been set to zero.

6.11.2.1.3.6 TCH_Construct_Chunked_Message State

On entry to the TCH_Construct_Chunked_Message state the Chunked Tx State Machine Shall:
 Construct a Message Chunk and pass it to the Protocol Layer.

Page 194 USB Power Delivery Specification Revision 3.0, Version 1.1
The Chunked Tx State Machine Shall transition to the TCH_Sending_Chunked_Message state when:
 The Message Chunk has been passed to the Protocol Layer.
The Chunked Tx State Machine Shall transition to the TCH_Wait_For_Message_Request_From_Policy_Engine state
when:
 The optional Abort Flag is set.

6.11.2.1.3.7 TCH_Sending_Chunked_Message State

The Chunked Tx State Machine Shall transition to the TCH_Wait_Chunk_Request state when:
 Message Transmitted is received from Protocol Layer and this was not the last chunk.
The Chunked Tx State Machine Shall transition to the TCH_Message_Sent state when:
 Message Transmitted is received from Protocol Layer and this was the last chunk.
The Chunked Tx State Machine Shall transition to the TCH_Report_Error state when:
 Transmission Error has been received from the Protocol Layer.

6.11.2.1.3.8 TCH_Wait_Chunk_Request State

On entry to the TCH_Wait_Chunk_Request state the Chunked Tx State Machine Shall:
 Increment Chunk Number to Send.
 Start ChunkSenderRequestTimer.
The Chunked Tx State Machine Shall transition to the TCH_Report_Error state when:
 A Chunk Request has been received and the Chunk Number does not equal Chunk Number to Send).
The Chunked Tx State Machine Shall transition to the TCH_Message_Sent state when:
 ChunkSenderRequestTimer has expired.
Note that this is the mechanism which allows the remote port partner or cable marker to omit the chunking layer.
The Policy Engine will receive a Message Sent signal if the remote port partner or cable marker is present (GoodCRC
Message received) but does not sent a Chunk Request. After this the remote port partner will send a Not_Supported
Message, or the Cable Marker will Ignore the Chunked Message.
The Chunked Tx State Machine Shall transition to the TCH_Message_Received state when:
 Any other message than Chunk Request is received.

6.11.2.1.3.9 TCH_Message_Received State

The Chunked Tx State Machine Shall enter the TCH_Message_Received state:
 When any Message is received and the Chunked Tx State Machine is not in the TCH_Wait_Chunk_Request state.
On entry to the TCH_Message_Received state the Chunked Tx State Machine Shall:
 Clear the Extended Message Buffers.
 Pass the received Message to Chunked Rx Engine.
The Chunked Tx State Machine Shall transition to the TCH_Wait_For_Message_Request_From_Policy_Engine state
when:
 The received message has been passed to the Chunked Rx Engine.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 195
 6.11.2.1.3.10 TCH_Report_Error State
On entry to the TCH_Report_Error state the Chunked Tx State Machine Shall:
 Report the error to the Policy Engine.
The Chunked Tx State Machine Shall transition to the TCH_Wait_For_Message_Request_From_Policy_Engine state
when:
 The error has been reported.

Page 196 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.11.2.1.4 Chunked Message Router State Diagram

Figure 6-49 shows the state behavior for the Chunked Message Router. This determines to which state machine an
incoming message is routed to (Chunked Rx, Chunked Tx or direct to Policy Engine).

Figure 6-49 Chunked Message Router State Diagram

Start
RTR_Wait_for_
Soft Reset occured | Message_From_
Exit from Hard Reset Protocol_Layer
Actions on entry:

Sent Sent

Received Ping
From Protocol Layer
Message (not Ping) Message (not Ping)
Received from Received from
Protocol Layer & Sent Protocol Layer &
Not Doing Tx Chunks1 Doing Tx Chunks1

RTR_Rx_Chunks RTR_Ping RTR_Tx_Chunks

Actions on entry: Actions on entry: Actions on entry:

Send message to Rx Chunk Send message to Policy Engine Send message to Tx Chunk
Machine Machine

1 Doing
Tx Chunks means that Chunked Tx State Machine is not in the
TCH_Wait_For_Message_Request_From_Policy_Engine state
2 Messages are taken to include notification about transmission success or otherwise of Messages

6.11.2.1.4.1 RTR_Wait_for_Message_From_Protocol_Layer State

In the RTR_Wait_for_Message_From_Protocol_Layer state the Chunked Message Router waits until the Protocol
Layer sends it a received Message.
The Chunked Message Router Shall transition to the RTR_Rx_Chunks state when:
 A Message other than a Ping Message is received from the Protocol Layer, and the combined Chunking is not
doing Tx Chunks.
The Chunked Message Router Shall transition to the RTR_Tx_Chunks state when:
 A Message other than a Ping Message is received from the Protocol Layer, and the combined Chunking is doing Tx
Chunks.
The Chunked Message Router Shall transition to the RTR_Ping state when:
 A Ping Message is received from the Protocol Layer.

6.11.2.1.4.2 RTR_Rx_Chunks State

On entry to the RTR_Rx_Chunks state the Chunked Message Router Shall:
 Send the message to the Chunked Rx State Machine.
 Transition to the RTR_Wait_for_Message_From_Protocol_Layer state.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 197
 6.11.2.1.4.3 RTR_Ping State
On entry to the RTR_Ping state the Chunked Message Router Shall:
 Send the message to the Policy Engine.
 Transition to the RTR_Wait_for_Message_From_Protocol_Layer state.

6.11.2.1.4.4 RTR_Tx_Chunks State

On entry to the RTR_Tx_Chunks state the Chunked Message Router Shall:
 Send the message to the Chunked Tx State Machine.
 Transition to the RTR_Wait_for_Message_From_Protocol_Layer state.

Page 198 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.11.2.2 Protocol Layer Message Transmission

6.11.2.2.1 Common Protocol Layer Message Transmission State Diagram

Figure 6-50 shows the state behavior, common between the Source and the Sink, for the Protocol Layer when
transmitting a Message.

Figure 6-50 Common Protocol Layer Message transmission State Diagram

Soft Reset Message from PHY Layer |

Start Exit from Hard Reset

PRL_Tx_Discard_Message Protocol Layer

PRL_Tx_PHY_Layer_Reset Actions on entry: message reception
If any message is currently awaiting in PRL_Rx_Store_MessageID state |
Actions on entry: Discarding transmission Discard4 and Fast Role Swap signal transmitted |
Reset PHY Layer increment MessageID Counter
complete Fast Role Swap signal detected

PRL_Tx_Layer_Reset_for
_Transmit
Actions on entry:
PHY Layer reset Reset MessageIDCounter.
complete Protocol Layer message reception
transitions to
PRL_Rx_Wait_for_PHY_Message
state.
Soft Reset Message request received Layer Reset Complete
from Policy Engine
PRL_Tx_Wait_for_ PRL_Tx_Construct_Message
Message_Request
Actions on entry:
Actions on entry: Message request received Construct message
Reset RetryCounter Pass message to PHY Layer
from Policy Engine (except Soft Reset)

(RetryCounter ≤ nRetryCount) &

Message sent to
Policy Engine informed not Cable Plug &
PHY Layer
of Transmission Error small Extended Message3

PRL_Tx_Transmission_Error (RetryCounter PRL_Tx_Check_RetryCounter PRL_Tx_Wait_for_PHY_response

Policy Engine > nRetryCount) | CRCReceiveTimer
Actions on entry: Actions on entry: Actions on entry:
informed Cable Plug | Timeout |
Increment MessageIDCounter If DFP or UFP increment and check Initialize and run CRCReceiveTimer1
message sent large RetryCounter Message discarded bus Idle2
Inform Policy Engine of
Transmission Error Extended Message3

GoodCRC response
MessageID mismatch received from PHY Layer

PRL_Tx_Message_Sent PRL_Tx_Match_MessageID
Actions on entry: MessageID match Actions on entry:
Increment MessageIDCounter Match MessageIDCounter and
Inform Policy Engine message response MessageID
sent

1The CRCReceiveTimer is only started after the PHY has sent the message. If the message is not sent due to a busy
channel then the CRCReceiveTimer will not be started (see Section 6.6.1).
2This indication is sent by the PHY Layer when a message has been Discarded due to CC being busy, and after CC
becomes idle again (see Section 5.7). The CRCReceiveTimer is not running in this case since no message has been
sent.
3A “small” Extended Message is either an Extended Message with Data Size ≤ MaxExtendedMsgLegacyLen bytes or
an Extended Message with Data Size > MaxExtendedMsgLegacyLen bytes that has been Chunked. A “large”
Extended Message is an Extended Message with Data Size > MaxExtendedMsgLegacyLen bytes that has not been
Chunked.
4 See Section 6.10 for details of when Messages are Discarded.

6.11.2.2.1.1 PRL_Tx_PHY_Layer_Reset State

The Protocol Layer Shall enter the PRL_Tx_PHY_Layer_Reset state:
 At startup.
 As a result of a Soft Reset request being received by the PHY Layer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 199
 On exit from a Hard Reset.
On entry to the PRL_Tx_PHY_Layer_Reset state the Protocol Layer Shall reset the PHY Layer (clear any outstanding
Messages and enable communications).
The Protocol Layer Shall transition to the PRL_Tx_Wait_for_Message_Request state when:
 When the PHY Layer reset is complete.

6.11.2.2.1.2 PRL_Tx_Wait_for_Message_Request State

In the PRL_Tx_Wait_for_Message_Request state the Protocol Layer waits until the Policy Engine directs it to send a
Message.
On entry to the PRL_Tx_Wait_for_Message_Request state the Protocol Layer Shall reset the RetryCounter.
The Protocol Layer Shall transition to the PRL_Tx_Construct_Message state when:
 A Message request is received from the Policy Engine which is not a Soft_Reset Message.
The Protocol Layer Shall transition to the PRL_Tx_Layer_Reset_for_Transmit state when:
 A Message request is received from the Policy Engine which is a Soft_Reset Message.

6.11.2.2.1.3 PRL_Tx_Layer_Reset_for_Transmit State

On entry to the PRL_Tx_Layer_Reset_for_Transmit state the Protocol Layer Shall reset the MessageIDCounter. The
Protocol Layer Shall transition Protocol Layer Message reception to the PRL_Rx_Wait_for_PHY_Message state (see
Section 6.11.2.3.1) in order to reset the stored MessageID.
The Protocol Layer Shall transition to the PRL_Tx_Construct_Message state when:
 The layer reset actions in this state have been completed.

6.11.2.2.1.4 PRL_Tx_Construct_Message State

On entry to the PRL_Tx_Construct_Message state the Protocol Layer Shall construct the Message requested by the
Policy Engine, or resend a previously constructed Message, and then pass this Message to the PHY Layer.
The Protocol Layer Shall transition to the PRL_Tx_Wait_for_PHY_Response state when:
 The Message has been sent to the PHY Layer.

6.11.2.2.1.5 PRL_Tx_Wait_for_PHY_Response State

On entry to the PRL_Tx_Wait_for_PHY_Response state, once the Message has been sent, the Protocol Layer Shall
initialize and run the CRCReceiveTimer (see Section 6.6.1).
The Protocol Layer Shall transition to the PRL_Tx_Match_MessageID state when:
 A GoodCRC Message response is received from the PHY Layer.
The Protocol Layer Shall transition to the PRL_Tx_Check_RetryCounter state when:
 The CRCReceiveTimer times out.
 Or the PHY Layer indicates that a Message has been Discarded due to the channel being busy but the channel is
now idle (see Section 5.7).

6.11.2.2.1.6 PRL_Tx_Match_MessageID State

On entry to the PRL_Tx_Match_MessageID state the Protocol Layer Shall compare the MessageIDCounter and the
MessageID of the received GoodCRC Message.
The Protocol Layer Shall transition to the PRL_Tx_Message_Sent state when:

Page 200 USB Power Delivery Specification Revision 3.0, Version 1.1
 The MessageIDCounter and the MessageID of the received GoodCRC Message match.
The Protocol Layer Shall transition to the PRL_Tx_Check_RetryCounter state when:
 The MessageIDCounter and the MessageID of the received GoodCRC Message do not match.

6.11.2.2.1.7 PRL_Tx_Message_Sent State

On entry to the PRL_Tx_Message_Sent state the Protocol Layer Shall increment the MessageIDCounter and inform
the Policy Engine that the Message has been sent.
The Protocol Layer Shall transition to the PRL_Tx_Wait_for_Message_Request state when:
 The Policy Engine has been informed that the Message has been sent.

6.11.2.2.1.8 PRL_Tx_Check_RetryCounter State

On entry to the PRL_Tx_Check_RetryCounter state the Protocol Layer in a DFP or UFP Shall increment the value of the
RetryCounter and then check it in order to determine whether it is necessary to retry sending the Message. Note that
Cable Plugs do not retry Messages and so do not use the RetryCounter.
The Protocol Layer Shall transition to the PRL_Tx_Construct_Message state in order to retry Message sending when:
 RetryCounter ≤ nRetryCount and
 This is not a Cable Plug and
 This is an Extended Message with Data Size ≤ MaxExtendedMsgLegacyLen or
 This is an Extended Message that has been Chunked.
The Protocol Layer Shall transition to the PRL_Tx_Transmission_Error state when:
 RetryCounter > nRetryCount or
 This is a Cable Plug, which does not retry.
 This is an Extended Message with Data Size > MaxExtendedMsgLegacyLen that has not been Chunked.

6.11.2.2.1.9 PRL_Tx_Transmission_Error State

On entry to the PRL_Tx_Transmission_Error state the Protocol Layer Shall increment the MessageIDCounter and
inform the Policy Engine of the transmission error.
The Protocol Layer Shall transition to the PRL_Tx_Wait_for_Message_Request state when:
 The Policy Engine has been informed of the transmission error.

6.11.2.2.1.10 PRL_Tx_Discard_Message State

Protocol Layer Message transmission Shall enter the PRL_Tx_Discard_Message state whenever:
 Protocol Layer Message reception receives an incoming Message or
 The Fast Role Swap signal is being transmitted (see Section 5.8.5.6)
 The Fast Role Swap signal is detected (see Section 5.8.6.3).
On entry to the PRL_Tx_Discard_Message state, if there is a Message queued awaiting transmission, the Protocol
Layer Shall Discard the Message according to the rules in Section 6.10 and increment the MessageIDCounter.
The Protocol Layer Shall transition to the PRL_Tx_PHY_Layer_Reset state when:
 Discarding is complete i.e. the Message queue is empty.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 201
 6.11.2.2.2 Source Protocol Layer Message Transmission State Diagram
Figure 6-51 shows the state behavior for the Protocol Layer in a Source when transmitting a Message.

Figure 6-51 Source Protocol Layer Message transmission State Diagram

PRL_Tx_Src_Sink_Tx

Actions on entry:
Set Rp = SinkTxOk

Rp set End of AMS notification received

from Policy Engine

PRL_Tx_Wait_for_Message_Request

Start of AMS notification

received from Policy Engine

PRL_Tx_Src_Source_Tx

Actions on entry:
Set Rp = SinkTxNG

Message request
from Policy Engine

PRL_Tx_Src_Pending

Actions on entry:
Start SinkTxTimer

Soft Reset Message pending & Message pending (except Soft Reset) &
SinkTxTimer timeout SinkTxTimer timeout

PRL_Tx_Layer_Reset_for_Transmit PRL_Tx_Construct_Message

6.11.2.2.2.1 PRL_Tx_Src_Sink_Tx State

In the PRL_Tx_Src_Sink_Tx state the Source sets Rp to SinkTxOk allowing the Sink to start an Atomic Message
Sequence (AMS).
The Protocol Layer in a Source Shall transition from the PRL_Tx_Wait_for_Message_Request state to the
PRL_Tx_Src_Sink_Tx state when:
 A notification is received from the Policy Engine that the end of an AMS has been reached.
On entry to the PRL_Tx_Src_Sink_Tx state the Protocol Layer Shall request the PHY Layer to Rp to SinkTxOk.

Page 202 USB Power Delivery Specification Revision 3.0, Version 1.1
The Protocol Layer Shall transition to the PRL_Tx_Wait_for_Message_Request state when:
 Rp has been set

6.11.2.2.2.2 PRL_Tx_Src_Source_Tx State

In the PRL_Tx_Src_Source_Tx state the Source sets Rp to SinkTxNG allowing the Source to start an Atomic Message
Sequence (AMS).
The Protocol Layer in a Source Shall transition from the PRL_Tx_Wait_for_Message_Request state to the
PRL_Tx_Src_Source_Tx state when:
 A notification is received from the Policy Engine that an AMS will be starting.
On entry to the PRL_Tx_Src_Source_Tx state the Protocol Layer Shall set Rp to SinkTxNG.
The Protocol Layer Shall transition to the PRL_Tx_Src_Pending state when:
 A Message request is received from the Policy Engine.

6.11.2.2.2.3 PRL_Tx_Src_Pending State

In the PRL_Tx_Src_Pending state the Protocol Layer has a Message buffered ready for transmission.
On entry to the PRL_Tx_Src_Pending state the SinkTxTimer Shall be initialized and run.
The Protocol Layer Shall transition to the PRL_Tx_Construct_Message state when:
 The pending Message request from the Policy Engine is not a Soft_Reset Message and
 The SinkTxTimer times out.
The Protocol Layer Shall transition to the PRL_Tx_Layer_Reset_for_Transmit state when:
 The pending Message request from the Policy Engine is a Soft_Reset Message and
 The SinkTxTimer times out.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 203
 6.11.2.2.3 Sink Protocol Layer Message Transmission State Diagram
Figure 6-52 shows the state behavior for the Protocol Layer in a Source when transmitting a Message.

Figure 6-52 Sink Protocol Layer Message transmission State Diagram

PRL_Tx_Wait_for_Message_Request

First Message in AMS notification received

from Policy Engine

PRL_Tx_Snk_Start_of_AMS

Actions on entry:

Message Request from Policy Engine

PRL_Tx_Snk_Pending

Actions on entry:

Soft Reset Message pending & Message pending (except Soft Reset) &
Rp = SinkTxOk Rp = SinkTxOk

PRL_Tx_Layer_Reset_for_Transmit PRL_Tx_Construct_Message

6.11.2.2.3.1 PRL_Tx_Snk_Start_of_AMS State

In the PRL_Tx_Snk_Start_of_AMS state the Protocol Layer waits for the first Message in a Sink initiated AMS.
The Protocol Layer in a Sink Shall transition from the PRL_Tx_Wait_for_Message_Request state to the
PRL_Tx_Snk_Start_of_AMS state when:
 A notification is received from the Policy Engine that the next Message the Sink will send is the start of an AMS.
The Protocol Layer Shall transition to the PRL_Tx_Snk_Pending state when:
 A Message request is received from the Policy Engine.

6.11.2.2.3.2 PRL_Tx_Snk_Pending State

In the PRL_Tx_Snk_Pending state the Protocol Layer has the first Message in a Sink initiated AMS ready to send and is
waiting for Rp to transition to SinkTxOk before sending the Message.
The Protocol Layer Shall transition to the PRL_Tx_Construct_Message state when:
 A Message is Pending that is not a Soft_Reset Message and
 Rp is set to SinkTxOk.
The Protocol Layer Shall transition to the PRL_Tx_Layer_Reset_for_Transmit state when:
 A Soft_Reset Message is pending and
 Rp is set to SinkTxOk.

Page 204 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.11.2.3 Protocol Layer Message Reception
Figure 6-53 shows the state behavior for the Protocol Layer when receiving a Message.

Figure 6-53 Protocol layer Message reception

PRL_Rx_Layer_Reset_
for_Receive
Actions on entry:
Reset MessageIDCounter and clear
stored MessageID value
Soft Reset request from Policy Engine | Protocol Layer message
transmission transitions to
Exit from Hard Reset PRL_Tx_PHY_Layer_Reset state.

Start
Soft Reset Message received Soft Reset complete
from PHY

Message received
PRL_Rx_Wait_for_PHY_ from PHY (except Soft Reset) PRL_Rx_Send_GoodCRC
message
Actions on entry:
Actions on entry:
Message discarded bus Idle1 Send GoodCRC message to PHY

MessageID = stored
Message passed to MessageID (GoodCRC sent | Message discarded bus Idle1)
Policy Engine

PRL_Rx_Store_MessageID
PRL_Rx_Check_MessageID
Actions on entry:
Actions on entry:
Protocol Layer message transmission MessageID <> stored If there is a stored value compare
transitions to PRL_Tx_Discard_Message MessageID | MessageID with stored value.
state2. no stored value
Store new MessageID
Pass message to Policy Engine

1This indication is sent by the PHY when a message has been Discarded due to CC being busy, and after CC
becomes idle again (see Section 5.7). Two alternate allowable transitions are shown.
2In the case of a Ping message being received, in order to maintain robust communications in the presence of
collisions, the outgoing message Should Not be Discarded.

6.11.2.3.1 PRL_Rx_Wait_for_PHY_Message state

The Protocol Layer Shall enter the PRL_Rx_Wait_for_PHY_Message state:
 At startup.
 As a result of a Soft Reset request from the Policy Engine.
 On exit from a Hard Reset.
In the PRL_Rx_Wait_for_PHY_Message state the Protocol Layer waits until the PHY Layer passes up a received
Message.
The Protocol Layer Shall transition to the PRL_Rx_Send_GoodCRC state when:
 A Message is passed up from the PHY Layer.
The Protocol Layer Shall transition to the PRL_Rx_Layer_Reset_for_Receive state when:
 A Soft_Reset Message is received from the PHY Layer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 205
 6.11.2.3.2 PRL_Rx_Layer_Reset_for_Receive state
On entry to the PRL_Rx_Layer_Reset_for_Receive state the Protocol Layer Shall reset the MessageIDCounter and
clear the stored MessageID. The Protocol Layer Shall transition Protocol Layer Message transmission to the
PRL_Tx_Wait_for_Message_Request state (see Section 6.11.2.2.1.1).
The Protocol Layer Shall transition to the PRL_Rx_Send_GoodCRC State when:
 The Soft Reset actions in this state have been completed.

6.11.2.3.3 PRL_Rx_Send_GoodCRC state

On entry to the PRL_Rx_Send_GoodCRC state the Protocol Layer Shall construct a GoodCRC Message and request the
PHY Layer to transmit it.
The Protocol Layer Shall transition to the PRL_Rx_Check_MessageID state when:
 The GoodCRC Message has been passed to the PHY Layer.
When the PHY Layer indicates that a Message has been Discarded due to CC being busy but CC is now idle (see
Section 5.7), the Protocol Layer Shall either:
 Transition to the PRL_Rx_Check_MessageID state or
 Transition to the PRL_Rx_Wait_for_PHY_Message state.

6.11.2.3.4 PRL_Rx_Check_MessageID state

On entry to the PRL_Rx_Check_MessageID state the Protocol Layer Shall compare the MessageID of the received
Message with its stored value if a value has previously been stored.
The Protocol Layer Shall transition to the PRL_Rx_Wait_for_PHY_Message state when:
 The MessageID of the received Message equals the stored MessageID value since this is a Message retry which
Shall be Discarded.
The Protocol Layer Shall transition to the PRL_Rx_Store_MessageID state when:
 The MessageID of the received Message does not equal the stored MessageID value since this is a new Message
or
 This is the first received Message and no MessageID value is currently stored.

6.11.2.3.5 PRL_Rx_Store_MessageID state

On entry to the PRL_Rx_Store_MessageID state the Protocol Layer Shall transition Protocol Layer Message
transmission to the PRL_Tx_Discard_Message state (except when a Ping Message has been received in which case the
PRL_Tx_Discard_Message state Should Not be entered), replace the stored value of MessageID with the value of
MessageID in the received Message and pass the Message up to the Policy Engine.
The Protocol Layer Shall transition to the PRL_Rx_Wait_for_PHY_Message state when:
 The Message has been passed up to the Policy Engine.

Page 206 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.11.2.4 Hard Reset operation
Figure 6-54 shows the state behavior for the Protocol Layer when receiving a Hard Reset or Cable Reset request from
the Policy Engine or Hard Reset Signaling or Cable Reset Signaling from the Physical Layer (see also Section 6.8.2 and
Section 6.8.3).

Figure 6-54 Hard/Cable Reset

Hard Reset request received from Policy Engine2 |

Cable Reset request received from Policy Engine4 |
Hard Reset signalling received By PHY Layer |
Cable Reset signalling received By PHY Layer3

PRL_HR_Reset_Layer
Actions on entry:
Reset MessageIDCounter.
Protocol Layer message transmission
transitions to
PRL_Tx_Wait_For_Message_Request state.
Protocol Layer message reception transitions
to PRL_Rx_Wait_for_PHY_Message state.

Protocol Layer reset complete & Protocol Layer reset complete &
(Hard Reset was Initiated by Policy Engine | (Hard Reset was initiated by Port Partner |
Cable Reset was Initiated by Policy Engine) Cable Reset received by Cable Plug)

PRL_HR_Request_Hard_Reset PRL_HR_Indicate_Hard_Reset
Actions on entry: Actions on entry:
Request PHY to perform a Hard Reset Inform the Policy Engine of the Hard
or Cable Reset Reset or Cable Reset

PHY Hard Reset request sent |

PHY Cable Reset request sent

PRL_HR_Wait_For_PHY_
Hard_Reset_Complete
Actions on entry:
Start HardResetCompleteTimer
Wait for Hard Reset or Cable Reset complete
indication from PHY

Policy Engine informed

Hard Reset complete from PHY |
Cable Reset complete from PHY |
HardResetCompleteTimer timeout1

PRL_HR_PHY_Hard_Reset_Requested
Actions on entry:
Inform Policy Engine Hard Reset or Cable
Reset request has been sent

Policy Engine informed

PRL_HR_Wait_For_PE_Hard_Reset_Complete
Actions on entry:
Wait for Hard Reset or Cable Reset complete indication
from Policy Engine.

Hard Reset complete from Policy Engine |

Cable Reset complete from Policy Engine

PRL_HR_PE_Hard_Reset_Complete
Actions on entry:
Inform Physical Layer Hard Reset or
Cable Reset is complete

Physical Layer informed

Exit from Hard Reset

1If the HardResetCompleteTimer timeout occurs this means that the PHY is still waiting to send the Hard Reset
due to a non-idle channel. This condition will be cleared once the PE Hard Reset is completed.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 207
 2 CablePlugs do not generate Hard Reset signaling but are required to monitor for Hard Reset signaling between
the Port Partners and respond by resetting.
3 Cable Reset signaling is only recognized by a Cable Plug.
4 Cable Reset signaling cannot be generated by Cable Plugs

6.11.2.4.1 PRL_HR_Reset_Layer state

The PRL_HR_Reset_Layer State defines the mode of operation of both the Protocol Layer transmission and reception
state machines during a Hard Reset or Cable Reset. During Hard Reset no USB Power Delivery protocol Messages are
sent or received; only Hard Reset Signaling is present after which the communication channel is assumed to have
been disabled by the Physical Layer until completion of the Hard Reset. During Cable Reset no USB Power Delivery
protocol Messages are sent to or received by the Cable Plug but other USB Power Delivery communication May
continue.
The Protocol Layer Shall enter the PRL_HR_Reset_Layer state from any other state when:
 A Hard Reset Request is received from the Policy Engine or
 Hard Reset Signaling is received from the Physical Layer or
 A Cable Reset Request is received from the Policy Engine or
 Cable Reset Signaling is received from the Physical Layer.
On entry to the PRL_HR_Reset_Layer state the Protocol Layer Shall reset the MessageIDCounter. It Shall also reset
the states of the Protocol Layer transmission and reception state machines to their starting points. The Protocol Layer
transmission state machine Shall transition to the PRL_Tx_Wait_for_Message_Request state. The Protocol Layer
reception state machine Shall transition to the PRL_Rx_Wait_for_PHY_Message state.
The Protocol Layer Shall transition to the PRL_HR_Request_Hard_Reset state when:
 The Protocol Layer’s reset is complete and
o The Hard Reset request has originated from the Policy Engine or
o The Cable Reset request has originated from the Policy Engine.
The Protocol Layer Shall transition to the PRL_HR_Indicate_Hard_Reset state when:
 The Protocol Layer’s reset is complete and
o The Hard Reset request has been passed up from the Physical Layer or
o A Cable Reset request has been passed up from the Physical Layer (Cable Plug only).

6.11.2.4.2 PRL_HR_Indicate_Hard_Reset state

On entry to the PRL_HR_Indicate_Hard_Reset state the Protocol Layer Shall indicate to the Policy Engine that either
Hard Reset Signaling or Cable Reset Signaling has been received.
The Protocol Layer Shall transition to the PRL_HR_Wait_for_PE_Hard_Reset_Complete state when:
 The Indication to the Policy Engine has been sent.

6.11.2.4.3 PRL_HR_Request_Hard_Reset state

On entry to the PRL_HR_Request_Hard_Reset state the Protocol Layer Shall request the Physical Layer to send either
Hard Reset Signaling or Cable Reset signaling.
The Protocol Layer Shall transition to the PRL_HR_Wait_for_PHY_Hard_Reset_Complete state when:
 The Physical Layer Hard Reset Signaling request has been sent or
 The Physical Layer Cable Reset Signaling request has been sent.

Page 208 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.11.2.4.4 PRL_HR_Wait_for_PHY_Hard_Reset_Complete state
In the PRL_HR_Wait_for_PHY_Hard_Reset_Complete state the Protocol Layer Shall start the
HardResetCompleteTimer and wait for the PHY Layer to indicate that the Hard Reset or Cable Reset has been
completed.
The Protocol Layer Shall transition to the PRL_HR_PHY_Hard_Reset_Requested state when:
 A Hard Reset complete indication is received from the PHY Layer or
 A Cable Reset complete indication is received from the PHY Layer or
 The HardResetCompleteTimer times out.

6.11.2.4.5 PRL_HR_PHY_Hard_Reset_Requested state

On entry to the PRL_HR_PHY_Hard_Reset_Requested state the Protocol Layer Shall inform the Policy Engine that the
PHY Layer has been requested to perform a Hard Reset or Cable Reset.
The Protocol Layer Shall transition to the PRL_HR_Wait_for_PE_Hard_Reset_Complete state when:
 The Indication to the Policy Engine has been sent.

6.11.2.4.6 PRL_HR_Wait_for_PE_Hard_Reset_Complete state

In the PRL_HR_Wait_for_PE_Hard_Reset_Complete state the Protocol Layer Shall wait for the Policy Engine to
indicate that the Hard Reset or Cable Reset has been completed.
The Protocol Layer Shall transition to the PRL_HR_PE_Hard_Reset_Complete state when:
 A Hard Reset complete indication is received from the Policy Engine or
 A Cable Reset complete indication is received from the Policy Engine.

6.11.2.4.7 PRL_HR_PE_Hard_Reset_Complete
On entry to the PRL_HR_PE_Hard_Reset_Complete state the Protocol Layer Shall inform the Physical Layer that the
Hard Reset or Cable Reset is complete.
The Protocol Layer Shall exit from the Hard Reset and return to normal operation when:
 The Physical Layer has been informed that the Hard Reset is complete so that it will re-enable the
communications channel. If Hard Reset Signaling is still pending due to a non-idle channel this Shall be cleared
and not sent or
 The Physical Layer has been informed that the Cable Reset is complete.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 209
 6.11.3 List of Protocol Layer States
Table 6-60 lists the states used by the various state machines.

Table 6-60 Protocol Layer States

State name Reference

Protocol Layer Message Transmission
Common Protocol Layer Message Transmission
PRL_Tx_PHY_Layer_Reset Section 6.11.2.2.1.1

PRL_Tx_Wait_for_Message_Request Section 6.11.2.2.1.2

PRL_Tx_Layer_Reset_for_Transmit Section 6.11.2.2.1.3

PRL_Tx_Construct_Message Section 6.11.2.2.1.4

PRL_Tx_Wait_for_PHY_Response Section 6.11.2.2.1.5

PRL_Tx_Match_MessageID Section 6.11.2.2.1.6

PRL_Tx_Message_Sent Section 6.11.2.2.1.7

PRL_Tx_Check_RetryCounter Section 6.11.2.2.1.8

PRL_Tx_Transmission_Error Section 6.11.2.2.1.9

PRL_Tx_Discard_Message Section 6.11.2.2.1.10

Source Protocol Layer Message Transmission
PRL_Tx_Src_Sink_Tx Section 6.11.2.2.2.1

PRL_Tx_Src_Source_Tx Section 6.11.2.2.2.2

PRL_Tx_Src_Pending Section 6.11.2.2.2.3

Sink Protocol Layer Message Transmission
PRL_Tx_Snk_Start_of_AMS Section 6.11.2.2.3.1

PRL_Tx_Snk_Pending Section 6.11.2.2.3.2

Protocol Layer Message Reception
PRL_Rx_Wait_for_PHY_Message Section 6.11.2.3.1

PRL_Rx_Layer_Reset_for_Receive Section 6.11.2.3.2

PRL_Rx_Send_GoodCRC Section 6.11.2.3.3

PRL_Rx_Check_MessageID Section 6.11.2.3.4

PRL_Rx_Store_MessageID Section 6.11.2.3.5

Hard Reset Operation
PRL_HR_Reset_Layer Section 6.11.2.4.1

PRL_HR_Indicate_Hard_Reset Section 6.11.2.4.2

PRL_HR_Request_Hard_Reset Section 6.11.2.4.3

PRL_HR_Wait_for_PHY_Hard_Reset_Complete Section 6.11.2.4.4

PRL_HR_PHY_Hard_Reset_Requested Section 6.11.2.4.5

PRL_HR_Wait_for_PE_Hard_Reset_Complete Section 6.11.2.4.6

PRL_HR_PE_Hard_Reset_Complete Section 6.11.2.4.7

Chunking
Chunked Rx
RCH_Wait_For_Message_From_Protocol_Layer Section 6.11.2.1.2.1

Page 210 USB Power Delivery Specification Revision 3.0, Version 1.1
 State name Reference
RCH_Pass_Up_Message Section 6.11.2.1.2.2

RCH_Processing_Extended_Message Section 6.11.2.1.2.3

RCH_Requesting_Chunk Section 6.11.2.1.2.4

RCH_Waiting_Chunk Section 6.11.2.1.2.5

RCH_Report_Error Section 6.11.2.1.2.6

Chunked Tx
TCH_Wait_For_Message_Request_From_Policy_Engine Section 6.11.2.1.3.1

TCH_Pass_Down_Message Section 6.11.2.1.3.2

TCH_Wait_For_Transmision_Complete Section 6.11.2.1.3.3

TCH_Message_Sent Section 6.11.2.1.3.4

TCH_Prepare_To_Send_Chunked_Message Section 6.11.2.1.3.5

TCH_Construct_Chunked_Message Section 6.11.2.1.3.6

TCH_Sending_Chunked_Message Section 6.11.2.1.3.7

TCH_Wait_Chunk_Request Section 6.11.2.1.3.8

TCH_Message_Received Section 6.11.2.1.3.9

TCH_Report_Error Section 6.11.2.1.3.10

Chunked Message Router
RTR_Wait_for_Message_From_Protocol_Layer Section 6.11.2.1.4.1

RTR_Rx_Chunks Section 6.11.2.1.4.2

RTR_Ping Section 6.11.2.1.4.3

RTR_Tx_Chunks Section 6.11.2.1.4.4

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 211
 6.12 Message Applicability
The following tables outline the Messages supported by a given port, depending on its capability.
When a Message is supported the feature and Message sequence implied by the Message Shall also be supported. For
example Sinks using power for charging that support the GotoMin Message Shall be able to reduce their current draw
when requested via a GotoMin Message.
The following abbreviations are used:
 N – Normative; Shall be supported by this Port/Cable Plug
 CN – Conditional Normative ; Shall be supported by a given Port/Cable Plug based on features
 R – Recommended; Should be supported by this Port/Cable Plug
 O – Optional; May be supported by this Port/Cable Plug
 NS – Not Supported; Shall result in a Not_Supported Message response by this Port/Cable Plug when received.
 I – Ignore; Shall be Ignored by this Port/Cable Plug when received.
 NK – NAK; this Port/Cable Plug Shall return Responder NAK to this Command when received
 NA – Not allowed; Shall Not be transmitted by this Port/Cable Plug.
 DR – Don't Recognize; there Shall no response at all (i.e. not even a GoodCRC Message) from this Port/Cable Plug
when received.
For the case of Conditional Normative a note has been added to indicate the condition. “CN/” notation is used to
indicate the level of support when the condition is not present.
“R/” and “O/” notation is used to indicate the response when the Recommended or Optional Message is not
supported.
Note: that where NS/RJ/NK is indicated for Received Messages this Shall apply to the PE_CBL_Ready, PE_SNK_Ready
or PE_SRC_Ready states only since unexpected Messages received during a Message sequence are Protocol Errors (see
Section 6.8.1).
This section covers Control and Data Message support for Sources, Sink and Cable Plugs. It also covers VDM
Command support for DFPs, UFPs and Cable Plugs.

Page 212 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.12.1 Applicability of Control Messages
Table 6-61 details Control Messages that Shall/Should/ Shall Not be transmitted and received by a Source, Sink or
Cable Plug. Requirements for Dual-Role Power Ports and Dual-Role Data Ports Shall override any requirements for
Source-only or Sink-Only Ports.

Table 6-61 Applicability of Control Messages

Message Type Source Sink Dual-Role Dual-Role Cable Plug

Power Data
Transmitted Message
Accept N N N

DR_Swap O O N NA

FR_Swap NA NA R NA

Get_Country_Codes CN10/NA CN10/NA NA

Get_PPS_Status NA CN9 NA
Get_Sink_Cap R NA N NA

Get_Source_Cap NA R N NA

Get_Source_Cap_Extended NA R R NA

Get_Status R R NA

GoodCRC N N N

GotoMin CN1/O NA NA

Ping O NA NA

PR_Swap NA NA N NA

PS_RDY N NA N NA

Reject N NA O O NA

Soft_Reset N N NA

VCONN_Swap R R NA

Wait CN2/O NA O O NA
Received Message
Accept N N N N I

DR_Swap O/NS O/NS N I

FR_Swap NS NS CN7/NS I

Get_Country_Codes CN10/NS CN10/NS I

Get_PPS_Status CN9/NS NS I

Get_Sink_Cap NS N N I

Get_Source_Cap N NS N I

Get_Source_Cap_Extended CN5/NS NS CN5/NS I

Get_Status CN6/NS CN6/NS CN6/NS I

GoodCRC N N N

GotoMin NS R3 I

Ping NS I I

PR_Swap NS NS N I

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 213
 Message Type Source Sink Dual-Role Dual-Role Cable Plug
Power Data
PS_RDY NS N N I

Reject CN8/NS N N N I

Soft_Reset N N N

VCONN_Swap CN4/ NS CN4/ NS I

Wait CN8/NS N N N I
Note 1: Shall be supported by a Hub with multiple Downstream Ports. Should be supported by a Host with
multiple Downstream Ports.
Note 2: Shall be supported when transmission of GotoMin Messages is supported.
Note 3: Should be supported by Sinks which use PD power for charging.
Note 4: Shall be supported by any Port that can operate as a VCONN Source.
Note 5: Shall be supported products that support the Source_Capabilities_Extended Message.
Note 6: Shall be supported by Sources that support the Alert Message.
Note 7: Shall be supported when the Fast Role Swap signal is supported.
Note 8: Shall be supported when VCONN_Swap is supported.
Note 9: Shall be supported when PPS is supported.
Note 10: Shall be supported when required by a country authority.

6.12.2 Applicability of Data Messages

Table 6-62 details Data Messages (except for VDM Commands) that Shall/Should/ Shall Not be transmitted and
received by a Source, Sink or Cable Plug. Requirements for Dual-Role Power Ports Shall override any requirements
for Source-only or Sink-Only Ports.

Table 6-62 Applicability of Data Messages

Message Type Source Sink Dual-Role Cable Plug

Power
Transmitted Message
Source_Capabilities N NA N NA

Request NA N NA

Get_Country_Info CN5/O CN5/O NA

BIST N1 N1 NA

Sink_Capabilities NA N N NA

Battery_Status CN2 CN2 NA

Alert R R NA
Received Message
Source_Capabilities NS N N I

Request N NS I

Get_Country_Info CN5/NS CN5/NS I

BIST N1 N1 N1

Sink_Capabilities CN4 NS CN4 I

Battery_Status CN3/NS CN3/NS I

Alert R/NS R/NS I

Page 214 USB Power Delivery Specification Revision 3.0, Version 1.1
 Message Type Source Sink Dual-Role Cable Plug
Power
Note 1: For details of which BIST Modes and Messages Shall be supported see Section 5.9 and
Section 6.4.3.
Note 2: Shall be supported by products that contain batteries.
Note 3: Shall be supported by products that support the Get_Battery_Status Message.
Note 4: Shall be supported by products that support the Get_Sink_Cap Message.
Note 5: Shall be supported when required by a country authority.

6.12.3 Applicability of Extended Messages

Table 6-63 details Extended Messages (except for Extended VDM Commands) that Shall/Should/ Shall Not be
transmitted and received by a Source, Sink or Cable Plug. Requirements for Dual-Role Power Ports Shall override any
requirements for Source-only or Sink-Only Ports.

Table 6-63 Applicability of Extended Messages

Message Type Source Sink Dual-Role Cable Plug

Power
Transmitted Message
Battery_Capabilities CN1/NA CN1/NA NA

Country_Codes CN10/NA CN10/NA NA

Country_Info CN10/NA CN10/NA NA

Firmware_Update_Request CN7/NA CN7/NA NA

Firmware_Update_Response CN7/NA CN7/NA CN7/NA

Get_Battery_Cap R R NA

Get_Battery_Status R R NA

Get_Manufacturer_Info R R NA

Manufacturer_Info R R R

PPS_Status CN8/NA NA NA

Security_Request CN6/NA CN6/NA NA

Security_Response CN6/NA CN6/NA CN6/NA

Source_Capabilities_Extended R NA R NA

Status R R R NA
Received Message
Battery_Capabilities CN4/NS CN4/NS I

Country_Codes CN10/NS CN10/NS I

Country_Info CN10/NS CN10/NS I

Firmware_Update_Request CN7/NS CN7/NS CN7/I

Firmware_Update_Response CN7/NS CN7/NS I

Get_Battery_Cap CN1/NS CN1/NS I

Get_Battery_Status CN1/NS CN1/NS I

Get_Manufacturer_Info R/NS R/NS R

Manufacturer_Info CN5/NS CN5/NS I

PPS_Status NS CN9/NS I

Security_Request CN6/NS CN6/NS CN6/I

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 215
 Message Type Source Sink Dual-Role Cable Plug
Power
Security_Response CN6/NS CN6/NS I

Source_Capabilities_Extended NS CN2/NS CN2/NS I

Status CN3/NS CN3/NS I

Note 1: Shall be supported by products that contain batteries.
Note 2: Shall be supported by products that can transmit the Get_Source_Cap_Extended Message.
Note 3: Shall be supported by products that can transmit the Get_Status Message.
Note 4: Shall be supported by products that can transmit the Get_Battery_Cap Message.
Note 5: Shall be supported by products that can transmit the Get_Manufacturer_Info Message
Note 6: Shall be supported by products that support USB security communication as defined in
[USBTypeCAuthentication 1.0]
Note 7: Shall be supported by products that support USB firmware update communication as defined
in [USBPDFirmwareUpdate 1.0]
Note 8: Shall be supported when PPS is supported.
Note 9: Shall be supported by products that can transmit the Get_PPS_Status.
Note 10: Shall be supported when required by a country authority.

6.12.4 Applicability of Structured VDM Commands

Table 6-64 details Structured VDM Commands that Shall/Should/ Shall Not be transmitted and received by a DFP,
UFP or Cable Plug. If Structured VDMs are not supported, the DFP or UFP receiving a VDM Command Shall send a
Not_Supported Message in response.

Table 6-64 Applicability of Structured VDM Commands

Command Type DFP UFP Cable Plug

Transmitted Command Request
Discover Identity CN1/R R2 NA

Discover SVIDs CN1/O O NA

Discover Modes CN1/O O NA

Enter Mode CN1/NA NA NA

Exit Mode CN1/NA NA NA

Attention O O NA
Received Command Request/Transmitted Command Response
Discover Identity O/NK3 CN1/R/NK3 N

Discover SVIDs O/NK3 CN1/NK3 CN1/NK

Discover Modes O/NK3 CN1/NK3 CN1/NK

Enter Mode NK3 CN1/NK3 CN1/NK

Exit Mode NK3 CN1/NK3 CN1/NK

Attention O/I3 O/I3 I

Note 1: Shall be supported when Modal Operation is supported.
Note 2: May be transmitted by a UFP/Source during discovery (see Section
6.4.4.3.1 and Section 8.3.3.22.3).
Note 3: If Structured VDMs are not supported, the DFP or UFP receiving a VDM
Command Shall send a Not_Supported Message in response.

Page 216 USB Power Delivery Specification Revision 3.0, Version 1.1
 6.12.5 Applicability of Reset Signaling
Table 6-65 details Reset Signaling that Shall/Should/ Shall Not be transmitted and received by a DFP/UFP or Cable
Plug.

Table 6-65 Applicability of Reset Signaling

Signaling Type DFP UFP Cable Plug

Transmitted Message/Signaling
Soft_Reset N N NA

Hard Reset N N NA

Cable Reset CN1 NA NA

Received Message/Signaling
Soft_Reset N N N

Hard Reset N N N

Cable Reset DR DR N
Note 1: Shall be supported when transmission of SOP’ Packets are supported.

6.12.6 Applicability of Fast Role Swap signal

Table 6-65 details the Fast Role Swap signal that Shall/Should/ Shall Not be transmitted and received by a Source or
Sink.

Table 6-66 Applicability of Fast Role Swap signal

Command Type Source Sink Dual-Role

Power
Transmitted Message/Signaling
Fast Role Swap NA NA R
Received Message/Signaling
Fast Role Swap NA NA R

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 217
 6.13 Value Parameters
Table 6-67 contains value parameters used in this section.

Table 6-67 Value Parameters

Parameter Description Value Unit Reference

MaxExtendedMsgLen Maximum length of an 260 Byte Section 6.5

Extended Message as
expressed in the Data Size
field.
MaxExtendedMsgChunkLen 26 Byte Section 6.5

MaxExtendedMsgLegacyLen 26 Byte Section 6.5

Page 218 USB Power Delivery Specification Revision 3.0, Version 1.1
7. Power Supply
7.1 Source Requirements
7.1.1 Behavioral Aspects
A USB PD Source exhibits the following behaviors:
 Shall be backward compatible with legacy VBUS ports.
 Shall supply the default [USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2] voltage and current to VBUS when
the USB cable is Attached (USB Default Operation).
 Shall supply the default [USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2] voltage and current to VBUS when a
Contract does not exist (USB Default Operation).
 Shall return vSafe0V for some time then return to vSafe5V when Hard Reset Signaling is received.
 Shall control VBUS voltage transitions as bound by undershoot, overshoot and transition time requirements.

7.1.2 Source Bulk Capacitance

The Source bulk capacitance Shall Not be placed between the transceiver isolation impedance and the USB receptacle.
The Source bulk capacitance consists of C1 and C2 as shown in Figure 7-1. The Ohmic Interconnect might consist of
PCB traces for power distribution or power switching devices. The capacitance might be a single capacitor, a
capacitor bank or distributed capacitance. If the power supply is shared across multiple ports, the bulk capacitance is
defined as cSrcBulkShared. If the power supply is dedicated to a single Port, the minimum bulk capacitance is
defined as cSrcBulk.
The Source bulk capacitance is allowed to change for a newly negotiated power level. The capacitance change Shall
occur before the Source is ready to operate at the new power level. During a Power Role Swap, the Default Source
Shall transition to Swap Standby before operating as the new Sink. Any change in bulk capacitance required to
complete the Power Role Swap Shall occur during Swap Standby.

Figure 7-1 Placement of Source Bulk Capacitance

SOURCE CABLE

Power Ohmic VBUS VBUS

Supply Interconnect
Data Data
...

...

C1
C2 Lines Lines

GND GND
SHIELD SHIELD
Source Bulk Capacitance

7.1.3 Types of Sources

Consistent with the Power Data Objects discussed in Section 6.4.1, the power supply types that are available as
Sources in a USB Power Delivery System are:
 The Fixed Supply PDO exposes well-regulated fixed voltage power supplies. Sources Shall support at least one
Fixed Supply capable of supplying vSafe5V. The output voltage of a Fixed Supply Shall remain within the range
defined by the relative tolerance vSrcNew and the absolute band vSrcValid as listed in Table 7-19 and described
in Section 7.1.8.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 219
 The Variable Supply (non-Battery) PDO exposes very poorly regulated Sources. The output voltage of a Variable
Supply (non-Battery) Shall remain within the absolute maximum output voltage and the absolute minimum
output voltage exposed in the Variable Supply PDO.
 The Battery Supply PDO exposes Batteries than can be connected directly as a Source to VBUS. The output voltage
of a Battery Supply Shall remain within the absolute maximum output voltage and the absolute minimum output
exposed in the Battery Supply PDO.
 The Programmable Power Supply (PPS) Augmented PDO (APDO) exposes a Source with an output voltage that
can be adjusted programmatically over a defined range. The output voltage of the Programmable Power Supply
Shall remain within a range defined by the relative tolerance vPpsNew and the absolute band vPpsValid.

7.1.4 Source Transitions

7.1.4.1 Fixed Supply Positive Voltage Transitions
The Source Shall transition VBUS from the starting voltage to the higher new voltage in a controlled manner. The
negotiated new voltage (e.g. 5V, 9V, 15V or 20V) defines the nominal value for vSrcNew. During the positive
transition the Source Shall be able to supply the Sink standby power and the transient current to charge the total bulk
capacitance on VBUS. The slew rate of the positive transition Shall Not exceed vSrcSlewPos. The transitioning Source
output voltage Shall settle within vSrcNew by tSrcSettle. The Source Shall be able to supply the negotiated power
level at the new voltage by tSrcReady. The positive voltage transition Shall remain monotonic while the transitioning
voltage is below vSrcValid min and Shall remain within the vSrcValid range upon crossing vSrcValid min as shown in
Figure 7-2. The starting time, t0, in Figure 7-2 starts tSrcTransition after the last bit of the EOP of the GoodCRC
Message has been received by the Source.

Figure 7-2 Transition Envelope for Positive Voltage Transitions

Upper bound of valid Source range

vSrcValid(max)

vSrcNew(max)

vSrcNew(typ)

vSrcNew(min)

vSrcValid(min)
Lower bound of valid Source range

≈
vSrcSlewPos

Starting voltage

≈ vSrcValid(min) beyond min/max limits of starting voltage

t0 tSrcSettle tSrcReady

At the start of the positive voltage transition the VBUS voltage level Shall Not droop vSrcValid min below either
vSrcNew (i.e., if the starting VBUS voltage level is not vSafe5V) or vSafe5V as applicable.

7.1.4.2 Fixed Supply Negative Voltage Transitions

Negative voltage transitions are defined as shown in Figure 7-3 and are specified in a similar manner to positive
voltage transitions. Figure 7-3 does not apply to vSafe0V transitions. The slew rate of the negative transition Shall

Page 220 USB Power Delivery Specification Revision 3.0, Version 1.1
Not exceed vSrcSlewNeg. The negative voltage transition Shall remain monotonic while the transitioning voltage is
above vSrcValid max and Shall remain within the vSrcValid range upon crossing vSrcValid max as shown in Figure
7-3. The starting time, t0, in Figure 7-3 starts tSrcTransition after the last bit of the EOP of the GoodCRC Message has
been received by the Source.

Figure 7-3 Transition Envelope for Negative Voltage Transitions

Starting voltage

vSrcSlewNeg

Upper bound of valid Source range

vSrcValid(max)

vSrcNew(max)

vSrcNew(typ)

vSrcNew(min)

vSrcValid(min)
Lower bound of valid Source range
≈
t0 tSrcSettle tSrcReady

If the newly negotiated voltage is vSafe5V, then the vSrcValid limits Shall determine the transition window and the
transitioning Source Shall settle within the vSafe5V limits by tSrcSettle.

7.1.4.3 Programmable Power Supply Voltage Transitions

The Programmable Power Supply (PPS) Shall transition VBUS over the defined voltage range in a controlled manner.
The Output Voltage value in the Programmable RDO defines the nominal value of the PPS output voltage after
completing a voltage change and Shall settle within the limits defined by vPpsNew by tPpsSrcTransition. Any
undershoot or overshoot beyond vPpsNew Shall Not exceed vPpsValid at any time. The PPS output voltage May
change in a step-wise or linear manner and the slew rate of either type of change Shall Not exceed vPpsSlewPos for
voltage increases or vPpsSlewNeg for voltage decreases. The nominal requested voltage of all linear voltage changes
Shall equate to an integer number of LSB changes. An LSB change of the PPS output voltage is defined as vPpsStep. A
PPS Shall be able to supply the negotiated current level as it change its output voltage to the requested level. All PPS
voltage increases Shall result in a voltage that is greater than the previous PPS output voltage. Likewise, all PPS
voltage decreases Shall result in a voltage that is less than the previous PPS output voltage.
Figure 7-4 and Figure 7-5 below show the output voltage behavior of a Programmable Power Supply in response to
positive and negative voltage change requests while operating with a PPS. The parameters vPpsMinVoltage and
vPpsMaxVoltage define the lower and upper limits of the PPS range respectively. vPpsMinVoltage corresponds to
Minimum Voltage field in the PPS APDO and vPpsMaxVoltage corresponds to Maximum Voltage field in the PPS
APDO. If the Sink negotiates for a new PPS APDO, then the transition between the two PPS APDOs Shall occur as
described in Section 7.3.18.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 221
 Figure 7-4 PPS Positive Voltage Transitions

V(4) > V(3) vPpsMaxVoltage V(4)

Programmable Power Supply Output Range

vPpsSlewPos

≈ ≈ vPpsValid ≈
V(3) > V(2)
≈
≈
Nominal V(3) vPpsNew

vPpsValid

vPpsSlewPos

vPpsMaxVoltage
V(3) = 1+n + vPpsMinVoltage
≈ ≈ ≈ ≈
vPpsValid

V(2) > V(1)

≈
≈
Nominal V(2) vPpsNew

V(2) = 1 + vPpsMinVoltage
vPpsValid
vPpsSlewPos

vPpsMinVoltage V(1)
vPpsMinVoltage

≈ ≈ ≈ ≈ ≈
0 Volts

Page 222 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 7-5 PPS Negative Voltage Transitions

vPpsMaxVoltage V(a)
Programmable Power Supply Output Range

vPpsSlewNeg

≈ vPpsValid ≈ ≈
vPpsNew
≈ Nominal V(b)
V(b) < V(a)

≈
vPpsValid

vPpsSlewNeg

vPpsMaxVoltage
V(b) = 1 + n + vPpsMinVoltage

≈ ≈ ≈ ≈
vPpsValid

vPpsNew
≈ Nominal V(c)
V(c) < V(b)

≈ vPpsSlewNeg
V(c) = 1 + vPpsMinVoltage

vPpsValid

V(d) < V(c) vPpsMinVoltage V(d)

vPpsMinVoltage
≈ ≈ ≈ ≈ ≈
0 Volts

The PPS output voltage ripple is expected to exceed the magnitude of one or more LSB as show in the Figure 7-6.

Figure 7-6 Expected PPS Ripple Relative to an LSB

voltage

+1 LSB
+1 LSB

time

7.1.4.4 Programmable Power Supply Current Foldback

The Programmable Power Supply Shall foldback its output current to the Operating Current value in the
Programmable RDO when the Sink attempts to draw more current than the Output Current level. The programming
step size for the Output Current is iPpsCfStep. All programming changes of the Operating Current Shall settle to the
new Operating Current value within tPpsCfProgramSettle. The PPS Operating Current regulation accuracy during
current foldback is defined as iPpsCfNew. The minimum programmable foldback level is iPpsCfMin. A Source that
supports PPS Shall support foldback programmability between iPpsCfMin and the Maximum Current value in the PPS
APDO.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 223
Any current overshoot or undershoot that occurs due to a load change during Current Foldback Shall Not exceed
iPpsCfTransient and Shall settle to the Operating Current value within tPpsCfSettle. Voltage overshoot or
undershoot caused by a transition from Current Foldback mode to Constant Voltage mode Shall Not exceed
vPpsCfCvTransient and Shall settle to the Operating Voltage value within tPpsCfCvTransient. Likewise, current
overshoot or undershoot caused by a transition from Constant Voltage mode to Current Foldback mode Shall Not
exceed iPpsCvCfTransient and Shall settle to the Operating Current value within tPpsCvCfTransient.
The PPS Shall maintain its output voltage within the Minimum Voltage and Maximum Voltage values advertised in the
PPS APDO for all static and dynamic load conditions during Current Foldback operation. The PPS is not expected to
deliver power if the load condition results in an output voltage that is lower than the Minimum Voltage value
advertised in the PPS APDO. Rather, the Source Shall send Hard Reset Signaling and discharge VBUS to vSafe0V then
resume default operation at vSafe5V.
The relationship between PPS programmable output voltage and PPS programmable Current Foldback Shall be as
shown in Figure 7-7.

Figure 7-7 PPS Programmable Voltage and Foldback

PPS APDO vPpsNew, vPpsValid tolerance band

Max Voltage
Programmable Voltage Only Programmable Voltage
Region &
Programmable Current Foldback Region
vPpsStep

Programmed PPS Operating Voltage

iPpsCfNew, iPpsCfValid tolerance band

PPS Minimum Current Foldback = iPpsCfMin

Programmed PPS Operating Current

PPS Output Voltage

iPpsCfStep
PPS APDO
Min Voltage vPpsNew, vPpsValid tolerance band

PPS Source protects itself and stops providing power

(0,0)
iPpsCfMin PPS Output Current PPS APDO Max Current

7.1.5 Response to Hard Resets

Hard Reset Signaling indicates a communication failure has occurred and the Source Shall stop driving VCONN, Shall
remove Rp from the VCONN pin and Shall drive VBUS to vSafe0V as shown in Figure 7-8. The USB connection May reset
during a Hard Reset since the VBUS voltage will be less than vSafe5V for an extended period of time. After establishing
the vSafe0V voltage condition on VBUS, the Source Shall wait tSrcRecover before re-applying VCONN and restoring VBUS
to vSafe5V. A Source Shall conform to the VCONN timing as specified in [USB Type-C 1.2].
Device operation during and after a Hard Reset is defined as follows:
 Self-powered devices Should Not disconnect from USB during a Hard Reset (see Section 9.1.2).
 Self-powered devices operating at more than vSafe5V May Not maintain full functionality after a Hard Reset.
 Bus powered devices will disconnect from USB during a Hard Reset due to the loss of their power source.
When a Hard Reset occurs the Source Shall stop driving VCONN, Shall remove Rp from the VCONN pin and Shall start to
transition the VBUS voltage to vSafe0V either:

Page 224 USB Power Delivery Specification Revision 3.0, Version 1.1
 tPSHardReset after the last bit of the Hard Reset Signaling has been received from the Sink or
 tPSHardReset after the last bit of the Hard Reset Signaling has been sent by the Source.
The Source Shall meet both tSafe5V and tSafe0V relative to the start of the voltage transition as shown in Figure 7-8.

Figure 7-8 Source VBUS and VCONN Response to Hard Reset

Old voltage

≈
vSafe5V(max), VCONN(max)

vSafe0V(max)

vVconnDischarge
0V
t0
vSrcNeg(max)
tVconnDischarge tVconnOn

tSafe5V
tSrcRecover
tSafe0V tSrcTurnOn

VCONN will meet tVconnDischarge relative to the start of the voltage transition as shown in Figure 7-8 due to the
discharge circuitry in the Cable Plug. VCONN Shall meet tVconnOn relative to VBUS reaching vSafe5V. Note tVconnOn
and tVconnDischarge are defined in [USB Type-C 1.2].

7.1.6 Changing the Output Power Capability

Some USB Power Delivery negotiations will require the Source to adjust its output power capability without changing
the output voltage. In this case the Source Shall be able to supply a higher or lower load current within tSrcReady.

7.1.7 Robust Source Operation

7.1.7.1 Output Over Current Protection
Sources Shall implement output over current protection to prevent damage from output current that exceeds the
current handling capability of the Source. The definition of current handling capability is left to the discretion of the
Source implementation and Shall take into consideration the current handling capability of the connector contacts.
The response to over current Shall Not interfere with the negotiated VBUS current level.
Sources Should attempt to send a Hard Reset message when over current protection engages followed by an Alert
Message indicating an OCP event once an Explicit Contract has been established. The over current protection
response May engage at either the port or system level. Systems or ports that have engaged over current protection
Should attempt to resume default operation after determining that the cause of over current is no longer present and
May latch off to protect the port or system. The definition of how to detect if the cause of over current is still present
is left to the discretion of the Source implementation.
The Source Shall renegotiate with the Sink (or Sinks) after choosing to resume default operation. The decision of how
to renegotiate after an over current event is left to the discretion of the Source implementation.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 225
The Source Shall prevent continual system or port cycling if over current protection continues to engage after initially
resuming either default operation or renegotiation. Latching off the port or system is an acceptable response to
recurring over current.
During the over current response and subsequent system or port shutdown, all affected Source ports operating with
VBUS greater than vSafe5V Shall discharge VBUS to vSafe5V by the time tSafe5V and vSafe0V by the time tSafe0V.

7.1.7.2 Over Temperature Protection

Sources Shall implement over temperature protection to prevent damage from temperature that exceeds the thermal
capability of the Source. The definition of thermal capability and the monitoring locations used to trigger the over
temperature protection are left to the discretion of the Source implementation.
Sources Should attempt to send a Hard Reset message when over temperature protection engages followed by an
Alert Message indicating an OTP event once an Explicit Contract has been established. The over temperature
protection response May engage at either the port or system level. Systems or ports that have engaged over
temperature protection Should attempt to resume default operation and May latch off to protect the port or system.
The Source Shall renegotiate with the Sink (or Sinks) after choosing to resume default operation. The decision of how
to renegotiate after an over temperature event is left to the discretion of the Source implementation.
The Source Shall prevent continual system or port cycling if over temperature protection continues to engage after
initially resuming either default operation or renegotiation. Latching off the port or system is an acceptable response
to recurring over temperature.
During the over temperature response and subsequent system or port shutdown, all affected Source ports operating
with VBUS greater than vSafe5V Shall discharge VBUS to vSafe5V by the time tSafe5V and vSafe0V by the time tSafe0V.

7.1.7.3 vSafe5V Externally Applied to Ports Supplying vSafe5V

Safe operation mandates that Power Delivery Sources Shall be tolerant of vSafe5V being present on VBUS when
simultaneously applying power to VBUS. Normal USB PD communication Shall be supported when this vSafe5V to
vSafe5V connection exists.

7.1.7.4 Detach
A USB Detach is detected electrically using CC detection on the USB Type-C connector. When the Source is Detached
the Source Shall transition to vSafe0V by tSafe0V relative to when the Detach event occurred. During the transition
to vSafe0V the VBUS voltage Shall be below vSafe5V max by tSafe5V relative to when the Detach event occurred and
Shall Not exceed vSafe5V max after this time.

7.1.8 Output Voltage Tolerance and Range

After a voltage transition is complete (i.e. after tSrcReady) and during static load conditions the Source output voltage
Shall remain within the vSrcNew or vSafe5V limits as applicable. The ranges defined by vSrcNew and vSafe5V
account for DC regulation accuracy, line regulation, load regulation and output ripple. After a voltage transition is
complete (i.e. after tSrcReady) and during transient load conditions the Source output voltage Shall Not go beyond
the range specified by vSrcValid. The amount of time the Source output voltage can be in the band between either
vSrcNew or vSafe5V and vSrcValid Shall Not exceed tSrcTransient. Refer to Table 7-19 for the output voltage
tolerance specifications. Figure 7-9 illustrates the application of vSrcNew and vSrcValid after the voltage transition is
complete.
The vSrcNew and vSrcValid limits Shall Not apply to VBUS during the VBUS discharge and switchover that occurs during
a Fast Role Swap as described in Section 7.1.13.

Page 226 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 7-9 Application of vSrcNew and vSrcValid limits after tSrcReady

vSrcValid(max)
tSrcTransient windows
vSrcNew(max)

vSrcNew(typ)

vSrcNew(min)
tSrcTransient window
vSrcValid(min)

≈
Sink Load I2

iLoadReleaseRate
iLoadStepRate

≈
≈

Sink Load I1

tSrcReady

The Source output voltage Shall be measured at the connector receptacle. The stability of the Source Shall be tested
in 25% load step increments from minimum load to maximum load and also from maximum load to minimum load.
The transient behavior of the load current is defined in Section 7.2.6. The time between each step Shall be sufficient
to allow for the output voltage to settle between load steps. In some systems it might be necessary to design the
Source to compensate for the voltage drop between the output stage of the power supply electronics and the
receptacle contact. The determination of whether compensation is necessary is left to the discretion of the Source
implementation.

7.1.8.1 Programmable Power Supply Output Voltage Tolerance and Range

After a voltage transition of a Programmable Power Supply is complete (i.e. after tPpsSrcTransition) and during
static load conditions the Source output voltage Shall remain within the vPpsNew limits. The range defined by
vPpsNew accounts for DC regulation accuracy, line regulation, load regulation and output ripple. After a voltage
transition is complete (i.e. after tPpsSrcTransition) and during transient load conditions the Source output voltage
Shall Not go beyond the range specified by vPpsValid. The amount of time the Source output voltage can be in the
band between vPpsNew and vPpsValid Shall Not exceed tPpsTransient.

7.1.9 Charging and Discharging the Bulk Capacitance on VBUS

The Source Shall charge and discharge the bulk capacitance on VBUS whenever the Source voltage is negotiated to a
different value. The charging or discharging occurs during the voltage transition and Shall Not interfere with the
Source’s ability to meet tSrcReady.

7.1.10 Swap Standby for Sources

Sources and Sinks of a Dual-Role Power Port Shall support Swap Standby. Swap Standby occurs for the Source after
the Source power supply has discharged the bulk capacitance on VBUS to vSafe0V as part of the Power Role Swap
transition.
While in Swap Standby:
 The Source Shall Not drive VBUS that is therefore expected to remain at vSafe0V.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 227
 Any discharge circuitry that was used to achieve vSafe0V Shall be removed from VBUS.
 The Dual-Role Power Port Shall be configured as a Sink.
 The USB connection Shall Not reset even though vSafe5V is no longer present on VBUS (see Section 9.1.2).
The PS_RDY Message associated with the Source being in Swap Standby Shall be sent after the VBUS drive is removed.
The time for the Source to transition to Swap Standby Shall Not exceed tSrcSwapStdby. Upon entering Swap Standby
the Source has relinquished its role as Source and is ready to become the new Sink. The transition time from Swap
Standby to being the new Sink Shall be no more than tNewSnk. The new Sink May start using power after the new
Source sends the PS_RDY Message.

7.1.11 Source Peak Current Operation

A Source that has the Fixed Supply PDO Peak Current bits set to 01b, 10b and 11b Shall be designed to support one of
the overload capabilities defined in Table 6-10. The overload conditions are bound in magnitude, duration and duty
cycle as listed in Table 6-10. Sources are not required to support continuous overload operation. When overload
conditions occur, the Source is allowed the range of vSrcPeak (instead of vSrcNew) relative to the nominal value (see
Figure 7-10). When the overload capability is exceeded, the Source is expected take whatever action is necessary to
prevent electrical or thermal damage to the Source. The Source May send a new Source_Capabilities Message with
the Fixed Supply PDO Peak Current bits set to 00b to prohibit overload operation even if an overload capability was
previously negotiated with the Sink.

Figure 7-10 Source Peak Current Overload

Operating range for supply that DOES

Source Port Voltage NOT support overload capability

Additional operating range for

vSrcNew(max)/
Fixed Supply that supports
vSrcPeak(max)
overload capability
Nominal Voltage

vSrcNew(min)

vSrcPeak(min)

Sink Port Current

IOC level % level with respect to IOC
as requested in the Operating as advertised in the Peak Current
Current field of an RDO field of Fixed Supply PDO

Page 228 USB Power Delivery Specification Revision 3.0, Version 1.1
 7.1.12 Source Capabilities Extended Parameters
Implementers can choose to make available certain characteristics of a USB PD Source as a set of static and/or
dynamic parameters to improve interoperability between external power sources and portable computing devices.
The complete list of reportable static parameters are described in full in Section 6.5.1 and listed in Figure 6-30. The
subset of parameters listed below directly represent Source capabilities and are described in the rest of this section.
 Voltage Regulation.
 Holdup Time.
 Compliance.
 Peak Current.
 Source Inputs.
 Batteries.

7.1.12.1 Voltage Regulation Field

The power consumption of a device can change dynamically. The ability of the Source to regulate its voltage output
might be important if the device is sensitive to fluctuations in voltage. The Voltage Regulation bit field is used to
convey information about the Sources output regulation and tolerance to various load steps.

7.1.12.1.1 Load Step Slew Rate

The default load step slew rate is established at 150mA/µs. A Source Shall meet the following requirements under
the load step reported in the Extended Source Capabilities:
 The Source Shall maintain VBUS regulation within the vSrcValid range.
 The noise on the CC line Shall remain below vNoiseIdle and vNoiseActive.
Test conditions require a change in both positive and negative load steps from 1Hz to 5000Hz, up to the advertised
Load Step Magnitude of the full load output including from both 10 mA and 10% initial load. The Source Shall ensure
that PD Communications meet the transmit and receive masks as specified in Section 5.8.2 under all load conditions.

7.1.12.1.2 Load Step Magnitude

The default load step magnitude rate Shall be 25% of IoC. The Source May report higher capability tolerating a load
step of 90% of IoC.

7.1.12.2 Holdup Time Field

The Holdup Time field Shall return a numeric value of the number of milliseconds the output voltage stays in
regulation upon a short interruption of AC mains.
A mains supplied Source Shall report its holdup time in this field. The holdup time is measured with the load at rated
maximum, with AC mains at 115VAC rms and 60Hz (or at 230VAC rms and 50Hz for a Source that does not support
115VAC mains). The reported time describes the minimum length of time from the last completed AC mains input
cycle (zero degree phase angle) until when the output voltage decays below vSrcValid(min). Power sources are
recommended to support a minimum of 3ms and are preferred to support over 10 milliseconds holdup time
(equivalent to a half cycle drop from the AC Mains).

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 229
 Figure 7-11 Holdup Time Measurement

AC mains voltage
≈
VBUS

vSrcValid(min)

Hold Up Time

7.1.12.3 Compliance Field

A Source claiming LPS, PS1 or PS2 compliance (see [IEC 62368-1]) Shall report its capabilities in the Compliance field.
Since the Source May have several potential output voltage and current settings, every Source supply (indicated by a
PDO) Shall be compliant to LPS requirements.
Note: according to the requirements of [IEC 60950-1], a device tested and certified with an LPS Source is prohibited
to use a non-LPS Source. Alternatively, [IEC 62368-1], classifies power sources according to their maximum,
constrained power output (15watts or 100watts).

7.1.12.4 Peak Current

The Source reports its ability to source peak current delivery in excess of the negotiated amount in the Peak Current
field. The duration of peak current Shall be followed by a current consumption below the Operating Current (IoC) in
order to maintain average power delivery below the IoC current.
A Source May have greater capability to source peak current than can be reported using the Peak Current field in the
Fixed Supply PDO. In this case the Source Shall report its additional capability in the Peak Current field in the
Source_Capabilities_Extended Message.
Each overload period Shall be followed by a period of reduced current draw such that the rolling average current over
the Overload Period field value with the specified Duty Cycle field value (see Section 6.5.1.8) Shall Not exceed the
negotiated current. This is calculated as:
Period of reduced current = (1 – value in Duty Cycle field/100) * value in Overload Period field

7.1.12.5 Source Inputs

The Source Inputs field identifies the possible inputs that provide power to the Source. Note some Sources are only
powered by a Battery (e.g., an automobile) rather than the more common mains.

Page 230 USB Power Delivery Specification Revision 3.0, Version 1.1
 7.1.12.6 Batteries
The Batteries field Shall report the number of Batteries the Source supports. The Source Shall independently report
the number of Hot Swappable Batteries and the number of Fixed batteries.

7.1.13 Fast Role Swap

A Fast Role Swap limits the interruption of VBUS power to a bus powered accessory connected to a Hub DFP that has a
UFP attached to a power source and a DRP attached to a Host port supporting DRP as shown in Figure 7-12 VBUS
Power during Fast Role Swap

Figure 7-12 VBUS Power during Fast Role Swap

DRP DRP DFP Bus Powered Power flow before the

Accessory Fast Role Swap
USB PD Capable USB PD Capable
Host Hub
Power flow after the
UFP Power Source Fast Role Swap

When the power source connected to the Hub UFP stops sourcing power and VBUS at the Hub DRP connector
discharges below vSrcValid(min), if VBUS has been negotiated to a higher voltage thanvSafe5V, or vSafe5V (min) the
Fast Role Swap signal Shall be sent from the Hub DRP to the Host DRP and the Hub DRP Shall sink power. In the Fast
Role Swap use case, the Hub DRP behaves like a bidirectional power path. The Hub DRP Shall Not enable VBUS
discharge circuitry when changing operation from initial Source to new Sink.
The new Sink Shall be limited to USB Type-C Current (see [USB Type-C 1.2]) until a new Explicit Contract is
negotiated. All Sink requirements Shall apply to the new Sink after the Fast Role Swap is complete. The Fast Role
Swap response of the Host DRP is described in Section 7.2.10 since the Host DRP is operating as the initial Sink prior
to the Fast Role Swap.
After the VBUS voltage level at the Hub DRP connector drops below vSafe5V a PS_RDY Message Shall be sent to the
Host DRP as shown in the Fast Role Swap transition diagram of Section 7.3.15.
Figure 7-13 shows the VBUS detection and timing for the new Source during a Fast Role Swap after the Fast Role Swap
signal has been received. The new Source May turn on the VBUS output switch once VBUS is below vSafe5V (max). In
this case, the new Source prevents VBUS from falling below vSafe5V (min). The new source Shall turn on the VBUS
output switch within tSrcFRSwap of falling below vSafe5V (min).
Note: VBUS might have started at vSafe5V or at higher voltage. When the Fast Role Swap Signal is detected, VBUS could
therefore be either above vSafe5V (max), within the vSafe5V range, or below vSafe5V (min).

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 231
 Figure 7-13 VBUS detection and timing during Fast Role Swap

Old Voltage VBUS

New Source may
turn on at any time
≈ after VBUS falls below
vSafe5V(max)
vSafe5V(max)

vSafe5V(min)
Old Source
detects power loss
and signals Fast
Role Swap
0V
tSrcFRSwap

7.1.14 Non-application of VBUS Slew Rate Limits

Scenarios where VBUS slew rate limits do not apply and VBUS May transition faster than specified are as follows:
 When first applying VBUS to a port operating as DFP.
 When discharging VBUS to vSafe0V during a Hard Reset.
 When increasing VBUS from vSafe0V to vSafe5V during a Hard Reset.
 During a Fast Role Swap when the VBUS power source connected to the Hub UFP stops sourcing power.

Page 232 USB Power Delivery Specification Revision 3.0, Version 1.1
 7.2 Sink Requirements
7.2.1 Behavioral Aspects
A USB PD Sink exhibits the following behaviors.
 Shall be backward compatible with legacy VBUS ports.
 Shall draw the default [USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2] VBUS current when the USB cable is
Attached (USB Default Operation).
 Shall draw the default [USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2] VBUS current when a Contract does
not exist (USB Default Operation).
 Shall return to the default [USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2] VBUS when responding to a Hard
Reset (USB Default Operation).
 Shall control VBUS in-rush current when increasing current consumption.

7.2.2 Sink Bulk Capacitance

The Sink bulk capacitance consists of C3 and C4 as shown in Figure 7-14. The Ohmic Interconnect might consist of
PCB traces for power distribution or power switching devices. The capacitance might be a single capacitor, a
capacitor bank or distributed capacitance. An upper bound of cSnkBulkPd Shall Not be exceeded so that the transient
charging, or discharging, of the total bulk capacitance on VBUS can be accounted for during voltage transitions.
The Sink bulk capacitance that is within the cSnkBulk max or cSnkBulkPd max limits is allowed to change to support
a newly negotiated power level. The capacitance can be changed when the Sink enters Sink Standby or during a
voltage transition or when the Sink begins to operate at the new power level. Changing the Sink bulk capacitance
Shall Not cause a transient current on VBUS that violates the present Contract. During a Power Role Swap the Default
Sink Shall transition to Swap Standby before operating as the new Source. Any change in bulk capacitance required to
complete the Power Role Swap Shall occur during Swap Standby.

Figure 7-14 Placement of Sink Bulk Capacitance

CABLE SINK

VBUS VBUS Ohmic

Load
Interconnect
Data Data
...

...

Lines Lines C3 C4

GND GND
SHIELD SHIELD
Sink Bulk Capacitance

7.2.3 Sink Standby

The Sink Shall transition to Sink Standby before a positive or negative voltage transition of VBUS. During Sink Standby
the Sink Shall reduce its power draw to pSnkStdby. This allows the Source to manage the voltage transition as well as
supply sufficient operating current to the Sink to maintain PD operation during the transition. The Sink Shall
complete this transition to Sink Standby within tSnkStdby after evaluating the Accept Message from the Source. The
transition when returning to Sink operation from Sink Standby Shall be completed within tSnkNewPower. The
pSnkStdby requirement Shall only apply if the Sink power draw is higher than this level.
See Section 7.3 for details of when pSnkStdby Shall be applied for any given transition.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 233
 7.2.3.1 Programmable Power Supply Sink Standby
A Sink is not required to transition to Sink Standby when operating within the negotiated PPS APDO. A Sink May
consume the Operating Current value in the Programmable RDO during PPS output voltage changes. However, prior
to operating the PPS in current foldback, the Sink Shall program the PPS Operating Voltage to the lowest practical
level that satisfies the Sink load requirement. Doing so will minimize the inrush current that occurs when the
transition to current foldback occurs. When operating with a PPS that is in current foldback, the Sink Shall Not
change its load in a manner that exceeds iPpsCfLoadStepRate or iPpsCfLoadReleaseRate. The load change
magnitude Shall Not exceed iPpsCfLoadStep or iPpsCfLoadRelease.
If the Sink negotiates for a new PPS APDO, then the Sink Shall transition to Sink Standby while changing between PPS
APDOs as described in Section 7.3.18.

7.2.4 Suspend Power Consumption

When Source has set its USB Suspend Supported flag (see Section 6.4.1.2.2.2), a Sink Shall go to the lowest power
state during USB suspend. The lowest power state Shall be pSnkSusp or lower for a PDUSB Peripheral and pHubSusp
or lower for a PDUSB Hub. There is no requirement for the Source voltage to be changed during USB suspend.

7.2.5 Zero Negotiated Current

When a Sink Requests zero current as part of a power negotiation with a Source, the Sink Shall go to the lowest power
state, pSnkSusp or lower, where it can still communicate using PD signaling.

7.2.6 Transient Load Behavior

When a Sink’s operating current changes due to a load step, load release or any other change in load level, the positive
or negative overshoot of the new load current Shall Not exceed the range defined by iOvershoot. For the purposes of
measuring iOvershoot the new load current value is defined as the average steady state value of the load current after
the load step has settled. The rate of change of any shift in Sink load current during normal operation Shall Not
exceed iLoadStepRate (for load steps) and iLoadReleaseRate (for load releases) as measured at the Sink receptacle.
The Sink’s operating current Shall Not change faster than the value reported in the Source’s Load Step Slew Rate field
and Shall ensure that PD Communications meet the transmit and receive masks as specified in Section 5.8.2.

7.2.7 Swap Standby for Sinks

The Sink capability in a Dual-Role Power Port Shall support Swap Standby. Swap Standby occurs for the Sink after
evaluating the Accept Message from the Source during a Power Role Swap negotiation. While in Swap Standby the
Sink’s current draw Shall Not exceed iSnkSwapStdby from VBUS and the Dual-Role Power Port Shall be configured as
a Source after VBUS has been discharged to vSafe0V by the existing Initial Source. The Sink’s USB connection Should
Not be reset even though vSafe5V is not present on the VBUS conductor (see Section 9.1.2). The time for the Sink to
transition to Swap Standby Shall be no more than tSnkSwapStdby. When in Swap Standby the Sink has relinquished
its role as Sink and will prepare to become the new Source. The transition time from Swap Standby to new Source
Shall be no more than tNewSrc.

7.2.8 Sink Peak Current Operation

Sinks Shall only make use of a Source overload capability when the corresponding Fixed Supply PDO Peak Current
bits are set to 01b, 10b and 11b (see Section 6.4.1.2.2.7). Sinks Shall manage thermal aspects of the overload event by
not exceeding the average negotiated output of a Fixed Supply that supports Peak Current operation.
Sinks that depend on the Peak Current capability for enhanced system performance Shall also function correctly
when Attached to a Source that does not offer the Peak Current capability or when the Peak Current capability has
been inhibited by the Source.

Page 234 USB Power Delivery Specification Revision 3.0, Version 1.1
 7.2.9 Robust Sink Operation
7.2.9.1 Sink Bulk Capacitance Discharge at Detach
When a Source is Detached from a Sink, the Sink Shall continue to draw power from its input bulk capacitance until
VBUS is discharged to vSafe5V or lower by no longer than tSafe5V from the Detach event. This safe Sink requirement
Shall apply to all Sinks operating with a negotiated VBUS level greater than vSafe5V and Shall apply during all low
power and high power operating modes of the Sink.
If the Detach is detected during a Sink low power state, such as USB Suspend, the Sink can then draw as much power
as needed from its bulk capacitance since a Source is no longer Attached. In order to achieve a successful Detach
detect based on VBUS voltage level droop, the Sink power consumption Shall be high enough so that VBUS will decay
below vSrcValid(min) well within tSafe5V after the Source bulk capacitance is removed due to the Detach. Once
adequate VBUS droop has been achieved, a discharge circuit can be enabled to meet the safe Sink requirement.
To illustrate the point, the following set of Sink conditions will not meet the safe Sink requirement without additional
discharge circuitry:
 Negotiated VBUS = 20V.
 Maximum allowable supplied VBUS voltage = 21.5V.
 Maximum bulk capacitance = 30µF.
 Power consumption at Detach = 12.5mW.
When the Detach occurs (hence removal of the Source bulk capacitance) the 12.5mW power consumption will draw
down the VBUS voltage from the worst-case maximum level of 21.5V to 17V in approximately 205ms. At this point,
with VBUS well below vSrcValid (min) an approximate 100mW discharge circuit can be enabled to increase the rate of
Sink bulk capacitance discharge and meet the safe Sink requirement. The power level of the discharge circuit is
dependent on how much time is left to discharge the remaining voltage on the Sink bulk capacitance. If a Sink has the
ability to detect the Detach in a different manner and in much less time than tSafe5V, then this different manner of
detection can be used to enable a discharge circuit, allowing even lower power dissipation during low power modes
such as USB Suspend.
In most applications, the safe Sink requirement will limit the maximum Sink bulk capacitance well below the
cSnkBulkPd limit. A Detach occurring during Sink high power operating modes must quickly discharge the Sink bulk
capacitance to vSafe5V or lower as long as the Sink continues to draw adequate power until V BUS has decayed to
vSafe5V or lower.

7.2.9.2 Input Over Voltage Protection

Sinks Shall implement input over voltage protection to prevent damage from input voltage that exceeds the voltage
handling capability of the Sink. The definition of voltage handling capability is left to the discretion of the Sink
implementation. The response to over voltage Shall Not interfere with the negotiated VBUS voltage level.
Sinks Should attempt to send a Hard Reset message when over voltage protection engages followed by an Alert
Message indicating an OVP event once an Explicit Contract has been established. The over voltage protection
response May engage at either the port or system level. Systems or ports that have engaged over voltage protection
Shall resume default operation when the Source has re-established vSafe5V on VBUS.
The Sink Shall be able to renegotiate with the Source after resuming default operation. The decision of how to
respond to renegotiation after an over voltage event is left to the discretion of the Sink implementation.
The Sink Shall prevent continual system or port cycling if over voltage protection continues to engage after initially
resuming either default operation or renegotiation. Latching off the port or system is an acceptable response to
recurring over voltage.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 235
 7.2.9.3 Over Temperature Protection
Sinks Shall implement over temperature protection to prevent damage from temperature that exceeds the thermal
capability of the Sink. The definition of thermal capability and the monitoring locations used to trigger the over
temperature protection are left to the discretion of the Sink implementation.
Sinks Shall attempt to send a Hard Reset message when over temperature protection engages followed by an Alert
Message indicating an OTP event once an Explicit Contract has been established. The over temperature protection
response May engage at either the port or system level. Systems or ports that have engaged over temperature
protection Should attempt to resume default operation after sufficient cooling is achieved and May latch off to protect
the port or system. The definition of sufficient cooling is left to the discretion of the Sink implementation.
The Sink Shall be able to renegotiate with the Source after resuming default operation. The decision of how to
respond to renegotiation after an over temperature event is left to the discretion of the Sink implementation.
The Sink Shall prevent continual system or port cycling if over temperature protection continues to engage after
initially resuming either default operation or renegotiation. Latching off the port or system is an acceptable response
to recurring over temperature.

7.2.9.4 Over Current Protection

Sinks that operate with a Programmable Power Supply Shall implement their own internal current protection
mechanism to protect against internal VBUS current faults as well as erratic Source current regulation. The Sink Shall
never draw higher current than the Maximum Current value in the PPS APDO.

7.2.10 Fast Role Swap

As described in Section 7.1.13 a Fast Role Swap limits the interruption of VBUS power to a bus powered accessory
connected to a Hub DFP that has a UFP attached to a power source and a DRP attached to a Host port that supports
DRP. This configuration is shown in Figure 7-12 VBUS Power during Fast Role Swap
When the Host DRP that supports Fast Role Swap detects the Fast Role Swap signal, the Host DRP Shall stop sinking
current and Shall be ready and able to source vSafe5V if the residual VBUS voltage level at the Host DRP connector is
greater than vSafe5V. When the residual VBUS voltage level at the Host DRP connector discharges below vSafe5V(min)
the Host DRP as the new Source Shall supply vSafe5V to the Hub DRP within tSrcFRSwap. The Host DRP Shall Not
enable VBUS discharge circuitry when changing roles from initial Sink to new Source.
The new Source Shall supply vSafe5V at USB Type-C Current (see [USB Type-C 1.2]) at the value advertised in the
Fast Role Swap USB Type-C Current field (see Section 6.4.1.3.1.6). All Source requirements Shall apply to the new
Source after the Fast Role Swap is complete The Fast Role Swap response of the Hub DRP is described in Section
7.1.13 since the Hub DRP is operating as the initial Source prior to the Fast Role Swap.
After the Host DRP is providing VBUS power to the Hub DRP, a PS_RDY Message Shall be sent to the Hub DRP as
defined by the Fast Role Swap signaling and messaging sequence detailed in Section 7.3.15.

Page 236 USB Power Delivery Specification Revision 3.0, Version 1.1
 7.3 Transitions
The following sections illustrate the power supply’s response to various types of negotiations. The negotiation cases
take into consideration for the examples are as follows:
 Higher Power Transitions
o Increase the current
o Increase the voltage
o Increase the voltage and the current
 Relatively Constant Power Transitions
o Increase the voltage and decrease the current
o Decrease the voltage and increase the current
 Lower Power Transitions
o Decrease the current
o Decrease the voltage
o Decrease the voltage and the current
 Power Role Swap Transitions
o Source requests a Power Role Swap
o Sink requests a Power Role Swap
 Go To Minimum Current Transition
 Response to Hard Reset Signaling
o Source issues Hard Reset Signaling
o Sink issues Hard Reset Signaling
 No change in Current or Voltage.
The transition from [USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2] operation into Power Delivery Mode can
also lead to a Power Transition since this is the initial Contract negotiation. The following types of Power Transitions
Shall also be applied when moving from [USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2] operation into Power
Delivery Mode:
 High Power
 Relatively Constant Power
 Lower Power Transitions
 No change in Current or Voltage.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 237
 7.3.1 Increasing the Current
The interaction of the System Policy, Device Policy, and power supply that Shall be followed when increasing the
current is shown in Figure 7-15. The sequence that Shall be followed is described in Table 7-1. The timing
parameters that Shall be followed are listed in Table 7-19 and Table 7-20. Note in this figure, the Sink has previously
sent a Request Message to the Source.

Figure 7-15 Transition Diagram for Increasing the Current

1 4
tSrcTransition
Source Port Send Send
Policy Engine Accept PS_RDY
Port to Port
2 5
Evaluate
PSTransitionTimer (running)
Evaluate
Messaging
Sink Port
Policy Engine Accept PS_RDY

3
Source Port Source
Device Policy Mgr ñI
Source Port
Source Port Interaction
Source VOLD t1 Source VOLD
Power Supply

6 7
Sink
Sink Port ... ñI
Device Policy Mgr
Sink Port
Sink Port Interaction
Sink ≤ IOLD t2 Sink ≤ INEW
Power Supply

Source Port
VBUS doesn’t change
Voltage
Source
VBUS Voltage

Sink Port
≤ INEW
Current
≤ IOLD Sink
≈

VBUS Current

Page 238 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 7-1 Sequence Description for Increasing the Current

Step Source Port Sink Port

1 Policy Engine sends the Accept Message to the
Sink. Policy Engine receives the Accept Message and starts
the PSTransitionTimer.
2 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. The Policy Engine tells the Device Policy Engine then evaluates the Accept Message.
Policy Manager to instruct the power supply to
modify its output power.
3 tSrcTransition after the GoodCRC Message was
received the power supply starts to change its
output power capability. The power supply Shall
be ready to operate at the new power level within
tSrcReady (t1). The power supply informs the
Device Policy Manager that it is ready to operate
at the new power level. The power supply status
is passed to the Policy Engine.
4 The Policy Engine sends the PS_RDY Message to The Policy Engine receives the PS_RDY Message from the
the Sink. Source.
5 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. Policy Engine then evaluates the PS_RDY Message from the
Source and tells the Device Policy Manager it is okay to
operate at the new power level.
6 The Sink May begin operating at the new power level any
time after evaluation of the PS_RDY Message. This time
duration is indeterminate.
7 The Sink Shall Not violate the transient load behavior
defined in Section 7.2.6 while transitioning to and
operating at the new power level. The time duration (t2)
depends on the magnitude of the load change.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 239
 7.3.2 Increasing the Voltage
The interaction of the System Policy, Device Policy, and power supply that Shall be followed when increasing the
voltage is shown in Figure 7-16. The sequence that Shall be followed is described in Table 7-2. The timing
parameters that Shall be followed are listed in Table 7-19, Table 7-20 and Table 7-21. Note in this figure, the Sink has
previously sent a Request Message to the Source.

Figure 7-16 Transition Diagram for Increasing the Voltage

1 5
tSrcTransition
Source Port Send Send
Policy Engine Accept PS_RDY
Port to Port
2 6
Evaluate
PSTransitionTimer (running)
Evaluate
Messaging
Sink Port
Policy Engine Accept PS_RDY

4
Source Port Source
Device Policy Mgr ñV
Source Port
Source Port Interaction
Source VOLD t2 Source VNEW
Power Supply

3 7 8
Sink to Sink Sink Standby
Sink Port
Standby ... to Sink
Device Policy Mgr
Sink Port
Sink Port Interaction
Sink ≤ IOLD t1 Sink pSnkStdby t3 Sink ≤ IOLD
Power Supply

Source Port
VNEW
Voltage
Source
VOLD VBUS Voltage

Sink Port I2
≤ IOLD ≤ IOLD
Current
I1 Sink
VBUS Current
≈

I1

I1 ≤ (pSnkStdby/VBUS) I2 ≤ (pSnkStdby/VBUS) + cSnkBulkPd(DVBUS/Dt)

Page 240 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 7-2 Sequence Description for Increasing the Voltage

Step Source Port Sink Port

1 Policy Engine sends the Accept Message to the Policy Engine receives the Accept Message and starts the
Sink. PSTransitionTimer.
2 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. The Policy Engine tells the Device Policy Engine. Policy Engine then evaluates the Accept
Policy Manager to instruct the power supply to Message.
modify its output power.
3 Policy Engine tells the Device Policy Manager to instruct
the power supply to reduce power consumption to
pSnkStdby within tSnkStdby (t1); t1 Shall complete
before tSrcTransition. The Sink Shall Not violate
transient load behavior defined in Section 7.2.6 while
transitioning to and operating at the new power level.
4 tSrcTransition after the GoodCRC Message was
received the power supply starts to change its
output power capability. The power supply Shall
be ready to operate at the new power level within
tSrcReady (t2). The power supply informs the
Device Policy Manager that it is ready to operate
at the new power level. The power supply status
is passed to the Policy Engine.
5 The Policy Engine sends the PS_RDY Message to The Policy Engine receives the PS_RDY Message from the
the Sink. Source.
6 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. Policy Engine then evaluates the PS_RDY Message from the
Source and tells the Device Policy Manager it is okay to
operate at the new power level.
7 The Sink May begin operating at the new power level any
time after evaluation of the PS_RDY Message. This time
duration is indeterminate.
8 The Sink Shall Not violate the transient load behavior
defined in Section 7.2.6 while transitioning to and
operating at the new power level. The time duration (t3)
depends on the magnitude of the load change.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 241
 7.3.3 Increasing the Voltage and Current
The interaction of the System Policy, Device Policy, and power supply that Shall be followed when increasing the
voltage and current is shown in Figure 7-17. The sequence that Shall be followed is described in Table 7-3. The
timing parameters that Shall be followed are listed in Table 7-19, Table 7-20 and Table 7-21. Note in this figure, the
Sink has previously sent a Request Message to the Source.

Figure 7-17 Transition Diagram for Increasing the Voltage and Current

1 5
tSrcTransition
Source Port Send Send
Policy Engine Accept PS_RDY
Port to Port
2 6 Messaging
PSTransitionTimer (running)
Sink Port Evaluate Evaluate
Policy Engine Accept PS_RDY

4
Source Port Source
Device Policy Mgr ñVñI
Source Port
Source Port
Interaction
Source VOLD t2 Source VNEW
Power Supply

3 7 8
Sink to Sink Sink Standby
Sink Port
Standby ... to Sink
Device Policy Mgr
Sink Port
Sink Port
Interaction
Sink ≤ IOLD t1 Sink pSnkStdby t3 Sink ≤ INEW
Power Supply

Source Port
VNEW
Voltage Source
VOLD
VBUS Voltage

Sink Port I2
≤ INEW
Current Sink
≤ IOLD
I1 VBUS Current
≈

I1

I1 ≤ (pSnkStdby/VBUS) I2 ≤ (pSnkStdby/VBUS) + cSnkBulkPd(DVBUS/Dt)

Page 242 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 7-3 Sequence Diagram for Increasing the Voltage and Current

Step Source Port Sink Port

1 Policy Engine sends the Accept Message to the Policy Engine receives the Accept Message and starts the
Sink. PSTransitionTimer.
2 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. The Policy Engine tells the Device Policy Engine then evaluates the Accept Message.
Policy Manager to instruct the power supply to
modify its output power.
3 Policy Engine tells the Device Policy Manager to instruct
the power supply to reduce power consumption to
pSnkStdby within tSnkStdby (t1); t1 Shall complete
before tSrcTransition. The Sink Shall Not violate
transient load behavior defined in Section 7.2.6 while
transitioning to and operating at the new power level.
4 tSrcTransition after the GoodCRC Message was
received the power supply starts to change its
output power capability. The power supply Shall
be ready to operate at the new power level within
tSrcReady (t2). The power supply informs the
Device Policy Manager that it is ready to operate
at the new power level. The power supply status
is passed to the Policy Engine.
5 The Policy Engine sends the PS_RDY Message to
the Sink. The Policy Engine receives the PS_RDY Message from
the Source.
6 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. Policy Engine then evaluates the PS_RDY Message from the
Source and tells the Device Policy Manager it is okay to
operate at the new power level.
7 The Sink May begin operating at the new power level any
time after evaluation of the PS_RDY Message. This time
duration is indeterminate.
8 The Sink Shall Not violate the transient load behavior
defined in Section 7.2.6 while transitioning to and
operating at the new power level. The time duration (t3)
depends on the magnitude of the load change.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 243
 7.3.4 Increasing the Voltage and Decreasing the Current
The interaction of the System Policy, Device Policy, and power supply that Shall be followed when increasing the
voltage and decreasing the current is shown in Figure 7-18. The sequence that Shall be followed is described in Table
7-4. The timing parameters that Shall be followed are listed in Table 7-19, Table 7-20 and Table 7-21. Note in this
figure, the Sink has previously sent a Request Message to the Source.

Figure 7-18 Transition Diagram for Increasing the Voltage and Decreasing the Current

1 5
tSrcTransition
Source Port Send Send
Policy Engine Accept PS_RDY
Port to Port
2 6
Evaluate
PSTransitionTimer (running)
Evaluate
Messaging
Sink Port
Policy Engine Accept PS_RDY

4
Source Port Source
Device Policy Mgr ñ V òI
Source Port
Source Port
Interaction
Source VOLD t2 Source VNEW
Power Supply

3 7 8
Sink to Sink Sink Standby
Sink Port
Standby ... to Sink
Device Policy Mgr
Sink Port
Sink Port
Interaction
Sink ≤ IOLD t1 Sink pSnkStdby t3 Sink ≤ INEW
Power Supply

Source Port
VNEW
Voltage
Source
VOLD VBUS Voltage

Sink Port I2
≤ IOLD
Current
I1 ≤ INEW Sink
VBUS Current
≈

I1

I1 ≤ (pSnkStdby/VBUS) I2 ≤ (pSnkStdby/VBUS) + cSnkBulkPd(DVBUS/Dt)

Page 244 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 7-4 Sequence Description for Increasing the Voltage and Decreasing the Current

Step Source Port Sink Port

1 Policy Engine sends the Accept Message to the Policy Engine evaluates the Accept Message and starts the
Sink. PSTransitionTimer.
2 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. The Policy Engine tells the Device Policy Engine then evaluates the Accept Message.
Policy Manager to instruct the power supply to
modify its output power.
3 Policy Engine tells the Device Policy Manager to instruct
the power supply to reduce power consumption to
pSnkStdby within tSnkStdby (t1); t1 Shall complete
before tSrcTransition. The Sink Shall Not violate
transient load behavior defined in Section 7.2.6 while
transitioning to and operating at the new power level.
4 tSrcTransition after the GoodCRC Message was
received the power supply starts to change its
output power capability. The power supply Shall
be ready to operate at the new power level within
tSrcReady (t2). The power supply informs the
Device Policy Manager that it is ready to operate
at the new power level. The power supply status
is passed to the Policy Engine.
5 The Policy Engine sends the PS_RDY Message to The Policy Engine receives the PS_RDY Message from the
the Sink. Source.
6 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. Policy Engine then evaluates the PS_RDY Message from the
Source and tells the Device Policy Manager it is okay to
operate at the new power level.
7 The Sink May begin operating at the new power level any
time after evaluation of the PS_RDY Message. This time
duration is indeterminate.
8 The Sink Shall Not violate the transient load behavior
defined in Section 7.2.6 while transitioning to and
operating at the new power level. The time duration (t3)
depends on the magnitude of the load change.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 245
 7.3.5 Decreasing the Voltage and Increasing the Current
The interaction of the System Policy, Device Policy, and power supply that Shall be followed when decreasing the
voltage and increasing the current is shown in Figure 7-19. The sequence that Shall be followed is described in Table
7-5. The timing parameters that Shall be followed are listed in Table 7-19, Table 7-20 and Table 7-21. Note in this
figure, the Sink has previously sent a Request Message to the Source.

Figure 7-19 Transition Diagram for Decreasing the Voltage and Increasing the Current

1 5
tSrcTransition
Source Port Send Send
Policy Engine Accept PS_RDY

2 6
Port to Port
PSTransitionTimer (running) Messaging
Sink Port Evaluate Evaluate
Policy Engine Accept PS_RDY

4
Source Port Source
Device Policy Mgr òVñI
Source Port
Source Port
Source VOLD t2 Source VNEW
Interaction
Power Supply

3 7 8
Sink to Sink Sink Standby
Sink Port
Standby ... to Sink
Device Policy Mgr
Sink Port
Sink Port
Sink ≤ IOLD t1 Sink pSnkStdby t3 Sink ≤ INEW
Interaction
Power Supply

Source Port
VOLD
Voltage
Source
VNEW VBUS Voltage

Sink Port ≤ INEW

Current ≤ IOLD
Sink
≈

I1
I1
VBUS Current
I2
I1 ≤ (pSnkStdby/VBUS) I2 ≤ (pSnkStdby/VBUS) + cSnkBulkPd(DVBUS/Dt)

Page 246 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 7-5 Sequence Description for Decreasing the Voltage and Increasing the Current

Step Source Port Sink Port

1 Policy Engine sends the Accept Message to the Policy Engine receives the Accept Message and starts the
Sink. PSTransitionTimer.
2 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. The Policy Engine tells the Device Policy Engine then evaluates the Accept Message.
Policy Manager to instruct the power supply to
modify its output power.
3 Policy Engine tells the Device Policy Manager to instruct
the power supply to reduce power consumption to
pSnkStdby within tSnkStdby (t1); t1 Shall complete
before tSrcTransition. The Sink Shall Not violate
transient load behavior defined in Section 7.2.6 while
transitioning to and operating at the new power level.
4 tSrcTransition after the GoodCRC Message was
received the power supply starts to change its
output power capability. The power supply Shall
be ready to operate at the new power level within
tSrcReady (t2). The power supply informs the
Device Policy Manager that it is ready to operate
at the new power level. The power supply status
is passed to the Policy Engine.
5 The Policy Engine sends the PS_RDY Message to The Policy Engine receives the PS_RDY Message from the
the Sink. Source.
6 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. Policy Engine then evaluates the PS_RDY Message from the
Source and tells the Device Policy Manager it is okay to
operate at the new power level.
7 The Sink May begin operating at the new power level any
time after evaluation of the PS_RDY Message. This time
duration is indeterminate.
8 The Sink Shall Not violate the transient load behavior
defined in Section 7.2.6 while transitioning to and
operating at the new power level. The time duration (t3)
depends on the magnitude of the load change.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 247
 7.3.6 Decreasing the Current
The interaction of the System Policy, Device Policy, and power supply that Shall be followed when decreasing the
current is shown in Figure 7-20. The sequence that Shall be followed is described in Table 7-6. The timing
parameters that Shall be followed are listed in Table 7-19, Table 7-20 and Table 7-21. Note in this figure, the Sink has
previously sent a Request Message to the Source.

Figure 7-20 Transition Diagram for Decreasing the Current

1 5
tSrcTransition
Source Port Send Send
Policy Engine Accept PS_RDY

2 6
Port to Port
PSTransitionTimer (running) Messaging
Sink Port Evaluate Evaluate
Policy Engine Accept PS_RDY

4
Source Port Source
Device Policy Mgr òI
Source Port
Source Port
Source VOLD t2 Source VOLD
Interaction
Power Supply

3
Sink Port Sink
Device Policy Mgr òI
Sink Port
Sink Port
Sink ≤ IOLD t1 Sink ≤ INEW
Interaction
Power Supply

Source Port
VBUS does not change
Voltage
Source
VBUS Voltage

Sink Port
≤ IOLD
Current
Sink
≤ INEW VBUS Current

Page 248 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 7-6 Sequence Description for Decreasing the Current

Step Source Port Sink Port

1 Policy Engine sends the Accept Message to the Policy Engine receives the Accept Message starts
Sink. PSTransitionTimer.
2 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. The Policy Engine tells the Device Policy Engine then evaluates the Accept Message. Policy
Policy Manager to instruct the power supply to Engine tells the Device Policy Manager to instruct the
modify its output power. power supply to reduce power consumption.
3 The Sink Shall Not violate the transient load behavior
defined in Section 7.2.6 while transitioning to and
operating at the new power level. The Sink Shall be able
to operate with lower current within tSnkNewPower (t1);
t1 Shall complete before tSrcTransition.
4 tSrcTransition after the GoodCRC Message was
received the power supply starts to change its
output power capability. The power supply Shall
be ready to operate at the new power level within
tSrcReady (t2). The power supply informs the
Device Policy Manager that it is ready to operate
at the new power level. The power supply status
is passed to the Policy Engine.
5 The Policy Engine sends the PS_RDY Message to The Policy Engine receives the PS_RDY Message from the
the Sink. Source.
6 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. Policy Engine evaluates the PS_RDY Message from the
Source. The Sink is already operating at the new power
level so no further action is required.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 249
 7.3.7 Decreasing the Voltage
The interaction of the System Policy, Device Policy, and power supply that Shall be followed when decreasing the
voltage is shown in Figure 7-21. The sequence that Shall be followed is described in Table 7-7. The timing
parameters that Shall be followed are listed in Table 7-19, Table 7-20 and Table 7-21. Note in this figure, the Sink has
previously sent a Request Message to the Source.

Figure 7-21 Transition Diagram for Decreasing the Voltage

1 5
tSrcTransition
Source Port Send Send
Policy Engine Accept PS_RDY
Port to Port
2 6
Evaluate
PSTransitionTimer (running)
Evaluate
Messaging
Sink Port
Policy Engine Accept PS_RDY

4
Source Port Source
Device Policy Mgr òV
Source Port
Source Port Interaction
Source VOLD t2 Source VNEW
Power Supply

3 7 8
Sink to Sink Sink Standby
Sink Port
Standby ... to Sink
Device Policy Mgr
Sink Port
Sink Port Interaction
Sink ≤ IOLD t1 Sink pSnkStdby t3 Sink ≤ IOLD
Power Supply

Source Port
VOLD
Voltage
Source
VNEW VBUS Voltage

Sink Port
≤ IOLD ≤ IOLD
Current
Sink
≈

I1
I1 VBUS Current
I2

I1 ≤ (pSnkStdby/VBUS) I2 ≤ (pSnkStdby/VBUS) + cSnkBulkPd(DVBUS/Dt)

Page 250 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 7-7 Sequence Description for Decreasing the Voltage

Step Source Port Sink Port

1 Policy Engine sends the Accept Message to the Policy Engine receives the Accept Message and starts the
Sink. PSTransitionTimer.
2 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. The Policy Engine tells the Device Policy Engine then evaluates the Accept Message.
Policy Manager to instruct the power supply to
modify its output power.
3 Policy Engine tells the Device Policy Manager to instruct
the power supply to reduce power consumption to
pSnkStdby within tSnkStdby (t1); t1 Shall complete
before tSrcTransition. The Sink Shall Not violate
transient load behavior defined in Section 7.2.6 while
transitioning to and operating at the new power level.
4 tSrcTransition after the GoodCRC Message was
received the power supply starts to change its
output power capability. The power supply Shall
be ready to operate at the new power level within
tSrcReady (t2). The power supply informs the
Device Policy Manager that it is ready to operate
at the new power level. The power supply status
is passed to the Policy Engine.
5 The Policy Engine sends the PS_RDY Message to The Policy Engine receives the PS_RDY Message from the
the Sink. Source.
6 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. Policy Engine then evaluates the PS_RDY Message from the
Source and tells the Device Policy Manager it is okay to
operate at the new power level.
7 The Sink May begin operating at the new power level any
time after evaluation of the PS_RDY Message. This time
duration is indeterminate.
8 The Sink Shall Not violate the transient load behavior
defined in Section 7.2.6 while transitioning to and
operating at the new power level. The time duration (t3)
depends on the magnitude of the load change.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 251
 7.3.8 Decreasing the Voltage and the Current
The interaction of the System Policy, Device Policy, and power supply that Shall be followed when decreasing the
voltage and current is shown in Figure 7-22. The sequence that Shall be followed is described in Table 7-8. The
timing parameters that Shall be followed are listed in Table 7-19, Table 7-20 and Table 7-21. Note in this figure, the
Sink has previously sent a Request Message to the Source.

Figure 7-22 Transition Diagram for Decreasing the Voltage and the Current

1 5
tSrcTransition
Source Port Send Send
Policy Engine Accept PS_RDY

2 6
Port to Port
PSTransitionTimer (running) Messaging
Sink Port Evaluate Evaluate
Policy Engine Accept PS_RDY

4
Source Port Source
Device Policy Mgr òVòI
Source Port
Source Port
Source VOLD t2 Source VNEW
Interaction
Power Supply

3 7
Sink to Sink Sink Standby
Sink Port
Standby ... to Sink
Device Policy Mgr
Sink Port
Sink Port
Sink ≤ IOLD t1 Sink pSnkStdby t3 Sink ≤ INEW
Interaction
Power Supply

Source Port
VOLD
Voltage
Source
VNEW VBUS Voltage

Sink Port
≤ IOLD
Current ≤ INEW
Sink
≈

I1
I1 VBUS Current
I2

I1 ≤ (pSnkStdby/VBUS) I2 ≤ (pSnkStdby/VBUS) + cSnkBulkPd(DVBUS/Dt)

Page 252 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 7-8 Sequence Description for Decreasing the Voltage and the Current

Step Source Port Sink Port

1 Policy Engine sends the Accept Message to the Policy Engine receives the Accept Message and starts the
Sink. PSTransitionTimer.
2 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. The Policy Engine tells the Device Policy Engine then evaluates the Accept Message.
Policy Manager to instruct the power supply to
modify its output power.
3 Policy Engine tells the Device Policy Manager to instruct
the power supply to reduce power consumption to
pSnkStdby within tSnkStdby (t1); t1 Shall complete
before tSrcTransition. The Sink Shall Not violate
transient load behavior defined in Section 7.2.6 while
transitioning to and operating at the new power level.
4 tSrcTransition after the GoodCRC Message was
received the power supply starts to change its
output power capability. The power supply Shall
be ready to operate at the new power level within
tSrcReady (t2). The power supply informs the
Device Policy Manager that it is ready to operate
at the new power level. The power supply status
is passed to the Policy Engine.
5 The Policy Engine sends the PS_RDY Message to The Policy Engine receives the PS_RDY Message from the
the Sink. Source.
6 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. Policy Engine then evaluates the PS_RDY Message from the
Source and tells the Device Policy Manager it is okay to
operate at the new power level.
7 The Sink May begin operating at the new power level any
time after evaluation of the PS_RDY Message. This time
duration is indeterminate.
8 The Sink Shall Not violate the transient load behavior
defined in Section 7.2.6 while transitioning to and
operating at the new power level. The time duration (t3)
depends on the magnitude of the load change.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 253
 7.3.9 Sink Requested Power Role Swap
The interaction of the System Policy, Device Policy, and power supply that Shall be followed during a Sink requested
Power Role Swap is shown in Figure 7-23. The sequence that Shall be followed is described in Table 7-9. The timing
parameters that Shall be followed are listed in Table 7-20. Note in this figure, the Sink has previously sent a PR_Swap
Message to the Source.

Figure 7-23 Transition Diagram for a Sink Requested Power Role Swap

1 5 9
tSrcTransition PSSourceOnTimer (running)
Initial Source Port Send Send Evaluate
Policy Engine Accept PS_RDY PS_RDY
Port to Port
2 6 8
Evaluate
PSSourceOffTimer (running)
Evaluate Send Messaging
Initial Sink Port
Policy Engine Accept PS_RDY PS_RDY

Initial Source 4 10 New Sink

Initial Source Port Source to Swap Standby
Device Policy Mgr Swap Standby to Sink
◄ Rp to Rd
Source Port
Source à Sink Interaction
Source VOLD t2 Swap Standby t4 Sink default current
Power Supply

Initial Sink 3 7 New Source

Initial Sink Port Sink to Swap Swap Standby
Device Policy Mgr Standby to Source
Rd to Rp ►
Sink Port
Sink à Source Interaction
Sink ≤ IOLD t1 Swap Standby t3 Source vSafe5V
Power Supply

Source Port
VOLD
Voltage vSafe5V
Source
Initial Source New Source
VBUS Voltage
not driven

Sink Port
IOLD
Current pSnkSusp
Sink
Initial Sink I2 New Sink
VBUS Current
I1 I1
not driven
I1 ≤ iSnkSwapStdby I2 I2 ≤ iSnkSwapStdby + cSnkBulkPd(DVBUS/Dt)

Page 254 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 7-9 Sequence Description for a Sink Requested Power Role Swap

Step Initial Source Port à New Sink Port Initial Sink Port à New Source Port
1 Policy Engine sends the Accept Message to the Policy Engine receives the Accept and starts the
Initial Sink. PSSourceOffTimer.
2 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Initial
from the Sink. The Policy Engine tells the Device Source. Policy Engine then evaluates the Accept Message.
Policy Manager to instruct the power supply to
modify its output power.
3 Policy Engine tells the Device Policy Manager to instruct
the power supply to transition to Swap Standby within
tSnkStdby (t1); t1 Shall complete before tSrcTransition.
When in Sink Standby the Initial Sink Shall Not draw more
than iSnkSwapStdby (I1). The Sink Shall Not violate
transient load behavior defined in Section 7.2.6 while
transitioning to and operating at the new power level.
4 tSrcTransition after the GoodCRC Message was
received the power supply starts to change its
output power capability to Swap Standby (see
Section 7.1.10). The power supply Shall complete
the transition to Swap Standby within
tSrcSwapStdby (t2). The power supply informs
the Device Policy Manager that it is ready to
operate as the new Sink. The CC termination is
changed from Rp to Rd (see [USB Type-C 1.2]).
The power supply status is passed to the Policy
Engine.
5 The power supply is ready and the Policy Engine
sends the PS_RDY Message to the device that will
become the new Source.
6 Protocol Layer receives the GoodCRC Message Policy Engine stops the PSSourceOffTimer.
from the device that will become the new Source. The Protocol Layer sends the GoodCRC Message to the
Policy Engine starts the PSSourceOnTimer. Upon new Sink.
sending the PS_RDY Message and receiving the Policy Engine tells the Device Policy to instruct the power
GoodCRC Message the Initial Source is ready to be supply to operate as the new Source.
the new Sink.
7 The CC termination is changed from Rd to Rp (see [USB
Type-C 1.2]). The power supply as the new Source
transitions from Swap Standby to sourcing default
vSafe5V within tNewSrc (t3). The power supply informs
the Device Policy Manager that it is operating as the new
Source.
8 Policy Engine receives the PS_RDY Message from Device Policy Manager informs the Policy Engine the
the Source. power supply is ready and the Policy Engine sends the
PS_RDY Message to the new Sink.
9 Policy Engine stops the PSSourceOnTimer. Protocol Layer receives the GoodCRC Message from the
Protocol Layer sends the GoodCRC Message to the new Sink.
new Source.
Policy Engine evaluates the PS_RDY Message from
the new Source and tells the Device Policy
Manager to instruct the power supply to draw
current as the new Sink.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 255
Step Initial Source Port à New Sink Port Initial Sink Port à New Source Port
10 The power supply as the new Sink transitions
from Swap Standby to drawing pSnkSusp within
tNewSnk (t4). The power supply informs the
Device Policy Manager that it is operating as the
new Sink. At this point subsequent negotiations
between the new Source and the new Sink May
proceed as normal. The Sink Shall Not violate the
transient load behavior defined in Section 7.2.6
while transitioning to and operating at the new
power level. The time duration (t4) depends on
the magnitude of the load change.

Page 256 USB Power Delivery Specification Revision 3.0, Version 1.1
 7.3.10 Source Requested Power Role Swap
The interaction of the System Policy, Device Policy, and power supply that Shall be followed during a Source
requested Power Role Swap is shown in Figure 7-24. The sequence that Shall be followed is described in Table 7-10.
The timing parameters that Shall be followed are listed in Table 7-19. Note in this figure, the Sink has previously sent
a PR_Swap Message to the Source.

Figure 7-24 Transition Diagram for a Source Requested Power Role Swap

2 4 8
PSSourceOnTimer (running)
Initial Source Port Evaluate Send Evaluate
Policy Engine Accept PS_RDY PS_RDY
tSrcTransition Port to Port
1 5 7
Send
PSSourceOffTimer (running)
Evaluate Send
Messaging
Initial Sink Port
Policy Engine Accept PS_RDY PS_RDY

Initial Source 3 9 New Sink

Initial Source Port Source to Swap Standby
Device Policy Mgr Swap Standby to Sink
◄ Rp to Rd
Source Port
Source à Sink Interaction
Source VOLD t2 Swap Standby t4 Sink default current
Power Supply

Initial Sink 2a 6 New Source

Initial Sink Port Sink to Swap Swap Standby
Device Policy Mgr Standby to Source
Rd to Rp ►
Sink Port
Sink à Source Interaction
Sink ≤ IOLD t1 Swap Standby t3 Source vSafe5V
Power Supply

Source Port
VOLD
Voltage vSafe5V
Source
VBUS Voltage
Initial Source New Source
not driven

Sink Port
IOLD
Current pSnkSusp
Sink
I2
I1 VBUS Current
Initial Sink I1 New Sink
not driven
I1 ≤ iSnkSwapStdby I2 I2 ≤ iSnkSwapStdby + cSnkBulkPd(DVBUS/Dt)

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 257
 Table 7-10 Sequence Description for a Source Requested Power Role Swap

Step Initial Source Portà New Sink Port Initial Sink Port à New Source Port
1 Policy Engine receives the Accept Message. Policy Engine sends the Accept Message to the Initial
Source.
2 Protocol Layer receives the GoodCRC Message Protocol Layer receives the GoodCRC Message from the
from the Sink. The Policy Engine tells the Device Initial Source. Policy Engine starts the PSSourceOffTimer.
Policy Manager to instruct the power supply to
modify its output power.
2a The Policy Engine tells the Device Policy Manager to
instruct the power supply to transition to Swap Standby.
The power supply Shall complete the transition to Swap
Standby within tSnkStdby (t1); t1 Shall complete before
tSrcTransition. The Sink Shall Not violate the transient
load behavior defined in Section 7.2.6 while transitioning
to and operating at the new power level. Policy Engine
starts PSSourceOffTimer. When in Sink Standby the
Initial Sink Shall Not draw more than iSnkSwapStdby (I1).
3 tSrcTransition after the GoodCRC Message was
received the power supply starts to change its
output power capability to Swap Standby (see
Section 7.1.10). The power supply Shall complete
the transition to Swap Standby within
tSrcSwapStdby (t2). The power supply informs
the Device Policy Manager that it is ready to
operate as the new Sink. The CC termination is
changed from Rp to Rd (see [USB Type-C 1.2]).
The power supply status is passed to the Policy
Engine.
4 The Policy Engine sends the PS_RDY Message to Policy Engine receives the PS_RDY Message and stops the
the soon to be new Source. PSSourceOffTimer.
5 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the new
from the soon to be new Source. Policy Engine Sink. Upon evaluating the PS_RDY Message the Initial Sink
starts the PSSourceOnTimer. At this point the is ready to operate as the new Source. Policy Engine tells
Initial Source is ready to be the new Sink. the Device Policy to instruct the power supply to operate
as the new Source.
6 The CC termination is changed from Rd to Rp (see [USB
Type-C 1.2]). The power supply as the new Source
transitions from Swap Standby to sourcing default
vSafe5V within tNewSrc (t3). The power supply informs
the Device Policy Manager that it is operating as the new
Source.
7 Policy Engine receives the PS_RDY Message and Device Policy Manager informs the Policy Engine the
stops the PSSourceOnTimer. power supply is ready and the Policy Engine sends the
PS_RDY Message to the new Sink.
8 Protocol Layer sends the GoodCRC Message to the Protocol Layer receives the GoodCRC Message from the
new Source. new Sink.
Policy Engine evaluates the PS_RDY Message from
the new Source and tells the Device Policy
Manager to instruct the power supply to draw
current as the new Sink.

Page 258 USB Power Delivery Specification Revision 3.0, Version 1.1
Step Initial Source Portà New Sink Port Initial Sink Port à New Source Port
9 The power supply as the new Sink transitions
from Swap Standby to drawing pSnkSusp within
tNewSnk (t4). The power supply informs the
Device Policy Manager that it is operating as the
new Sink. At this point subsequent negotiations
between the new Source and the new Sink May
proceed as normal. The new Sink Shall Not
violate the transient load behavior defined in
Section 7.2.6 while transitioning to and operating
at the new power level. The time duration (t4)
depends on the magnitude of the load change.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 259
 7.3.11 GotoMin Current Decrease
The interaction of the System Policy, Device Policy, and power supply that Shall be followed during a GotoMin current
decrease is shown in Figure 7-25. The sequence that Shall be followed is described in Table 7-11. The timing
parameters that Shall be followed are listed in Table 7-19 and Table 7-11.

Figure 7-25 Transition Diagram for a GotoMin Current Decrease

1 5
tSrcTransition
Source Port Send Send
Policy Engine Go To Min PS_RDY
Port to Port
2 6
Evaluate
PSTransitionTimer (running)
Evaluate
Messaging
Sink Port
Policy Engine Go To Min PS_RDY

4
Source Port Source
Device Policy Mgr òI
Source Port
Source Port Interaction
Source VOLD t2 Source VOLD
Power Supply

3
Sink Port Sink
Device Policy Mgr òI
Sink Port
Sink Port Interaction
Sink ≤ IOLD t1 Sink previously negotiated go to min current
Power Supply

Source Port
VBUS doesn’t change
Voltage
Source
VBUS Voltage

Sink Port
≤ IOLD
Current
Sink
go to min current VBUS Current

Page 260 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 7-11 Sequence Description for a GotoMin Current Decrease

Step Source Port Sink Port

1 Policy Engine sends the GotoMin Message to the Policy Engine receives the GotoMin Message and starts the
Sink. PSTransitionTimer.
2 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. The Policy Engine tells the Device Policy Engine then evaluates the GotoMin Message.
Policy Manager to instruct the power supply to
modify its output power.
3 Policy Engine tells the Device Policy Manager to instruct
the power supply to reduce power consumption, within
tSnkNewPower (t1), to the pre-negotiated go to reduced
power level); t1 Shall complete before tSrcTransition.
The Sink Shall Not violate the transient load behavior
defined in Section 7.2.6 while transitioning to and
operating at the new power level.
4 tSrcTransition after the GoodCRC Message was
received the power supply starts to change its
output power capability. The power supply Shall
be ready to operate at the new power level within
tSrcReady (t2). The power supply informs the
Device Policy Manager that it is ready to operate
at the new power level. The power supply status
is passed to the Policy Engine.
5 The Policy Engine sends the PS_RDY Message to The Policy Engine receives the PS_RDY Message.
the Sink.
6 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. Policy Engine evaluates the PS_RDY Message from the
Source and no further action is required.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 261
 7.3.12 Source Initiated Hard Reset
The interaction of the System Policy, Device Policy, and power supply that Shall be followed during a Source Initiated
Hard Reset is shown in Figure 7-26. The sequence that Shall be followed is described in Table 7-12. The timing
parameters that Shall be applied are listed in Table 7-19 and Table 7-20.

Figure 7-26 Transition Diagram for a Source Initiated Hard Reset

1
Send tPSHardReset
Source Port
Policy Engine Hard Reset
Port to Port
2
Process
Messaging
Sink Port
Policy Engine Hard Reset

4 5
Source Port Source Source
Device Policy Mgr Hard Reset Recover
Source Port
Source Port Interaction
Source VOLD t2 Source vSafe0V t4 Source vSafe5V
Power Supply

Sink Port Sink

Device Policy Mgr Prepare
Sink Port
Sink Port Interaction
Sink ≤ IOLD t1 Ready to recover and power up
Power Supply

Source Port tSrcRecover

VOLD vSafe5V
Voltage
Source
≈ VBUS Voltage
vSafe0V

Sink Port
≤ IOLD Default current draw
Current
Sink
≈ VBUS Current
iSafe0mA

Page 262 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 7-12 Sequence Description for a Source Initiated Hard Reset

Step Source Port Sink Port

1 Policy Engine sends Hard Reset Signaling to the Sink receives Hard Reset Signaling.
Sink.
2 Policy Engine is informed of the Hard Reset. Policy Engine
tells the Device Policy Manager to instruct the power
supply to prepare for a Hard Reset.
3 The Sink prepares for the Hard Reset within
tSnkHardResetPrepare (t1) ) and passes an indication to
the Device Policy Manger The Sink Shall Not draw more
than iSafe0mA when VBUS is driven to vSafe0V.
4 Policy Engine waits tPSHardReset after sending
Hard Reset Signaling and then tells the Device
Policy Manager to instruct the power supply to
perform a Hard Reset. The transition to vSafe0V
Shall occur within tSafe0V (t2).
5 After tSrcRecover the Source applies power to The Sink Shall Not violate the transient load behavior
VBUS in an attempt to re-establish communication defined in Section 7.2.6 while transitioning to and
with the Sink and resume USB Default Operation. operating at the new power level.
The transition to vSafe5V Shall occur within
tSrcTurnOn (t4).

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 263
 7.3.13 Sink Initiated Hard Reset
The interaction of the System Policy, Device Policy, and power supply that Shall be followed during a Sink Initiated
Hard Reset is shown in Figure 7-27. The sequence that Shall be followed is described in Table 7-13. The timing
parameters that Shall be followed are listed in Table 7-19 and Table 7-20.

Figure 7-27 Transition Diagram for a Sink Initiated Hard Reset

4
Source Port Evaluate
Policy Engine Hard Reset
Port to Port
1
Send tPSHardReset Messaging
Sink Port
Policy Engine Hard Reset

2 5 6
Process Source Source
Source Port Hard Reset
Device Policy Mgr Hard Reset Recover
Source Port
Source Port Interaction
Source VOLD t2 Source vSafe0V t4 Source vSafe5V
Power Supply

3
Sink Port Sink
Device Policy Mgr Prepare
Sink Port
Sink Port Interaction
Sink ≤ IOLD t1 Ready to recover and power up
Power Supply

Source Port tSrcRecover

VOLD vSafe5V
Voltage
Source
≈ VBUS Voltage
vSafe0V

Sink Port Defalt current

≤ IOLD
Current draw
Sink
≈ VBUS Current
iSafe0mA

Page 264 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 7-13 Sequence Description for a Sink Initiated Hard Reset

Step Source Port Sink Port

1 Policy Engine sends Hard Reset Signaling to the Source.
2 Policy Engine tells the Device Policy Manager to instruct
the power supply to prepare for a Hard Reset.
3 The Sink prepares for the Hard Reset within
tSnkHardResetPrepare (t1) and passes an indication to
the Device Policy Manger. The Sink Shall Not draw more
than iSafe0mA when VBUS is driven to vSafe0V.
4 Policy Engine is informed of the Hard Reset.
5 Policy Engine waits tPSHardReset after receiving
Hard Reset Signaling and then tells the Device
Policy Manager to instruct the power supply to
perform a Hard Reset. The transition to vSafe0V
Shall occur within tSafe0V (t2).
6 After tSrcRecover the Source applies power to The Sink Shall Not violate the transient load behavior
VBUS in an attempt to re-establish communication defined in Section 7.2.6 while transitioning to and
with the Sink and resume USB Default Operation. operating at the new power level.
The transition to vSafe5V Shall occur within
tSrcTurnOn (t4).

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 265
 7.3.14 No change in Current or Voltage
The interaction of the System Policy, Device Policy, and power supply that Shall be followed when the Sink requests
the same Voltage and Current as it is currently operating at is shown in Figure 7-28. The sequence that Shall be
followed is described in Table 7-14. The timing parameters that Shall be followed are listed in Table 7-19 and Table
7-20.

Figure 7-28 Transition Diagram for no change in Current or Voltage

1 3
tSrcTransition
Source Port Send Send
Policy Engine Accept PS_RDY
Port to Port
2 4
Evaluate
PSTransitionTimer (running)
Evaluate
Messaging
Sink Port
Policy Engine Accept PS_RDY

Source Port
Device Policy Mgr
Source Port
Source Port Interaction
Source VOLD
Power Supply

Sink Port
Device Policy Mgr
Sink Port
Sink Port Interaction
Sink ≤ IOLD
Power Supply

Source Port
VBUS doesn’t change
Voltage
Source
VBUS Voltage

Sink Port
Current
Current doesn’t change Sink
VBUS Current

Page 266 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 7-14 Sequence Description for no change in Current or Voltage

Step Source Port Sink Port

1 Policy Engine sends the Accept Message to the
Sink. Policy Engine receives the Accept Message and starts
the PSTransitionTimer.
2 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. Policy Engine then evaluates the Accept Message.
3 The Policy Engine waits tSrcTransition then Policy Engine receives the PS_RDY Message.
sends the PS_RDY Message to the Sink.
4 Policy Engine receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the Source.
from the Sink. Policy Engine evaluates the PS_RDY Message.
Note: the decision that no power transition is
required could be made either by the Device
Policy Manager or the power supply depending
on implementation.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 267
 7.3.15 Fast Role Swap
The interaction of the System Policy, Device Policy, and power supply that Shall be followed during a Fast Role Swap
is shown in Figure 7-29. The sequence that Shall be followed is described in Table 7-15. The timing parameters that
Shall be followed are listed in Table 7-19 and Table 7-20. Negotiations between the new Source and the new Sink
May occur after the new Source sends the final PS_RDY Message. Note: in Figure 7-29 and Table 7-15 numbers are
used to indicate Message related steps and letters are used to indicate other events.

Figure 7-29 Transition Diagram for Fast Role Swap

B 2 3 5 8
Signal Evaluate Send Send Evaluate
Source Port Fast Swap FR_Swap Accept PS_RDY PS_RDY
Policy Engine Port to Port
C 1 4 6 7 Signaling &
Detect tFRSwapInit Send Evaluate Evaluate Send
Sink Port Messaging
Fast Swap FR_Swap Accept PS_RDY PS_RDY
Policy Engine

A D1 F
Source Port Source VBUS < Rp Changed
Device Policy Mgr Stops vSafe5V to Rd
Source Port
Source Port Interaction
Power Path Source Sink

D2 E G
VBUS < < tSrcFRSwap Source Rd Changed
Sink Port
vSafe5V VBUS to Rp
Device Policy Mgr
Sink Port
Sink Port Interaction
Sink Ready & Able to Source vSafe5V Source vSafe5V
Power Path

Source Port
Old Source
Voltage discharging to
vSafe0V New Source = vSafe5V Source
VBUS Voltage

Sink Port
rges
Current age discha New Sink
ent as VBUS volt Sink
se in curr
s the increa VBUS Current
Old Sink Represent

Table 7-15 Sequence Description for Fast Role Swap

Step Initial Source Portà New Sink Port Initial Sink Port à New Source Port
A The Source connected to the Hub UFP (see Figure
7-12) stops sourcing VBUS.
B Policy Engine signals the Fast Role Swap to the
initial Sink on the CC wire.
C Policy Engine detects the Fast Role swap signal on the CC
wire from the initial Source and Shall send the FR_Swap
Message back to the initial Source (that is no longer
powering VBUS) within time tFRSwapInit.
D1 The Policy engine monitors for VBUS ≤ vSafe5V so
that a PS_RDY Message can be sent to the new
Source at Step 5 of the messaging sequence.
D2 The Policy engine monitors for VBUS ≤ vSafe5V so the initial
Sink can assume the role of new Source and begin to
source VBUS.

Page 268 USB Power Delivery Specification Revision 3.0, Version 1.1
Step Initial Source Portà New Sink Port Initial Sink Port à New Source Port
E When VBUS = vSafe5V the new Source May provide power
to VBUS. When VBUS < vSafe5V the new Source Shall
provide power to VBUS within tSrcFRSwap and the PS_RDY
Message can be sent to the new Sink at Step 7 of the
messaging sequence.
F The CC termination is changed from Rp to Rd (see
[USB Type-C 1.2]) before the new Sink sends the
PS_RDY Message of Step 5 to the new Source.
G The CC termination is changed from Rd to Rp (see [USB
Type-C 1.2]) before the new Source sends the PS_RDY
Message of Step 7 to the new Sink.
1 Policy Engine receives the FR_Swap Message Policy Engine sends the FR_Swap Message to the initial
from the initial Sink that is transitioning to be the Source(that is no longer powering VBUS) after detecting the
new Source. Fast Role Swap signal of Step C.
2 Protocol Layer sends the GoodCRC Message to the Protocol Layer receives the GoodCRC Message from the
initial Sink. Policy Engine then evaluates the initial Source.
FR_Swap Message.
3 Policy Engine sends an Accept Message to the Policy Engine receives the Accept Message from the initial
initial Sink that is transitioning to be the new Source that is transitioning to be the new Sink.
Source.
4 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message to the initial
from the initial Sink that is transitioning to be the Source that is transitioning to be the new Sink.
new Source.
5 Policy Engine sends a PS_RDY Message to the Policy Engine receives the PS_RDY Message from the new
initial Sink that is transitioning to be the new Sink.
Source. The Policy Engine Shall wait for Step D1
before sending the PS_RDY Message.
6 Protocol Layer receives the GoodCRC Message Protocol Layer sends the GoodCRC Message from the
from the new Source. initial Sink that has completed the transition to new
Source. Policy Engine then evaluates the PS_RDY Message.
7 Policy Engine receives the PS_RDY Message from Policy Engine sends a PS_RDY Message to the new Sink.
the new Source. The Policy Engine Shall wait for Step E before sending the
PS_RDY Message.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 269
 7.3.16 Increasing the Programmable Power Supply Voltage
The interaction of the System Policy, Device Policy, and power supply that Shall be followed when increasing the
voltage is shown in Figure 7-30. The sequence that Shall be followed is described in Table 7-16. The timing
parameters that Shall be followed are listed in Table 7-19 and Table 7-20. Note in this figure, the Sink has previously
sent a Request Message to the Source.

Figure 7-30 Transition Diagram for Increasing the Programmable Power Supply Voltage
1 4
tPpsSrcTransition
Source Port Send Send
Policy Engine Accept PS_RDY
Port to Port
2 5
Evaluate
PpsTransitionTimer (running)
Evaluate
Messaging
Sink Port
Policy Engine Accept PS_RDY

3
Source Port Source
Device Policy Mgr ñV
Source Port
Source Port Interaction
Source VOLD Pps Transition Interval Source VNEW
Power Supply

Sink Port
Device Policy Mgr
Sink Port
Sink Port Interaction
Sink draws current continuously (not to exceed negotiated current)
Power Supply

Source Port
VNEW
Voltage
Source
VOLD VBUS Voltage

Sink Port INEW

Current IOLD
Sink
VBUS Current

Table 7-16 Sequence Description for Increasing the Programmable Power Supply Voltage

Step Source Port Sink Port

1 Policy Engine sends the Accept Message to the Sink. Policy Engine receives the Accept Message and starts the
PSTransitionTimer.
2 Protocol Layer receives the GoodCRC Message from Protocol Layer sends the GoodCRC Message to the
the Sink. The Policy Engine tells the Device Policy Source. Policy Engine. Policy Engine then evaluates the
Manager to instruct the power supply to increase Accept Message.
its output voltage.
3 After sending the Accept Message, the
Programmable Power Supply starts to increase its
output voltage. The Programmable Power Supply
new voltage Shall be reached by
tPpsSrcTransition. The power supply informs the
Device Policy Manager that it is has reached the
new level. The power supply status is passed to the
Policy Engine.
4 The Policy Engine sends the PS_RDY Message to the The Policy Engine receives the PS_RDY Message from the
Sink. Source.

Page 270 USB Power Delivery Specification Revision 3.0, Version 1.1
Step Source Port Sink Port
5 Protocol Layer receives the GoodCRC Message from Protocol Layer sends the GoodCRC Message to the
the Sink. Source. Policy Engine then evaluates the PS_RDY
Message from the Source and tells the Device Policy
Manager that the Programmable Power Supply is
operating at the new voltage.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 271
 7.3.17 Decreasing the Programmable Power Supply Voltage
The interaction of the System Policy, Device Policy, and power supply that Shall be followed when decreasing the
voltage is shown in Figure 7-31. The sequence that Shall be followed is described in Table 7-17. The timing
parameters that Shall be followed are listed in Table 7-19 and Table 7-20. Note in this figure, the Sink has previously
sent a Request Message to the Source.

Figure 7-31 Transition Diagram for Decreasing the Programmable Power Supply Voltage
1 4
tPpsSrcTransition
Source Port Send Send
Policy Engine Accept PS_RDY
Port to Port
2 5
Evaluate
PpsTransitionTimer (running)
Evaluate
Messaging
Sink Port
Policy Engine Accept PS_RDY

3
Source Port Source
Device Policy Mgr òV
Source Port
Source Port Interaction
Source VOLD Pps Transition Interval Source VNEW
Power Supply

Sink Port
Device Policy Mgr
Sink Port
Sink Port Interaction
Sink draws current continuously (not to exceed negotiated current)
Power Supply

Source Port
VOLD
Voltage
Source
VNEW VBUS Voltage

Sink Port IOLD

Current INEW
Sink
VBUS Current

Table 7-17 Sequence Description for Decreasing the Programmable Power Supply Voltage

Step Source Port Sink Port

1 Policy Engine sends the Accept Message to the Sink. Policy Engine receives the Accept Message and starts the
PSTransitionTimer.
2 Protocol Layer receives the GoodCRC Message from Protocol Layer sends the GoodCRC Message to the
the Sink. The Policy Engine tells the Device Policy Source. Policy Engine. Policy Engine then evaluates the
Manager to instruct the power supply to decrease its Accept Message.
output voltage.
3 After sending the Accept Message, the Programmable
Power Supply starts to decrease its output voltage.
The Programmable Power Supply new voltage Shall
be reached by tPpsSrcTransition. The power supply
informs the Device Policy Manager that it is has
reached the new level. The power supply status is
passed to the Policy Engine.
4 The Policy Engine sends the PS_RDY Message to the The Policy Engine receives the PS_RDY Message from the
Sink. Source.

Page 272 USB Power Delivery Specification Revision 3.0, Version 1.1
Step Source Port Sink Port
5 Protocol Layer receives the GoodCRC Message from Protocol Layer sends the GoodCRC Message to the
the Sink. Source. Policy Engine then evaluates the PS_RDY
Message from the Source and tells the Device Policy
Manager that the Programmable Power Supply is
operating at the new voltage.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 273
 7.3.18 Changing the Source PDO or APDO
The interaction of the Device Policy Manager, the port Policy Engine and the Power Supply when changing between
Source PDOs and APDOs, as listed below, is shown in Figure 7-32.
 PDO to PDO
 PDO to APDO
 APDO to APDO
 APDO to PDO
The Source voltage as the transition starts Shall be any voltage within the Valid VBUS range of the previous Source
PDO or APDO. The Source voltage after the transition is complete Shall be any voltage within the Valid VBUS range of
the new Source PDO or APDO. The sequence that Shall be followed is described in Table 7-18. The timing parameters
that Shall be followed are listed in Table 7-19 and Table 7-20. Note in this figure, the Sink has previously sent a
Request Message to the Source.

Figure 7-32 Transition Diagram for Changing the Source PDO or APDO
1 5
tSrcTransition
Source Port Send Send
Policy Engine Accept PS_RDY
Port to Port
2 6
Evaluate
PSTransitionTimer (running)
Evaluate
Messaging
Sink Port
Policy Engine Accept PS_RDY

4
Source Port Source
Device Policy Mgr Change
Source Port
Source Port Interaction
Previous Source PDO or APDO t2 New Source PDO or APDO
Power Supply

3 7 8
Sink to Sink Sink Standby
Sink Port
Standby ... to Sink
Device Policy Mgr
Sink Port
Sink Port Interaction
Sink ≤ IOLD t1 Sink pSnkStdby t3 Sink ≤ INEW
Power Supply

Source Port
Voltage
Previous PDO or APDO VBUS New PDO or APDO VBUS Source
VBUS Voltage

Sink Port I2
≤ IOLD ≤ INEW
Current
I1 Sink
VBUS Current
≈

I1

I1 ≤ pSnkStdby/VBUS) I2 ≤ pSnkStdby/VBUS) + cSnkBulkPd(DVBUS/Dt)

Table 7-18 Sequence Description for Changing the Source PDO or APDO

Step Source Port Sink Port

1 Policy Engine sends the Accept Policy Engine receives the Accept Message
Message to the Sink. and starts the PSTransitionTimer.
2 Protocol Layer receives the GoodCRC Protocol Layer sends the GoodCRC Message
Message from the Sink. The Policy to the Source. Policy Engine. Policy Engine
Engine tells the Device Policy Manager then evaluates the Accept Message.
to instruct the power supply to change
to the new Source PDO or APDO.

Page 274 USB Power Delivery Specification Revision 3.0, Version 1.1
Step Source Port Sink Port
3 After sending the Accept Message, the
Source starts to change to the new
PDO or APDO. The Source transition
to the new PDO or APDO VBUS voltage
Shall be completed by
tSrcTransition. The power supply
informs the Device Policy Manager
that the transition to the new PDO or
APDO is complete. The power supply
status is passed to the Policy Engine.
4 The Policy Engine sends the PS_RDY The Policy Engine receives the PS_RDY
Message to the Sink. Message from the Source.
5 Protocol Layer receives the GoodCRC Protocol Layer sends the GoodCRC Message
Message from the Sink. to the Source. Policy Engine then evaluates
the PS_RDY Message from the Source and
tells the Device Policy Manager that the
Source is operating at the new PDO or APDO.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 275
 7.4 Electrical Parameters
7.4.1 Source Electrical Parameters
The Source Electrical Parameters that Shall be followed are specified in Table 7-19.

Table 7-19 Source Electrical Parameters

Parameter Description MIN TYP MAX UNITS Reference

cSrcBulk1 Source bulk capacitance 10 µF Section 7.1.2

when a Port is powered
from a dedicated supply.
cSrcBulkShared1 Source bulk capacitance 120 µF Section 7.1.2
when a Port is powered
from a shared supply.
iPpsCfMin Minimum current 1 A Section 7.1.4.4
foldback setting.
iPpsCfNew Current foldback Section 7.1.4.4
accuracy
1A ≤ Operating Current -150 150 mA
≤ 3A
Operating current > 3A -5 5 %
iPpsCfStep PPS current foldback 50 mA Section 7.1.4.4
programming step size.
iPpsCfTransient CF load transient -250 250 mA Section 7.1.4.4
current bounds.
iPpsCvCfTransient CV to CF transient -100 500 mA Section 7.1.4.4
current bounds
assuming the Operating
Voltage reduction of
Section 7.2.3.1.
tNewSnk Time allowed for an 15 ms Figure 7-23,
initial Source in Swap Figure 7-24
Standby to transition
new Sink operation.
tPpsCfCvTransient CF to CV transient 25 ms Section 7.1.4.4
voltage settling time.
tPpsCfProgramSettle PPS current foldback 125 250 ms Section 7.1.4.4
programming settling
time
tPpsCfSettle CF load transient 125 250 ms Section 7.1.4.4
current settling time.
tPpsCvCfTransient CV to CF transient 125 250 ms Section 7.1.8.1
settling time.
tPpsSrcTransition The time the 0 25 ms Section 7.3
Programmable Power
Supply Shall transition
between requested
voltages.
tPpsTransient The maximum time for 5 ms Section 7.1.8.1
the Programmable
power Supply to be
between vPpsNew and
vPpsValid in response
to a load transient

Page 276 USB Power Delivery Specification Revision 3.0, Version 1.1
 Parameter Description MIN TYP MAX UNITS Reference

tSrcFRSwap Time from the initial Sink 150 µs Section 7.1.13

detecting that VBUS has
dropped below vSafe5V
until the initial Sink/new
Source is able to supply
USB Type-C Current (see
[USB Type-C 1.2])
tSrcReady Time from 285 ms Figure 7-2,
positive/negative Figure 7-3
transition start (t0) to
when the Source is ready
to provide the newly
negotiated power level.
tSrcRecover Time allotted for the 0.66 1 s Section 7.1.5
Source to recover.
tSrcSettle Time from 275 ms Figure 7-2
positive/negative
transition start (t0) to
when the transitioning
voltage is within the
range vSrcNew.
tSrcSwapStdby The maximum time for 650 ms Table 7-9
the Source to transition Table 7-10
to Swap Standby.
tSrcTransient The maximum time for 5 ms Section 7.1.8
the Source output voltage
to be between vSrcNew
and vSrcValid in
response to a load
transient.
tSrcTransition The time the Source Shall 25 35 ms Section 7.3
wait before transitioning
the power supply to
ensure that the Sink has
sufficient time to
prepare.
tSrcTurnOn Transition time from 275 ms Table 7-12
vSafe0V to vSafe5V. Table 7-13
vPpsCfCvTransient CF to CV load transient Operatin Operatin V Section 7.1.4.4
voltage bounds. g Voltage g Voltage
* 0.95 – * 1.05 +
0.1V 0.1V
vPpsCvCfTransient CV to CF transient Operatin Operatin V Section 7.1.8.1
voltage bounds g Voltage g Voltage
assuming the Operating – 1.0V + 0.5V
Voltage reduction of
Section 7.2.3.1.
vPpsMaxVoltage Maximum Voltage Field APDO APDO V Section 7.1.4.3
in the Programmable Voltage Voltage *
Power Supply APDO. *0.95 1.05
vPpsMinVoltage Minimum Voltage Field in APDO APDO V Section 7.1.4.3
the Programmable Power Voltage Voltage *
Supply APDO. *0.95 1.05
vPpsNew Programmable RDO RDO RDO RDO V Section 7.1.8.1
Output Voltage Output Output Output

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 277
 Parameter Description MIN TYP MAX UNITS Reference

measured at the Source Voltage Voltage Voltage

receptacle. *0.95 *1.05
vPpsSlewNeg Programmable Power -30 mV/µs Section 7.1.8.1
Supply maximum slew
rate for negative voltage
changes
vPpsSlewPos Programmable Power 30 mV/µs Section 7.1.8.1
Supply maximum slew
rate for positive voltage
changes
vPpsStep PPS voltage 20 mV Section 7.1.8.1
programming step size.
vPpsValid The range in addition to -0.1 0.1 V Section 7.1.8.1
vPpsNew which the
Programmable Power
Supply output is
considered Valid in
response to a load step.
vSrcNeg Most negative voltage -0.3 V Figure 7-8
allowed during
transition.
vSrcNew Fixed Supply output PDO PDO PDO V Figure 7-2
measured at the Source Voltage Voltage Voltage Figure 7-3
receptacle. *0.95 *1.05
Variable Supply output PDO PDO V
measured at the Source Minimum Maximum
receptacle. Voltage Voltage
Battery Supply output PDO PDO V
measured at the Source Minimum Maximum
receptacle. Voltage Voltage
vSrcPeak The range that a Fixed PDO PDO V Table 6-10
Supply in Peak Current Voltage Voltage Figure 7-10
operation is allowed *0.90 *1.05
when overload
conditions occur.
vSrcSlewNeg Maximum slew rate -30 mV/µs Section 7.1.4.2
allowed for negative Figure 7-3
voltage transitions.
Limits current based on a
3 A connector rating and
maximum Sink bulk
capacitance of 100 µF.
vSrcSlewPos Maximum slew rate 30 mV/µs Section 7.1.4
allowed for positive Figure 7-2
voltage transitions.
Limits current based on a
3 A connector rating and
maximum Sink bulk
capacitance of 100 µF.

Page 278 USB Power Delivery Specification Revision 3.0, Version 1.1
 Parameter Description MIN TYP MAX UNITS Reference

vSrcValid The range in addition to -0.5 0.5 V Figure 7-2

vSrcNew which a newly Figure 7-3
negotiated voltage is
considered Valid during
and after a transition.
This range also applies to
vSafe5V.
Note 1: The Source Shall charge and discharge the total bulk capacitance to meet the transition time requirements.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 279
 7.4.2 Sink Electrical Parameters
The Sink Electrical Parameters that Shall be followed are specified in Table 7-20.

Table 7-20 Sink Electrical Parameters

Parameter Description MIN TYP MAX UNITS Reference

cSnkBulk1 Sink bulk capacitance on VBUS 1 10 µF
at Attach.
Section 7.2.2

cSnkBulkPd Bulk capacitance on VBUS a 1 100 µF

Sink is allowed after a
Section 7.2.2
successful negotiation.
iLoadReleaseRate Load release di/dt . Refer to -150 mA/µs
Section 7.2.6
[USB Type-C 1.2] Section
3.7.3.3.2 for cable details.
iLoadStepRate Load step di/dt . Refer to 150 mA/µs
Section 7.2.6
[USB Type-C 1.2] Section
3.7.3.3.2 for cable details.
iOvershoot Positive or negative -230 230 mA
overshoot when a load
Section 7.2.6
change occurs less than or
equal to iLoadStepRate;
relative to the settled value
after the load change. Refer
to USB [USB Type-C 1.2]
Section 3.7.3.3.2 for cable
details.
iPpsCfLoadRelease Maximum load release -500 mA
decrease during Current
Section 7.2.3.1
Foldback.
iPpsCfLoadReleaseRate Maximum load decrease -150 mA/µs
slew rate during Current
Section 7.2.3.1
Foldback.
iPpsCfLoadStep Maximum load step 500 mA
increase during Current Section 7.2.3.1
Foldback.
iPpsCfLoadStepRate Maximum load increase 150 mA/µs
slew rate during Current
Section 7.2.3.1
Foldback.
iSafe0mA Maximum current a Sink is 1.0 mA
allowed to draw when VBUS is
Figure 7-26
driven to vSafe0V. Figure 7-27

iSnkSwapStdby Maximum current a Sink can 2.5 mA

draw during Swap Standby.
Section 7.2.7
Ideally this current is very
near to 0 mA largely
influenced by Port leakage
current.
pHubSusp Suspend power consumption 125 mW
for a hub. 25mW + 25mW
Section 7.2.3
per downstream Port for up
to 4 ports.
pSnkStdby Maximum power 2.5 W
consumption while in Sink Section 7.2.3
Standby.

Page 280 USB Power Delivery Specification Revision 3.0, Version 1.1
 Parameter Description MIN TYP MAX UNITS Reference
pSnkSusp Suspend power consumption 25 mW
for a peripheral device.
Section 7.2.3

tNewSrc Maximum time allowed for 275 ms

an initial Sink in Swap
Section 7.2.7
Standby to transition to new Table 7-9
Source operation.
Table 7-10

tSnkHardResetPrepare Time allotted for the Sink 15 ms

power electronics to prepare Table 7-13
for a Hard Reset.
tSnkNewPower Maximum transition time 15 ms
between power levels.
Section 7.2.3

tSnkRecover Time for the Sink to resume 150 ms

USB Default Operation. Table 7-12

tSnkStdby Time to transition to Sink 15 ms

Standby from Sink. Section 7.2.3

tSnkSwapStdby Maximum time for the Sink 15 ms

to transition to Swap
Section 7.2.7
Standby.

Note 1: If more bypass capacitance than cSnkBulk max or cSnkBulkPd max is required in the device, then the
device Shall incorporate some form of VBUS surge current limiting as described in [USB 3.1] Section 11.4.4.1.

7.4.3 Common Electrical Parameters

Electrical Parameters that are common to both the Source and the Sink that Shall be followed are specified in Table
7-21.

Table 7-21 Common Source/Sink Electrical Parameters

Parameter Description MIN TYP MAX UNITS Reference

tSafe0V Time to reach vSafe0V max. 650 ms Section 7.1.5

Figure 7-8
Table 7-12
Table 7-13
tSafe5V Time to reach vSafe5V max. 275 ms Section 7.1.4.2
Figure 7-8

vSafe0V Safe operating voltage at “zero volts”. 0 0.8 V

Section 7.1.5

vSafe5V Safe operating voltage at 5V. See [USB 2.0] and 4.75 5.5 V
[USB 3.1] for allowable VBUS voltage range. Section 7.1.5

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 281
8. Device Policy
8.1 Overview
This section describes the Device Policy and Policy Engine that implements it. For an overview of the architecture and
how the Device Policy Manager fits into this architecture, please see Section 2.7.

8.2 Device Policy Manager

The Device Policy Manager is responsible for managing the power used by one or more USB Power Delivery ports. In
order to have sufficient knowledge to complete this task it needs relevant information about the device it resides in.
Firstly it has a priori knowledge of the device including the capabilities of the power supply and the receptacles on
each Port since these will for example have specific current ratings. It also has to know information from the USB-C
Port Control module regarding cable insertion, type and rating of cable etc. It also has to have information from the
power supply about changes in its capabilities as well as being able to request power supply changes. With all of this
information the Device Policy Manager is able to provide up to date information regarding the capabilities available to
a specific Port and to manage the power resources within the device.
When working out the capabilities for a given Source Port the Device Policy Manager will take into account firstly the
current rating of the Port’s receptacle and whether the inserted cable is PD or non-PD rated and if so what is the
capability of the plug. This will set an upper bound for the capabilities which might be offered. After this the Device
Policy Manager will consider the available power supply resources since this will bound which voltages and currents
might be offered. Finally, the Device Policy Manager will consider what power is currently allocated to other ports,
which power is in the Power Reserve and any other amendments to Policy from the System Policy Manager. The
Device Policy Manager will offer a set of capabilities within the bounds detailed above.
When selecting a capability for a given Sink Port the Device Policy Manager will look at the capabilities offered by the
Source. This will set an upper bound for the capabilities which might be requested. The Device Policy Manager will
also consider which capabilities are required by the Sink in order to operate. If an appropriate match for Voltage and
Current can be found within the limits of the receptacle and cable then this will be requested from the Source. If an
appropriate match cannot be found then a request for an offered voltage and current will be made, along with an
indication of a capability mismatch.
For Dual-Role Power Ports the Device Policy Manager manages the functionality of both a Source and a Sink. In
addition it is able to manage the Power Role Swap process between the two. In terms of power management this
could mean that a Port which is initially consuming power as a Sink is able to become a power resource as a Source.
Conversely, Attached Sources might request that power be provided to them.
The functionality within the Device Policy Manager (and to a certain extent the Policy Engine) is scalable depending
on the complexity of the device, including the number of different power supply capabilities and the number of
different features supported for example System Policy Manager interface or Capability Mismatch, and the number of
ports being managed. Within these parameters it is possible to implement devices from very simple power supplies
to more complex power supplies or devices such as USB hubs or Hard Drives. Within multiport devices it is also
permitted to have a combination of USB Power Delivery and non-USB Power Delivery ports which Should all be
managed by the Device Policy Manager.
As noted in Section 2.7 the logical architecture used in the PD specification will vary depending on the
implementation. This means that different implementations of the Device Policy Manager might be relative small or
large depending on the complexity of the device, as indicated above. It is also possible to allocate different
responsibilities between the Policy Engine and the Device Policy Manager, which will lead to different types of
architectures and interfaces.
The Device Policy Manager is responsible for the following:
 Maintaining the Local Policy for the device.
 For a Source, monitoring the present capabilities and triggering notifications of the change.

Page 282 USB Power Delivery Specification Revision 3.0, Version 1.1
 For a Sink, evaluating and responding to capabilities related requests from the Policy Engine for a given Port.
 Control of the Source/Sink in the device.
 Control of the USB-C Port Control module for each Port.
 Interface to the Policy Engine for a given Port.
The Device Policy Manager is responsible for the following Optional features when implemented:
 Communications with the System Policy over USB.
 For Sources with multiple ports monitoring and balancing power requirements across these ports.
 Monitoring of batteries and AC power supplies.
 Managing Modes in its Port Partner and Cable Plug(s).

8.2.1 Capabilities
The Device Policy Manager in a Provider Shall know the power supplies available in the device and their capabilities.
In addition it Shall be aware of any other PD Sources of power such as batteries and AC inputs. The available power
sources and existing demands on the device Shall be taken into account when presenting capabilities to a Sink.
The Device Policy Manager in a Consumer Shall know the requirements of the Sink and use this to evaluate the
capabilities offered by a Source. It Shall be aware of its own power sources e.g. Batteries or AC supplies where these
have a bearing on its operation as a Sink.
The Device Policy Manager in a Dual-Role Power Device Shall combine the above capabilities and Shall also be able to
present the dual-role nature of the device to an Attached PD Capable device.

8.2.2 System Policy

A given PD Capable device might have no USB capability, or PD might have been added to a USB device in such a way
that PD is not integrated with USB. In these two cases there Shall be no requirement for the Device Policy Manager to
interact with the USB interface of the device. The following requirements Shall only apply to PD devices that expose
PD functionality over USB.
The Device Policy Manager Shall communicate over USB with the System Policy Manager according to the
requirements detailed in [USBTypeCBridge 1.0]. Whenever requested the Device Policy Manager Shall implement a
Local Policy according to that requested by the System Policy Manager. For example the System Policy Manager might
request that a battery powered Device temporarily stops charging so that there is sufficient power for a HDD to spin
up.
Note: that due to timing constraints, a PD Capable device Shall be able to respond autonomously to all time-critical PD
related requests.

8.2.3 Control of Source/Sink

The Device Policy Manager for a Provider Shall manage the power supply for each PD Source Port and Shall know at
any given time what the negotiated power is. It Shall request transitions of the supply and inform the Policy Engine
whenever a transition completes.
The Device Policy Manager for a Consumer Shall manage the Sink for each PD Sink Port and Shall know at any given
time what the negotiated power is.
The Device Policy Manager for a Dual-Role Power Device Shall manage the transition between Source/Sink roles for
each PD Dual-Role Power Port and Shall know at any given time what operational role the Port is in.

8.2.4 Cable Detection

8.2.4.1 Device Policy Manager in a Provider
The Device Policy Manager in the Provider Shall control the USB-C Port Control module and Shall be able to use the
USB-C Port Control module to determine the Attachment status.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 283
Note: that it might be necessary for the Device Policy Manager to also initiate additional discovery using the Discover
Identity Command in order to determine the full capabilities of the cabling (see Section 6.4.4.2).

8.2.4.2 Device Policy Manager in a Consumer

The Device Policy Manager in a Consumer controls the USB-C Port Control module and Shall be able to use the USB-C
Port Control module to determine the Attachment status.

8.2.4.3 Device Policy Manager in a Consumer/Provider

The Device Policy Manager in a Consumer/Provider inherits characteristics of Consumers and Providers and Shall
control the USB-C Port Control module in order to support the Dead Battery back-powering case to determine the
following for a given Port:
 Attachment of a USB Power Delivery Provider/Consumer which supports Dead Battery back-powering.
 Presence of VBUS.

8.2.4.4 Device Policy Manager in a Provider/Consumer

The Device Policy Manager in a Provider/Consumer inherits characteristics of Consumers and Providers and May
control the USB-C Port Control module in order to support the Dead Battery back-powering case to determine the
following for a given Port:
 Presence of VBUS.

8.2.5 Managing Power Requirements

The Device Policy Manager in a Provider Shall be aware of the power requirements of all devices connected to its
Source Ports. This includes being aware of any reserve power that might be required by devices in the future and
ensuring that power is shared optimally amongst Attached PD Capable devices. This is a key function of the Device
Policy Manager, whose implementation is critical to ensuring that all PD Capable devices get the power they require in
a timely fashion in order to facilitate smooth operation. This is balanced by the fact that the Device Policy Manager is
responsible for managing the sources of power that are, by definition, finite.
The Consumer’s Device Policy Manager Shall ensure that it takes no more power than is required to perform its
functions and gives back unneeded power whenever possible (in such cases the Provider Shall maintain a Power
Reserve to ensure future operation is possible).

8.2.5.1 Managing the Power Reserve

There might be some products where a Device has certain functionality at one power level and a greater functionality
at another, for example a Printer/Scanner that operates only as a printer with one power level and as a scanner if it
can get more power. Visibility of the linkage between power and functionality will only be apparent at the USB Host;
however the Device Policy Manager provides the mechanisms to manage the power requirements of such Devices.
Devices with the GiveBack flag cleared report Operating Current and Maximum Operating Current (see Section
6.4.1.3.4). For many Devices the Operating Current and the Maximum Operating Current will be the same. Devices
with highly variable loads, such as Hard Disk Drives, might use Maximum Operating Current.
Devices with the GiveBack flag set report Operating Current and Minimum Operating Current (see Section 6.4.1.3.4).
For many Devices the Operating Current and the Minimum Operating Current will be the same. Devices that charge
their own batteries might use the Minimum Operating Current and GiveBack flag.
For example in the first case, a mobile device might require 500mA to operate, but would like an additional 1000mA
to charge its Battery. The mobile device would set the GiveBack flag (see Section 6.4.2.2) and request 500mA in the
Minimum Operating Current field and 1500mA in the Operating Current field (provided that 1500mA was offered by
the Source) indicating to the Provider that it could temporarily recover the 1000mA to meet a transitory request.
In the second case, a Hard Disk Drive (HDD) might require 2A to spin-up, but only 1A to operate. At startup the HDD
would request Maximum Operating Current of 2A and an Operating Current of 2A. After the drive is spun-up and
Page 284 USB Power Delivery Specification Revision 3.0, Version 1.1
ready to operate it would make another request of 1A for its Operating Current and 2A for its Maximum Operating
Current. Over time, its inactivity timers might expire and the HDD will go to a lower power state. When the HDD is
next accessed, it has to spin-up again. So it will request an Operating Current of 2A and a Maximum Operating Current
of 2A. The Provider might have the extra power available immediately and can immediately honor the request. If the
power is not available, the Provider might have to harvest power, for example use the GotoMin Message to get back
some power before honoring the HDD’s request. In such a case, the HDD would be told to wait using a Wait Message.
The HDD continues to Request additional power until the request is finally granted.
It Shall be the Device Policy Manager’s responsibility to allocate power and maintain a Power Reserve so as not to
over-subscribe its available power resource. A Device with multiple ports such as a Hub Shall always be able to meet
the incremental demands of the Port requiring the highest incremental power from its Power Reserve.
The GotoMin Message is designed to allow the Provider to reclaim power from one Port to support a Consumer on
another Port that temporarily requires additional power to perform some short term operation. In the example
above, the mobile device that is being charged reduces its charge rate to allow a Device Policy Manager to meet a
request from an HDD for start-up current required to spin-up its platters. Any power which is available to be
reclaimed using a GotoMin Message May be counted as part of the Power Reserve.
A Consumer requesting power Shall take into account its operational requirements when advertising its ability to
temporarily return power. For example, a mobile device with a Dead Battery that is being used to make a call Should
make a request that retains sufficient power to continue the call. When the Consumer’s requirements change, it Shall
re-negotiate its power to reflect the changed requirements.

8.2.5.2 Power Capability Mismatch

A capability mismatch occurs when a Consumer cannot obtain required power from a Provider (or the Source is not
PD Capable) and the Consumer requires such capabilities to operate. Different actions are taken by the Device Policy
Manager and the System Policy Manager in this case.

8.2.5.2.1 Local device handling of mismatch

The Consumer’s Device Policy Manager Shall cause a Message to be displayed to the end user that a power capability
mismatch has occurred. Examples of such feedback can include:
 For a simple Device an LED May be used to indicate the failure. For example, during connection the LED could be
solid amber. If the connection is successful the LED could change to green. If the connection fails it could be red
or alternately blink amber.
 A more sophisticated Device with a user interface, e.g., a mobile device or monitor, Should provide notification
through the user interface on the Device.
The Provider’s Device Policy Manager May cause a Message to be displayed to the user of the power capability
mismatch.

8.2.5.2.2 Device Policy Manager Communication with System Policy

In a USB Power Delivery aware system with an active System Policy manager (see Section 8.2.2), the Device Policy
Manager Shall notify the System Policy Manager of the mismatch. This information Shall be passed back to the
System Policy Manager using the mechanisms described in Chapter 0. The System Policy Manager Should ensure that
the user is informed of the condition. When another Port in the system could satisfy the Consumer’s power
requirements the user Should be directed to move the Device to the alternate Port.
In order to identify a more suitable Source Port for the Consumer the System Policy Manager Shall communicate with
the Device Policy Manager in order to determine the Consumer’s requirements. The Device Policy Manager Shall use
a Get_Sink_Cap Message (see Section 6.3.8) to discover which power levels can be utilized by the Consumer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 285
 8.2.6 Use of “Unconstrained Power” bit with Batteries and AC supplies
The Device Policy Manager in a Provider or Consumer May monitor the status of any variable sources of power that
could have an impact on its capabilities as a Source such as Batteries and AC supplies and reflect this in the
“Unconstrained Power” bit (see Section 6.4.1.2.2.3 and Section 6.4.1.3.1.3) provided as part of the Source or Sink
Capabilities Message (see Section 6.4.1). When monitored, and a USB interface is supported, the External Power
status (see [USBTypeCBridge 1.0]) and the Battery state (see Section 9.4.1) Shall also be reported to the System
Policy Manager using the USB interface.

8.2.6.1 AC Supplies
The Unconstrained Power bit provided by Sources and Sinks (see Section 6.4.1.2.2.3 and Section 6.4.1.3.1.3) notifies a
connected device that it is acceptable to use the advertised power for charging as well as for what is needed for
normal operation. A device that sets the Unconstrained Power bit has either an external source of power that is
sufficient to adequately power the system while charging external devices, or expects to charge external devices as a
primary state of function (such as a battery pack).
In the case of the external power source, the power can either be from an AC supply directly connected to the device
or from an AC supply connected to an Attached device, which is also getting unconstrained power from its power
supply. The Unconstrained Power bit is in this way communicated through a PD system indicating that the origin of
the power is from a single or multiple AC supplies, from a battery bank, or similar:
 If the “Unconstrained Power” bit is set then that power is originally sourced from an AC supply.
 Devices capable of consuming on multiple ports can only claim that they have “Unconstrained Power” for the
power advertised as a provider Port if there is unconstrained power beyond that needed for normal operation
coming from external supplies, (e.g. multiple AC supplies).
 This concept applies as the power is routed through multiple provider and Consumer tiers, so, as an example.
Power provided out of a monitor that is connected to a monitor that gets power from an AC supply, will claim it
has "Unconstrained Power” even though it is not directly connected to the AC supply.
An example use case is a Tablet computer that is used with two USB A/V displays that are daisy chained (see Figure
8-1). The tablet and 1st display are not externally powered, (meaning, they have no source of power outside of USB
PD). The 2nd display has an external supply Attached which could either be a USB PD based supply or some other
form of external supply. When the displays are connected as shown, the power adapter Attached to the 2nd display is
able to power both the 1st display and the tablet. In this case the 2nd display will indicate the presence of a
sufficiently-sized wall wart to the 1st display, by setting its “Unconstrained Power” bit. The 1st display will then in
turn assess and indicate the presence of the extra power to the tablet by setting its “Unconstrained Power” bit. Power
is transmitted through the system to all devices, provided that there is sufficient power available from the external
supply.

Page 286 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-1 Example of daisy chained displays
Tablet

Display 1

Display 2

AC

Another example use case is a Laptop computer that is attached to both an external supply and a Tablet computer. In
this situation, if the external supply is large enough to power the laptop in its normal state as well as charge an
external device, the laptop would set its “Unconstrained Power” bit and the tablet will allow itself to charge at its peak
rate. If the external supply is small, however, and would not prevent the laptop from discharging if maximal power is
drawn by the external device, the laptop would not set its “Unconstrained Power” bit, and the tablet can choose to
draw less than what is offered. This amount could be just enough to prevent the tablet from discharging, or none at
all. Alternatively, if the tablet determines that the laptop has significantly larger battery with more charge than the
tablet has, the tablet can still choose to charge itself, although possibly not at the maximal rate.
In this way, Sinks that do not receive the "Unconstrained Power" bit from the connected Source can still choose to
charge their batteries, or charge at a reduced rate, if their policy determines that the impact to the Source is minimal --
such as in the case of a phone with a small battery charging from a laptop with a large battery. These policies can be
decided via further USB PD communication.

8.2.6.2 Battery Supplies

When monitored, and a USB interface is supported, the Battery state Shall be reported to the System Policy Manager
using the USB interface.
If the device is battery-powered but is in a state that is primarily for charging external devices, the device is
considered to be an unconstrained source of power and thus Should set the “Unconstrained Power” bit.
A simplified algorithm is detailed below to ensure that Battery powered devices will get charge from non-Battery
powered devices when possible, and also to ensure that devices do not constantly Power Role Swap back and forth.
When two devices are connected that do not have Unconstrained Power, they Should define their own policies so as
to prevent constant Power Role Swapping.
This algorithm uses the “Unconstrained Power” bit (see Section 6.4.1.2.2.3 and Section 6.4.1.3.1.3), thus the decisions
are based on the availability and sufficiency of an external supply, not the full capabilities of a system or device or
product.
Recommendations:

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 287
1. Provider/Consumers using large external sources (“Unconstrained Power” bit set) Should always deny Power
Role Swap requests from Consumer/Providers not using external sources (“Unconstrained Power” bit cleared).
2. Provider/Consumers not using large external sources (“Unconstrained Powered” bit cleared) Should always
accept a Power Role Swap request from a Consumer/Provider using large external power sources
(“Unconstrained Power” bit set) unless the requester is not able to provide the requirements of the present
Provider/Consumer.

8.2.7 Interface to the Policy Engine

The Device Policy Manager Shall maintain an interface to the Policy Engine for each Port in the device.

8.2.7.1 Device Policy Manager in a Provider

The Device Policy Manager in a Provider Shall also provide the following functions to the Policy Engine:
 Inform the Policy Engine of changes in cable/ device Attachment status for a given cable.
 Inform the Policy Engine whenever the Source capabilities available for a Port change.
 Evaluate requests from an Attached Consumer and provide responses to the Policy Engine.
 Respond to requests for power supply transitions from the Policy Engine.
 Indication to Policy Engine when power supply transitions are complete.
 Maintain a Power Reserve for devices operating on a Port at less than maximum power.

8.2.7.2 Device Policy Manager in a Consumer

The Device Policy Manager in a Consumer Shall also provide the following functions to the Policy Engine:
 Inform the Policy Engine of changes in cable/device Attachment status.
 Inform the Policy Engine whenever the power requirements for a Port change.
 Evaluate Source capabilities and provide suitable responses:
o Request from offered capabilities
o Indicate whether additional power is required
 Respond to requests for Sink transitions from the Policy Engine.

8.2.7.3 Device Policy Manager in a Dual-Role Power Device

The Device Policy Manager in a Dual-Role Power Device Shall provide the following functions to the Policy Engine:
 Provider Device Policy Manager
 Consumer Device Policy Manager
 Interface for the Policy Engine to request power supply transitions from Source to Sink and vice versa.
 Indications to Policy Engine during Power Role Swap transitions.

8.2.7.4 Device Policy Manager in a Dual-Role Power Device Dead Battery handling
The Device Policy Manager in a Dual-Role Power Device with a Dead Battery Should:
 Switch Ports to Sink-only or Sinking DFP operation to obtain power from the next Attached Source
 Use VBUS from the Attached Source to power the USB Power Delivery communications as well as charging to
enable the negotiation of higher input power.

Page 288 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3 Policy Engine
8.3.1 Introduction
There is one Policy Engine instance per Port that interacts with the Device Policy Manager in order to implement the
present Local Policy for that particular Port. This section includes:
 Message sequences for various operations.
 State diagrams covering operation of Sources, Sinks and Cable Plugs.

8.3.2 Atomic Message Sequence Diagrams

8.3.2.1 Introduction
The Device Policy Engine drives the Message sequences and responses based on both the expected Message
sequences and the present Local Policy.
An AMS Shall be defined as a Message sequence that starts and/or ends in either the PE_SRC_Ready, PE_SNK_Ready
or PE_CBL_Ready states (see Section 8.3.3.2, Section 8.3.3.3 and Section 8.3.3.22).
In addition the Cable Plug discovery sequence specified in Section 8.3.3.22.3 Shall be defined as an AMS.
The Source and Sink indicate to the Protocol Layer when an AMS starts and ends on entry to/exit from PE_SRC_Ready
or PE_SNK_Ready (see Section 8.3.3.2 and Section 8.3.3.3).
Section 8.3.2.1.3 gives details of which of these AMS’s are interruptible or non-interruptible.
This section contains sequence diagrams that highlight some of the more interesting transactions. It is by no means a
complete summary of all possible combinations, but is illustrative in nature.

8.3.2.1.1 Basic Message Exchange

Figure 8-2 Basic Message Exchange (Successful) below illustrates how a Message is sent. Note that the sender might
be either a Source or Sink while the receiver might be either a Sink or Source. The basic Message sequence is the
same. It starts when the Message Sender’s Protocol Layer at the behest of its Policy Engine forms a Message that it
passes to the Physical Layer.

Figure 8-2 Basic Message Exchange (Successful)

Message Sender Message Receiver

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send message
2: Message
3: Message + CRC
4: Message
Start CRCReceiveTimer
Check MessageID against
local copy
Store copy of MessageID

5: Message received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC Consume message

Check and increment MessageIDCounter

Stop CRCReceiveTimer

9: Message sent

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 289
 Table 8-1 Basic Message Flow

Step Message Sender Message Receiver

1 Policy Engine directs Protocol Layer to send a
Message.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends a CRC and sends the Message. Physical Layer receives the Message and checks the CRC to
verify the Message.
4 Physical Layer removes the CRC and forwards the Message to
the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value and
then stores a copy of the new value.
Protocol Layer forwards the received Message information to
the Policy Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and passes it to
the Physical Layer.
7 Physical Layer receives the Message and checks the Physical Layer appends CRC and sends the GoodCRC
CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
Protocol Layer checks and increments the
MessageIDCounter and stops CRCReceiveTimer.
9 Protocol Layer informs the Policy Engine that the
Message was successfully sent.

8.3.2.1.2 Errors in Basic Message flow

There are various points during the Message flow where failures in communication or other issues can occur. Figure
8-3 is an annotated version of Figure 8-2 indicating at which point issues can occur.

Figure 8-3 Basic Message flow indicating possible errors

 Message currently being received  Message does not arrive  Message is a retry
 Channel unavailable  Message has bad CRC

Message Sender Message Receiver

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send message
2: Message
A 3: Message + CRC B C
4: Message
Start CRCReceiveTimer
Check MessageID against
local copy
Store copy of MessageID
D
5: Message received
E 6: GoodCRC
F 7: GoodCRC + CRC
G 8: GoodCRC Consume message

Check and increment MessageIDCounter

Stop CRCReceiveTimer  Message currently being received
 Channel unavailable
9: Message sent
 GoodCRC does not arrive  Message is unexpected
 GoodCRC has a bad CRC  Message is unknown
 GoodCRC has the wrong MessageID
 Response is not GoodCRC

Page 290 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 8-2 Potential issues in Basic Message Flow

Point Possible issues

A 1. There is an incoming Message on the channel meaning that the PHY Layer is unable to send. In this
case the outgoing Message is removed from the queue and the incoming Message processed.
2. Due to some sort of noise on the line it is not possible to transmit. In this case the outgoing Message is
Discarded by the PHY Layer. Retransmission is via the Protocol Layer’s normal mechanism.
B 1. Message does not arrive at the Physical Layer due to noise on the channel.
2. Message arrives but has been corrupted and has a bad CRC.
There is no Message to pass up to the Protocol Layer on the receiver which means a GoodCRC Message is
not sent. This leads to a CRCReceiveTimer timeout in the Message Sender.
C 1. MessageID of received Message matches stored MessageID so this is a retry. Message is not passed up
to the Policy Engine.
D 1. Policy Engine receives a known Message that it was not expecting.
2. Policy Engine receives an unknown (unrecognized) Message.
These cases are errors in the protocol which leads to the generation of a Soft_Reset Message.
E Same as point A but at the Message Receiver side.
F 1. GoodCRC Message response does not arrive at the Message Sender side due to the noise on the channel.
2. GoodCRC Message response arrives but has a bad CRC.
A GoodCRC Message is not received by the Message Sender’s Protocol Layer. This leads to a
CRCReceiveTimer timeout in the Message Sender.
G 1. GoodCRC Message is received but does contain the same MessageID as the transmitted Message.
2. A Message is received but it is not a GoodCRC Message (similar case to that of an unexpected or
unknown Message but this time detected in the Protocol Layer).
Both of these issues indicate errors in receiving an expected GoodCRC Message which will lead to a
CRCReceiveTimer timeout in the Protocol Layer and a subsequent retry (except for communications with
Cable Plugs).

Figure 8-4 illustrates one of these cases; the basic Message flow with a retry due to a bad CRC at the Message Receiver.
It starts when the Message Sender’s Protocol Layer at the behest of its Policy Engine forms a Message that it passes to
the Physical Layer. The Protocol Layer is responsible for retries on a “’n’ strikes and you are out” basis
(nRetryCount).

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 291
 Figure 8-4 Basic Message Flow with Bad CRC followed by a Retry
Message Sender Message Receiver

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send message
2: Message
3: Message + CRC

Start CRCReceiveTimer Message is not received or CRC

is bad so message is not passed
to the protocol layer

CRCReceiveTimer expires
Retry and increment RetryCounter

4: Message
5: Message + CRC
6: Message
Start CRCReceiveTimer
Check MessageID against
local copy
Store copy of MessageID

7: Message received
8: GoodCRC
9: GoodCRC + CRC
10: GoodCRC Consume message

Check and increment MessageIDCounter

Reset RetryCounter
Stop CRCReceiveTimer

11: Message sent

Table 8-3 Basic Message Flow with CRC failure

Step Message Sender Message Receiver

1 Policy Engine directs Protocol Layer to send a
Message.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends a CRC and sends the Message. Physical Layer receives no Message or a Message with an
incorrect CRC. Nothing is passed to Protocol Layer.
4 Since no response is received, the CRCReceiveTimer
will expire and trigger the first retry by the Protocol
Layer. The RetryCounter is incremented. Protocol
Layer passes the Message to the Physical Layer. Starts
CRCReceiveTimer.
5 Physical Layer appends a CRC and sends the Message. Physical Layer receives the Message and checks the CRC to
verify the Message.
6 Physical Layer removes the CRC and forwards the Message to
the Protocol Layer.
7 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value and
then stores a copy of the new value.
Protocol Layer forwards the received Message information to
the Policy Engine that consumes it.
8 Protocol Layer generates a GoodCRC Message and passes it to
the Physical Layer.

Page 292 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Message Sender Message Receiver
9 Physical Layer receives the Message and checks the Physical Layer appends CRC and sends the GoodCRC
CRC to verify the Message. Message.
10 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
11 Protocol Layer verifies the MessageID, stops
CRCReceiveTimer and resets the RetryCounter.
Protocol Layer informs the Policy Engine that the
Message was successfully sent.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 293
 8.3.2.1.3 Interruptible and Non-interruptible Atomic Message Sequences
Table 8-4 details which AMS (as defined in Section 8.3.2) Shall be treated as Interruptible or Non-interruptible during
the sequence. Every AMS which starts with the same Message Shall obey the Interruptible/Non-interruptible
requirement. Note that every AMS is Interruptible until the first Message in the sequence has been successfully sent
(GoodCRC Message received). Any Sequence of VDMs Shall be Interruptible. After the AMS that caused the
interruption has completed, if the original AMS is still needed the interrupted AMS Shall be Re-run.

Table 8-4 Interruptible and Non-interruptible AMS

AMS Interruptible Reference

Power Negotiation No Section 8.3.3.2, 8.3.3.3
GotoMin No Section 8.3.3.2, Section 8.3.3.3
Soft Reset No Section 8.3.3.4
Hard Reset No Section 8.3.3.2, Section 8.3.3.3
Cable Reset No Section 8.3.3.22.2.3
Get Source Capabilities No Section 8.3.3.2, Section 8.3.3.3
Get Sink Capabilities No Section 8.3.3.2, Section 8.3.3.3
Power Role Swap No Section 8.3.3.16.3, Section 8.3.3.16.4
Fast Role Swap No Section 8.3.3.16.5, Section 8.3.3.16.6
Data Role Swap No Section 8.3.3.16.1, Section 8.3.3.16.2
VCONN Swap No Section 8.3.3.17
Source Alert N/A Section 8.3.3.7
Getting Source Extended Capabilities No Section 8.3.3.8
Getting Source/Sink Status No Section 8.3.3.9
Getting Battery Capabilities No Section 8.3.3.10
Getting Battery Status No Section 8.3.3.11
Getting Manufacturer Information No Section 8.3.3.12
Security Yes Section 8.3.3.13
Firmware Update Yes Section 8.3.3.15
Discover Identity Yes Section 8.3.3.18.1, Section 8.3.3.19.1
Source startup Cable Plug Discover Identity Yes Section 8.3.3.18.1, Section8.3.3.22.3
Discover SVIDs Yes Section 8.3.3.18.2, Section 8.3.3.19.2
Discover Modes Yes Section 8.3.3.18.3, Section 8.3.3.19.3
DFP to UFP Enter Mode Yes Section 8.3.3.20.1, Section 8.3.3.21.1
Yes Section 8.3.3.20.2, Section 8.3.3.21.2
DFP to UFP Exit Mode
DFP to Cable Plug Enter Mode Yes Section 8.3.3.20.1, Section 8.3.3.22.4.1
DFP to Cable Plug Exit Mode Yes Section 8.3.3.20.1, Section 8.3.3.22.4.2
Attention N/A Section 8.3.3.18.4
Built in Self-Test (BIST) No Section 8.3.2.14
Sequence of Unstructured VDMs Yes Section 6.4.4.1
Sequence of Structured VDMs using Vendor Commands Yes Section 6.4.4.2

Page 294 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.2.2 Power Negotiation
Figure 8-5 illustrates an example of a successful Message flow during Power Negotiation. The negotiation goes
through 5 distinct phases:
 The Source sends out its power capabilities in a Source_Capabilities Message.
 The Sink evaluates these capabilities and in the request phase selects one power level by sending a Request
Message.
 The Source evaluates the request and accepts the request with an Accept Message.
 The Source transitions to the new power level and then informs the Sink by sending a PS_RDY Message.
 The Sink starts using the new power level.

Figure 8-5 Successful Power Negotiation

Source Sink

: Source Policy Engine : Protocol : PHY : PHY : Protocol : Sink Policy Engine

Cable Capabilities detected

Plug type detected

1: Send Capabilities
2: Capabilities
3: Capabilities + CRC
Start CRCReceiveTimer 4: Capabilities

Check MessageID against local copy

Store copy of MessageID

5: Capabilities received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

9: Capabilities sent
Evaluate Capabilities
Start SenderResponseTimer Detect plug type

10: Send Request

11: Request
12: Request + CRC
13: Request Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Request received

15: GoodCRC
Stop SenderResponseTimer 16: GoodCRC + CRC
17: GoodCRC
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Request sent

Evaluate Request Start SenderResponseTimer

19: Send Accept

20: Accept
21: Accept + CRC
Start CRCReceiveTimer 22: Accept
Check MessageID against local copy
Store copy of MessageID

23: Accept received

24: GoodCRC
25: GoodCRC + CRC Stop SenderResponseTimer
26: GoodCRC Start PSTransitionTimer
Reduce current
Check and increment MessageIDCounter
Stop CRCReceiveTimer

27: Accept sent

Power supply adjusted to negotiated output

Send Ping if required to maintain activity Prepare for new power

28: Send PS_RDY

29: PS_RDY
30: PS_RDY + CRC
Start CRCReceiveTimer 31: PS_RDY

Check MessageID against local copy

Store copy of MessageID

32: PS_RDY received

33: GoodCRC
34: GoodCRC + CRC
35: GoodCRC Stop PSTransitionTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

36: PS_RDY sent

New Power level

Table 8-5 below provides a detailed explanation of what happens at each labeled step in Figure 8-5 above.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 295
 Table 8-5 Steps for a successful Power Negotiation

Step Source Sink

1 The Cable Capabilities or Plug Type are detected if
these are not already known (see Section 4.4). Policy
Engine directs the Protocol Layer to send a
Source_Capabilities Message that represents the
power supply’s present capabilities.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Source_Capabilities
Source_Capabilities Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Source_Capabilities Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Source_Capabilities Message information to the
Policy Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Source_Capabilities Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine evaluates the Source_Capabilities
Message sent by the Source, detects the plug type if
this is necessary (see Section 4.4) and selects which
power it would like. It tells the Protocol Layer to form
the data (e.g. Power Data Object) that represents its
Request into a Message.
11 Protocol Layer creates the Request Message and
passes to Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Request Message and Physical Layer appends a CRC and sends the Request
compares the CRC it calculated with the one sent to Message.
verify the Message.
13 Physical Layer removes the CRC and forwards the
Request Message to the Protocol Layer.
14 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer passes the Request information
to the Policy Engine. Policy Engine stops
SenderResponseTimer.
15 The Protocol Layer generates a GoodCRC Message
and passes it to its Physical Layer.
16 Physical Layer appends CRC and sends the Message. Physical Layer receives the Message and compares
the CRC it calculated with the one sent to verify the
Message.

Page 296 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Sink
17 Physical Layer forwards the GoodCRC Message to the
Protocol Layer.
18 The protocol Layer verifies and increments the
MessageIDCounter. It informs the Policy Engine that
the Request Message was successfully sent. The
Protocol Layer stops the CRCReceiveTimer.
The Policy Engine starts SenderResponseTimer.
19 Policy Engine evaluates the Request Message sent by
the Sink and decides if it can meet the request. It
tells the Protocol Layer to form an Accept Message.
20 The Protocol Layer forms the Accept Message that is
passed to the Physical Layer and starts the
CRCReceiveTimer.
21 Physical Layer appends CRC and sends the Accept Physical Layer receives the Message and compares
Message. the CRC it calculated with the one sent to verify the
Message.
22 Physical Layer forwards the Accept Message to the
Protocol Layer.
23 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
Protocol Layer informs the Policy Engine that an
Accept Message has been received. The Policy Engine
stops SenderResponseTimer, starts the
PSTransitionTimer and reduces its current draw.
The Device Policy Manager prepares the Power
supply for transition to the new power level.
24 The Protocol Layer generates a GoodCRC Message
and passes it to its Physical Layer.
25 Physical Layer receives the Message and compares Physical Layer appends CRC and sends the Message.
the CRC it calculated with the one sent to verify the
Message.
26 Physical Layer forwards the GoodCRC Message to the
Protocol Layer. The Protocol Layer verifies and
increments the MessageIDCounter and stops the
CRCReceiveTimer.
27 The Protocol Layer informs the Policy Engine that an
Accept Message was successfully sent.
power supply Adjusts its Output to the Negotiated Value
28 The Device Policy Manager informs the Policy Engine
that the power supply has settled at the new
operating condition and tells the Protocol Layer to
send a PS_RDY Message.
29 The Protocol Layer forms the PS_RDY Message and
starts the CRCReceiveTimer.
30 Physical Layer appends CRC and sends the PS_RDY Physical Layer receives the PS_RDY Message and
Message. compares the CRC it calculated with the one sent to
verify the Message.
31 Physical Layer forwards the PS_RDY Message to the
Protocol Layer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 297
 Step Source Sink
32 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
Protocol Layer informs the Policy Engine that a
RS_RDY has been received. The Policy Engine stops
the PSTransitionTimer.
33 The Protocol Layer generates a GoodCRC Message
and passes it to its Physical Layer.
34 Physical Layer receives the Message and compares Physical Layer appends CRC and sends the Message.
the CRC it calculated with the one sent to verify the
Message.
35 Physical Layer forwards the GoodCRC Message to the
Protocol Layer. The Protocol Layer verifies and
increments the MessageIDCounter. Stops the
CRCReceiveTimer.
36 The Protocol Layer informs the Policy Engine that
the PS_RDY Message was successfully sent.

Page 298 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.2.3 Reclaiming Power with GotoMin Message
This is an example of a GotoMin operation. Figure 8-6 shows the Messages as they flow across the bus and within the
devices to accomplish the GotoMin.

Figure 8-6 Successful GotoMin operation

Source Sink

: Source Policy Engine : Protocol : PHY : PHY : Protocol : Sink Policy Engine

1: Send GotoMin
2: GotoMin
3: GotoMin + CRC
Start CRCReceiveTimer 4: GotoMin
Check MessageID against local copy
Store copy of MessageID

5: GotoMin received
6: GoodCRC
7: GoodCRC + CRC Start PSTransitionTimer
8: GoodCRC Reduce current
Check and increment MessageIDCounter
Stop CRCReceiveTimer

9: GotoMin sent

Power supply adjusted to pre-negotiated output current

10: Send PS_RDY

11: PS_RDY
12: PS_RDY + CRC
Start CRCReceiveTimer 13: PS_RDY

Check MessageID against local copy

Store copy of MessageID

14: PS_RDY received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC Stop PSTransitionTimer

Check and increment MessageIDCounter

Stop CRCReceiveTimer

18: PS_RDY sent

New Power level

The table below provides a detailed explanation of what happens at each labeled step in Figure 8-6 above.

Table 8-6 Steps for a GotoMin Negotiation

Step Source Sink

1 Policy Engine tells the Protocol Layer to form a
GotoMin Message.
2 The Protocol Layer forms the GotoMin Message that
is passed to the Physical Layer and starts the
CRCReceiveTimer.
3 Physical Layer appends CRC and sends the GotoMin Physical Layer receives the Message and compares
Message. the CRC it calculated with the one sent to verify the
Message.
4 Physical Layer forwards the GotoMin Message to the
Protocol Layer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 299
 Step Source Sink
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
Protocol Layer informs the Policy Engine that a
GotoMin Message has been received. The Policy
starts the PSTransitionTimer and reduces its current
draw.
The Policy Engine prepares the Power supply for
transition to the new power level.
6 The Protocol Layer generates a GoodCRC Message
and passes it to its Physical Layer.
7 Physical Layer receives the Message and compares Physical Layer appends CRC and sends the Message.
the CRC it calculated with the one sent to verify the
Message.
8 Physical Layer forwards the GoodCRC Message to the
Protocol Layer. The Protocol Layer verifies and
increments the MessageIDCounter and stops the
CRCReceiveTimer.
9 The Protocol Layer informs the Policy Engine that a
GotoMin Message was successfully sent.
power supply Adjusts its Output to the Negotiated Value
10 Policy Engine sees the power supply has settled at
the new operating condition and tells the Protocol
Layer to send a PS_RDY Message.
11 The Protocol Layer forms the PS_RDY Message and
starts the CRCReceiveTimer.
12 Physical Layer appends CRC and sends the PS_RDY Physical Layer receives the Message and compares
Message. the CRC it calculated with the one sent to verify the
Message.
13 Physical Layer forwards the PS_RDY Message to the
Protocol Layer.
14 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
Protocol Layer informs the Policy Engine that a
PS_RDY Message has been received. The Policy
Engine stops the PSTransitionTimer.
15 The Protocol Layer generates a GoodCRC Message
and passes it to its Physical Layer.
16 Physical Layer receives the Message and compares Physical Layer appends CRC and sends the Message.
the CRC it calculated with the one sent to verify the
Message.
17 Physical Layer forwards the GoodCRC Message to the
Protocol Layer. The Protocol Layer verifies and
increments the MessageIDCounter and stops the
CRCReceiveTimer.
18 The Protocol Layer informs the Policy Engine that
the PS_RDY Message was successfully sent.

Page 300 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.2.4 Soft Reset
This is an example of a Soft Reset operation. Figure 8-7 shows the Messages as they flow across the bus and within
the devices to accomplish the Soft Reset.

Figure 8-7 Soft Reset

Reset Initiator Reset Responder

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send Soft Reset

Reset MessageIDCounter, stored

MessageID and RetryCounter

2: Soft Reset
3: Soft Reset + CRC
Start CRCReceiveTimer 4: Soft Reset

Reset MessageIDCounter, stored

MessageID and RetryCounter

5: Soft Reset received

6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

9: Soft Reset sent

Start SenderResponseTimer

10: Send Accept

11: Accept
12: Accept + CRC
Start CRCReceiveTimer
13: Accept

Store copy of MessageID

14: Accept received

15: GoodCRC 16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Accept sent

Reset Complete, Explicit Contract negotiation

Table 8-7 below provides a detailed explanation of what happens at each labeled step in Figure 8-7 above.

Table 8-7 Steps for a Soft Reset

Step Reset Initiator Reset Responder

1 The Policy Engine directs the Protocol Layer to
generate a Soft_Reset Message to request a Soft
Reset.
2 Protocol Layer resets MessageIDCounter, stored
MessageID and RetryCounter. Protocol Layer
creates the Message and passes to Physical Layer.
Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Soft_Reset Message and
Soft_Reset Message. compares the CRC it calculated with the one sent to
verify the Message.
4 Physical Layer removes the CRC and forwards the
Soft_Reset Message to the Protocol Layer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 301
 Step Reset Initiator Reset Responder
5 Protocol Layer does not check the MessageID in the
incoming Message and resets MessageIDCounter,
stored MessageID and RetryCounter.
The Protocol Layer forwards the received Soft_Reset
Message information to the Policy Engine that
consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC and checks the Physical Layer appends CRC and sends the GoodCRC
CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Soft_Reset Message was successfully sent. Policy
Engine starts SenderResponseTimer.
10 Policy Engine tells the Protocol Layer to form an
Accept Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the Message.
the CRC it calculated with the one sent to verify the
Message.
13 Protocol Layer stores the MessageID of the incoming
Message.
14 The Protocol Layer forwards the received Accept
Message information to the Policy Engine that
consumes it.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Accept Message was successfully sent.
The reset is complete and protocol communication can restart. Port Partners perform an Explicit Contract
negotiation to re-synchronize their state machines.

Page 302 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.2.5 Hard Reset
The following sections describe the steps required for a USB Power Delivery Hard Reset. The Hard Reset returns the
operation of the USB Power Delivery to default role and operating voltage/current. During the Hard Reset USB Power
Delivery PHY Layer communications Shall be disabled preventing communication between the Port partners.
Note: Hard Reset, in this case, is applied to the USB Power Delivery capability of an individual Port on which the Hard
Reset is requested. A side effect of the Hard Reset is that it might reset other functions on the Port such as USB.

8.3.2.5.1 Source Initiated Hard Reset

This is an example of a Hard Reset operation when initiated by a Source. Figure 8-8 shows the Messages as they flow
across the bus and within the devices to accomplish the Hard Reset.

Figure 8-8 Source initiated Hard Reset

Source Sink

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send Hard Reset

Start NoResponseTimer
Wait tPSHardReset Reset MessageIDCounter and
Reset Power Supply RetryCounter
Reset Port Data Role to DFP
Turn off VCONN
2: Send Hard Reset
3: Hard Reset
4: Hard Reset received
Channel disabled
Channel disabled
Reset MessageIDCounter and
RetryCounter

5: Hard Reset received

Reset Power Sink

Reset Port Data Role to UFP
Turn off VCONN

Power Sink Reset

6: Power Sink Reset

7: Hard Reset Complete

Channel enabled

Power Supply Reset

Turn on VCONN

8: Power Supply Reset

9: Hard Reset Complete

Channel enabled

Hard Reset Complete

10: Send Capabilities

11: Capabilities
12: Capabilities + CRC
Start CRCReceiveTimer 13: Capabilities

Store copy of MessageID

14: Capabilities received

15: GoodCRC
16: GoodCRC + CRC
Evaluate Capabilities
17: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

18: Capabilities sent

Stop NoResponseTimer
Start SenderResponseTimer

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 303
 Table 8-8 Steps for Source initiated Hard Reset

Step Source Sink

1 The Policy Engine directs the Protocol Layer to
generate Hard Reset Signaling.
The Policy Engine starts the NoResponseTimer and
requests the Device Policy Manager to reset the
power supply to USB Default Operation. The Policy
Engine requests the Device Policy Manager to reset
the Port Data Role to DFP and to turn off VCONN if this
is on.
2 Protocol Layer resets MessageIDCounter and
RetryCounter.
Protocol Layer requests the Physical Layer send
Hard Reset Signaling.
3 Physical Layer sends Hard Reset Signaling and then Physical Layer receives the Hard Reset Signaling and
disables the PHY Layer communications channel for disables the PHY Layer communications channel for
transmission and reception. transmission and reception.
4 Physical Layer informs the Protocol Layer of the Hard
Reset.
Protocol Layer resets MessageIDCounter and
RetryCounter.
5 The Protocol Layer informs the Policy Engine of the
Hard Reset.
The Policy Engine requests the Device Policy Manager
to reset the Power Sink to default operation. The
Policy Engine requests the Device Policy Manager to
reset the Port Data Role to UFP and to turn off VCONN
if this is on.
6 The Power Sink returns to default operation.
The Policy Engine informs the Protocol Layer that the
Power Sink has been reset.
7 The Protocol Layer informs the PHY Layer that the
Hard Reset is complete.
The PHY Layer enables the PHY Layer
communications channel for transmission and
reception.
8 The power supply is reset to default operation and
VCONN is turned on.
The Policy Engine informs the Protocol Layer that
the power supply has been reset.
9 The Protocol Layer informs the PHY Layer that the
Hard Reset is complete. The PHY Layer enables the
PHY Layer communications channel for transmission
and reception.
The reset is complete and protocol communication can restart.
10 Policy Engine directs the Protocol Layer to send a
Source_Capabilities Message that represents the
power supply’s present capabilities.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer appends CRC and sends the Physical Layer receives the Source_Capabilities
Source_Capabilities Message. Message and checks the CRC to verify the Message.
13 Physical Layer removes the CRC and forwards the
Source_Capabilities Message to the Protocol Layer.

Page 304 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Sink
14 Protocol Layer stores the MessageID of the incoming
Message.
The Protocol Layer forwards the received
Source_Capabilities Message information to the
Policy Engine that consumes it.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Source_Capabilities Message was successfully sent.
Policy Engine stops the NoResponseTimer and starts
the SenderResponseTimer.
USB Power Delivery communication is re-established.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 305
 8.3.2.5.2 Sink Initiated Hard Reset
This is an example of a Hard Reset operation when initiated by a Sink. Figure 8-9 shows the Messages as they flow
across the bus and within the devices to accomplish the Hard Reset.

Figure 8-9 Sink Initiated Hard Reset

Source Sink

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send Hard Reset

Reset MessageIDCounter, Reset Power Sink

stored copy of MessageID and Reset Port Data Role to UFP
RetryCounter Turn off VCONN

2: Send Hard Reset

3: Hard Reset
4: Hard Reset received

Channel disabled
Reset MessageIDCounter, stored Channel disabled
copy of MessageID and
RetryCounter Power Sink Reset

5: Hard Reset received

6: Power Sink Reset
7: Hard Reset Complete
Start NoResponseTimer
Reset Power Supply
Channel enabled
Reset Port Data Role to DFP
Turn off VCONN

Power Supply Reset

Turn on VCONN

8: Power Supply Reset

9: Hard Reset Complete

Channel enabled

Hard Reset Complete

10: Send Capabilities

11: Capabilities
12: Capabilities + CRC
Start CRCReceiveTimer 13: Capabilities

Store copy of MessageID

14: Capabilities received

15: GoodCRC
16: GoodCRC + CRC
Evaluate Capabilities
17: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

18: Capabilities sent

Stop NoResponseTimer
Start SenderResponseTimer

Page 306 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 8-9 Steps for Sink initiated Hard Reset

Step Source Sink

1 The Policy Engine directs the Protocol Layer to
generate Hard Reset Signaling.
The Policy Engine requests the Device Policy Manager
to reset the power supply to USB Default Operation.
The Policy Engine requests the Device Policy Manager
to reset the Port Data Role to UFP and to turn off
VCONN if this is on.
2 Protocol Layer resets MessageIDCounter, stored
copy of MessageID and RetryCounter.
Protocol Layer requests the Physical Layer send Hard
Reset Signaling.
3 Physical Layer receives the Hard Reset Signaling and Physical Layer sends the Hard Reset Signaling and
disables the PHY Layer communications channel for then disables the PHY Layer communications channel
transmission and reception. for transmission and reception.
4 Physical Layer informs the Protocol Layer of the
Hard Reset.
Protocol Layer resets MessageIDCounter, stored
copy of MessageID and RetryCounter.
5 The Protocol Layer Informs the Policy Engine of the
Hard Reset.
The Policy Engine starts the NoResponseTimer and
requests the Device Policy Manager to reset the
Power Sink to default operation. The Policy Engine
requests the Device Policy Manager to reset the Port
Data Role to DFP and to turn off VCONN if this is on.
6 The Power Sink returns to USB Default Operation.
The Policy Engine informs the Protocol Layer that the
Power Sink has been reset.
7 The Protocol Layer informs the PHY Layer that the
Hard Reset is complete.
The PHY Layer enables the PHY Layer
communications channel for transmission and
reception.
8 The power supply is reset to USB Default Operation
and VCONN is turned on.
The Policy Engine informs the Protocol Layer that
the power supply has been reset.
9 The Protocol Layer informs the PHY Layer that the
Hard Reset is complete. The PHY Layer enables the
PHY Layer communications channel for transmission
and reception.
The reset is complete and protocol communication can restart.
10 Policy Engine directs the Protocol Layer to send a
Source_Capabilities Message that represents the
power supply’s present capabilities.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer appends CRC and sends the Physical Layer receives the Source_Capabilities
Source_Capabilities Message. Message and checks the CRC to verify the Message.
13 Physical Layer removes the CRC and forwards the
Source_Capabilities Message to the Protocol Layer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 307
 Step Source Sink
14 Protocol Layer stores the MessageID of the incoming
Message.
The Protocol Layer forwards the received
Source_Capabilities Message information to the
Policy Engine that consumes it.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Source_Capabilities Message was successfully sent.
Policy Engine stops the NoResponseTimer and starts
the SenderResponseTimer.
USB Power Delivery communication is re-established.

Page 308 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.2.5.3 Source Initiated Hard Reset – Sink Long Reset
This is an example of a Hard Reset operation when initiated by a Source. In this example the Sink is slow responding
to the reset causing the Source to send multiple Source_Capabilities Messages before it receives a GoodCRC Message
response. Figure 8-10 shows the Messages as they flow across the bus and within the devices to accomplish the Hard
Reset.

Figure 8-10 Source initiated reset - Sink long reset

Source Sink

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send Hard Reset

2: Send Hard Reset
Start NoResponseTimer 3: Hard Reset
Wait tPSHardReset 4: Hard Reset received
Reset Power Supply 5: Hard Reset received
Reset Port Data Role to DFP Channel disabled
Turn off VCONN Channel disabled
Reset Power Sink
Reset Port Data Role to UFP
Turn off VCONN

Power Supply Reset

Turn on VCONN

6: Power Supply Reset

Reset MessageIDCounter, stored

copy of MessageID and
RetryCounter

7: Hard Reset Complete

Channel enabled
8: Send Capabilities
9: Capabilities
10: Capabilities + CRC
Run SourceCapabilityTimer Power Sink Reset
Send Capabilities messages
until GoodCRC response is
11: Power Sink Reset
received.
Reset MessageIDCounter, stored
copy of MessageID and
RetryCounter

12: Hard Reset Complete

Channel enabled

Hard Reset Complete

13: Send Capabilities

14: Capabilities
15: Capabilities + CRC
Start CRCReceiveTimer 16: Capabilities

Store copy of MessageID

17: Capabilities received

18: GoodCRC
19: GoodCRC + CRC
20: GoodCRC Evaluate Capabilities

Check and increment MessageIDCounter

Stop CRCReceiveTimer

21: Capabilities sent

Stop SourceCapabilitiesTimer
Stop NoResponseTimer
Start SenderResponseTimer

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 309
 Table 8-10 Steps for Source initiated Hard Reset – Sink long reset

Step Source Sink

1 The Policy Engine directs the Protocol Layer to
generate Hard Reset Signaling.
The Policy Engine starts the NoResponseTimer and
requests the Device Policy Manager to reset the
power supply to USB Default Operation. The Policy
Engine requests the Device Policy Manager to reset
the Port Data Role to DFP and to turn off VCONN if this
is on.
2 Protocol Layer resets MessageIDCounter, stored
copy of MessageID and RetryCounter.
Protocol Layer requests the Physical Layer send
Hard Reset Signaling.
3 Physical Layer sends the Hard Reset Signaling and Physical Layer receives the Hard Reset Signaling and
then disables the PHY Layer communications disables the PHY Layer communications channel for
channel for transmission and reception. transmission and reception.
4 Physical Layer informs the Protocol Layer of the Hard
Reset.
Protocol Layer resets MessageIDCounter, stored
copy of MessageID and RetryCounter.
5 The Protocol Layer Informs the Policy Engine of the
Hard Reset.
The Policy Engine requests the Device Policy Manager
to reset the Power Sink to default operation. The
Policy Engine requests the Device Policy Manager to
reset the Port Data Role to UFP and to turn off VCONN
if this is on.
6 The power supply is reset to USB Default Operation
and VCONN is turned on.
The Policy Engine informs the Protocol Layer that
the power supply has been reset.
7 The Protocol Layer informs the PHY Layer that the
Hard Reset is complete.
The PHY Layer enables the PHY Layer
communications channel for transmission and
reception.
The reset is complete and protocol communication can restart.
8 Policy Engine directs the Protocol Layer to send a
Source_Capabilities Message that represents the
power supply’s present capabilities. Policy Engine
starts the SourceCapabilityTimer. The
SourceCapabilityTimer times out one or more times
until a GoodCRC Message response is received.
9 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
10 Physical Layer appends CRC and sends the Note: Source_Capabilities Message not received since
Source_Capabilities Message. channel is disabled.
11 The Power Sink returns to USB Default Operation.
The Policy Engine informs the Protocol Layer that the
Power Sink has been reset.
12 The Protocol Layer informs the PHY Layer that the
Hard Reset is complete.
The PHY Layer enables the PHY Layer
communications channel for transmission and
reception.

Page 310 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Sink
The reset is complete and protocol communication can restart.
13 Policy Engine directs the Protocol Layer to send a
Source_Capabilities Message that represents the
power supply’s present capabilities. Starts the
SourceCapabilityTimer.
14 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
15 Physical Layer appends CRC and sends the Physical Layer receives the Source_Capabilities
Source_Capabilities Message. Message and checks the CRC to verify the Message.
16 Physical Layer removes the CRC and forwards the
Source_Capabilities Message to the Protocol Layer.
17 Protocol Layer stores the MessageID of the incoming
Message.
The Protocol Layer forwards the received
Source_Capabilities Message information to the
Policy Engine that consumes it.
18 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
19 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
20 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
21 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Source_Capabilities Message was successfully sent.
Policy Engine stops the SourceCapabilityTimer,
stops the NoResponseTimer and starts the
SenderResponseTimer.
USB Power Delivery communication is re-established.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 311
 8.3.2.6 Power Role Swap

8.3.2.6.1 Source Initiated Power Role Swap without subsequent Power Negotiation
This is an example of a successful Power Role Swap operation initiated by a Port which initially, at the start of this
Message sequence, is acting as a Source and therefore has Rp pulled up on its CC wire. It does not include any
subsequent Power Negotiation which is required in order to establish an Explicit Contract (see Section 8.3.2.2).
There are four distinct phases to the Power Role Swap negotiation:
1. A PR_Swap Message is sent.
2. An Accept Message in response to the PR_Swap Message.
3. The new Sink sets its power output to vSafe0V, then asserts Rd and sends a PS_RDY Message when this process is
complete.
4. The new Source asserts Rp, then sets its power output to vSafe5V and sends a PS_RDY Message when it is ready
to supply power.
Figure 8-11 shows the Messages as they flow across the bus and within the devices to accomplish the Power Role
Swap sequence.

Page 312 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-11 Successful Power Role Swap Sequence Initiated by the Source

Initial Source Port Initial Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Source Port Power Role = Sink

CC = Rp CC = Rd
1: Send PR_Swap
2:PR_Swap
3: PR_Swap + CRC
Start CRCReceiveTimer 4: PR_Swap

Check MessageID against local copy

Store copy of MessageID

5: PR_Swap received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC
Check and increment MessageIDCounter
Stop CRCReceiveTimer

9:PR_Swap sent
Evaluate PR_Swap
Start SenderResponseTimer request

10: Send Accept

11: Accept
12: Accept + CRC
13: Accept Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Accept received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Tell Power Supply to stop sourcing power Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Accept sent

Start PSSourceOffTimer
Power Supply stops sourcing power
Tell Power Sink to stop
CC -> Rd
sinking current

19: Send PS_RDY

Port Power Role -> Sink

20: PS_RDY
21: PS_RDY + CRC
Start CRCReceiveTimer 22: PS_RDY

Check MessageID against local copy

Store copy of MessageID

23: PS_RDY received

24: GoodCRC
25: GoodCRC + CRC
26: GoodCRC Port Power Role -> Source

Check and increment MessageIDCounter

Stop CRCReceiveTimer Stop PSSourceOffTimer
CC -> Rp
27: PS_RDY sent
Set Power Supply to 5V output
Start PSSourceOnTimer

Power Supply reaches 5V

output

28: Send PS_RDY

29: PS_RDY
30: PS_RDY + CRC
31: PS_RDY
Start CRCReceiveTimer
Check MessageID against local copy
Store copy of MessageID

32: PS_RDY received

33: GoodCRC
34: GoodCRC + CRC
Stop PSSourceOnTimer 35: GoodCRC
Tell Power Sink to start
sinking power Check and increment MessageIDCounter
Reset Protocol Layer Stop CRCReceiveTimer

36: PS_RDY sent

Reset CapsCounter
Reset Protocol Layer
Start SwapSourceStartTimer

New Power Roles

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 313
Table 8-11below provides a detailed explanation of what happens at each labeled step in Figure 8-11 above.

Table 8-11 Steps for a Successful Source Initiated Power Role Swap Sequence

Step Initial Source Port Initially Sink Port

1 The Port has Port Power Role set to Source and the The Port has Port Power Role set to Sink with the Rd
Rp pull up on its CC wire. pull down on its CC wire.
Policy Engine directs the Protocol Layer to send a
PR_Swap Message.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the PR_Swap Physical Layer receives the PR_Swap Message and
Message. checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
PR_Swap Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received PR_Swap
Message information to the Policy Engine that
consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
PR_Swap Message was successfully sent. Policy
Engine starts SenderResponseTimer.
10 Policy Engine evaluates the PR_Swap Message sent by
the Source and decides that it is able and willing to do
the Power Role Swap. It tells the Protocol Layer to
form an Accept Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the Accept
the CRC it calculated with the one sent to verify the Message.
Accept Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received PR_Swap
Message information to the Policy Engine that
consumes it.
14 The Policy Engine requests its power supply to stop
supplying power and stops the
SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.

Page 314 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Initial Source Port Initially Sink Port
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Accept Message was successfully sent. The Policy
Engine starts the PSSourceOffTimer and tells the
power supply to stop sinking current.
19 The Policy Engine determines its power supply is no
longer supplying VBUS. The Policy Engine requests
the Device Policy Manager to assert the Rd pull down
on the CC wire. The Policy Engine then directs the
Protocol Layer to generate a PS_RDY Message, with
the Port Power Role bit in the Message Header set to
“Sink”, to tell its Port Partner that it can begin to
Source VBUS.
20 Protocol Layer sets the Port Power Role bit in the
Message Header set to “Sink”, creates the Message
and passes to Physical Layer. Starts
CRCReceiveTimer.
21 Physical Layer appends CRC and sends the PS_RDY Physical Layer receives the PS_RDY Message and
Message. checks the CRC to verify the Message.
22 Physical Layer removes the CRC and forwards the
PS_RDY Message to the Protocol Layer.
23 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received PS_RDY
Message information to the Policy Engine that
consumes it. The Policy Engine stops the
PSSourceOffTimer, directs the Device Policy Manager
to apply the Rp pull up and then starts switching the
power supply to vSafe5V Source operation.
24 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
25 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
26 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
27 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
PS_RDY Message was successfully sent. Policy
Engine starts PSSourceOnTimer.
28 Policy Engine, when its power supply is ready to
supply power, tells the Protocol Layer to form a
PS_RDY Message. The Port Power Role bit used in
this and subsequent Message Headers is now set to
“Source”.
29 Protocol Layer creates the PS_RDY Message and
passes to Physical Layer. Starts CRCReceiveTimer.
30 Physical Layer receives the PS_RDY Message and Physical Layer appends a CRC and sends the PS_RDY
compares the CRC it calculated with the one sent to Message.
verify the Message.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 315
 Step Initial Source Port Initially Sink Port
31 Physical Layer removes the CRC and forwards the
PS_RDY Message to the Protocol Layer.
32 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received PS_RDY
Message information to the Policy Engine that
consumes it.
33 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
34 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. The Policy Engine stops the compares the CRC it calculated with the one sent to
PSSourceOnTimer, informs the power supply it can verify the Message.
now Sink power and resets the Protocol Layer.
35 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
36 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
PS_RDY Message was successfully sent. The Policy
Engine resets the CapsCounter, resets the Protocol
Layer and starts the SwapSourceStartTimer which
must timeout before sending any Source_Capabilities
Messages.
The Power Role Swap is complete, the roles have been reversed and the Port Partners are free to negotiate for
more power.

Page 316 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.2.6.2 Sink Initiated Power Role Swap without subsequent Power Negotiation
This is an example of a successful Power Role Swap operation initiated by a Port which initially, at the start of this
Message sequence, is acting as a Sink and therefore has Rd pulled down on its CC wire. It does not include any
subsequent Power Negotiation which is required in order to establish an Explicit Contract (see Section 8.3.2.2).
There are four distinct phases to the Power Role Swap negotiation:
1. A PR_Swap Message is sent.
2. An Accept Message in response to the PR_Swap Message.
3. The new Sink sets its power output to vSafe0V, then asserts Rd and sends a PS_RDY Message when this process is
complete.
4. The new Source asserts Rp, then sets its power output to vSafe5V and sends a PS_RDY Message when it is ready to
supply power.
Figure 8-12 shows the Messages as they flow across the bus and within the devices to accomplish the Power Role
Swap.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 317
 Figure 8-12 Successful Power Role Swap Sequence Initiated by the Sink

Initial Sink Port Initial Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp

1: Send PR_Swap
2:PR_Swap
3: PR_Swap + CRC
Start CRCReceiveTimer 4: PR_Swap

Check MessageID against local copy

Store copy of MessageID

5: PR_Swap received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC
Check and increment MessageIDCounter
Stop CRCReceiveTimer

9:PR_Swap sent
Evaluate PR_Swap
Start SenderResponseTimer request

10: Send Accept

11: Accept
12: Accept + CRC
13: Accept Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Accept received

15: GoodCRC
16: GoodCRC + CRC
Stop SenderResponseTimer 17: GoodCRC
Start PSSourceOffTimer
Check and increment MessageIDCounter
Tell Power Sink to stop
Stop CRCReceiveTimer
sinking current
18: Accept sent

Tell Power Supply to stop sourcing power

Power Supply stops sourcing power

CC -> Rd

19: Send PS_RDY

Port Power Role -> Sink

20: PS_RDY
21: PS_RDY + CRC
22: PS_RDY
Start CRCReceiveTimer
Check MessageID against local copy
Store copy of MessageID

23: PS_RDY received

24: GoodCRC
25: GoodCRC + CRC
Port Power Role -> Source 26: GoodCRC
Check and increment MessageIDCounter
Stop CRCReceiveTimer
Stop PSSourceOffTimer
CC -> Rp 27: PS_RDY sent
Set Power Supply to 5V output
Start PSSourceOnTimer

Power Supply reaches 5V

output

28: Send PS_RDY

29: PS_RDY
30: PS_RDY + CRC
Start CRCReceiveTimer 31: PS_RDY

Check MessageID against local copy

Store copy of MessageID

32: PS_RDY received

33: GoodCRC
34: GoodCRC + CRC
35: GoodCRC Stop PSSourceOnTimer
Check and increment MessageIDCounter Tell Power Supply to start
Stop CRCReceiveTimer sinking power
Reset Protocol Layer
36: PS_RDY sent

Reset CapsCounter
Reset Protocol Layer
Start SwapSourceStartTimer

New Power Roles

Page 318 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 8-12 Steps for a Successful Sink Initiated Power Role Swap Sequence

Step Initial Sink Port Initial Source Port

1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
PR_Swap Message.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the PR_Swap Physical Layer receives the PR_Swap Message and
Message. checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
PR_Swap Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received PR_Swap
Message information to the Policy Engine that
consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
PR_Swap Message was successfully sent. Policy
Engine starts SenderResponseTimer.
10 Policy Engine evaluates the PR_Swap Message sent by
the Sink and decides that it is able and willing to do
the Power Role Swap. It tells the Protocol Layer to
form an Accept Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the Accept
the CRC it calculated with the one sent to verify the Message.
Accept Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received PR_Swap
Message information to the Policy Engine that
consumes it.
14 The Policy Engine stops the SenderResponseTimer,
starts the PSSourceOffTimer and tells the power
supply to stop sinking current.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 319
 Step Initial Sink Port Initial Source Port
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Accept Message was successfully sent. The Policy
Engine tells the power supply to stop supplying
power.
19 The Policy Engine determines its power supply is no
longer supplying VBUS. The Policy Engine requests the
Device Policy Manager to assert the Rd pull down on
the CC wire. The Policy Engine then directs the
Protocol Layer to generate a PS_RDY Message, with
the Port Power Role bit in the Message Header set to
“Sink”, to tell its Port Partner that it can begin to
Source VBUS.
20 Protocol Layer sets the Port Power Role bit in the
Message Header set to “Sink”, creates the Message
and passes to Physical Layer. Starts
CRCReceiveTimer.
21 Physical Layer receives the PS_RDY Message and Physical Layer appends CRC and sends the PS_RDY
checks the CRC to verify the Message. Message.
22 Physical Layer removes the CRC and forwards the
PS_RDY Message to the Protocol Layer.
23 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received PS_RDY
Message information to the Policy Engine that
consumes it. The Policy Engine stops the
PSSourceOffTimer, directs the Device Policy
Manager to apply the Rp pull up and then starts
switching the power supply to vSafe5V Source
operation.
24 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
25 Physical Layer appends CRC and sends the GoodCRC Physical Layer receives the GoodCRC Message and
Message. checks the CRC to verify the Message.
26 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
27 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
PS_RDY Message was successfully sent. Policy Engine
starts PSSourceOnTimer.
28 Policy Engine, when its power supply is ready to
supply power, tells the Protocol Layer to form a
PS_RDY Message. The Port Power Role bit used in
this and subsequent Message Headers is now set to
“Source”.
29 Protocol Layer creates the PS_RDY Message and
passes to Physical Layer. Starts CRCReceiveTimer.
30 Physical Layer appends a CRC and sends the PS_RDY Physical Layer receives the PS_RDY Message and
Message. compares the CRC it calculated with the one sent to
verify the Message.
31 Physical Layer removes the CRC and forwards the
PS_RDY Message to the Protocol Layer.

Page 320 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Initial Sink Port Initial Source Port
32 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received PS_RDY
Message information to the Policy Engine that
consumes it. The Policy Engine stops the
PSSourceOnTimer, informs the power supply that it
can start consuming power.
33 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
34 Physical Layer receives GoodCRC Message and Physical Layer appends a CRC and sends the GoodCRC
compares the CRC it calculated with the one sent to Message. The Policy Engine stops the
verify the Message. PSSourceOnTimer, informs the power supply it can
now Sink power and resets the Protocol Layer.
35 Physical Layer removes the CRC and forwards the
GoodCRC to the Protocol Layer.
36 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
PS_RDY Message was successfully sent. The Policy
Engine resets the CapsCounter, resets the Protocol
Layer and starts the SwapSourceStartTimer which
must timeout before sending any
Source_Capabilities Messages.
The Power Role Swap is complete, the roles have been reversed and the Port Partners are free to negotiate for
more power.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 321
 8.3.2.7 Fast Role Swap
This is an example of a successful Fast Role Swap operation initiated by a Port that is initially a Source and therefore
has Rp pulled up on its CC Wire and which has lost power and needs to get vSafe5V quickly. It does not include any
subsequent Power Negotiation which is required in order to establish an Explicit Contract (see Section 8.3.2.2).
There are several distinct phases to the Fast Role Swap negotiation:
1. The initial Source stops driving its power output which starts transitioning to vSafe0V and signals Fast Role Swap on the
CC Wire.
2. The initial Sink stops Sinking power. At this point the new Source still has Rd asserted and the new Sink still has Rp
asserted.
3. An FR_Swap Message is sent by the new Source within tFRSwapInit of detecting the Fast Swap signal.
4. An Accept Message is sent by the new Sink in response to the FR_Swap Message.
5. The new Sink asserts Rd and sends a PS_RDY Message indicating that the voltage on VBUS is at or below vSafe5V.
6. The new Source asserts Rp and sends a PS_RDY Message indicating that it is acting as a Source and is supplying
vSafe5V. Note: that the new Source can start applying at any point VBUS is at or below vSafe5V but will start driving
VBUS to vSafe5V no later than tSrcFRSwap after detecting that VBUS has dropped below vSafe5V. This can happen at
any point after the Fast Role Swap signal is detected.
Figure 8-13 shows the Messages as they flow across the bus and within the devices to accomplish the Fast Role Swap.

Page 322 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-13 Successful Fast Role Swap Sequence

Initial Sink Port Initial Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp
Fast Swap signal
(CC driven to Gnd through
Tell Power Supply to Stop sourcing power and
rFRSwapTx or
switch to Sink operation
rFRSwapCableTx)
Signal Fast Swap on the CC Wire

Fast Role Swap signal detected on CC Wire

Tell Power Supply to stop sinking current.

1: Send FR_Swap
2:FR_Swap
3: FR_Swap + CRC
Start CRCReceiveTimer 4: FR_Swap

Check MessageID against local copy

Store copy of MessageID

5: FR_Swap received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC
Check and increment MessageIDCounter
Stop CRCReceiveTimer

9:FR_Swap sent
Evaluate FR_Swap request
Start SenderResponseTimer

10: Send Accept

11: Accept
12: Accept + CRC
13: Accept Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Accept received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Start PSSourceOffTimer
Stop CRCReceiveTimer

18: Accept sent

Power Supply acting as a Sink and

VBUS at or below vSafe5V
CC -> Rd

19: Send PS_RDY

Port Power Role -> Sink

20: PS_RDY
21: PS_RDY + CRC
22: PS_RDY
Start CRCReceiveTimer
Check MessageID against local copy
Store copy of MessageID

23: PS_RDY received

24: GoodCRC
25: GoodCRC + CRC
Port Power Role -> Source 26: GoodCRC
Check and increment MessageIDCounter
Stop CRCReceiveTimer

27: PS_RDY sent

Start PSSourceOnTimer

vSafe5V is being sourced by the new Source

Stop PSSourceOffTimer
CC -> Rp

28: Send PS_RDY

29: PS_RDY
30: PS_RDY + CRC
Start CRCReceiveTimer 31: PS_RDY

Check MessageID against local copy

Store copy of MessageID

32: PS_RDY received

33: GoodCRC
34: GoodCRC + CRC
35: GoodCRC

Check and increment MessageIDCounter

Stop PSSourceOnTimer
Stop CRCReceiveTimer
Reset Protocol Layer
36: PS_RDY sent

Reset CapsCounter
Reset Protocol Layer
Start SwapSourceStartTimer

New Power Roles

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 323
 Table 8-13 Steps for a Successful Fast Role Swap Sequence

Step Initial Sink Port Initial Source Port

1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
The Device Policy Manager detects Fast Swap on the The Device Policy Manager tells the Power Supply to
CC Wire and tells the power supply to stop sinking stop sourcing power and switch to Sink operation.
current. The Device Policy Manager signals Fast Swap on the
CC Wire by driving CC to ground with a resistance of
less than rFRSwapTx for at least tFRSwapTx.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the FR_Swap Physical Layer receives the FR_Swap Message and
Message. checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
PR_Swap Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received FR_Swap
Message information to the Policy Engine that
consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
FR_Swap Message was successfully sent. Policy
Engine starts SenderResponseTimer.
10 Policy Engine evaluates the PR_Swap Message sent by
the Sink and decides that it is able and willing to do
the Power Role Swap. It tells the Protocol Layer to
form an Accept Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the Accept
the CRC it calculated with the one sent to verify the Message.
Accept Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received PR_Swap
Message information to the Policy Engine that
consumes it.
14 The Policy Engine stops the SenderResponseTimer,
starts the PSSourceOffTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.

Page 324 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Initial Sink Port Initial Source Port
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Accept Message was successfully sent.
19 The Policy Engine determines its power supply is no
longer supplying VBUS and is acting as a Sink. The
Policy Engine requests the Device Policy Manager to
assert the Rd pull down on the CC wire. The Policy
Engine then directs the Protocol Layer to generate a
PS_RDY Message, with the Port Power Role bit in the
Message Header set to “Sink”, to tell its Port Partner
that it can begin to Source VBUS.
20 Protocol Layer sets the Port Power Role bit in the
Message Header set to “Sink”, creates the Message
and passes to Physical Layer. Starts
CRCReceiveTimer.
21 Physical Layer receives the PS_RDY Message and Physical Layer appends CRC and sends the PS_RDY
checks the CRC to verify the Message. Message.
22 Physical Layer removes the CRC and forwards the
PS_RDY Message to the Protocol Layer.
23 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received PS_RDY
Message information to the Policy Engine that
consumes it. The Policy Engine stops the
PSSourceOffTimer.
24 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
25 Physical Layer appends CRC and sends the GoodCRC Physical Layer receives the GoodCRC Message and
Message. checks the CRC to verify the Message.
26 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
27 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
PS_RDY Message was successfully sent. Policy Engine
starts PSSourceOnTimer.
28 The Policy Engine directs the Device Policy Manager
to apply the Rp pull up. Note: at some point (either
before or after receiving the PS_RDY Message) the
new Source has applied vSafe5V no later
tSrcFRSwap after detecting that VBUS has dropped
below vSafe5V.
When the Source output reaches vSafe5V the Policy
Engine directs the Protocol Layer to send an
FR_Swap Message within tFRSwapInit of detecting
the Fast Swap signal.
Policy Engine, when its power supply is ready to
supply power, tells the Protocol Layer to form a
PS_RDY Message. The Port Power Role bit used in
this and subsequent Message Headers is now set to
“Source”.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 325
 Step Initial Sink Port Initial Source Port
29 Protocol Layer creates the PS_RDY Message and
passes to Physical Layer. Starts CRCReceiveTimer.
30 Physical Layer appends a CRC and sends the PS_RDY Physical Layer receives the PS_RDY Message and
Message. compares the CRC it calculated with the one sent to
verify the Message.
31 Physical Layer removes the CRC and forwards the
PS_RDY Message to the Protocol Layer.
32 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received PS_RDY
Message information to the Policy Engine that
consumes it. The Policy Engine stops the
PSSourceOnTimer.
33 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
34 Physical Layer receives GoodCRC Message and Physical Layer appends a CRC and sends the GoodCRC
compares the CRC it calculated with the one sent to Message. The Policy Engine resets the Protocol Layer.
verify the Message.
35 Physical Layer removes the CRC and forwards the
GoodCRC to the Protocol Layer.
36 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
PS_RDY Message was successfully sent. The Policy
Engine resets the CapsCounter, resets the Protocol
Layer and starts the SwapSourceStartTimer which
must timeout before sending any
Source_Capabilities Messages.
The Fast Role Swap is complete, the roles have been reversed and the Port Partners are free to negotiate for
more power.

Page 326 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.2.8 Data Role Swap

8.3.2.8.1 Data Role Swap, Initiated by UFP Operating as Sink

Figure 8-14 shows an example sequence between a Port, which is initially a UFP (Device) and a Sink (Rd asserted),
and a Port which is initially a DFP (Host) and a Source (Rp asserted). A Data Role Swap is initiated by the UFP. During
the process the Port Partners maintain their operation as either a Source or a Sink (power and Rp/Rd remain
constant) but exchange data roles between DFP (Host) and UFP (Device).

Figure 8-14 Data Role Swap, UFP operating as Sink initiates

Initial UFP Sink Port Initial DFP Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

CC = Rd (Sink) CC = Rp (Source)
Port Data Role = UFP (Device) Port Data Role = DFP (Host)

1: Send Dr_Swap
2:Dr_Swap
3: Dr_Swap + CRC
Start CRCReceiveTimer 4: Dr_Swap

Check MessageID against local copy

Store copy of MessageID

5: Dr_Swap received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC Evaluate Dr_Swap request
CC = Rp (Source)
Check and increment MessageIDCounter Port Data Role = DFP (Host)
Stop CRCReceiveTimer

9:Dr_Swap sent

Start SenderResponseTimer
CC = Rd (Sink) 10: Send Accept
Port Data Role = UFP (Device) 11: Accept
12: Accept + CRC
13: Accept Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Accept received

15: GoodCRC
16: GoodCRC + CRC
Stop SenderResponseTimer
17: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

18: Accept sent

CC = Rd (Sink) CC = Rp (Source)
Port Data Role -> DFP (Host) Port Data Role -> UFP (Device)

New Host/Device Roles

Table 8-14 below provides a detailed explanation of what happens at each labeled step in Figure 8-14 above.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 327
 Table 8-14 Steps for Data Role Swap, UFP operating as Sink initiates

Step Initial UFP Sink Port Initial DFP Source Port

1 Port starts as a UFP (Device) operating as a Sink with Port starts as a DFP (Host) operating as Source with Rp
Rd asserted and Port Data Role set to UFP. The asserted and Port Data Role set to DFP.
Policy Engine directs the Protocol Layer to send a
DR_Swap Message.
2 Protocol Layer creates the DR_Swap Message and
passes to Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the DR_Swap Physical Layer receives the DR_Swap Message and
Message. checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
DR_Swap Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received DR_Swap
Message information to the Policy Engine that consumes
it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
DR_Swap Message was successfully sent. Policy
Engine starts SenderResponseTimer.
10 Policy Engine evaluates the DR_Swap Message and
decides that it is able and willing to do the Data Role
Swap. It tells the Protocol Layer to form an Accept
Message.
11 Protocol Layer creates the Accept Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Accept Message and Physical Layer appends a CRC and sends the Accept
checks the CRC to verify the Message. Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Accept
Message information to the Policy Engine that
consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.

Page 328 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Initial UFP Sink Port Initial DFP Source Port
18 The Policy Engine requests that Data Role is changed Protocol Layer verifies and increments the
from UFP (Device) to DFP (Host). MessageIDCounter and stops CRCReceiveTimer.
The Power Delivery role is now a DFP (Host), with Protocol Layer informs the Policy Engine that the Accept
Port Data Role set to DFP, still operating as a Sink Message was successfully sent.
(Rd asserted). The Policy Engine requests that the Data Role is changed
to UFP (Device), with Port Data Role set to UFP and
continues supplying power as a Source (Rp asserted).
The Data Role Swap is complete; the data roles have been reversed while maintaining the direction of power
flow.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 329
 8.3.2.8.2 Data Role Swap, Initiated by UFP Operating as Source
Figure 8-15 shows an example sequence between a Port, which is initially a UFP (Device) and a Source (Rp asserted),
and a Port which is initially a DFP (Host) and a Sink (Rd asserted). A Data Role Swap is initiated by the UFP. During
the process the Port Partners maintain their operation as either a Source or a Sink (power and Rp/Rd remain
constant) but exchange data roles between DFP (Host) and UFP (Device).

Figure 8-15 Data Role Swap, UFP operating as Source initiates

Initial UFP Source Port Initially DFP Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

CC = Rp (Source) CC = Rd (Sink)
Port Data Role = UFP (Device) Port Data Role = DFP (Host)

1: Send Dr_Swap
2:Dr_Swap
3: Dr_Swap + CRC
Start CRCReceiveTimer 4: Dr_Swap

Check MessageID against local copy

Store copy of MessageID

5: Dr_Swap received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC
Check and increment MessageIDCounter
Evaluate Dr_Swap request
Stop CRCReceiveTimer
CC = Rd (Sink)
9:Dr_Swap sent Port Data Role = DFP (Host)

Start SenderResponseTimer
CC = Rp (Source) 10: Send Accept
Port Data Role = UFP (Device) 11: Accept
12: Accept + CRC
13: Accept Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Accept received

15: GoodCRC
16: GoodCRC + CRC
Stop SenderResponseTimer 17: GoodCRC
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Accept sent

CC = Rp (Source) CC = Rd (Sink)
Port Data Role -> DFP (Host) Port Data Role -> UFP (Device)

New Host/Device Roles

Table 8-15 below provides a detailed explanation of what happens at each labeled step in Figure 8-15 above.

Table 8-15 Steps for Data Role Swap, UFP operating as Source initiates

Step Initial UFP Source Port Initial DFP Sink Port

1 Port starts as a UFP (Device) operating as Source with Port starts as a DFP (Host) operating as a Sink with Rd
Rp asserted and Port Data Role set to UFP. The Policy asserted and Port Data Role set to DFP.
Engine directs the Protocol Layer to send a DR_Swap
Message.
2 Protocol Layer creates the DR_Swap Message and
passes to Physical Layer. Starts CRCReceiveTimer.

Page 330 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Initial UFP Source Port Initial DFP Sink Port
3 Physical Layer appends CRC and sends the DR_Swap Physical Layer receives the DR_Swap Message and
Message. checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
DR_Swap Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received DR_Swap
Message information to the Policy Engine that
consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
DR_Swap Message was successfully sent. Policy Engine
starts SenderResponseTimer.
10 Policy Engine evaluates the DR_Swap Message and
decides that it is able and willing to do the Data Role
Swap. It tells the Protocol Layer to form an Accept
Message.
11 Protocol Layer creates the Accept Message and passes
to Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Accept Message and checks Physical Layer appends a CRC and sends the Accept
the CRC to verify the Message. Message.
13 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received Accept
Message information to the Policy Engine that
consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the GoodCRC Physical Layer receives GoodCRC Message and
Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 The Policy Engine requests that Data Role is changed Protocol Layer verifies and increments the
from UFP (Device) to DFP (Host). MessageIDCounter and stops CRCReceiveTimer.
The Power Delivery role is now a DFP (Host), and Port Protocol Layer informs the Policy Engine that the
Data Role set to DFP, and continues supplying power as Accept Message was successfully sent. The Policy
a Source (Rp asserted). Engine requests that the Data Role is changed to UFP
(Device), with Port Data Role set to UFP and still
operating as a Sink (Rp asserted).
The Data Role Swap is complete; the data roles have been reversed while maintaining the direction of power flow.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 331
 8.3.2.8.3 Data Role Swap, Initiated by DFP Operating as Source
Figure 8-16 shows an example sequence between a Port, which is initially a UFP (Device) and a Sink (Rd asserted),
and a Port which is initially a DFP and a Source (Rp asserted). A Data Role Swap is initiated by the DFP. During the
process the Port Partners maintain their operation as either a Source or a Sink (power and Rp/Rd remain constant)
but exchange data roles between DFP (Host) and UFP (Device).

Figure 8-16 Data Role Swap, DFP operating as Source initiates

Initial UFP Sink Port Initial DFP Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

CC = Rd (Sink) CC = Rp (Source)
Port Data Role = UFP (Device) Port Data Role = DFP (Host)

1: Send Dr_Swap
2: Dr_Swap
3: Dr_Swap + CRC
4: Dr_Swap Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

5: Dr_Swap received 6: GoodCRC

7: GoodCRC + CRC
8: GoodCRC
Evaluate Dr_Swap request
CC = Rd (Sink) Check and increment MessageIDCounter
Port Data Role =UFP (Device) Stop CRCReceiveTimer

9: Dr_Swap sent

Start SenderResponseTimer
10: Send Accept CC = Rp (Source)
11:Accept Port Data Role = DFP (Host)
12: Accept + CRC
Start CRCReceiveTimer 13: Accept

Check MessageID against local copy

Store copy of MessageID

14: Accept received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18:Accept sent

CC = Rd (Sink) CC = Rp (Source)
Port Data Role -> DFP (Host) Port Data Role -> UFP (Device)

New Host/Device Roles

Table 8-16 below provides a detailed explanation of what happens at each labeled step in Figure 8-16 above.

Table 8-16 Steps for Data Role Swap, DFP operating as Source initiates

Step Initial UFP Sink Port Initial DFP Source Port

1 Port starts as a UFP (Device) operating as a Sink with Port starts as a DFP (Host) operating as Source with
Rd asserted and Port Data Role set to UFP. Rp asserted and Port Data Role set to DFP. The
Policy Engine directs the Protocol Layer to send a
DR_Swap Message.
2 Protocol Layer creates the DR_Swap Message and
passes to Physical Layer. Starts CRCReceiveTimer.

Page 332 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Initial UFP Sink Port Initial DFP Source Port
3 Physical Layer receives the DR_Swap Message and Physical Layer appends CRC and sends the DR_Swap
checks the CRC to verify the Message. Message.
4 Physical Layer removes the CRC and forwards the
DR_Swap Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received DR_Swap
Message information to the Policy Engine that
consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer appends CRC and sends the GoodCRC Physical Layer receives the GoodCRC Message and
Message. checks the CRC to verify the Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
DR_Swap Message was successfully sent. Policy
Engine starts SenderResponseTimer.
10 Policy Engine evaluates the DR_Swap Message and
decides that it is able and willing to do the Data Role
Swap. It tells the Protocol Layer to form an Accept
Message.
11 Protocol Layer creates the Accept Message and
passes to Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer appends a CRC and sends the Accept Physical Layer receives the Accept Message and
Message. checks the CRC to verify the Message.
13 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received Accept
Message information to the Policy Engine that
consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer receives GoodCRC Message and Physical Layer appends a CRC and sends the GoodCRC
compares the CRC it calculated with the one sent to Message.
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the The Policy Engine requests that Data Role is changed
MessageIDCounter and stops CRCReceiveTimer. from DFP (Host) to UFP (Device).
Protocol Layer informs the Policy Engine that the The Power Delivery role is now a UFP (Device), with
Accept Message was successfully sent. . The Policy Port Data Role set to UFP, and continues supplying
Engine requests that the Data Role is changed to DFP power as a Source (Rp asserted).
(Host), with Port Data Role set to DFP, still
operating as a Sink (Rd asserted).
The Data Role Swap is complete; the data roles have been reversed while maintaining the direction of power
flow.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 333
 8.3.2.8.4 Data Role Swap, Initiated by DFP Operating as Sink
Figure 8-17 shows an example sequence between a Port, which is initially a UFP (Device) and a Source (Rp asserted),
and a Port which is initially a DFP (Host) and a Sink (Rd asserted). A Data Role Swap is initiated by the DFP. During
the process the Port Partners maintain their operation as either a Source or a Sink (power and Rp/Rd remain
constant) but exchange data roles between DFP (Host) and UFP (Device).

Figure 8-17 Data Role Swap, DFP operating as Sink initiates

Initial UFP Source Port Initial DFP Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

CC = Rp (Source) CC = Rd (Sink)
Port Data Role = UFP (Device) Port Data Role = DFP (Host)

1: Send Dr_Swap
2: Dr_Swap
3: Dr_Swap + CRC
4: Dr_Swap Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

5: Dr_Swap received 6: GoodCRC

7: GoodCRC + CRC
8: GoodCRC
Evaluate Dr_Swap request
CC = Rp (Source) Check and increment MessageIDCounter
Port Data Role = UFP (Device) Stop CRCReceiveTimer

9: Dr_Swap sent

Start SenderResponseTimer
10: Send Accept CC = Rd (Sink)
11:Accept Port Data Role = DFP (Host)
12: Accept + CRC
Start CRCReceiveTimer 13: Accept

Check MessageID against local copy

Store copy of MessageID

14: Accept received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18:Accept sent

CC = Rp (Source) CC = Rd (Sink)
Port Data Role -> DFP (Host) Port Data Role -> UFP (Device)

New Host/Device Roles

Table 8-17 below provides a detailed explanation of what happens at each labeled step in Figure 8-17 above.

Table 8-17 Steps for Data Role Swap, DFP operating as Sink initiates

Step Initial UFP Source Port Initial DFP Sink Port

1 Port starts as a UFP (Device) operating as Source with Port starts as a DFP (Host) operating as a Sink with Rd
Rp asserted and Port Data Role set to UFP. asserted and Port Data Role set to DFP. The Policy
Engine directs the Protocol Layer to send a DR_Swap
Message.
2 Protocol Layer creates the DR_Swap Message and
passes to Physical Layer. Starts CRCReceiveTimer.

Page 334 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Initial UFP Source Port Initial DFP Sink Port
3 Physical Layer receives the DR_Swap Message and Physical Layer appends CRC and sends the DR_Swap
checks the CRC to verify the Message. Message.
4 Physical Layer removes the CRC and forwards the
DR_Swap Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received DR_Swap
Message information to the Policy Engine that
consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer appends CRC and sends the GoodCRC Physical Layer receives the GoodCRC Message and
Message. checks the CRC to verify the Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
DR_Swap Message was successfully sent. Policy
Engine starts SenderResponseTimer.
10 Policy Engine evaluates the DR_Swap Message and
decides that it is able and willing to do the Data Role
Swap. It tells the Protocol Layer to form an Accept
Message.
11 Protocol Layer creates the Accept Message and passes
to Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer appends a CRC and sends the Accept Physical Layer receives the Accept Message and
Message. checks the CRC to verify the Message.
13 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received Accept
Message information to the Policy Engine that
consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer receives GoodCRC Message and Physical Layer appends a CRC and sends the GoodCRC
compares the CRC it calculated with the one sent to Message.
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the The Policy Engine requests that Data Role is changed
MessageIDCounter and stops CRCReceiveTimer. from DFP (Host) to UFP (Device).
Protocol Layer informs the Policy Engine that the The Power Delivery role is now a UFP (Device), with
Accept Message was successfully sent. The Policy Port Data Role set to UFP, still operating as a Sink (Rd
Engine requests that the Data Role is changed to DFP asserted).
(Host), with Port Data Role set to DFP, and continues
supplying power as a Source (Rp asserted).
The Data Role Swap is complete; the data roles have been reversed while maintaining the direction of power flow.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 335
 8.3.2.9 VCONN Swap

8.3.2.9.1 Source to Sink VCONN Source Swap

Figure 8-18 shows an example sequence between a Source and Sink, where the Source is initially supplying VCONN and
then tells the Sink to supply VCONN. During the process the Port Partners, keep their role as Source or Sink, maintain
their operation as either a Source or a Sink (power remains constant) but exchange the VCONN Source from the Source
to the Sink.

Figure 8-18 Source to Sink VCONN Source Swap

Source (Initially VCONN Source Port) Sink (initially VCONN off)

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

VCONN Source VCONN off

1: Send VCONN_Swap
2:VCONN_Swap
3: VCONN_Swap + CRC
Start CRCReceiveTimer 4: VCONN_Swap

Check MessageID against local copy

Store copy of MessageID

5: VCONN_Swap received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC
Check and increment MessageIDCounter
Stop CRCReceiveTimer

9:VCONN_Swap sent Evaluate VCONN_Swap

Start SenderResponseTimer request

10: Send Accept

11: Accept
12: Accept + CRC
13: Accept Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Accept received

15: GoodCRC
16: GoodCRC + CRC
Stop SenderResponseTimer 17: GoodCRC
Start VCONNOnTimer Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Accept sent

Tell power supply to

start supplying VCONN

Vconn is on

19: Send PS_RDY

20: PS_RDY
21: PS_RDY + CRC
22: PS_RDY
Start CRCReceiveTimer
Check MessageID against local copy
Store copy of MessageID

23: PS_RDY received

24: GoodCRC
25: GoodCRC + CRC
Stop VCONNOnTimer 26: GoodCRC
Tell power supply to turn off VCONN
Check and increment MessageIDCounter
Stop CRCReceiveTimer

27: PS_RDY sent

VCONN is off

Sink is supplying VCONN

Table 8-18 below provides a detailed explanation of what happens at each labeled step in Figure 8-18 above.

Page 336 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 8-18 Steps for Source to Sink VCONN Source Swap

Step Source (initially VCONN Source) Sink (Initially VCONN off)

1 The Source starts as the VCONN Source. The Policy The Sink starts with VCONN off.
Engine directs the Protocol Layer to send a
VCONN_Swap Message.
2 Protocol Layer creates the VCONN_Swap Message
and passes to Physical Layer. Starts
CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the VCONN_Swap Message
VCONN_Swap Message. and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
VCONN_Swap Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
VCONN_Swap Message information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
VCONN_Swap Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine evaluates the VCONN_Swap Message
sent by the Source and decides that it is able and
willing to do the VCONN Swap. It tells the Protocol
Layer to form an Accept Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Accept Message and Physical Layer appends a CRC and sends the Accept
compares the CRC it calculated with the one sent to Message.
verify the Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Accept
Message information to the Policy Engine that
consumes it.
14 The Policy Engine stops the SenderResponseTimer
and starts the VCONNOnTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 337
 Step Source (initially VCONN Source) Sink (Initially VCONN off)
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Accept Message was successfully sent. The Policy
Engine asks the Device Policy Manager to turn on
VCONN.
19 The Device Policy Manager informs the Policy Engine
that its power supply is supplying VCONN. The Policy
Engine directs the Protocol Layer to generate a
PS_RDY Message to tell the Source it can turn off
VCONN.
20 Protocol Layer creates the PS_RDY Message and
passes to Physical Layer. Starts CRCReceiveTimer.
21 Physical Layer receives the PS_RDY Message and Physical Layer appends a CRC and sends the PS_RDY
compares the CRC it calculated with the one sent to Message.
verify the Message.
22 Physical Layer removes the CRC and forwards the
PS_RDY Message to the Protocol Layer.
23 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received PS_RDY
Message information to the Policy Engine that
consumes it.
24 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
25 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. The Policy Engine stops the compares the CRC it calculated with the one sent to
VCONNOnTimer, and tells the power supply to stop verify the Message.
sourcing VCONN.
26 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
27 VCONN is off. Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
PS_RDY Message was successfully sent.
The Sink is now the VCONN Source and the Source has VCONN turned off.

Page 338 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.2.9.2 Sink to Source VCONN Source Swap
Figure 8-19 shows an example sequence between a Source and Sink, where the Sink is initially supplying VCONN and
then the Source tells the Sink that it will become the VCONN Source. During the process the Port Partners, keep their
role as Source or Sink, maintain their operation as either a Source or a Sink (power remains constant) but exchange
the VCONN Source from the Sink to the Source.

Figure 8-19 Sink to Source VCONN Source Swap

Source (Initially VCONN off) Sink (initially VCONN Source Port)

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

VCONN Off VCONN Source

1: Send VCONN_Swap
2:VCONN_Swap
3: VCONN_Swap + CRC
Start CRCReceiveTimer 4: VCONN_Swap

Check MessageID against local copy

Store copy of MessageID

5: VCONN_Swap received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC
Check and increment MessageIDCounter
Stop CRCReceiveTimer

9:VCONN_Swap sent Evaluate VCONN_Swap

Start SenderResponseTimer request

10: Send Accept

11: Accept
12: Accept + CRC
13: Accept Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Accept received

15: GoodCRC
16: GoodCRC + CRC
Stop SenderResponseTimer 17: GoodCRC
Tell power supply to start Check and increment MessageIDCounter
supplying VCONN Stop CRCReceiveTimer

18: Accept sent

Start VCONNOnTimer

Vconn is on

19: Send PS_RDY

20: PS_RDY
21: PS_RDY + CRC
Start CRCReceiveTimer 22: PS_RDY

Check MessageID against local copy

Store copy of MessageID

23: PS_RDY received

24: GoodCRC
25: GoodCRC + CRC
26: GoodCRC Stop VCONNOnTimer
Tell power supply to turn off VCONN
Check and increment MessageIDCounter
Stop CRCReceiveTimer

27: PS_RDY sent

VCONN is off

Source is supplying VCONN

Table 8-19 below provides a detailed explanation of what happens at each labeled step in Figure 8-19 above.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 339
 Table 8-19 Steps for Sink to Source VCONN Source Swap

Step Source Sink

1 The Source starts with VCONN off. The Policy Engine The Sink starts as the VCONN Source.
directs the Protocol Layer to send a VCONN_Swap
Message.
2 Protocol Layer creates the VCONN_Swap Message
and passes to Physical Layer. Starts
CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the VCONN_Swap Message
VCONN_Swap Message. and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
VCONN_Swap Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
VCONN_Swap Message information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
VCONN_Swap Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine evaluates the VCONN_Swap Message
sent by the Source and decides that it is able and
willing to do the VCONN Swap. It tells the Protocol
Layer to form an Accept Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Accept Message and Physical Layer appends a CRC and sends the Accept
compares the CRC it calculated with the one sent to Message.
verify the Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Accept
Message information to the Policy Engine that
consumes it.
14 The Policy Engine stops the SenderResponseTimer.
The Policy Engine tells the Device Policy Manger to
turn on VCONN.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.

Page 340 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Sink
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Accept Message was successfully sent.
The Policy Engine starts the VCONNOnTimer.
19 The Device Policy Manager tells the Policy Engine
that its power supply is supplying VCONN. The Policy
Engine directs the Protocol Layer to generate a
PS_RDY Message to tell the Sink it can turn off VCONN.
20 Protocol Layer creates the PS_RDY Message and
passes to Physical Layer. Starts CRCReceiveTimer.
21 Physical Layer appends a CRC and sends the PS_RDY Physical Layer receives the PS_RDY Message and
Message. compares the CRC it calculated with the one sent to
verify the Message.
22 Physical Layer removes the CRC and forwards the
PS_RDY Message to the Protocol Layer.
23 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received PS_RDY
Message information to the Policy Engine that
consumes it.
24 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
25 Physical Layer receives GoodCRC Message and Physical Layer appends a CRC and sends the GoodCRC
compares the CRC it calculated with the one sent to Message. The Policy Engine stops the
verify the Message. VCONNOnTimer, and tells the power supply to stop
sourcing VCONN.
26 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
27 Protocol Layer verifies and increments the VCONN is off.
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
PS_RDY Message was successfully sent.
The Source is now the VCONN Source and the Sink has VCONN turned off.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 341
 8.3.2.10 Additional Capabilities, Status and Information

8.3.2.10.1 Alert

8.3.2.10.1.1 Source sends Alert to a Sink

Figure 8-20 shows an example sequence between a Source and a Sink where the Source alerts the Sink that there has
been a status change. This AMS will be followed by getting the Source status to determine further details of the alert
(see Section 8.3.2.10.2).

Figure 8-20 Source Alert to Sink

Sink Port Source Port

: Sink Policy Engine : Protocol : PHY : PHY : Protocol : Source Policy Engine

1: Send Alert
2: Alert
3: Alert + CRC
4: Alert Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

5: Alert received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC
Check and increment MessageIDCounter
Stop CRCReceiveTimer

9: Alert sent

Table 8-59 below provides a detailed explanation of what happens at each labeled step in Figure 8-20 above.

Table 8-20 Steps for Source Alert to Sink

Step Sink Source

1 The Device Policy Manager indicates a Source alert
condition. The Policy Engine tells the Protocol Layer
to form an Alert Message.
2 Protocol Layer creates the Alert Message and passes
to Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer receives the Alert Message and Physical Layer appends a CRC and sends the Alert
compares the CRC it calculated with the one sent to Message.
verify the Message.
4 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Alert
Message to the Policy Engine that consumes it.
5 The Policy Engine informs the Device Policy
Manager.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.

Page 342 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Sink Source
7 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Alert Message was successfully sent.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 343
 8.3.2.10.1.1 Sink sends Alert to a Source
Figure 8-20 shows an example sequence between a Source and a Sink where the Sink alerts the Source that there has
been a status change. This AMS will be followed by getting the Sink status to determine further details of the alert
(see Section 8.3.2.10.2).

Figure 8-21 Sink Alert to Source

Source Port Sink Port

: Source Policy Engine : Protocol : PHY : PHY : Protocol : Sink Policy Engine

1: Send Alert
2: Alert
3: Alert + CRC
4: Alert Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

5: Alert received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC
Check and increment MessageIDCounter
Stop CRCReceiveTimer

9: Alert sent

Table 8-59 below provides a detailed explanation of what happens at each labeled step in Figure 8-20 above.

Table 8-21 Steps for Sink Alert to Source

Step Source Sink

1 The Device Policy Manager indicates a Sink alert
condition. The Policy Engine tells the Protocol Layer
to form an Alert Message.
2 Protocol Layer creates the Alert Message and passes
to Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer receives the Alert Message and Physical Layer appends a CRC and sends the Alert
compares the CRC it calculated with the one sent to Message.
verify the Message.
4 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Alert
Message to the Policy Engine that consumes it.
5 The Policy Engine informs the Device Policy
Manager.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.

Page 344 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Sink
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Alert Message was successfully sent.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 345
 8.3.2.10.2 Status

8.3.2.10.2.1 Sink Gets Source Status

Figure 8-22 shows an example sequence between a Source and a Sink where, after the Sink has received an alert (see
Section 8.3.2.10.1) that there has been a status change, the Sink gets more details on the change.

Figure 8-22 Sink Gets Source Status

Sink Port Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp
1: Send Get_Status
2:Get_Status
3: Get_Status + CRC
Start CRCReceiveTimer 4: Get_Status

Check MessageID against local copy

Store copy of MessageID

5: Get_Status received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Source Status
9:Get_Status sent Information from DPM

Start SenderResponseTimer

10: Send Status

11: Status
12: Status + CRC
13: Status Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Status received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Status sent

Table 8-22below provides a detailed explanation of what happens at each labeled step in Figure 8-22 above.

Table 8-22 Steps for a Sink getting Source status Sequence

Step Sink Port Source Port
1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Status Message.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Status Message and
Get_Status Message. checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Status Message to the Protocol Layer.

Page 346 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Sink Port Source Port
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received Get_Status
Message information to the Policy Engine that
consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Status Message was successfully sent. Policy
Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the present
Source status which is provided.
The Policy Engine tells the Protocol Layer to form a
Status Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the Status
the CRC it calculated with the one sent to verify the Message.
Status Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Status
Message information to the Policy Engine that
consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Status Message was successfully sent.
The Source has informed the Sink of its present status.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 347
 8.3.2.10.2.2 Source Gets Sink Status
Figure 8-22 shows an example sequence between a Source and a Sink where, after the Source has received an alert
(see Section 8.3.2.10.1) that there has been a status change, the Source gets more details on the change.

Figure 8-23 Source Gets Sink Status

Source Port Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp
1: Send Get_Status
2:Get_Status
3: Get_Status + CRC
Start CRCReceiveTimer 4: Get_Status

Check MessageID against local copy

Store copy of MessageID

5: Get_Status received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Source Status
9:Get_Status sent Information from DPM

Start SenderResponseTimer

10: Send Status

11: Status
12: Status + CRC
13: Status Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Status received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Status sent

Table 8-22below provides a detailed explanation of what happens at each labeled step in Figure 8-22 above.

Table 8-23 Steps for a Source getting Sink status Sequence

Step Source Port Sink Port

1 The Port has Port Power Role set to Source and the The Port has Port Power Role set to Sink with the Rd
Rp pull up on its CC wire. pull down on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Status Message.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Status Message and
Get_Status Message. checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Status Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received Get_Status
Message information to the Policy Engine that
consumes it.

Page 348 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Port Sink Port
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Status Message was successfully sent. Policy
Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the present
Source status which is provided.
The Policy Engine tells the Protocol Layer to form a
Status Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the Status
the CRC it calculated with the one sent to verify the Message.
Status Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Status
Message information to the Policy Engine that
consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Status Message was successfully sent.
The Sink has informed the Source of its present status.

8.3.2.10.2.3 Sink Gets Source PPS Status

Figure 8-24 shows an example sequence between a Source and a Sink where, after the Sink has received an alert (see
Section 8.3.2.10.1) that there has been a PPS status change, the Sink gets more details on the change.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 349
 Figure 8-24 Sink Gets Source PPS Status

Sink Port Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp
1: Send Get_PPS_Status
2:Get_PPS_Status
3: Get_PPS_Status + CRC
Start CRCReceiveTimer 4: Get_PPS_Status

Check MessageID against local copy

Store copy of MessageID

5: Get_PPS_Status received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Source PPS Status
9:Get_PPS_Status sent Information from DPM

Start SenderResponseTimer

10: Send PPS_Status

11: PPS_Status
12: PPS_Status + CRC
13: PPS_Status Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: PPS_Status received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: PPS_Status sent

Table 8-24below provides a detailed explanation of what happens at each labeled step in Figure 8-24 above.

Table 8-24 Steps for a Sink getting Source PPS status Sequence

Step Sink Port Source Port

1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_PPS_Status Message.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_PPS_Status Message
Get_PPS_Status Message. and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Status Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_PPS_Status Message information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.

Page 350 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Sink Port Source Port
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_PPS_Status Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the present
Source status which is provided.
The Policy Engine tells the Protocol Layer to form a
PPS_Status Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the PPS_Status Message.
PPS_Status Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
PPS_Status Message information to the Policy Engine
that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
PPS_Status Message was successfully sent.
The Source has informed the Sink of its present PPS status.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 351
 8.3.2.10.3 Source/Sink Capabilities

8.3.2.10.3.1 Sink Gets Source Capabilities

Figure 8-25 shows an example sequence between a Source and a Sink when the Sink gets the Source’s capabilities.

Figure 8-25 Sink Gets Source’s Capabilities

Sink Port Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp
1: Send Get_Source_Cap
2:Get_Source_Cap
3: Get_Source_Cap + CRC
Start CRCReceiveTimer 4: Get_Source_Cap

Check MessageID against local copy

Store copy of MessageID

5: Get_Source_Cap received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Source capability
9:Get_Source_Cap sent Information from DPM

Start SenderResponseTimer

10: Send Source_Capabilities

11: Source_Capabilities
12: Source_Capabilities + CRC
13: Source_Capabilities Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Source_Capabilities received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Source_Capabilities sent

Table 8-25 below provides a detailed explanation of what happens at each labeled step in Figure 8-25 above.

Table 8-25 Steps for a Sink getting Source capabilities Sequence

Step Sink Port Source Port

1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Source_Cap Message.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Source_Cap Message
Get_Source_Cap Message. and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Source_Cap Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Source_Cap Message information to the Policy
Engine that consumes it.

Page 352 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Sink Port Source Port
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Source_Cap Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the present
Source capabilities which are provided.
The Policy Engine tells the Protocol Layer to form a
Source_Capabilities Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Source_Capabilities Message.
Source_Capabilities Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Source_Capabilities Message information to the
Policy Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Source_Capabilities Message was successfully sent.
The Source has informed the Sink of its capabilities.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 353
 8.3.2.10.3.2 Dual-Role Source Gets Source Capabilities from a Dual-Role Sink
Figure 8-26 shows an example sequence between a Dual-Role Source and a Dual-Role Sink when the Source gets the
Sink’s capabilities as a Source.

Figure 8-26 Dual-Role Source Gets Dual-Role Sink’s Capabilities as a Source

Dual-Role Source Port Dual-Role Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Source Port Power Role = Sink

CC = Rp CC = Rd

1: Send Get_Source_Cap
2:Get_Source_Cap
3: Get_Source_Cap + CRC
Start CRCReceiveTimer 4: Get_Source_Cap

Check MessageID against local copy

Store copy of MessageID

5: Get_Source_Cap received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Source capability
9:Get_Source_Cap sent Information from DPM

Start SenderResponseTimer

10: Send Source_Capabilities

11: Source_Capabilities
12: Source_Capabilities + CRC
13: Source_Capabilities Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Source_Capabilities received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Source_Capabilities sent

Table 8-26 below provides a detailed explanation of what happens at each labeled step in Figure 8-26 above.

Table 8-26 Steps for a Dual-Role Source getting Dual-Role Sink’s capabilities as a Source Sequence

Step Dual-Role Source Port Dual-Role Sink Port

1 The Port has Port Power Role set to Source and the The Port has Port Power Role set to Sink with the Rd
Rp pull up on its CC wire. pull down on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Source_Cap Message.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Source_Cap Message
Get_Source_Cap Message. and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Source_Cap Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Source_Cap Message information to the Policy
Engine that consumes it.

Page 354 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Dual-Role Source Port Dual-Role Sink Port
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Source_Cap Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the present
Source capabilities which are provided.
The Policy Engine tells the Protocol Layer to form a
Source_Capabilities Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Source_Capabilities Message.
Source_Capabilities Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Source_Capabilities Message information to the
Policy Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Source_Capabilities Message was successfully sent.
The Dual-Role Sink has informed the Dual-Role Source of its capabilities.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 355
 8.3.2.10.3.3 Source Gets Sink Capabilities
Figure 8-27 shows an example sequence between a Source and a Sink when the Source gets the Sink’s capabilities.

Figure 8-27 Source Gets Sink’s Capabilities

Source Port Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Source Port Power Role = Sink

CC = Rp CC = Rd
1: Send Get_Sink_Cap
2:Get_Sink_Cap
3: Get_Sink_Cap + CRC
Start CRCReceiveTimer 4: Get_Sink_Cap

Check MessageID against local copy

Store copy of MessageID

5: Get_Sink_Cap received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Sink capability
9:Get_Sink_Cap sent Information from DPM

Start SenderResponseTimer

10: Send Sink_Capabilities

11: Sink_Capabilities
12: Sink_Capabilities + CRC
13: Sink_Capabilities Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Sink_Capabilities received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Sink_Capabilities sent

Table 8-27 below provides a detailed explanation of what happens at each labeled step in Figure 8-27 above.

Table 8-27 Steps for a Source getting Sink capabilities Sequence

Step Source Port Sink Port

1 The Port has Port Power Role set to Source and the The Port has Port Power Role set to Sink with the Rd
Rp pull up on its CC wire. pull down on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Sink_Cap Message.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Sink_Cap Message
Get_Sink_Cap Message. and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Sink_Cap Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Sink_Cap Message information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.

Page 356 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Port Sink Port
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Sink_Cap Message was successfully sent. Policy
Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the present Sink
capabilities which are provided.
The Policy Engine tells the Protocol Layer to form a
Sink_Capabilities Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Sink_Capabilities Message.
Sink_Capabilities Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Sink_Capabilities Message information to the Policy
Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Sink_Capabilities Message was successfully sent.
The Sink has informed the Source of its capabilities.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 357
 8.3.2.10.3.4 Dual-Role Sink Get Sink Capabilities from a Dual-Role Source
Figure 8-28 shows an example sequence between a Dual-Role Source and a Dual-Role Sink when the Dual-Role Sink
gets the Dual-Role Source’s capabilities as a Sink.

Figure 8-28 Dual-Role Sink Gets Dual-Role Source’s Capabilities as a Sink

Dual-Role Sink Port Dual-Role Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp
1: Send Get_Sink_Cap
2:Get_Sink_Cap
3: Get_Sink_Cap + CRC
Start CRCReceiveTimer 4: Get_Sink_Cap

Check MessageID against local copy

Store copy of MessageID

5: Get_Sink_Cap received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Sink capability
9:Get_Sink_Cap sent Information from DPM

Start SenderResponseTimer

10: Send Sink_Capabilities

11: Sink_Capabilities
12: Sink_Capabilities + CRC
13: Sink_Capabilities Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Sink_Capabilities received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Sink_Capabilities sent

Table 8-28 below provides a detailed explanation of what happens at each labeled step in Figure 8-28 above.

Table 8-28 Steps for a Dual-Role Sink getting Dual-Role Source capabilities as a Sink Sequence

Step Dual-Role Sink Port Dual-Role Source Port

1 The Port has Port Power Role set to Dual-Role Sink The Port has Port Power Role set to Dual-Role Source
with the Rd pull down on its CC wire. and the Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Sink_Cap Message.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Sink_Cap Message
Get_Sink_Cap Message. and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Sink_Cap Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Sink_Cap Message information to the Policy
Engine that consumes it.

Page 358 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Dual-Role Sink Port Dual-Role Source Port
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Sink_Cap Message was successfully sent. Policy
Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the present Dual-
Role Source capabilities which are provided.
The Policy Engine tells the Protocol Layer to form a
Sink_Capabilities Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Sink_Capabilities Message.
Sink_Capabilities Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Sink_Capabilities Message information to the Policy
Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Sink_Capabilities Message was successfully sent.
The Dual-Role Source has informed the Dual-Role Sink of its capabilities as a Sink.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 359
 8.3.2.10.4 Extended Capabilities

8.3.2.10.4.1 Sink Gets Source Extended Capabilities

Figure 8-29 shows an example sequence between a Source and a Sink when the Sink gets the Source’s extended
capabilities.

Figure 8-29 Sink Gets Source’s Extended Capabilities

Sink Port Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp
1: Send Get_Source_Cap_Extended
2:Get_Source_Cap_Extended
3: Get_Source_Cap_Extended + CRC
Start CRCReceiveTimer 4: Get_Source_Cap_Extended
Check MessageID against local copy
Store copy of MessageID
5: Get_Source_Cap_Extended
received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer Get extended Source
9:Get_Source_Cap_Extended sent capability Information
from DPM
Start SenderResponseTimer

10: Send Source_Capabilities_Extended

12: Source_Capabilities_Extended 11: Source_Capabilities_Extended
+ CRC
13: Source_Capabilities_Extended Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID
14: Source_Capabilities_Extended
received
15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Source_Capabilities_Extended sent

Table 8-29 below provides a detailed explanation of what happens at each labeled step in Figure 8-29 above.

Table 8-29 Steps for a Sink getting Source extended capabilities Sequence

Step Sink Port Source Port

1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Source_Cap_Extended Message.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the
Get_Source_Cap_Extended Message. Get_Source_Cap_Extended Message and checks the
CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Source_Cap_Extended Message to the Protocol
Layer.

Page 360 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Sink Port Source Port
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Source_Cap_Extended Message information to
the Policy Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Source_Cap_Extended Message was successfully
sent. Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the present
extended Source capabilities which are provided.
The Policy Engine tells the Protocol Layer to form a
Source_Capabilities_Extended Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Source_Capabilities_Extended Message.
Source_Capabilities_Extended Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Source_Capabilities_Extended Message information
to the Policy Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Source_Capabilities_Extended Message was
successfully sent.
The Source has informed the Sink of its extended capabilities.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 361
 8.3.2.10.4.2 Dual-Role Source Gets Source Capabilities Extended from a Dual-Role Sink
Figure 8-29 shows an example sequence between a Source and a Sink when the Dual-Role Source gets the Dual-Role
Sink’s extended capabilities as a Source.

Figure 8-30 Dual-Role Source Gets Dual-Role Sink’s Extended Capabilities

Dual-Role Source Port Dual-Role Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp
1: Send Get_Source_Cap_Extended
2:Get_Source_Cap_Extended
3: Get_Source_Cap_Extended + CRC
Start CRCReceiveTimer 4: Get_Source_Cap_Extended
Check MessageID against local copy
Store copy of MessageID
5: Get_Source_Cap_Extended
received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer Get extended Source
9:Get_Source_Cap_Extended sent capability Information
from DPM
Start SenderResponseTimer

10: Send Source_Capabilities_Extended

12: Source_Capabilities_Extended 11: Source_Capabilities_Extended
+ CRC
13: Source_Capabilities_Extended Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID
14: Source_Capabilities_Extended
received
15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Source_Capabilities_Extended sent

Table 8-29 below provides a detailed explanation of what happens at each labeled step in Figure 8-29 above.

Table 8-30 Steps for a Dual-Role Source getting Dual-Role Sink extended capabilities Sequence

Step Dual-Role Source Port Dual-Role Sink Port

1 The Port has Port Power Role set to Source and the The Port has Port Power Role set to Sink with the Rd
Rp pull up on its CC wire. pull down on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Source_Cap_Extended Message.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the
Get_Source_Cap_Extended Message. Get_Source_Cap_Extended Message and checks the
CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Source_Cap_Extended Message to the Protocol
Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Source_Cap_Extended Message information to
the Policy Engine that consumes it.

Page 362 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Dual-Role Source Port Dual-Role Sink Port
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Source_Cap_Extended Message was successfully
sent. Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the present
extended Source capabilities which are provided.
The Policy Engine tells the Protocol Layer to form a
Source_Capabilities_Extended Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Source_Capabilities_Extended Message.
Source_Capabilities_Extended Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Source_Capabilities_Extended Message information
to the Policy Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Source_Capabilities_Extended Message was
successfully sent.
The Dual-Role Sink has informed the Dual-Role Source of its extended capabilities as a Source.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 363
 8.3.2.10.5 Battery Capabilities and Status

8.3.2.10.5.1 Sink Gets Battery Capabilities

Figure 8-31 shows an example sequence between a Source and a Sink when the Sink gets the Source’s Battery
capabilities for a given Battery.

Figure 8-31 Sink Gets Source’s Battery Capabilities

Sink Port Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Battery

CC = Rd CC = Rp
1: Send Get_Battery_Cap
2:Get_Battery_Cap
3: Get_Battery_Cap + CRC
Start CRCReceiveTimer 4: Get_Battery_Cap

Check MessageID against local copy

Store copy of MessageID

5: Get_Battery_Cap received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Battery capability
9:Get_Battery_Cap sent Information from DPM

Start SenderResponseTimer

10: Send Battery_Capabilities

11: Battery_Capabilities
12: Battery_Capabilities + CRC
13: Battery_Capabilities Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Battery_Capabilities received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Battery_Capabilities sent

Table 8-31 below provides a detailed explanation of what happens at each labeled step in Figure 8-31 above.

Table 8-31 Steps for a Sink getting Source Battery capabilities Sequence
Step Sink Port Source Port
1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Battery_Cap Message containing the number of
the Battery for which capabilities are being
requested.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Battery_Cap Message
Get_Battery_Cap Message. and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Battery_Cap Message to the Protocol Layer.

Page 364 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Sink Port Source Port
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Battery_Cap Message information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Battery_Cap Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the present
Source Battery capabilities, for the requested Battery
number, which are provided.
The Policy Engine tells the Protocol Layer to form a
Battery_Capabilities Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Battery_Capabilities Message.
Battery_Capabilities Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Battery_Capabilities Message information to the
Policy Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Battery_Capabilities Message was successfully sent.
The Source has informed the Sink of the Battery capabilities for the requested Battery.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 365
 8.3.2.10.5.2 Source Gets Battery Capabilities
Figure 8-32 shows an example sequence between a Source and a Sink when the Source gets the Sink’s Battery
capabilities for a given Battery.

Figure 8-32 Source Gets Sink’s Battery Capabilities

Source Port Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Battery Port Power Role = Sink

CC = Rp CC = Rd

1: Send Get_Battery_Cap
2:Get_Battery_Cap
3: Get_Battery_Cap + CRC
Start CRCReceiveTimer 4: Get_Battery_Cap

Check MessageID against local copy

Store copy of MessageID

5: Get_Battery_Cap received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Battery capability
9:Get_Battery_Cap sent Information from DPM

Start SenderResponseTimer

10: Send Battery_Capabilities

11: Battery_Capabilities
12: Battery_Capabilities + CRC
13: Battery_Capabilities Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Battery_Capabilities received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Battery_Capabilities sent

Table 8-32 below provides a detailed explanation of what happens at each labeled step in Figure 8-32 above.

Table 8-32 Steps for a Source getting Sink Battery capabilities Sequence

Step Source Port Sink Port

1 The Port has Port Power Role set to Source and the The Port has Port Power Role set to Sink with the Rd
Rp pull up on its CC wire. pull down on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Battery_Cap Message containing the number of
the Battery for which capabilities are being
requested.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Battery_Cap Message
Get_Battery_Cap Message. and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Battery_Cap Message to the Protocol Layer.

Page 366 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Port Sink Port
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Battery_Cap Message information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Battery_Cap Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the present
Source Battery capabilities, for the requested Battery
number, which are provided.
The Policy Engine tells the Protocol Layer to form a
Battery_Capabilities Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Battery_Capabilities Message.
Battery_Capabilities Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Battery_Capabilities Message information to the
Policy Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Battery_Capabilities Message was successfully sent.
The Sink has informed the Source of the Battery capabilities for the requested Battery.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 367
 8.3.2.10.5.3 Sink Gets Battery Status
Figure 8-33 shows an example sequence between a Source and a Sink when the Sink gets the Source’s Battery status
for a given Battery.

Figure 8-33 Sink Gets Source’s Battery Status

Sink Port Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Battery

CC = Rd CC = Rp
1: Send Get_Battery_Status
2:Get_Battery_Status
3: Get_Battery_Status + CRC
Start CRCReceiveTimer 4: Get_Battery_Status

Check MessageID against local copy

Store copy of MessageID

5: Get_Battery_Status received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Battery status
9:Get_Battery_Status sent Information from DPM

Start SenderResponseTimer

10: Send Battery_Status

11: Battery_Status
12: Battery_Status + CRC
13: Battery_Status Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Battery_Status received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Battery_Status sent

Table 8-33 below provides a detailed explanation of what happens at each labeled step in Figure 8-33 above.

Table 8-33 Steps for a Sink getting Source Battery status Sequence

Step Sink Port Source Port

1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Battery_Status Message containing the number
of the Battery for which status is being requested.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Battery_Status
Get_Battery_Status Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Battery_Status Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Battery_Status Message information to the Policy
Engine that consumes it.

Page 368 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Sink Port Source Port
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Battery_Status Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the present
Source Battery status, for the requested Battery
number, which are provided.
The Policy Engine tells the Protocol Layer to form a
Battery_Status Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Battery_Status Message.
Battery_Status Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Battery_Status Message information to the Policy
Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Battery_Status Message was successfully sent.
The Source has informed the Sink of the Battery status for the requested Battery.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 369
 8.3.2.10.5.4 Source Gets Battery Status
Figure 8-34 shows an example sequence between a Source and a Sink when the Source gets the Sink’s Battery status
for a given Battery.

Figure 8-34 Source Gets Sink’s Battery Status

Source Port Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Battery Port Power Role = Sink

CC = Rp CC = Rd

1: Send Get_Battery_Status
2:Get_Battery_Status
3: Get_Battery_Status + CRC
Start CRCReceiveTimer 4: Get_Battery_Status

Check MessageID against local copy

Store copy of MessageID

5: Get_Battery_Status received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Battery status
9:Get_Battery_Status sent Information from DPM

Start SenderResponseTimer

10: Send Battery_Status

11: Battery_Status
12: Battery_Status + CRC
13: Battery_Status Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Battery_Status received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Battery_Status sent

Table 8-34 below provides a detailed explanation of what happens at each labeled step in Figure 8-34 above.

Table 8-34 Steps for a Source getting Sink Battery status Sequence

Step Source Port Sink Port

1 The Port has Port Power Role set to Source and the The Port has Port Power Role set to Sink with the Rd
Rp pull up on its CC wire. pull down on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Battery_Status Message containing the number
of the Battery for which status is being requested.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Battery_Status
Get_Battery_Status Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Battery_Status Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Battery_Status Message information to the Policy
Engine that consumes it.

Page 370 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Port Sink Port
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Battery_Status Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the present
Source Battery status, for the requested Battery
number, which are provided.
The Policy Engine tells the Protocol Layer to form a
Battery_Status Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Battery_Status Message.
Battery_Status Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Battery_Status Message information to the Policy
Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Battery_Status Message was successfully sent.
The Sink has informed the Source of the Battery status for the requested Battery.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 371
 8.3.2.10.6 Manufacturer Information

8.3.2.10.6.1 Source Gets Port Manufacturer Information from a Sink

Figure 8-35 shows an example sequence between a Source and a Sink when the Source gets the Sink’s Manufacturer
information for the Port.

Figure 8-35 Source Gets Sink’s Port Manufacturer Information

Source Port Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Source Port Power Role = Sink

CC = Rp CC = Rd
1: Send Get_Manufacturer_Info
2:Get_Manufacturer_Info
3: Get_Manufacturer_Info + CRC
Start CRCReceiveTimer 4: Get_Manufacturer_Info
Check MessageID against local copy
Store copy of MessageID
5: Get_Manufacturer_Info
received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Manufacturer
9:Get_Manufacturer_Info sent Information from DPM

Start SenderResponseTimer

10: Send Manufacturer_Info

12: Manufacturer_Info 11: Manufacturer_Info
+ CRC
13: Manufacturer_Info Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID
14: Manufacturer_Info
received
15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Manufacturer_Info sent

Table 8-32 below provides a detailed explanation of what happens at each labeled step in Figure 8-35 above.

Table 8-35 Steps for a Source getting Sink’s Port Manufacturer information Sequence

Step Source Port Sink Port

1 The Port has Port Power Role set to Source and the The Port has Port Power Role set to Sink with the Rd
Rp pull up on its CC wire. pull down on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Manufacturer_Info Message with a request for
Port information.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Manufacturer_Info
Get_Manufacturer_Info Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Manufacturer_Info Message to the Protocol
Layer.

Page 372 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Port Sink Port
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Manufacturer_Info Message information to the
Policy Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Manufacturer_Info Message was successfully
sent. Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the Port’s
manufacturer information which is provided.
The Policy Engine tells the Protocol Layer to form a
Manufacturer_Info Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Manufacturer_Info Message.
Manufacturer_Info Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Manufacturer_Info Message information to the
Policy Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Manufacturer_Info Message was successfully sent.
The Sink has informed the Source of the manufacturer information for the Port.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 373
 8.3.2.10.6.2 Sink Gets Port Manufacturer Information from a Source
Figure 8-36 shows an example sequence between a Source and a Sink when the Source gets the Sink’s Manufacturer
information for the Port.

Figure 8-36 Sink Gets Source’s Port Manufacturer Information

Sink Port Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp
1: Send Get_Manufacturer_Info
2:Get_Manufacturer_Info
3: Get_Manufacturer_Info + CRC
Start CRCReceiveTimer 4: Get_Manufacturer_Info
Check MessageID against local copy
Store copy of MessageID
5: Get_Manufacturer_Info
received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Manufacturer
9:Get_Manufacturer_Info sent Information from DPM

Start SenderResponseTimer

10: Send Manufacturer_Info

12: Manufacturer_Info 11: Manufacturer_Info
+ CRC
13: Manufacturer_Info Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID
14: Manufacturer_Info
received
15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Manufacturer_Info sent

Table 8-36 below provides a detailed explanation of what happens at each labeled step in Figure 8-36 above.

Table 8-36 Steps for a Source getting Sink’s Port Manufacturer information Sequence

Step Sink Port Source Port

1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Manufacturer_Info Message with a request for
Port information.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Manufacturer_Info
Get_Manufacturer_Info Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Manufacturer_Info Message to the Protocol
Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Manufacturer_Info Message information to the
Policy Engine that consumes it.

Page 374 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Sink Port Source Port
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Manufacturer_Info Message was successfully
sent. Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the Port’s
manufacturer information which is provided.
The Policy Engine tells the Protocol Layer to form a
Manufacturer_Info Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Manufacturer_Info Message.
Manufacturer_Info Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Manufacturer_Info Message information to the
Policy Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Manufacturer_Info Message was successfully sent.
The Sink has informed the Source of the manufacturer information for the Port.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 375
 8.3.2.10.6.3 Source Gets Battery Manufacturer Information from a Sink
Figure 8-37 shows an example sequence between a Source and a Sink when the Source gets the Sink’s Manufacturer
information for one of its Batteries.

Figure 8-37 Source Gets Sink’s Battery Manufacturer Information

Source Port Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Source Port Power Role = Sink

CC = Rp CC = Rd
1: Send Get_Manufacturer_Info
2:Get_Manufacturer_Info
3: Get_Manufacturer_Info + CRC
Start CRCReceiveTimer 4: Get_Manufacturer_Info
Check MessageID against local copy
Store copy of MessageID
5: Get_Manufacturer_Info
received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Manufacturer
9:Get_Manufacturer_Info sent Information from DPM

Start SenderResponseTimer

10: Send Manufacturer_Info

12: Manufacturer_Info 11: Manufacturer_Info
+ CRC
13: Manufacturer_Info Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID
14: Manufacturer_Info
received
15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Manufacturer_Info sent

Table 8-37 below provides a detailed explanation of what happens at each labeled step in Figure 8-37 above.

Table 8-37 Steps for a Source getting Sink’s Battery Manufacturer information Sequence

Step Source Port Sink Port

1 The Port has Port Power Role set to Source and the The Port has Port Power Role set to Sink with the Rd
Rp pull up on its CC wire. pull down on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Manufacturer_Info Message with a request for
Battery information for a given Battery.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Manufacturer_Info
Get_Manufacturer_Info Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Manufacturer_Info Message to the Protocol
Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Manufacturer_Info Message information to the
Policy Engine that consumes it.

Page 376 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Port Sink Port
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Manufacturer_Info Message was successfully
sent. Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the Battery’s
manufacturer information for a given Battery which is
provided.
The Policy Engine tells the Protocol Layer to form a
Manufacturer_Info Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Manufacturer_Info Message.
Manufacturer_Info Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Manufacturer_Info Message information to the
Policy Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Manufacturer_Info Message was successfully sent.
The Sink has informed the Source of the manufacturer information for the requested Battery.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 377
 8.3.2.10.6.4 Sink Gets Battery Manufacturer Information from a Source
Figure 8-38 shows an example sequence between a Source and a Sink when the Source gets the Sink’s Manufacturer
information for the Port.

Figure 8-38 Sink Gets Source’s Battery Manufacturer Information

Sink Port Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp
1: Send Get_Manufacturer_Info
2:Get_Manufacturer_Info
3: Get_Manufacturer_Info + CRC
Start CRCReceiveTimer 4: Get_Manufacturer_Info
Check MessageID against local copy
Store copy of MessageID
5: Get_Manufacturer_Info
received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Manufacturer
9:Get_Manufacturer_Info sent Information from DPM

Start SenderResponseTimer

10: Send Manufacturer_Info

12: Manufacturer_Info 11: Manufacturer_Info
+ CRC
13: Manufacturer_Info Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID
14: Manufacturer_Info
received
15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Manufacturer_Info sent

Table 8-38 below provides a detailed explanation of what happens at each labeled step in Figure 8-38 above.

Table 8-38 Steps for a Source getting Sink’s Battery Manufacturer information Sequence

Step Sink Port Source Port

1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Manufacturer_Info Message with a request for
Battery information for a given Battery.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Manufacturer_Info
Get_Manufacturer_Info Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Manufacturer_Info Message to the Protocol
Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Manufacturer_Info Message information to the
Policy Engine that consumes it.

Page 378 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Sink Port Source Port
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Manufacturer_Info Message was successfully
sent. Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the Battery’s
manufacturer information for a given Battery which is
provided.
The Policy Engine tells the Protocol Layer to form a
Manufacturer_Info Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Manufacturer_Info Message.
Manufacturer_Info Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Manufacturer_Info Message information to the
Policy Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Manufacturer_Info Message was successfully sent.
The Sink has informed the Source of the manufacturer information for the requested Battery.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 379
 8.3.2.10.6.5 VCONN Source Gets Manufacturer Information from a Cable Plug
Figure 8-39 shows an example sequence between a VCONN Source (Source or Sink) and a Cable Plug when the VCONN
Source gets the Cable Plug’s Manufacturer information.

Figure 8-39 VCONN Source Gets Cable Plug’s Manufacturer Information

VCONN Source Port Cable Plug

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send Get_Manufacturer_Info
2:Get_Manufacturer_Info
3: Get_Manufacturer_Info + CRC
Start CRCReceiveTimer 4: Get_Manufacturer_Info
Check MessageID against local copy
Store copy of MessageID
5: Get_Manufacturer_Info
received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Manufacturer
9:Get_Manufacturer_Info sent Information from DPM

Start SenderResponseTimer

10: Send Manufacturer_Info

12: Manufacturer_Info 11: Manufacturer_Info
+ CRC
13: Manufacturer_Info Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID
14: Manufacturer_Info
received
15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Manufacturer_Info sent

Table 8-39 below provides a detailed explanation of what happens at each labeled step in Figure 8-39 above.

Table 8-39 Steps for a VCONN Source getting Sink’s Port Manufacturer information Sequence

Step VCONN Source Cable Plug

1 The Port is currently acting as the VCONN Source.
Policy Engine directs the Protocol Layer to send a
Get_Manufacturer_Info Message with a request for
Port information.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Manufacturer_Info
Get_Manufacturer_Info Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Manufacturer_Info Message to the Protocol
Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Manufacturer_Info Message information to the
Policy Engine that consumes it.

Page 380 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step VCONN Source Cable Plug
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Manufacturer_Info Message was successfully
sent. Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the Cable Plug’s
manufacturer information which is provided.
The Policy Engine tells the Protocol Layer to form a
Manufacturer_Info Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Manufacturer_Info Message.
Manufacturer_Info Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Manufacturer_Info Message information to the
Policy Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Manufacturer_Info Message was successfully sent.
The Cable Plug has informed the Source of its manufacturer information.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 381
 8.3.2.10.7 Country Codes

8.3.2.10.7.1 Source Gets Country Codes from a Sink

Figure 8-40 shows an example sequence between a Source and a Sink when the Source gets the Sink’s Country Codes.

Figure 8-40 Source Gets Sink’s Country Codes

Source Port Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Source Port Power Role = Sink

CC = Rp CC = Rd
1: Send Get_Country_Codes
2:Get_Country_Codes
3: Get_Country_Codes + CRC
Start CRCReceiveTimer 4: Get_Country_Codes
Check MessageID against local copy
Store copy of MessageID
5: Get_Country_Codes
received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Country Codes
9:Get_Country_Codes sent Information from DPM

Start SenderResponseTimer

10: Send Country_Codes

12: Country_Codes 11: Country_Codes
+ CRC
13: Country_Codes Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID
14: Country_Codes
received
15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Country_Codes sent

Table 8-40 below provides a detailed explanation of what happens at each labeled step in Figure 8-40 above.

Table 8-40 Steps for a Source getting Country Codes Sequence

Step Source Port Sink Port

1 The Port has Port Power Role set to Source and the The Port has Port Power Role set to Sink with the Rd
Rp pull up on its CC wire. pull down on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Country_Codes Message with a request for Port
information.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Country_Codes
Get_Country_Codes Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Country_Codes Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Country_Codes Message information to the Policy
Engine that consumes it.

Page 382 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Port Sink Port
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Country_Codes Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the Port’s
manufacturer information which is provided.
The Policy Engine tells the Protocol Layer to form a
Country_Codes Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Country_Codes Message.
Country_Codes Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Country_Codes Message information to the Policy
Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Country_Codes Message was successfully sent.
The Sink has informed the Source of the country codes.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 383
 8.3.2.10.7.2 Sink Gets Country Codes from a Source
Figure 8-41 shows an example sequence between a Source and a Sink when the Source gets the Sink’s country codes.

Figure 8-41 Sink Gets Source’s Country Codes

Sink Port Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp
1: Send Get_Country_Codes
2:Get_Country_Codes
3: Get_Country_Codes + CRC
Start CRCReceiveTimer 4: Get_Country_Codes
Check MessageID against local copy
Store copy of MessageID
5: Get_Country_Codes
received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get country codes
9:Get_Country_Codes sent Information from DPM

Start SenderResponseTimer

10: Send Country_Codes

12: Country_Codes 11: Country_Codes
+ CRC
13: Country_Codes Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID
14: Country_Codes
received
15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Country_Codes sent

Table 8-41 below provides a detailed explanation of what happens at each labeled step in Figure 8-41 above.

Table 8-41 Steps for a Source getting Sink’s Country Codes Sequence

Step Sink Port Source Port

1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Country_Codes Message with a request for Port
information.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Country_Codes
Get_Country_Codes Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Country_Codes Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Country_Codes Message information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.

Page 384 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Sink Port Source Port
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Country_Codes Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the Port’s
manufacturer information which is provided.
The Policy Engine tells the Protocol Layer to form a
Country_Codes Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Country_Codes Message.
Country_Codes Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Country_Codes Message information to the Policy
Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Country_Codes Message was successfully sent.
The Sink has informed the Source of the country codes.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 385
 8.3.2.10.7.3 VCONN Source Gets Country Codes from a Cable Plug
Figure 8-42 shows an example sequence between a VCONN Source (Source or Sink) and a Cable Plug when the VCONN
Source gets the Cable Plug’s Country Codes.

Figure 8-42 VCONN Source Gets Cable Plug’s Country Codes

VCONN Source Port Cable Plug

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send Get_Country_Codes
2:Get_Country_Codes
3: Get_Country_Codes + CRC
Start CRCReceiveTimer 4: Get_Country_Codes
Check MessageID against local copy
Store copy of MessageID
5: Get_Country_Codes
received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get country codes from
9:Get_Country_Codes sent DPM

Start SenderResponseTimer

10: Send Country_Codes

12: Country_Codes 11: Country_Codes
+ CRC
13: Country_Codes Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID
14: Country_Codes
received
15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Country_Codes sent

Table 8-42 below provides a detailed explanation of what happens at each labeled step in Figure 8-42 above.

Table 8-42 Steps for a VCONN Source getting Sink’s Country Codes Sequence

Step VCONN Source Cable Plug

1 The Port is currently acting as the VCONN Source.
Policy Engine directs the Protocol Layer to send a
Get_Country_Codes Message with a request for Port
information.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Country_Codes
Get_Country_Codes Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Country_Codes Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Country_Codes Message information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.

Page 386 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step VCONN Source Cable Plug
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Country_Codes Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the Cable Plug’s
manufacturer information which is provided.
The Policy Engine tells the Protocol Layer to form a
Country_Codes Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Country_Codes Message.
Country_Codes Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Country_Codes Message information to the Policy
Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Country_Codes Message was successfully sent.
The Cable Plug has informed the Source of its country codes.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 387
 8.3.2.10.8 Country Information

8.3.2.10.8.1 Source Gets Country Information from a Sink

Figure 8-43 shows an example sequence between a Source and a Sink when the Source gets the Sink’s country
information.

Figure 8-43 Source Gets Sink’s Country Information

Source Port Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Source Port Power Role = Sink

CC = Rp CC = Rd
1: Send Get_Country_Info
2:Get_Country_Info
3: Get_Country_Info + CRC
Start CRCReceiveTimer 4: Get_Country_Info
Check MessageID against local copy
Store copy of MessageID
5: Get_Country_Info
received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Country Information
9:Get_Country_Info sent from DPM

Start SenderResponseTimer

10: Send Country_Info

12: Country_Info 11: Country_Info
+ CRC
13: Country_Info Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID
14: Country_Info
received
15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Country_Info sent

Table 8-43 below provides a detailed explanation of what happens at each labeled step in Figure 8-43 above.

Table 8-43 Steps for a Source getting Country Information Sequence

Step Source Port Sink Port

1 The Port has Port Power Role set to Source and the The Port has Port Power Role set to Sink with the Rd
Rp pull up on its CC wire. pull down on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Country_Info Message with a request for Port
information for a specific Country Code.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Country_Info
Get_Country_Info Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Country_Info Message to the Protocol Layer.

Page 388 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Port Sink Port
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Country_Info Message information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Country_Info Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the Port’s
manufacturer information which is provided.
The Policy Engine tells the Protocol Layer to form a
Country_Info Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Country_Info Message.
Country_Info Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Country_Info Message information to the Policy
Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Country_Info Message was successfully sent.
The Sink has informed the Source of the country information.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 389
 8.3.2.10.8.2 Sink Gets Country Information from a Source
Figure 8-44 shows an example sequence between a Source and a Sink when the Source gets the Sink’s country codes.

Figure 8-44 Sink Gets Source’s Country Information

Sink Port Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp
1: Send Get_Country_Info
2:Get_Country_Info
3: Get_Country_Info + CRC
Start CRCReceiveTimer 4: Get_Country_Info
Check MessageID against local copy
Store copy of MessageID
5: Get_Country_Info
received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get country information
9:Get_Country_Info sent from DPM

Start SenderResponseTimer

10: Send Country_Info

12: Country_Info 11: Country_Info
+ CRC
13: Country_Info Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID
14: Country_Info
received
15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Country_Info sent

Table 8-44 below provides a detailed explanation of what happens at each labeled step in Figure 8-44 above.

Table 8-44 Steps for a Source getting Sink’s Country Information Sequence

Step Sink Port Source Port

1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
Get_Country_Info Message with a request for Port
information for a specific country code.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Country_Info
Get_Country_Info Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Country_Info Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Country_Info Message information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.

Page 390 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Sink Port Source Port
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Country_Info Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the Port’s
manufacturer information which is provided.
The Policy Engine tells the Protocol Layer to form a
Country_Info Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Country_Info Message.
Country_Info Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Country_Info Message information to the Policy
Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Country_Info Message was successfully sent.
The Sink has informed the Source of the country information.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 391
 8.3.2.10.8.1 VCONN Source Gets Country Information from a Cable Plug
Figure 8-45 shows an example sequence between a VCONN Source (Source or Sink) and a Cable Plug when the VCONN
Source gets the Cable Plug’s country information.

Figure 8-45 VCONN Source Gets Cable Plug’s Country Information

VCONN Source Port Cable Plug

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send Get_Country_Info
2:Get_Country_Info
3: Get_Country_Info + CRC
Start CRCReceiveTimer 4: Get_Country_Info
Check MessageID against local copy
Store copy of MessageID
5: Get_Country_Info
received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get Country Information
9:Get_Country_Info sent from DPM

Start SenderResponseTimer

10: Send Country_Info

12: Country_Info 11: Country_Info
+ CRC
13: Country_Info Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID
14: Country_Info
received
15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop SenderResponseTimer
Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Country_Info sent

Table 8-45 below provides a detailed explanation of what happens at each labeled step in Figure 8-45 above.

Table 8-45 Steps for a VCONN Source getting Sink’s Country Information Sequence

Step VCONN Source Cable Plug

1 The Port is currently acting as the VCONN Source.
Policy Engine directs the Protocol Layer to send a
Get_Country_Info Message with a request for Port
information for a specific country code.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Get_Country_Info
Get_Country_Info Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Get_Country_Info Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Get_Country_Info Message information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.

Page 392 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step VCONN Source Cable Plug
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Get_Country_Info Message was successfully sent.
Policy Engine starts SenderResponseTimer.
10 Policy Engine requests the DPM for the Cable Plug’s
manufacturer information which is provided.
The Policy Engine tells the Protocol Layer to form a
Country_Info Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Country_Info Message.
Country_Info Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Country_Info Message information to the Policy
Engine that consumes it.
14 The Policy Engine stops the SenderResponseTimer.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Country_Info Message was successfully sent.
The Cable Plug has informed the Source of its country information.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 393
 8.3.2.11 Security

8.3.2.11.1 Source requests security exchange with Sink

Figure 8-46 shows an example sequence for a security exchange between a Source and a Sink.

Figure 8-46 Source requests security exchange with Sink

Source Port Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Source Port Power Role = Sink

CC = Rp CC = Rd
1: Send Security_Request
2:Security_Request
3: Security_Request + CRC
Start CRCReceiveTimer 4: Security_Request

Check MessageID against local copy

Store copy of MessageID

5: Security_Request received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get security response
9:Security_Request sent from DPM

10: Send Security_Response

11: Security_Response
12: Security_Response + CRC
13: Security_Response Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Security_Response received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

18: Security_Response sent

Table 8-46 below provides a detailed explanation of what happens at each labeled step in Figure 8-46 above.

Table 8-46 Steps for a Source requesting a security exchange with a Sink Sequence

Step Source Port Sink Port

1 The Port has Port Power Role set to Source and the The Port has Port Power Role set to Sink with the Rd
Rp pull up on its CC wire. pull down on its CC wire.
Policy Engine directs the Protocol Layer to send a
Security_Request Message using a payload supplied
by the DPM.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Security_Request
Security_Request Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Security_Request Message to the Protocol Layer.

Page 394 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Port Sink Port
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Security_Request Message information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Security_Request Message was successfully sent.
10 Policy Engine requests the DPM for the response to
the security request which is provided.
The Policy Engine tells the Protocol Layer to form a
Security_Response Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Security_Response Message.
Security_Response Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Security_Response Message information to the
Policy Engine that consumes it.
14 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
15 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
16 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
17 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Security_Response Message was successfully sent.
The security exchange is complete.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 395
 8.3.2.11.2 Sink requests security exchange with Source
Figure 8-47 shows an example sequence for a security exchange between a Sink and a Source.

Figure 8-47 Sink requests security exchange with Source

Sink Port Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp

1: Send Security_Request
2:Security_Request
3: Security_Request + CRC
Start CRCReceiveTimer 4: Security_Request

Check MessageID against local copy

Store copy of MessageID

5: Security_Request received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get security response
9:Security_Request sent from DPM

10: Send Security_Response

11: Security_Response
12: Security_Response + CRC
13: Security_Response Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Security_Response received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

18: Security_Response sent

Table 8-47 below provides a detailed explanation of what happens at each labeled step in Figure 8-47 above.

Table 8-47 Steps for a Sink requesting a security exchange with a Source Sequence

Step Sink Port Source Port

1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
Security_Request Message using a payload supplied
by the DPM.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Security_Request
Security_Request Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Security_Request Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Security_Request Message information to the Policy
Engine that consumes it.

Page 396 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Sink Port Source Port
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Security_Request Message was successfully sent.
10 Policy Engine requests the DPM for the response to
the security request which is provided.
The Policy Engine tells the Protocol Layer to form a
Security_Response Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Security_Response Message.
Security_Response Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Security_Response Message information to the
Policy Engine that consumes it.
14 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
15 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
16 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
17 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Security_Response Message was successfully sent.
The security exchange is complete.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 397
 8.3.2.11.3 Vconn Source requests security exchange with Cable Plug
Figure 8-48 shows an example sequence for a security exchange between a Vconn Source and a Cable Plug.

Figure 8-48 Vconn Source requests security exchange with Cable Plug

Vconn Source Cable Plug

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send Security_Request
2:Security_Request
3: Security_Request + CRC
Start CRCReceiveTimer 4: Security_Request

Check MessageID against local copy

Store copy of MessageID

5: Security_Request received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get security response
9:Security_Request sent from DPM

10: Send Security_Response

11: Security_Response
12: Security_Response + CRC
13: Security_Response Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Security_Response received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

18: Security_Response sent

Table 8-48 below provides a detailed explanation of what happens at each labeled step in Figure 8-48 above.

Table 8-48 Steps for a Vconn Source requesting a security exchange with a Cable Plug Sequence

Step Vconn Source Cable Plug

1 Policy Engine directs the Protocol Layer to send a
Security_Request Message using a payload supplied
by the DPM.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the Security_Request
Security_Request Message. Message and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Security_Request Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Security_Request Message information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.

Page 398 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Vconn Source Cable Plug
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Security_Request Message was successfully sent.
10 Policy Engine requests the DPM for the response to
the security request which is provided.
The Policy Engine tells the Protocol Layer to form a
Security_Response Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Security_Response Message.
Security_Response Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Security_Response Message information to the
Policy Engine that consumes it.
14 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
15 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
16 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
17 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Security_Response Message was successfully sent.
The security exchange is complete.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 399
 8.3.2.12 Firmware Update

8.3.2.12.1 Source requests firmware update exchange with Sink

Figure 8-49 shows an example sequence for a firmware update exchange between a Source and a Sink.

Figure 8-49 Source requests firmware update exchange with Sink

Source Port Sink Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Source Port Power Role = Sink

CC = Rp CC = Rd
1: Send Firmware_Update_Request
2:Firmware_Update_Request
3: Firmware_Update_Request + CRC 4: Firmware_Update_Request
Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

5: Firmware_Update_Request received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get firmware update
9:Firmware_Update_Request sent response from DPM

10: Send Firmware_Update_Response

11: Firmware_Update_Response
12: Firmware_Update_Response + CRC Start CRCReceiveTimer
13: Firmware_Update_Response

Check MessageID against local copy

Store copy of MessageID

14: Firmware_Update_Response received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

18: Firmware_Update_Response sent

Table 8-49 below provides a detailed explanation of what happens at each labeled step in Figure 8-49 above.

Table 8-49 Steps for a Source requesting a firmware update exchange with a Sink Sequence

Step Source Port Sink Port

1 The Port has Port Power Role set to Source and the The Port has Port Power Role set to Sink with the Rd
Rp pull up on its CC wire. pull down on its CC wire.
Policy Engine directs the Protocol Layer to send a
Firmware_Update_Request Message using a payload
supplied by the DPM.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the
Firmware_Update_Request Message. Firmware_Update_Request Message and checks the
CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Firmware_Update_Request Message to the Protocol
Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Firmware_Update_Request Message information to
the Policy Engine that consumes it.

Page 400 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Port Sink Port
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Firmware_Update_Request Message was
successfully sent.
10 Policy Engine requests the DPM for the response to
the firmware update request which is provided.
The Policy Engine tells the Protocol Layer to form a
Firmware_Update_Response Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Firmware_Update_Response Message.
Firmware_Update_Response Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Firmware_Update_Response Message information
to the Policy Engine that consumes it.
14 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
15 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
16 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
17 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Firmware_Update_Response Message was
successfully sent.
The firmware update exchange is complete.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 401
 8.3.2.12.2 Sink requests firmware update exchange with Source
Figure 8-50 shows an example sequence for a firmware update exchange between a Sink and a Source.

Figure 8-50 Sink requests firmware update exchange with Source

Sink Port Source Port

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

Port Power Role = Sink Port Power Role = Source

CC = Rd CC = Rp
1: Send Firmware_Update_Request
2:Firmware_Update_Request
3: Firmware_Update_Request + CRC 4: Firmware_Update_Request
Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

5: Firmware_Update_Request received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get firmware update
9:Firmware_Update_Request sent response from DPM

10: Send Firmware_Update_Response

11: Firmware_Update_Response
12: Firmware_Update_Response + CRC Start CRCReceiveTimer
13: Firmware_Update_Response

Check MessageID against local copy

Store copy of MessageID

14: Firmware_Update_Response received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

18: Firmware_Update_Response sent

Table 8-50 below provides a detailed explanation of what happens at each labeled step in Figure 8-50 above.

Table 8-50 Steps for a Sink requesting a firmware update exchange with a Source Sequence

Step Sink Port Source Port

1 The Port has Port Power Role set to Sink with the Rd The Port has Port Power Role set to Source and the
pull down on its CC wire. Rp pull up on its CC wire.
Policy Engine directs the Protocol Layer to send a
Firmware_Update_Request Message using a payload
supplied by the DPM.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the
Firmware_Update_Request Message. Firmware_Update_Request Message and checks the
CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Firmware_Update_Request Message to the Protocol
Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Firmware_Update_Request Message information to
the Policy Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.

Page 402 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Sink Port Source Port
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Firmware_Update_Request Message was
successfully sent.
10 Policy Engine requests the DPM for the response to
the firmware update request which is provided.
The Policy Engine tells the Protocol Layer to form a
Firmware_Update_Response Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Firmware_Update_Response Message.
Firmware_Update_Response Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Firmware_Update_Response Message information
to the Policy Engine that consumes it.
14 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
15 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
16 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
17 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Firmware_Update_Response Message was
successfully sent.
The firmware update exchange is complete.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 403
 8.3.2.12.3 Vconn Source requests firmware update exchange with Cable Plug
Figure 8-51 shows an example sequence for a firmware update exchange between a Vconn Source and a Cable Plug.

Figure 8-51 Vconn Source requests firmware update exchange with Cable Plug

VCONN Source Cable Plug

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send Firmware_Update_Request
2:Firmware_Update_Request
3: Firmware_Update_Request + CRC 4: Firmware_Update_Request
Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

5: Firmware_Update_Request received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
Get firmware update
9:Firmware_Update_Request sent response from DPM

10: Send Firmware_Update_Response

11: Firmware_Update_Response
12: Firmware_Update_Response + CRC Start CRCReceiveTimer
13: Firmware_Update_Response

Check MessageID against local copy

Store copy of MessageID

14: Firmware_Update_Response received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

18: Firmware_Update_Response sent

Table 8-51 below provides a detailed explanation of what happens at each labeled step in Figure 8-51 above.

Table 8-51 Steps for a Vconn Source requesting a firmware update exchange with a Cable Plug Sequence

Step Vconn Source Cable Plug

1 Policy Engine directs the Protocol Layer to send a
Firmware_Update_Request Message using a payload
supplied by the DPM.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Physical Layer receives the
Firmware_Update_Request Message. Firmware_Update_Request Message and checks the
CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Firmware_Update_Request Message to the Protocol
Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received
Firmware_Update_Request Message information to
the Policy Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.

Page 404 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Vconn Source Cable Plug
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Firmware_Update_Request Message was
successfully sent.
10 Policy Engine requests the DPM for the response to
the firmware update request which is provided.
The Policy Engine tells the Protocol Layer to form a
Firmware_Update_Response Message.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer receives the Message and compares Physical Layer appends a CRC and sends the
the CRC it calculated with the one sent to verify the Firmware_Update_Response Message.
Firmware_Update_Response Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received
Firmware_Update_Response Message information
to the Policy Engine that consumes it.
14 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
15 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
16 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
17 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Firmware_Update_Response Message was
successfully sent.
The firmware update exchange is complete.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 405
 8.3.2.13 Structured VDM

8.3.2.13.1 DFP to UFP Discover Identity

Figure 8-52 shows an example sequence between a DFP and UFP, where both Port Partners are in an Explicit Contract
and the DFP attempts to discover identity information from the UFP.

Figure 8-52 DFP to UFP Discover Identity

DFP UFP

: DFP Policy Engine : Protocol : PHY : PHY : Protocol : UFP Policy Engine

Explicit PD Contract Explicit PD Contract

1: Send Discover Identity

2: Discover Identity
3: Discover Identity + CRC
Start CRCReceiveTimer 4: Discover Identity
Check MessageID against local copy
Store copy of MessageID

5: Discover Identity received

6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

9: Discover Identity sent

Start VDMResponseTimer Request Identity information from

Device Policy Manager

10: Send Discover Identity ACK

11: Discover Identity ACK
12: Discover Identity ACK + CRC
13: Discover Identity ACK Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Discover Identity ACK received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop VDMResponseTimer Check and increment MessageIDCounter
DPM evaluates UFP Identity Stop CRCReceiveTimer
information
18: Discover Identity ACK sent

Table 8-52 below provides a detailed explanation of what happens at each labeled step in Figure 8-52 above.

Table 8-52 Steps for DFP to UFP Discover Identity

Step DFP UFP

1 The DFP has an Explicit Contract. The Policy Engine The UFP has an Explicit Contract.
directs the Protocol Layer to send a Discover
Identity Command request.
2 Protocol Layer creates the Discover Identity
Command request and passes to Physical Layer.
Starts CRCReceiveTimer.

Page 406 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step DFP UFP
3 Physical Layer appends CRC and sends the Discover Physical Layer receives the Discover Identity
Identity Command request. Command request and checks the CRC to verify the
Message.
4 Physical Layer removes the CRC and forwards the
Discover Identity Command request to the Protocol
Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received Discover
Identity Command request information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Discover Identity Command request was
successfully sent.
Policy Engine starts the VDMResponseTimer.
10 Policy Engine requests the identity information from
the Device Policy Manager. The Policy Engine tells
the Protocol Layer to form a Discover Identity
Command ACK response.
11 Protocol Layer creates the Discover Identity
Command ACK response and passes to Physical Layer.
Starts CRCReceiveTimer.
12 Physical Layer receives the Discover Identity Physical Layer appends a CRC and sends the Discover
Command ACK response and compares the CRC it Identity Command ACK response.
calculated with the one sent to verify the Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Discover
Identity Command ACK response information to the
Policy Engine that consumes it.
14 The Policy Engine stops the VDMResponseTimer and
passed the Identity information to the Device Policy
Manager for evaluation.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Discover Identity Command ACK response was
successfully sent.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 407
 8.3.2.13.2 Source Port to Cable Plug Discover Identity
Figure 8-53 shows an example sequence between Source and a Cable Plug, where the Source attempts to discover
identity information from the Cable Plug prior to establishing an Explicit Contract with its Port Partner.

Figure 8-53 Source Port to Cable Plug Discover Identity

Source Port Cable Plug

: Source Policy Engine : Protocol : PHY : PHY : Protocol : Cable Plug Policy Engine

No or Implicit Contract

1: Send Discover Identity

2: Discover Identity
3: Discover Identity + CRC
Start CRCReceiveTimer 4: Discover Identity
Check MessageID against local copy
Store copy of MessageID

5: Discover Identity received

6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

9: Discover Identity sent

Evaluate Discover Identity request
Start VDMResponseTimer Enter USB Operation
Wait tCableMessage before transmission

10: Send Discover Identity ACK

11: Discover Identity ACK
12: Discover Identity ACK + CRC
13: Discover Identity ACK Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Discover Identity ACK received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop VDMResponseTimer Check and increment MessageIDCounter
Use Cable information to specify Stop CRCReceiveTimer
Capabilities
18: Discover Identity ACK sent

Table 8-53 below provides a detailed explanation of what happens at each labeled step in Figure 8-53 above.

Table 8-53 Steps for Source Port to Cable Plug Discover Identity

Step Source Port Cable Plug

1 The Source has no Contract or an Implicit Contract
with its Port Partner. The Policy Engine directs the
Protocol Layer to send a Discover Identity Command
request.
2 Protocol Layer creates the Discover Identity
Command request and passes to Physical Layer.
Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Discover Physical Layer receives the Discover Identity
Identity Command request. Command request and checks the CRC to verify the
Message.
4 Physical Layer removes the CRC and forwards the
Discover Identity Command request to the Protocol
Layer.

Page 408 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Source Port Cable Plug
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received Discover
Identity Command request information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Discover Identity Command request was
successfully sent.
Policy Engine starts the VDMResponseTimer.
10 Policy Engine requests the identity information from
the Device Policy Manager. . tCableMessage after the
GoodCRC Message was sent the Policy Engine tells the
Protocol Layer to form a Discover Identity Command
ACK response.
11 Protocol Layer creates the Discover Identity
Command ACK response and passes to Physical Layer.
Starts CRCReceiveTimer.
12 Physical Layer receives the Discover Identity Physical Layer appends a CRC and sends the Discover
Command ACK response and compares the CRC it Identity Command ACK response.
calculated with the one sent to verify the Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Discover
Identity Command ACK response information to the
Policy Engine that consumes it.
14 The Policy Engine stops the VDMResponseTimer and
passes the identity information to the Device Policy
Manager for evaluation.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 The Source uses the Cable Plug information as input Protocol Layer verifies and increments the
to its offered capabilities. MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Accept Message was successfully sent.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 409
 8.3.2.13.3 DFP to Cable Plug Discover Identity
Figure 8-54 shows an example sequence between a DFP and a Cable Plug, where the DFP attempts to discover identity
information from the Cable Plug.

Figure 8-54 DFP to Cable Plug Discover Identity

DFP Cable Plug

: DFP Policy Engine : Protocol : PHY : PHY : Protocol : Cable Plug Policy Engine

Explicit PD Contract

1: Send Discover Identity

2: Discover Identity
3: Discover Identity + CRC
Start CRCReceiveTimer 4: Discover Identity
Check MessageID against local copy
Store copy of MessageID

5: Discover Identity received

6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

9: Discover Identity sent

Evaluate Discover Identity request
Start VDMResponseTimer Enter USB Operation
Wait tCableMessage before transmission

10: Send Discover Identity ACK

11: Discover Identity ACK
12: Discover Identity ACK + CRC
13: Discover Identity ACK Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Discover Identity ACK received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop VDMResponseTimer Check and increment MessageIDCounter
Use Cable information to specify Stop CRCReceiveTimer
Capabilities
18: Discover Identity ACK sent

Table 8-54 below provides a detailed explanation of what happens at each labeled step in Figure 8-54 above.

Table 8-54 Steps for DFP to Cable Plug Discover Identity

Step DFP Cable Plug

1 The DFP has an Explicit Contract with its Port
Partner. The Policy Engine directs the Protocol Layer
to send a Discover Identity Command request.
2 Protocol Layer creates the Discover Identity
Command request and passes to Physical Layer.
Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Discover Physical Layer receives the Discover Identity
Identity Command request. Command request and checks the CRC to verify the
Message.

Page 410 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step DFP Cable Plug
4 Physical Layer removes the CRC and forwards the
Discover Identity Command request to the Protocol
Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received Discover
Identity Command request information to the Policy
Engine that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Discover Identity Command request was
successfully sent.
Policy Engine starts the VDMResponseTimer.
10 Policy Engine requests the identity information from
the Device Policy Manager. tCableMessage after the
GoodCRC Message was sent the Policy Engine tells the
Protocol Layer to form a Discover Identity Command
ACK response.
11 Protocol Layer creates the Discover Identity
Command ACK response and passes to Physical Layer.
Starts CRCReceiveTimer.
12 Physical Layer receives the Discover Identity Physical Layer appends a CRC and sends the Discover
Command ACK response and compares the CRC it Identity Command ACK response.
calculated with the one sent to verify the Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Discover
Identity Command ACK response information to the
Policy Engine that consumes it.
14 The Policy Engine stops the Discover Identity
Command ACK response and passes the identity
information to the Device Policy Manager for
evaluation.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 The DFP when acting as a Source uses the Cable Plug Protocol Layer verifies and increments the
information as input to its offered capabilities. MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Accept Message was successfully sent.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 411
 8.3.2.13.4 DFP to UFP Enter Mode
Figure 8-55 shows an example sequence between a DFP and a UFP that occurs after the DFP has discovered supported
SVIDs and Modes at which point it selects and enters a Mode.

Figure 8-55 DFP to UFP Enter Mode

DFP UFP

: DFP Policy Engine : Protocol : PHY : PHY : Protocol : UFP Policy Engine

USB Operation USB Operation

Supported SVIDS/Modes discovered

Enter USB Safe State

37: Send Enter Mode

38: Enter Mode
39: Enter Mode + CRC
Start CRCReceiveTimer 40: Enter Mode
Check MessageID against local copy
Store copy of MessageID

41: Enter Mode received

42: GoodCRC
43: GoodCRC + CRC
44: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

45: Enter Mode sent

Start VDMModeEntryTimer Evaluate Enter Mode request

Enter New Mode

46: Send Enter Mode ACK

47: Enter Mode ACK
48: Enter Mode ACK + CRC
49: Enter Mode ACK Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

50: Enter Mode ACK received

51: GoodCRC
52: GoodCRC + CRC
53: GoodCRC
Stop VDMModeEntryTimer
Enter New Mode Check and increment MessageIDCounter
Stop CRCReceiveTimer

54: Enter Mode ACK sent

New Mode Entered

Table 8-55 below provides a detailed explanation of what happens at each labeled step in Figure 8-55 above.

Table 8-55 Steps for DFP to UFP Enter Mode

Step DFP UFP

1 The DFP has an Explicit Contract The UFP has an Explicit Contract.
The DFP has discovered the supported SVIDS using
the Discover SVIDs Command request and the
supported Modes using the Discover Modes
Command request
The DFP goes to USB Safe State. The Device Policy
Manager requests the Policy Engine to enter a Mode.
The Policy Engine directs the Protocol Layer to send
an Enter Mode Command request.
2 Protocol Layer creates the Enter Mode Command
request and passes to Physical Layer. Starts
CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Enter Physical Layer receives the Enter Mode Command
Mode Command request. request and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Enter Mode Command request to the Protocol Layer.

Page 412 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step DFP UFP
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received Enter Mode
Command request information to the Policy Engine
that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Enter Mode Command request was successfully sent.
Policy Engine starts the VDMModeEntryTimer.
10 Policy Engine requests the Device Policy Manager to
enter the new Mode. The Policy Engine tells the
Protocol Layer to form an Enter Mode Command ACK
response.
11 Protocol Layer creates the Enter Mode Command
ACK response and passes to Physical Layer. Starts
CRCReceiveTimer.
12 Physical Layer receives the Enter Mode Command Physical Layer appends a CRC and sends the Enter
ACK response and compares the CRC it calculated Mode Command ACK response.
with the one sent to verify the Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Enter
Mode Command ACK response information to the
Policy Engine that consumes it.
14 The Policy Engine stops the VDMModeEntryTimer
and requests the Device Policy Manager to enter the
new Mode.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Enter Mode Command ACK response was successfully
sent.
DFP and UFP are operating in the new Mode

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 413
 8.3.2.13.5 DFP to UFP Exit Mode
Figure 8-56 shows an example sequence between a DFP and a UFP, where the DFP commands the UFP to exit the only
Active Mode.

Figure 8-56 DFP to UFP Exit Mode

DFP UFP

: DFP Policy Engine : Protocol : PHY : PHY : Protocol : UFP Policy Engine

In Mode In Mode
Enter USB Safe State

1: Send Exit Mode

2: Exit Mode
3: Exit Mode + CRC
Start CRCReceiveTimer 4: Exit Mode
Check MessageID against local copy
Store copy of MessageID

5: Exit Mode received

6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

9: Exit Mode sent

Start VDMModeExitTimer Evaluate Exit Mode request

Enter USB Operation

10: Send Exit Mode ACK

11: Exit Mode ACK
12: Exit Mode ACK + CRC
13: Exit Mode ACK Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Exit Mode ACK received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop VDMModeExitTimer
Enter USB Operation Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Exit Mode ACK sent

USB operation

Table 8-56 below provides a detailed explanation of what happens at each labeled step in Figure 8-56 above.

Table 8-56 Steps for DFP to UFP Exit Mode

Step DFP UFP

1 The DFP is in a Mode and then enters USB Safe State. The UFP is in a Mode.
The Policy Engine directs the Protocol Layer to send
an Exit Mode Command request.
2 Protocol Layer creates the Exit Mode Command
request and passes to Physical Layer. Starts
CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Exit Mode Physical Layer receives the Exit Mode Command
Command request. request and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Exit Mode Command request to the Protocol Layer.

Page 414 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step DFP UFP
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received Exit Mode
Command request information to the Policy Engine
that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Exit Mode Command request was successfully sent.
Policy Engine starts the VDMModeExitTimer.
10 Policy Engine requests the Device Policy Manager to
enter USB operation. The Policy Engine tells the
Protocol Layer to form an Exit Mode Command ACK
response.
11 Protocol Layer creates the Exit Mode Command ACK
response and passes to Physical Layer. Starts
CRCReceiveTimer.
12 Physical Layer receives the Exit Mode Command ACK Physical Layer appends a CRC and sends the Exit
response and compares the CRC it calculated with Mode Command ACK response.
the one sent to verify the Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Exit Mode
Command ACK response information to the Policy
Engine that consumes it.
14 The Policy Engine stops the VDMModeExitTimer and
requests the Device Policy Manager to enter USB
Operation.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the Exit
Mode Command ACK response was successfully sent.
Both DFP and UFP are in USB Operation

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 415
 8.3.2.13.6 DFP to Cable Plug Enter Mode
Figure 8-57 shows an example sequence between a DFP and a Cable Plug that occurs after the DFP has discovered
supported SVIDs and Modes at which point it selects and enters a Mode.

Figure 8-57 DFP to Cable Plug Enter Mode

DFP Cable Plug

: DFP Policy Engine : Protocol : PHY : PHY : Protocol : Cable Plug Policy Engine

USB Mode USB Mode

Supported SVIDs/Modes Discovered

Enter USB Safe Mode
Wait tCableMessage before
transmission

19: Send Enter Mode

20: Enter Mode
21: Enter Mode + CRC
Start CRCReceiveTimer 22: Enter Mode
Check MessageID against local copy
Store copy of MessageID

23: Enter Mode received

24: GoodCRC
25: GoodCRC + CRC
26: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

27: Enter Mode sent

Evaluate Enter Mode request
Start VDMModeEntryTimer Enter New Mode
Wait tCableMessage before transmission

10: Send Enter Mode ACK

11: Enter Mode ACK
12: Enter Mode ACK + CRC
13: Enter Mode ACK Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Enter Mode ACK received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop VDMModeEntryTimer
Enter New Mode Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Enter Mode ACK sent

New Mode Entered

Table 8-57 below provides a detailed explanation of what happens at each labeled step in Figure 8-57 above.

Page 416 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 8-57 Steps for DFP to Cable Plug Enter Mode

Step DFP Cable Plug

1 The DFP has an Explicit Contract
The DFP has discovered the supported SVIDS using
the Discover SVIDs Command request and the
supported Modes using the Discover Modes
Command request
The DFP goes to USB Safe State. The Device Policy
Manager requests the Policy Engine to enter a Mode.
tCableMessage after the last GoodCRC Message was
sent the Policy Engine directs the Protocol Layer to
send an Enter Mode Command request.
2 Protocol Layer creates the Enter Mode Command
request and passes to Physical Layer. Starts
CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Enter Physical Layer receives the Enter Mode Command
Mode Command request. request and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Enter Mode Command request to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received Enter Mode
Command request information to the Policy Engine
that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Enter Mode Command request was successfully sent.
Policy Engine starts the VDMModeEntryTimer.
10 Policy Engine requests the Device Policy Manager to
enter the new Mode. tCableMessage after the
GoodCRC Message was sent the Policy Engine tells the
Protocol Layer to form an Enter Mode Command ACK
response.
11 Protocol Layer creates the Enter Mode Command
ACK response and passes to Physical Layer. Starts
CRCReceiveTimer.
12 Physical Layer receives the Enter Mode Command Physical Layer appends a CRC and sends the Enter
ACK response and compares the CRC it calculated Mode Command ACK response.
with the one sent to verify the Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Enter
Mode Command ACK response information to the
Policy Engine that consumes it.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 417
 Step DFP Cable Plug
14 The Policy Engine stops the VDMModeEntryTimer
and requests the Device Policy Manager to enter the
new Mode.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Enter Mode Command ACK response was successfully
sent.
DFP and Cable Plug are operating in the new Mode

Page 418 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.2.13.7 DFP to Cable Plug Exit Mode
Figure 8-58 shows an example sequence between a USB Type-C DFP and a Cable Plug, where the DFP commands the
Cable Plug to exit an Active Mode.

Figure 8-58 DFP to Cable Plug Exit Mode

DFP Cable Plug

: DFP Policy Engine : Protocol : PHY : PHY : Protocol : Cable Plug Policy Engine

In Mode In Mode
Enter USB Safe State

1: Send Exit Mode

2: Exit Mode
3: Exit Mode + CRC
Start CRCReceiveTimer 4: Exit Mode
Check MessageID against local copy
Store copy of MessageID

5: Exit Mode received

6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

9: Exit Mode sent

Evaluate Exit Mode request
Start VDMModeExitTimer Enter USB Operation
Wait tCableMessage before transmission

10: Send Exit Mode ACK

11: Exit Mode ACK
12: Exit Mode ACK + CRC
13: Exit Mode ACK Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

14: Exit Mode ACK received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC
Stop VDMModeExitTimer
Enter USB Operation Check and increment MessageIDCounter
Stop CRCReceiveTimer

18: Exit Mode ACK sent

USB operation

Table 8-58 below provides a detailed explanation of what happens at each labeled step in Figure 8-58 above.

Table 8-58 Steps for DFP to Cable Plug Exit Mode

Step DFP Cable Plug

1 The DFP is in a Mode and then enters USB Safe State. The Cable Plug is in a Mode.
The Policy Engine directs the Protocol Layer to send
an Exit Mode Command request.
2 Protocol Layer creates the Exit Mode Command
request and passes to Physical Layer. Starts
CRCReceiveTimer.
3 Physical Layer appends CRC and sends the Exit Mode Physical Layer receives the Exit Mode Command
Command request. request and checks the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
Exit Mode Command request to the Protocol Layer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 419
 Step DFP Cable Plug
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received Exit Mode
Command request information to the Policy Engine
that consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC Message and Physical Layer appends CRC and sends the GoodCRC
checks the CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Exit Mode Command request was successfully sent.
Policy Engine starts the VDMModeExitTimer.
10 Policy Engine requests the Device Policy Manager to
enter USB operation. tCableMessage after the
GoodCRC Message was sent the Policy Engine tells the
Protocol Layer to form an Exit Mode Command ACK
response.
11 Protocol Layer creates the Exit Mode Command ACK
response and passes to Physical Layer. Starts
CRCReceiveTimer.
12 Physical Layer receives the Exit Mode Command ACK Physical Layer appends a CRC and sends the Exit
response and compares the CRC it calculated with Mode Command ACK response.
the one sent to verify the Message.
13 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Exit Mode
Command ACK response information to the Policy
Engine that consumes it.
14 The Policy Engine stops the VDMModeExitTimer and
requests the Device Policy Manager to enter USB
Operation.
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
16 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the Exit
Mode Command ACK response was successfully sent.
Both DFP and Cable Plug are in USB Operation

Page 420 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.2.13.8 UFP to DFP Attention
Figure 8-59 shows an example sequence between a USB Type-C DFP and a UFP, where the UFP requests attention
from the DFP.

Figure 8-59 UFP to DFP Attention

DFP UFP

: DFP Policy Engine : Protocol : PHY : PHY : Protocol : UFP Policy Engine

1: Send Attention
2: Attention
3: Attention + CRC
4: Attention Start CRCReceiveTimer

Check MessageID against local copy

Store copy of MessageID

5: Attention received
6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC
Check and increment MessageIDCounter
Stop CRCReceiveTimer

9: Attention sent

Table 8-59 below provides a detailed explanation of what happens at each labeled step in Figure 8-59 above.

Table 8-59 Steps for UFP to DFP Attention

Step DFP UFP

1 The Device Policy Manager requests attention. The
Policy Engine tells the Protocol Layer to form an
Attention Command request.
2 Protocol Layer creates the Attention Command
request and passes to Physical Layer. Starts
CRCReceiveTimer.
3 Physical Layer receives the Attention Command Physical Layer appends a CRC and sends the
request and compares the CRC it calculated with the Attention Command request.
one sent to verify the Message.
4 Protocol Layer checks the MessageID in the
incoming Message is different from the previously
stored value and then stores a copy of the new value.
The Protocol Layer forwards the received Attention
Command request information to the Policy Engine
that consumes it.
5 The Policy Engine informs the Device Policy Manager
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer appends a CRC and sends the Physical Layer receives GoodCRC Message and
GoodCRC Message. compares the CRC it calculated with the one sent to
verify the Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 421
 Step DFP UFP
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
Attention Command request was successfully sent.

Page 422 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.2.14 Built in Self-Test (BIST)

8.3.2.14.1 BIST Carrier Mode

The following is an example of a BIST Carrier Mode test between a Tester and a UUT. When the UUT is connected to
the Tester the sequence below is executed.
Figure 8-60 shows the Messages as they flow across the bus and within the devices. This test enables the
measurement of power supply noise and frequency drift.
1. Connection is established and stable.
2. Tester sends a BIST Message with a BIST Carrier Mode BIST Data Object.
3. UUT answers with a GoodCRC Message.
4. UUT starts sending the Test Pattern.
5. Operator does the measurements.
6. The test ends after tBISTContMode.
See also Section 5.9.1 and Section 6.4.3.1.

Figure 8-60 BIST Carrier Mode Test

Tester UUT

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send BIST(Carrier Mode)

2: BIST(Carrier Mode)
3: BIST(Carrier Mode) + CRC
Start CRCReceiveTimer 4: BIST(Carrier Mode)

Check MessageID against

local copy
Store copy of MessageID

5: BIST(Carrier Mode) received

Go to BIST Carrier Mode

6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer
10: Go to BIST Carrier Mode
11: Go to BIST Carrier Mode
9: BIST(Carrier Mode) sent

Enter BIST Carrier Mode mode

12: Send Test Pattern

13: Send Test Pattern
14: Test Pattern

End of Test (after tBISTContMode)

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 423
 Table 8-60 Steps for BIST Carrier Mode Test

Step Tester UUT

1 The Policy Engine directs the Protocol Layer to
generate a BIST Message, with a BIST Data Object of
BIST Carrier Mode, to put the UUT into BIST Carrier
Mode test mode.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the BIST Physical Layer receives the BIST Message and checks
Message. the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
BIST Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received BIST
Message information to the Policy Engine that
consumes it.
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC and checks the Physical Layer appends CRC and sends the GoodCRC
CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
BIST Message was successfully sent.
10 Policy Engine tells Protocol Layer to go into BIST
Carrier Mode. The Policy Engine goes to BIST
Carrier Mode.
11 Protocol Layer tells Physical Layer to go into BIST
Carrier Mode.
UUT enters BIST Carrier Mode
12 The Policy Engine directs the Protocol Layer to start
generation of the Test Pattern.
13 Protocol Layer directs the PHY Layer to generate the
Test Pattern.
14 Physical Layer receives the Test Pattern stream. Physical Layer generates a continuous Test Pattern
stream.
The UUT exits BIST Carrier Mode after tBISTContMode.

Page 424 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.2.14.2 BIST Test Data
The following is an example of a BIST Test Data test between a Tester and a UUT. When the UUT is connected to the
Tester the sequence below is executed.
Figure 8-60 shows the Messages as they flow across the bus and within the devices.
1. Connection is established and stable.
2. Tester sends a BIST Message with a BIST Test Data BIST Data Object.
3. UUT answers with a GoodCRC Message.
4. Steps 2and 3 are repeated any number of times.
5. The test ends after Hard Reset Signaling is issued.
See also Section 5.9.2 and Section 6.4.3.2.

Figure 8-61 BIST Test Data Test

Tester UUT

: Policy Engine : Protocol : PHY : PHY : Protocol : Policy Engine

1: Send BIST(Test Data)

2: BIST(Test Data)
3: BIST(Test Data) + CRC
Start CRCReceiveTimer 4: BIST(Test Data)

Check MessageID against

local copy
Store copy of MessageID

5: BIST(Test Data) received

Go to BIST Test Data mode

6: GoodCRC
7: GoodCRC + CRC
8: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

9: BIST(Test Data) sent

Enter BIST Test Data mode

10: Send BIST(Test Data)

11: BIST(Test Data)
12: BIST(Test Data) + CRC
Start CRCReceiveTimer 13: BIST(Test Data)

Check MessageID against

local copy
Store copy of MessageID

14: BIST(Test Data) received

15: GoodCRC
16: GoodCRC + CRC
17: GoodCRC

Check and increment MessageIDCounter

Stop CRCReceiveTimer

18: BIST(Test Data) sent

End of Test (Hard Reset)

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 425
 Table 8-61 Steps for BIST Test Data Test

Step Tester UUT

1 The Policy Engine directs the Protocol Layer to
generate a BIST Message, with a BIST Data Object of
BIST Test Data, to put the UUT into BIST Test Data
test mode.
2 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
3 Physical Layer appends CRC and sends the BIST Physical Layer receives the BIST Message and checks
Message. the CRC to verify the Message.
4 Physical Layer removes the CRC and forwards the
BIST Message to the Protocol Layer.
5 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received BIST
Message information to the Policy Engine that
consumes it.
The Policy Engine goes into BIST Test Data Mode
where it sends no further Messages except for
GoodCRC Messages in response to received Messages
(see Section 6.4.3.2).
6 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.
7 Physical Layer receives the GoodCRC and checks the Physical Layer appends CRC and sends the GoodCRC
CRC to verify the Message. Message.
8 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
9 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
BIST Message was successfully sent.
UUT enters BIST Test Data test mode
10 The Policy Engine directs the Protocol Layer to
generate a BIST Message, with a BIST Data Object of
BIST Test Data, to put the UUT into BIST Test Data
test mode.
11 Protocol Layer creates the Message and passes to
Physical Layer. Starts CRCReceiveTimer.
12 Physical Layer appends CRC and sends the BIST Physical Layer receives the BIST Message and checks
Message. the CRC to verify the Message.
13 Physical Layer removes the CRC and forwards the
BIST Message to the Protocol Layer.
14 Protocol Layer checks the MessageID in the incoming
Message is different from the previously stored value
and then stores a copy of the new value.
The Protocol Layer forwards the received BIST
Message information to the Policy Engine that
consumes it.
The Policy Engine goes into BIST Test Data Mode
where it sends no further Messages except for
GoodCRC Messages in response to received Messages
(see Section 6.4.3.2).
15 Protocol Layer generates a GoodCRC Message and
passes it Physical Layer.

Page 426 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Tester UUT
16 Physical Layer receives the GoodCRC and checks the Physical Layer appends CRC and sends the GoodCRC
CRC to verify the Message. Message.
17 Physical Layer removes the CRC and forwards the
GoodCRC Message to the Protocol Layer.
18 Protocol Layer verifies and increments the
MessageIDCounter and stops CRCReceiveTimer.
Protocol Layer informs the Policy Engine that the
BIST Message was successfully sent.
Repeat steps 10-18 any number of times
The UUT exits BIST Test Data test mode after a Hard Reset

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 427
 8.3.3 State Diagrams
8.3.3.1 Introduction to state diagrams used in Chapter 8
The state diagrams defined in Section 8.3.3 are Normative and Shall define the operation of the Power Delivery Policy
Engine. Note that these state diagrams are not intended to replace a well written and robust design.

Figure 8-62 Outline of States

<Name of State>
Actions on entry:
“List of actions to carry out on entering the
state”

Actions on exit:
“List of actions to carry out on exiting the
state”
Power (VI) = “Present power level”
PD = “attachment status”

Figure 8-62 shows an outline of the states defined in the following sections. At the top there is the name of the state.
This is followed by “Actions on entry” a list of actions carried out on entering the state. If there are also “Actions on
exit” a list of actions carried out on exiting the state then these are listed as well; otherwise this box is omitted from
the state. At the bottom the status of PD is listed:
 “Power” which indicates the present output power for a Source Port or input power for a Sink Port.
 “PD” which indicates the present Attachment status either “Attached”, “Detached”, or “unknown”.
Transitions from one state to another are indicated by arrows with the conditions listed on the arrow. Where there
are multiple conditions these are connected using either a logical OR “|” or a logical AND “&”.
In some cases there are transitions which can occur from any state to a particular state. These are indicated by an
arrow which is unconnected to a state at one end, but with the other end (the point) connected to the final state.
In some state diagrams it is necessary to enter or exit from states in other diagrams (e.g. Source Port or Sink Port state
diagrams). Figure 8-63 indicates how such references are made. The reference is indicated with a hatched box. The
box contains the name of the state and whether the state is a DFP or UFP. It has also been necessary to indicate
conditional entry to either Source Port or Sink Port state diagrams. This is achieved by the use of a bulleted list
indicating the pre-conditions (see example in Figure 8-64). It is also possible that the entry and return states are the
same. Figure 8-65 indicates a state reference where each referenced state corresponds to either the entry state or the
exit state.

Figure 8-63 References to states

<Name of reference state>

(<DFP | UFP>)

Figure 8-64 Example of state reference with conditions

Hard Reset:

 Consumer or
Consumer/Provider ->
PE_SNK_....
 Provider/Consumer in
Source role ->
PE_SRC_...

Page 428 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-65 Example of state reference with the same entry and exit

<Name of reference state 1> or

<Name of reference state 2>
(<DFP | UFP>)

Timers are included in many of the states. Timers are initialized (set to their starting condition) and run (timer is
counting) in the particular state it is referenced. As soon as the state is exited then the timer is no longer active.
Where the timers continue to run outside of the state (such as the NoResponseTimer), this is called out in the text.
Timeouts of the timers are listed as conditions on state transitions.
Conditions listed on state transitions will come from one of three sources and, when there is a conflict, Should be
serviced in the following order:
1. Message and related indications passed up to the Policy Engine from the Protocol Layer (Message sent, Message
received etc.)
2. Events triggered within the Policy Engine e.g. timer timeouts.
3. Information and requests coming from the Device Policy manager relating either to Local Policy, or to other
modules which the Device Policy Manager controls such as power supply and USB-C Port Control.
Note: The following state diagrams are not intended to cover all possible corner cases that could be encountered. For
example where an outgoing Message is Discarded, due to an incoming Message by the Protocol Layer (see Section
6.11.2.3) it will be necessary for the higher layers of the system to handle a retry of the Message sequence that was
being initiated, after first handling the incoming Message.

8.3.3.2 Policy Engine Source Port State Diagram

Figure 8-66 below shows the state diagram for the Policy Engine in a Source Port. The following sections describe
operation in each of the states.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 429
 Figure 8-66 Source Port Policy Engine State Diagram
Hard reset signalling received
Start
PE_SRC_Hard_Reset_Received PE_SRC_Transition_to_default
Actions on entry:
Actions on entry:
Request Device Policy Manager to request power Power source at default PE_SRC_Startup
Start PSHardResetTimer
supply Hard Resets to vSafe5V via vSafe0V
Actions on entry:
Power = DefauIt (5V) or Reset local HW
Reset CapsCounter
Implicit/Explicit Contract Request Device Policy Manager to set Port Data
Reset Protocol Layer
PD = Connected/not Connected Role to DFP and turn off VCONN
Start SwapSourceStartTimer (only after Swap)
Actions on exit:
PSHardResetTimer Power = DefauIt (5V) or Implicit Contract
Request Device Policy Manager to turn on VCONN
timeout PD = Connected/not Connected
Initialize and start NoResponseTimer
Inform Protocol Layer Hard Reset complete Protocol LayerReset4 |
(SourceCapabilityTimer timeout & CapsCounter > nCapsCount1) |
SwapSourceStartTimer timeout
Power = rising/falling to default (5V) not previously PD Connected6 &
PD = not Connected PE_SRC_Discovery NoResponseTimer timeout &
HardResetCounter > nHardResetCount1)
Actions on entry:
PSHardResetTimer Initialize and run SourceCapabilityTimer
timeout
Power = Default (5V) or Implicit Contract
PD = not Connected
PE_SRC_Hard_Reset
PE_SRC_Disabled
Actions on entry: (SourceCapabilityTimer timeout &
Generate Hard Reset signalling CapsCounter nCapsCount1) Capabilities message sending failure Actions on entry:
Start PSHardResetTimer (without GoodCRC) &not presently PD Connected6 Disable Power Delivery
Increment HardResetCounter
Power = DefauIt (5V) or Power = DefauIt (5V)
PE_SRC_Wait_New_Capabilities Implicit/Explicit Contract PD =not Connected
PD = Connected/not Connected PE_SRC_Send_Capabilities
Actions on entry:
Wait for new Source Capabilities9 Actions on entry:
Request present source capabilities from Device Policy Manager not previously PD Connected6&
Power = DefauIt (5V) Send PD Capabilities message NoResponseTimer timeout &
PD =Connected SenderResponseTimer timeout Increment CapsCounter (optional)1 HardResetCounter > nHardResetCount1
If GoodCRC received:
 stop NoResponseTimer
 reset HardResetCounter and CapsCounter
Source capability Explicit Contract &
 initialize and run SenderResponseTimer
change Reject message sent &
(from Device Contract Invalid4 Power = DefauIt (5V) or Implicit/Explicit Contract
previously PD Connected6 &
Policy Manager) PD = Connected/not Connected
NoResponseTimer timeout &
Request message received HardResetCount
> nHardResetCount

Request can’t be met | PE_SRC_Negotiate_Capability

PE_SRC_Capability_Response Request met later Actions on entry:
from Power Reserve Get Device Policy Manager evaluation of sink request:
Actions on entry:
no Explicit Contract & Send Reject message if request can’t  Can be met
(Reject message sent | be met  Can’t be met ErrorRecovery
Wait message sent) Send Wait message if request could  Could be met later from Power Reserve
be met later from the Power If the sink request for Operating Current or Operating Power can be met,
Reserve and present Contract is still but the sink still requires more power “Capability Mismatch” this
valid information will be passed to Device Policy Manager4
Power = DefauIt (5V) or Implicit/Explicit Contract
Power = DefauIt (5V) or Implicit/ PD = Connected
Explicit Contract
Request message Request can be met
PD = Connected
received

Explicit Contract PE_SRC_Transition_Supply

(Reject message sent &
Actions on entry:
Contract still valid) |
If GotoMin send GotoMin message
Wait message sent
Else send Accept message (within tReceiverResponse)
Protocol Error Request Device Policy Manager to transition Power Supply

Actions on exit:
Send PS_RDY message
Power = transition
PD = Connected

GotoMin request from Power supply ready

Device Policy Manager

PE_SRC_Ready
Actions on entry:
Notify Protocol Layer of end of
AMS8
Initialize and run
DiscoverIdentityTimer7
Source capability change Initialize and run
(from Device Policy Manager) | SourcePPSCommTimer10 get sink capabilities request
Get_Source_Cap message received
from Device Policy Manager PE_SRC_Get_Sink_Cap
Actions on exit:
SourcePPSCommTimer timeout If the Source is initiating an Actions on entry:
AMS then notify the Protocol Send Get_Sink_Cap message
Layer than the first Message in Sink capabilities Initialize and run
an AMS will follow8 message received | SenderResponseTimer
SenderResponseTimer
Actions on exit:
timeout
Pass sink capabilities/outcome to
Power = Explicit Contract Device Policy Manager
PD = Connected Power = Explicit Contract
PD = Connected

1Implementation of the CapsCounter is Optional. In the case where this is not implemented the Source Shall
continue to send Source_Capabilities Messages each time the SourceCapabilityTimer times out.
2Since the Sink is required to make a Valid request from the offered capabilities the expected transition is via
“Request can be met” unless the Source capabilities have changed since the last offer.

Page 430 USB Power Delivery Specification Revision 3.0, Version 1.1
3 “Contract Invalid” means that the previously negotiated Voltage and Current values are no longer included in the
Source’s new Capabilities. If the Sink fails to make a Valid Request in this case then Power Delivery operation is no
longer possible and Power Delivery mode is exited with a Hard Reset.
4 After
a Power Swap the new Source is required to wait an additional tSwapSourceStart before sending a
Source_Capabilities Message. This delay is not required when first starting up a system.
5PD Connected is defined as a situation when the Port Partners are actively communicating. The Port Partners
remain PD Connected after a Swap until there is a transition to Disabled or the connector is able to identify a Detach.
6Port Partners are no longer PD Connected after a Hard Reset but consideration needs to be given as to whether there
has been a PD Connection while the Ports have been Attached to prevent unnecessary USB Type-C Error Recovery.
7The DiscoverIdentityTimer is run when this is a VCONN Source and a PD Connection with a Cable Plug needs to be
established i.e. no GoodCRC Message has yet been received in response to a Discover Identity Command.
8 If transition into the PE_SRC_Ready state will result in an immediate transition out of the PE_SRC_Ready state e.g. it is
due to a Protocol Error that has not resulted in a Soft Reset then the notifications of the end of AMS and first Message
in an AMS May Not be sent to avoid changing the Rp value unnecessarily.
9In the PE_SRC_Wait_New_Capabilities State the Device Policy Manager Should either decide to send no further
Source Capabilities or Should send a different set of Source Capabilities. Continuing to send the same set of Source
Capabilities could result in a live lock situation.
10The SourcePPSCommTimer is only initialized and run when the present Explicit Contract is for a PPS APDO.
Source’s that do not support PPS do not need to implement the SourcePPSCommTimer.

8.3.3.2.1 PE_SRC_Startup State

PE_SRC_Startup Shall be the starting state for a Source Policy Engine either on power up or after a Hard Reset. On
entry to this state the Policy Engine Shall reset the CapsCounter and reset the Protocol Layer. Note that resetting the
Protocol Layer will also reset the MessageIDCounter and stored MessageID (see Section 6.11.2.3).
The Policy Engine Shall transition to the PE_SRC_Send_Capabilities state:
 When the Protocol Layer reset has completed if the PE_SRC_Startup state was entered due to the system first
starting up.
 When the SwapSourceStartTimer times out if the PE_SRC_Startup state was entered as the result of a Power
Role Swap.
Note: Sources Shall remain in the PE_SRC_Startup state, without sending any Source_Capabilities Messages until a
plug is Attached.

8.3.3.2.2 PE_SRC_Discovery State

On entry to the PE_SRC_Discovery state the Policy Engine Shall initialize and run the SourceCapabilityTimer in order
to trigger sending a Source_Capabilities Message.
The Policy Engine Shall transition to the PE_SRC_Send_Capabilities state when:
 The SourceCapabilityTimer times out and CapsCounter ≤ nCapsCount.
The Policy Engine May Optionally go to the PE_SRC_Disabled state when:
 The Port Partners are not presently PD Connected
 And the SourceCapabilityTimer times out
 And CapsCounter > nCapsCount.
The Policy Engine Shall go to the PE_SRC_Disabled state when:
 The Port Partners have not been PD Connected (the Source Port remains Attached to a Port it has not had a PD
Connection with during this Attachment)

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 431
 And the NoResponseTimer times out
 And the HardResetCounter > nHardResetCount.
Note in the PE_SRC_Disabled state the Attached device is assumed to be unresponsive. The Policy Engine operates as
if the device is Detached until such time as a Detach/re-Attach is detected.

8.3.3.2.3 PE_SRC_Send_Capabilities State

Note: this state can be entered from the PE_SRC_Soft_Reset state.
On entry to the PE_SRC_Send_Capabilities state the Policy Engine Shall request the present Port capabilities from the
Device Policy Manager. The Policy Engine Shall then request the Protocol Layer to send a Source_Capabilities
Message containing these capabilities and increment the CapsCounter (if implemented).
If a GoodCRC Message is received then the Policy Engine Shall:
 Stop the NoResponseTimer .
 Reset the HardResetCounter and CapsCounter to zero. Note that the HardResetCounter Shall only be set to
zero in this state and at power up; its value Shall be maintained during a Hard Reset.
 Initialize and run the SenderResponseTimer.
Once a Source_Capabilities Message has been received and acknowledged by a GoodCRC Message, the Sink is required to
then send a Request Message within tSenderResponse.
The Policy Engine Shall transition to the PE_SRC_Negotiate_Capability state when:
 A Request Message is received from the Sink.
The Policy Engine Shall transition to the PE_SRC_Discovery state when:
 The Protocol Layer indicates that the Message has not been sent and we are presently not Connected. This is part
of the Capabilities sending process whereby successful Message sending indicates connection to a PD Sink Port.
The Policy Engine Shall transition to the PE_SRC_Hard_Reset state when:
 The SenderResponseTimer times out. In this case a transition back to USB Default Operation is required.
When:
 The Port Partners have not been PD Connected (the Source Port remains Attached to a Port it has not had a PD
Connection with during this Attachment)
 And the NoResponseTimer times out
 And the HardResetCounter > nHardResetCount.
The Policy Engine Shall do one of the following:
 Transition to the PE_SRC_Discovery state.
 Transition to the PE_SRC_Disabled state.
Note that in either case the Attached device is assumed to be unresponsive. The Policy Engine Should operate as if the
device is Detached until such time as a Detach/re-Attach is detected.
The Policy Engine Shall go to the ErrorRecovery state when:
 The Port Partners have previously been PD Connected (the Source Port remains Attached to a Port it has had a PD
Connection with during this Attachment)
 And the NoResponseTimer times out.
 And the HardResetCounter > nHardResetCount.

Page 432 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.3.2.4 PE_SRC_Negotiate_Capability State
On entry to the PE_SRC_Negotiate_Capability state the Policy Engine Shall ask the Device Policy Manager to evaluate
the Request from the Attached Sink. The response from the Device Policy Manager Shall be one of the following:
 The Request can be met.
 The Request cannot be met
 The Request could be met later from the Power Reserve.
The Policy Engine Shall transition to the PE_SRC_Transition_Supply state when:
 The Request can be met.
The Policy Engine Shall transition to the PE_SRC_Capability_Response state when:
 The Request cannot be met.
 Or the Request can be met later from the Power Reserve.

8.3.3.2.5 PE_SRC_Transition_Supply State

The Policy Engine Shall be in the PE_SRC_Transition_Supply state while the power supply is transitioning from one
power to another.
On entry to the PE_SRC_Transition_Supply state, the Policy Engine Shall request the Protocol Layer to either send a
GotoMin Message (if this was requested by the Device Policy Manager) or otherwise an Accept Message and inform
the Device Policy Manager that it Shall transition the power supply to the Requested power level. Note: that if the
power supply is currently operating at the requested power no change will be necessary.
On exit from the PE_SRC_Transition_Supply state the Policy Engine Shall request the Protocol Layer to send a PS_RDY
Message.
The Policy Engine Shall transition to the PE_SRC_Ready state when:
 The Device Policy Manager informs the Policy Engine that the power supply is ready.
The Policy Engine Shall transition to the PE_SRC_Hard_Reset state when:
 A Protocol Error occurs.

8.3.3.2.6 PE_SRC_Ready State

In the PE_SRC_Ready state the PD Source Shall operating at a stable power with no ongoing negotiation. It Shall
respond to requests from the Sink, events from the Device Policy Manager.
On entry to the PE_SRC_Ready state the Source Shall notify the Protocol Layer of the end of the Atomic Message
Sequence (AMS). If the transition into PE_SRC_Ready is the result of Protocol Error that has not caused a Soft Reset
(see Section 8.3.3.4.1) then the notification to the Protocol Layer of the end of the AMS Shall Not be sent since there is
a Message to be processed.
On entry to the PE_SRC_Ready state if this is a DFP which needs to establish communication with a Cable Plug, the
DFP Shall:
 Initialize and run the DiscoverIdentityTimer (no GoodCRC Message response yet received to Discover Identity
Message).
On entry to the PE_SNK_Ready state if the current Explicit Contract is for a PPS APDO, then the Policy Engine Shall do
the following:
 Initialize and run the SourcePPSCommTimer.
On exit from the PE_SRC_Ready, if the Source is initiating an AMS then the Policy Engine Shall notify the Protocol
Layer that the first Message in an AMS will follow.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 433
The Policy Engine Shall transition to the PE_SRC_Send_Capabilities state when:
 The Device Policy Manager indicates that Source Capabilities have changed or
 A Get_Source_Cap Message is received.
The Policy Engine Shall transition to the PE_SRC_Transition_Supply state when:
 A GotoMin request is received from the Device Policy Manager for the Attached Device to go to minimum power.
The Policy Engine Shall transition to the PE_SRC_Get_Sink_Cap state when:
 The Device Policy Manager asks for the Sink’s capabilities.

8.3.3.2.7 PE_SRC_Disabled State

In the PE_SRC_Disabled state the PD Source supplies default power and is unresponsive to USB Power Delivery
messaging, but not to Hard Reset Signaling.

8.3.3.2.8 PE_SRC_Capability_Response State

The Policy Engine Shall enter the PE_SRC_Capability_Response state if there is a Request received from the Sink that
cannot be met based on the present capabilities. When the present Contract is not within the present capabilities it is
regarded as Invalid and a Hard Reset will be triggered.
On entry to the PE_SRC_Capability_Response state the Policy Engine Shall request the Protocol Layer to send one of
the following:
 Reject Message – if the request cannot be met or the present Contract is Invalid.
 Wait Message – if the request could be met later from the Power Reserve. A Wait Message Shall Not be sent if the
present Contract is Invalid.
The Policy Engine Shall transition to the PE_SRC_Ready state when:
 There is an Explicit Contract and
 A Reject Message has been sent and the present Contract is still Valid or
 A Wait Message has been sent.
The Policy Engine Shall transition to the PE_SRC_Hard_Reset state when:
 There is an Explicit Contract and
 The Reject Message has been sent and the present Contract is Invalid (i.e. the Sink had to request a new value so
instead we will return to USB Default Operation).
The Policy Engine Shall transition to the PE_SRC_Wait_New_Capabilities state when:
 There is no Explicit Contract and
 A Reject Message has been sent or
 A Wait Message has been sent.

8.3.3.2.9 PE_SRC_Hard_Reset State

On entry to the PE_SRC_Hard_Reset state the Policy Engine Shall request the generation of Hard Reset Signaling by
the PHY Layer, initialize and run the PSHardResetTimer and increment the HardResetCounter. Note that the
NoResponseTimer Shall continue to run in every state until it is stopped or times out.
The Policy Engine Shall transition to the PE_SRC_Transition_to_default state when:
 The PSHardResetTimer times out.

8.3.3.2.10 PE_SRC_Hard_Reset_Received State

The Policy Engine Shall transition from any state to the PE_SRC_Hard_Reset_Received state when:
Page 434 USB Power Delivery Specification Revision 3.0, Version 1.1
 Hard Reset Signaling is detected.
On entry to the PE_SRC_Hard_Reset_Received state the Policy Engine Shall initialize and run the PSHardResetTimer.
The Policy Engine Shall transition to the PE_SRC_Transition_to_default state when:
 The PSHardResetTimer times out.

8.3.3.2.11 PE_SRC_Transition_to_default State

On entry to the PE_SRC_Transition_to_default state the Policy Engine Shall:
 indicate to the Device Policy Manager that the power supply Shall Hard Reset (see Section 7.1.5)
 request a reset of the local hardware
 request the Device Policy Manager to set the Port Data Role to DFP and turn off VCONN.
On exit from the PE_SRC_Transition_to_default state the Policy Engine Shall:
 request the Device Policy Manager to turn on VCONN
 initialize and run the NoResponseTimer. Note that the NoResponseTimer Shall continue to run in every state
until it is stopped or times out.
 inform the Protocol Layer that the Hard Reset is complete.
The Policy Engine Shall transition to the PE_SRC_Startup state when:
 The Device Policy Manager indicates that the power supply has reached the default level.

8.3.3.2.12 PE_SRC_Get_Sink_Cap State

In this state the Policy Engine, due to a request from the Device Policy Manager, Shall request the capabilities from the
Attached Sink.
On entry to the PE_SRC_Get_Sink_Cap state the Policy Engine Shall request the Protocol Layer to send a Get_Sink_Cap
Message in order to retrieve the Sink’s capabilities. The Policy Engine Shall then start the SenderResponseTimer.
On exit from the PE_SRC_Get_Sink_Cap state the Policy Engine Shall inform the Device Policy Manager of the outcome
(capabilities or response timeout).
The Policy Engine Shall transition to the PE_SRC_Ready state when:
 A Sink_Capabilities Message is received.
 Or SenderResponseTimer times out.

8.3.3.2.13 PE_SRC_Wait_New_Capabilities State

In this state the Policy Engine has been unable to negotiate an Explicit Contract and is waiting for new Capabilities
from the Device Policy Manager.
The Policy Engine Shall transition to the PE_SRC_Send_Capabilities state when:
 The Device Policy Manager indicates that Source Capabilities have changed.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 435
 8.3.3.3 Policy Engine Sink Port State Diagram
Figure 8-67 below shows the state diagram for the Policy Engine in a Sink Port. The following sections describe
operation in each of the states.

Figure 8-67 Sink Port State Diagram

Hard reset signalling received

Start
PE_SNK_Transition_to_default
Actions on entry: PE_SNK_Startup
Request Device Policy Manager to request power Power Sink
sink transition to default Actions on entry:
at default
Reset local HW Reset Protocol Layer
Set Port Data Role to UFP and turn off VCONN
Power = DefauIt (0V or 5V) or
Implicit Contract
Actions on exit: PD = Connected/not Connected
Inform Protocol Layer Hard Reset complete
Protocol Layer Reset
Power = rising/falling to default (5V)
PD = not Connected
((SinkWaitCapTimer timeout |
PSTransitionTimer timeout) & PE_SNK_Discovery
(HardResetCounter nHardResetCount)) | Hard Reset complete
Hard Reset request from Actions on entry:
Device Policy Manager Wait for VBUS
PE_SNK_Hard_Reset
Actions on entry: Power = Default (0V or 5V) or
Generate Hard Reset signalling. Implicit Contract
Increment HardResetCounter. PD = Connected/not Connected

Power = DefauIt (5V) or

VBUS present4
Implicit/Explicit Contract
PD = Connected/not Connected

PE_SNK_Wait_for_Capabilities
Actions on entry:
Initialize and run SinkWaitCapTimer
SenderResponseTimer
Timeout Power = Default (0V or 5V) or
Implicit Contract
PD = Connected/not Connected

Source capabilities message received1

PE_SNK_Evaluate_Capability
Actions on entry:
Reset HardResetCounter to zero.
Ask Device Policy Manager to evaluate the options based on supplied
capabilities, any Power Reserve that it needs, and respond indicating
the selected capability and, Optionally, a Capability Mismatch

Power = DefauIt (5V) or Implicit Contract

PD = Connected
no Explicit Contract &
Device Policy Manager Response received (Reject message received |
Wait message received)
PE_SNK_Select_Capability
Actions on entry:
Send Request based on Device Policy Manager response:
 Request from present capabilities
 Optionally Indicate that other capabilities would be preferred
Capability Mismatch
Initialize and run SenderResponseTimer

Power = DefauIt (5V) or Implicit Contract Explicit Contract &

PD = Connected (Reject message received |
Wait message received)
New power required | Accept message
SinkRequestTimer received
Timeout |
SinkPPSPeriodicTimer PE_SNK_Transition_Sink
Protocol Error Timeout
Actions on entry:
Initialize and run PSTransitionTimer
Actions on exit:
Request Device Policy Manager transitions sink
power supply to new power (if required)
Power = transition
PD = Connected

GotoMin message PS_RDY message

received received

Source capabilities
message received1 PE_SNK_Ready
Actions on entry:
Initialize and run SinkRequestTimer2 (on receiving Wait)
Initialize and run DiscoverIdentityTimer4
Initialize and run the SinkPPSPeriodicTimer5

Actions on exit:
If the Sink is initiating an AMS then notify the Protocol Layer
that the first Message in the AMS will follow.

Power = Explicit Contract

PD = Connected

Get_Sink_Cap message Update remote capabilities

received Sink capabilities Get_Source_Cap request from
message sent Message sent Device Policy Manager

PE_SNK_Give_Sink_Cap
PE_SNK_Get_Source_Cap
Actions on entry:
Actions on entry:
Get present sink capabilities from Device Policy Manager
Send Get_Source_Cap message
Send Capabilities message (based on Device Policy
Manager response)
Power = Explicit Contract
Power = Explicit Contract PD = Connected
PD = Connected

Page 436 USB Power Delivery Specification Revision 3.0, Version 1.1
1Source capabilities messages received in states other than PE_SNK_Wait_for_Capabilities and PE_SNK_Ready
constitute a Protocol Error.
2The SinkRequestTimer Should Not be stopped if a Ping Message is received in the PE_SNK_Ready state since it
represents the maximum time between requests after a Wait Message which is not reset by a Ping Message.
3During a Hard Reset the Source voltage will transition to vSafe0V and then transition to vSafe5V. Sinks need to
ensure that VBUS present is not indicated until after the Source has completed the Hard Reset process by detecting
both of these transitions.
4The DiscoverIdentityTimer is run when this is a VCONN Source and a PD Connection with a Cable Plug needs to be
established i.e. no GoodCRC Message has yet been received in response to a Discover Identity Command.
5The SinkPPSPeriodicTimer is only initialized and run when the present Explicit Contract is for a PPS APDO. Sink’s
that do not support PPS do not need to implement the SinkPPSPeriodicTimer.

8.3.3.3.1 PE_SNK_Startup State

PE_SNK_Startup Shall be the starting state for a Sink Policy Engine either on power up or after a Hard Reset. On entry
to this state the Policy Engine Shall reset the Protocol Layer. Note that resetting the Protocol Layer will also reset the
MessageIDCounter and stored MessageID (see Section 6.11.2.3).
Once the reset process completes, the Policy Engine Shall transition to the PE_SNK_Discovery state.

8.3.3.3.2 PE_SNK_Discovery State

In the PE_SNK_Discovery state the Sink Policy Engine waits for VBUS to be present.
The Policy Engine Shall transition to the PE_SNK_Wait_for_Capabilities state when:
 The Device Policy Manager indicates that VBUS has been detected.

8.3.3.3.3 PE_SNK_Wait_for_Capabilities State

On entry to the PE_SNK_Wait_for_Capabilities state the Policy Engine Shall initialize and start the
SinkWaitCapTimer.
The Policy Engine Shall transition to the PE_SNK_Evaluate_Capability state when:
 A Source_Capabilities Message is received.
When the SinkWaitCapTimer times out, the Policy Engine will perform a Hard Reset.

8.3.3.3.4 PE_SNK_Evaluate_Capability State

The PE_SNK_Evaluate_Capability state is first entered when the Sink receives its first Source_Capabilities Message
from the Source. At this point the Sink knows that it is Attached to and communicating with a PD capable Source.
On entry to the PE_SNK_Evaluate_Capability state the Policy Engine Shall request the Device Policy Manager to
evaluate the supplied Source capabilities based on Local Policy. The Device Policy Manager Shall indicate to the
Policy Engine the new power level required, selected from the present offered capabilities. The Device Policy
Manager Shall also indicate to the Policy engine a Capability Mismatch if the offered power does not meet the device's
requirements.
The Policy Engine Shall transition to the PE_SNK_Select_Capability state when:
 A response is received from the Device Policy Manager.

8.3.3.3.5 PE_SNK_Select_Capability State

On entry to the PE_SNK_Select_Capability state the Policy Engine Shall request the Protocol Layer to send a response
Message, based on the evaluation from the Device Policy Manager. The Message Shall be one of the following:

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 437
 A Request from the offered Source Capabilities.
 A Request from the offered Source Capabilities with an indication that another power level would be preferred
(“Capability Mismatch” bit set).
The Policy Engine Shall initialize and run the SenderResponseTimer.
The Policy Engine Shall transition to the PE_SNK_Transition_Sink state when:
 An Accept Message is received from the Source.
The Policy Engine Shall transition to the PE_SNK_Wait_for_Capabilities state when:
 There is no Explicit Contract in place and
 A Reject Message is received from the Source or
 A Wait Message is received from the Source.
The Policy Engine Shall transition to the PE_SNK_Ready state when:
 There is an Explicit Contract in place and
 A Reject Message is received from the Source or
 A Wait Message is received from the Source.
The Policy Engine Shall transition to the PE_SNK_Hard_Reset state when:
 A SenderResponseTimer timeout occurs.

8.3.3.3.6 PE_SNK_Transition_Sink State

On entry to the PE_SNK_Transition_Sink state the Policy Engine Shall initialize and run the PSTransitionTimer
(timeout will lead to a Hard Reset see Section 8.3.3.3.8 and Shall then request the Device Policy Manager to transition
the Sink’s power supply to the new power level. Note that if there is no power level change the Device Policy Manager
Should Not affect any change to the power supply.
On exit from the PE_SNK_Transition_Sink state the Policy Engine Shall request the Device Policy Manager to
transition the Sink’s power supply to the new power level.
The Policy Engine Shall transition to the PE_SNK_Ready state when:
 A PS_RDY Message is received from the Source.
The Policy Engine Shall transition to the PE_SNK_Hard_Reset state when:
 A Protocol Error occurs.

8.3.3.3.7 PE_SNK_Ready State

In the PE_SNK_Ready state the PD Sink Shall be operating at a stable power level with no ongoing negotiation. It
Shall respond to requests from the Source, events from the Device Policy Manager and May monitor for Ping
Messages to maintain the PD link.
On entry to the PE_SNK_Ready state as the result of a wait the Policy Engine Should do the following:
 Initialize and run the SinkRequestTimer.
On entry to the PE_SNK_Ready state if this is a DFP which needs to establish communication with a Cable Plug, then
the Policy Engine Shall do the following:
 Initialize and run the DiscoverIdentityTimer (no GoodCRC Message response yet received to Discover Identity
Message).
On entry to the PE_SNK_Ready state if the current Explicit Contract is for a PPS APDO, then the Policy Engine Shall do
the following:

Page 438 USB Power Delivery Specification Revision 3.0, Version 1.1
 Initialize and run the SinkPPSPeriodicTimer.
On exit from the PE_SNK_Ready state, if the transition is as a result of a DPM request to start a new Atomic Message
Sequence (AMS) then the Policy Engine Shall notify the Protocol Layer that the first Message in an AMS will follow.
The Policy Engine Shall transition to the PE_SNK_Evaluate_Capability state when:
 A Source_Capabilities Message is received.
The Policy Engine Shall transition to the PE_SNK_Select_Capability state when:
 A new power level is requested by the Device Policy Manager.
 A SinkRequestTimer timeout occurs.
The Policy Engine Shall transition to the PE_SNK_Transition_Sink state when:
 A GotoMin Message is received.
The Policy Engine Shall transition back to the PE_SNK_Ready state when:
 A Ping Message is received. Note this Should Not cause the SinkRequestTimer to be reinitialized.
The Policy Engine Shall transition to the PE_SNK_Give_Sink_Cap state when:
 A Get_Sink_Cap Message is received from the Protocol Layer.
The Policy Engine Shall transition to the PE_SNK_Get_Source_Cap state when:
 The Device Policy Manager requests an update of the remote Source’s capabilities.

8.3.3.3.8 PE_SNK_Hard_Reset State

The Policy Engine Shall transition to the PE_SNK_Hard_Reset state from any state when:
 ((SinkWaitCapTimer timeout |
 PSTransitionTimer timeout |
 NoResponseTimer timeout) &
 (HardResetCounter ≤ nHardResetCount)) |
 Hard Reset request from Device Policy Manager.
Note: if the NoResponseTimer times out and the HardResetCounter is greater than nHardResetCount the Sink Shall
assume that the Source is non-responsive.
Note: The HardResetCounter is reset on a power cycle or Detach.
On entry to the PE_SNK_Hard_Reset state the Policy Engine Shall request the generation of Hard Reset Signaling by
the PHY Layer and increment the HardResetCounter.
The Policy Engine Shall transition to the PE_SNK_Transition_to_default state when:
 The Hard Reset is complete.

8.3.3.3.9 PE_SNK_Transition_to_default State

The Policy Engine Shall transition from any state to PE_SNK_Transition_to_default state when:
 Hard Reset Signaling is detected.
When Hard Reset Signaling is received or transmitted then the Policy Engine Shall transition from any state to
PE_SNK_Transition_to_default. This state can also be entered from the PE_SNK_Hard_Reset state.
On entry to the PE_SNK_Transition_to_default state the Policy Engine Shall:
 indicate to the Device Policy Manager that the Sink Shall transition to default

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 439
 request a reset of the local hardware
 request the Device Policy Manger that the Port Data Role is set to UFP.
The Policy Engine Shall transition to the PE_SNK_Startup state when:
 The Device Policy Manager indicates that the Sink has reached the default level.

8.3.3.3.10 PE_SNK_Give_Sink_Cap State

On entry to the PE_SNK_Give_Sink_Cap state the Policy Engine Shall request the Device Policy Manager for the current
system capabilities. The Policy Engine Shall then request the Protocol Layer to send a Sink_Capabilities Message
containing these capabilities.
The Policy Engine Shall transition to the PE_SNK_Ready state when:
 The Sink_Capabilities Message has been successfully sent.

8.3.3.3.11 PE_SNK_Get_Source_Cap State

In the PE_SNK_Get_Source_Cap state the Policy Engine, due to a request from the Device Policy Manager, Shall request
the capabilities from the Attached Source.
On entry to the PE_SNK_Get_Source_Cap state the Policy Engine Shall request the Protocol Layer to send a
Get_Source_Cap Message in order to retrieve the Source’s capabilities.
The Policy Engine Shall transition to the PE_SNK_Ready state when:
 The Get_Source_Cap Message is sent.

Page 440 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.3.4 Soft Reset and Protocol Error State Diagrams

8.3.3.4.1 Source Port Soft Reset and Protocol Error State Diagram
Figure 8-68 below shows the state diagram for the Policy Engine in a Source Port when performing a Soft Reset of its
Port Partner. The following sections describe operation in each of the states.

Figure 8-68 Source Port Soft Reset and Protocol Error State Diagram

Accept message
received
PE_SRC_Send_Capabilities
PE_SRC_Ready

Accept message Protocol Error2 during Interruptible AMS |

sent Protocol Error2 before first Message
in AMS sent (no GoodCRC received)
SenderResponseTimer
Timeout |
PE_SRC_Soft_Reset Transmission Transmission PE_SRC_Send_Soft_Reset
Error indication Error indication
from Protocol Layer Actions on entry:
Actions on entry: from Protocol Layer
PE_SRC_Hard_Reset Reset Protocol Layer
Reset Protocol Layer
Send Soft Reset message
Send Accept message
Initialize and run SenderResponseTimer
Power = DefauIt/Implicit or Power = DefauIt/Implicit or Explicit Contract
Explicit Contract PD = Connected
PD = Connected

Soft Reset message Message not sent after retries (no GoodCRC received)1 |
received Protocol Error2 during Non-interruptable AMS

1 Excludes the Soft_Reset Message itself.

2An unrecognized or unsupported Message will result in a Not_Supported Message response being generated (see
Section 6.3.14).

8.3.3.4.1.1 PE_SRC_Send_Soft_Reset State

The PE_SRC_Send_Soft_Reset state Shall be entered from any state when a Protocol Error is detected by the Protocol
Layer during a Non-interruptible AMS (see Section 6.8.1) or when a Message has not been sent after retries to the
Sink. The main exceptions to this rule are when:
 The source is in the PE_SRC_Send_Capabilities state, there is a Source_Capabilities Message sending failure
(without GoodCRC) and the source is not presently Attached (as indicated in Figure 8-66). In this case, the
PE_SRC_Discovery state is entered (see Section 8.3.3.2.3).
 When the voltage is in transition due to a new Explicit Contract being negotiated (see Section 8.3.3.2). In this case
a Hard Reset will be generated.
 During a Power Role Swap when the power supply is in transition (see Section 8.3.3.16.3 and Section 8.3.3.16.4).
In this case USB Type-C Error Recovery will be triggered directly.
 During a Data Role Swap when there is a mismatch in the Port Date Role field (see Section 6.2.1.1.6). In this case
USB Type-C Error Recovery will be triggered directly.
Note that Protocol Errors occurring in the following situations Shall Not lead to a Soft Reset, but Shall result in a
transition to the PE_SRC_Ready state where the Message received will be handled as if it had been received in the
PE_SRC_Ready state:
 Protocol Errors occurring during an Interruptible AMS.
 Protocol Errors occurring during any AMS where the first Message in the sequence has not yet been sent i.e. an
unexpected Message is received instead of the expected GoodCRC Message response.
On entry to the PE_SRC_Send_Soft_Reset state the Policy Engine Shall request the Protocol Layer to perform a Soft
Reset, then Shall send a Soft_Reset Message to the Sink, and initialize and run the SenderResponseTimer.
The Policy Engine Shall transition to the PE_SRC_Send_Capabilities state when:
USB Power Delivery Specification Revision 3.0, Version 1.1 Page 441
 An Accept Message has been received.
The Policy Engine Shall transition to the PE_SRC_Hard_Reset state when:
 A SenderResponseTimer timeout occurs.
 Or the Protocol Layer indicates that a transmission error has occurred.

8.3.3.4.1.2 PE_SRC_Soft_Reset State

The PE_SRC_Soft_Reset state Shall be entered from any state when a Soft_Reset Message is received from the Protocol
Layer.
On entry to the PE_SRC_Soft_Reset state the Policy Engine Shall reset the Protocol Layer and Shall then request the
Protocol Layer to send an Accept Message.
The Policy Engine Shall transition to the PE_SRC_Send_Capabilities state (see Section 8.3.3.2.3) when:
 The Accept Message has been sent.
The Policy Engine Shall transition to the PE_SRC_Hard_Reset state when:
 The Protocol Layer indicates that a transmission error has occurred.

8.3.3.4.2 Sink Port Soft Reset and Protocol Error State Diagram
Figure 8-69 below shows the state diagram for the Policy Engine in a Sink Port when performing a Soft Reset of its
Port Partner. The following sections describe operation in each of the states.

Figure 8-69 Sink Port Soft Reset and Protocol Error Diagram

Accept message
received
PE_SNK_Wait_for_Capabilities
PE_SNK_Ready

Accept message Protocol Error2 during Non-interruptable AMS |

sent Protocol Error2 before first Message
in AMS sent (no GoodCRC received)
Transmission
Error indication SenderResponseTimer
from Protocol Layer Timeout | PE_SNK_Send_Soft_Reset
PE_SNK_Soft_Reset Transmission
Error indication Actions on entry:
Actions on entry: from Protocol Layer Reset Protocol Layer
Reset Protocol Layer PE_SNK_Hard_Reset
Send Soft Reset message
Send Accept message
Initialize and run SenderResponseTimer
Power = DefauIt/Implicit or Power = DefauIt/Implicit or Explicit Contract
Explicit Contract PD = Connected
PD = Connected

Message not sent after retries (no GoodCRC received)1 |

Soft Reset message Protocol Error2 during Non-interruptable AMS
received

1 Excludes the Soft_Reset Message itself.

2An unrecognized or unsupported Message will result in a Not_Supported Message response being generated (see
Section 6.3.14).

8.3.3.4.2.1 PE_SNK_Send_Soft_Reset State

The PE_SNK_Send_Soft_Reset state Shall be entered from any state when a Protocol Error is detected by the Protocol
Layer during a Non-interruptible AMS (see Section 6.8.1) or when a Message has not been sent after retries to the
Source. The main exceptions to this rule are when:
• When the voltage is in transition due to a new Explicit Contract being negotiated (see Section 8.3.3.3). In this case
a Hard Reset will be generated.

Page 442 USB Power Delivery Specification Revision 3.0, Version 1.1
• During a Power Role Swap when the power supply is in transition (see Section 8.3.3.16.3 and Section 8.3.3.16.4).
In this case a hard reset will be triggered directly.
• During a Data Role Swap when the DFP/UFP roles are changing. In this case USB Type-C Error Recovery will be
triggered directly.
Note that Protocol Errors occurring in the following situations Shall Not lead to a Soft Reset, but Shall result in a
transition to the PE_SNK_Ready state where the Message received will be handled as if it had been received in the
PE_SNK_Ready state:
 Protocol Errors occurring during an Interruptible AMS.
 Protocol Errors occurring during any AMS where the first Message in the sequence has not yet been sent i.e. an
unexpected Message is received instead of the expected GoodCRC Message response.
On entry to the PE_SNK_Send_Soft_Reset state the Policy Engine Shall request the Protocol Layer to perform a Soft
Reset, then Shall send a Soft_Reset Message to the Source, and initialize and run the SenderResponseTimer.
The Policy Engine Shall transition to the PE_SNK_Wait_for_Capabilities state when:
• An Accept Message has been received.
The Policy Engine Shall transition to the PE_SNK_Hard_Reset state when:
• A SenderResponseTimer timeout occurs.
• Or the Protocol Layer indicates that a transmission error has occurred.

8.3.3.4.2.2 PE_SNK_Soft_Reset State

The PE_SNK_Soft_Reset state Shall be entered from any state when a Soft_Reset Message is received from the
Protocol Layer.
On entry to the PE_SNK_Soft_Reset state the Policy Engine Shall reset the Protocol Layer and Shall then request the
Protocol Layer to send an Accept Message.
The Policy Engine Shall transition to the PE_SNK_Wait_for_Capabilities state when:
 The Accept Message has been sent.
The Policy Engine Shall transition to the PE_SNK_Hard_Reset state when:
 The Protocol Layer indicates that a transmission error has occurred.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 443
 8.3.3.5 Not Supported Message State Diagrams

8.3.3.5.1 Source Port Not Supported Message State Diagram

Figure 8-70 shows the state diagram for a Not_Supported Message sent or received by a Source Port.

Figure 8-70 Source Port Not Supported Message State Diagram

PE_SRC_Chunk_Received
ChunkingNotSupportedTimer
timeout Actions on entry:
Start ChunkingNotSupportedTimer

Power = Explicit Contract

PD = connected

Protocol Error1 &

Chunk from
a multi-Chunk Message2

Protocol Error1 &

not a Chunk from
a multi-Chunk Message Not_Supported Message
PE_SRC_Send_Not_Supported received1 PE_SRC_Not_Supported_Received
PE_SRC_Ready
Actions on entry: Actions on entry:
Send Not_Supported Message Not_Supported Inform Device Policy Manager of
Message sent DPM informed Not_Supported Message
Power = Explicit Contract
PD = connected Power = Explicit Contract
PD = connected

1Transition can either be the result of a Protocol Error during an interruptible AMS or as a result of an unsupported
Message being received in the PE_SRC_Ready state directly (see also Section 8.3.3.4.1).
2Transition can only occur where a manufacturer has opted not to implement a Chunking state machine (see Section
6.11.2.1) and is communicating with a system which is attempting to send it Chunks.

8.3.3.5.1.1 PE_SRC_Send_Not_Supported State

The PE_SRC_Send_Not_Supported state Shall be entered from the PE_SRC_Ready state either as the result of a
Protocol Error received during an interruptible AMS or as a result of an unsupported Message being received in the
PE_SRC_Ready state directly except for the first Chunk in a multi-Chunk Message (see also Section 6.11.2.1 and
Section 8.3.3.4.1).
On entry to the PE_SRC_Send_Not_Supported state (from the PE_SRC_Ready state) the Policy Engine Shall request the
Protocol Layer to send a Not_Supported Message.
The Policy Engine Shall transition back to the previous state (PE_SRC_Ready see Figure 8-70) when:
• The Not_Supported Message has been successfully sent.

8.3.3.5.1.2 PE_SRC_Not_Supported_Received State

The PE_SRC_Not_Supported_Received state Shall be entered from the PE_SRC_Ready state when a Not_Supported
Message is received.
On entry to the PE_SRC_Not_Supported_Received state the Policy Engine Shall inform the Device Policy Manager.
The Policy Engine Shall transition back to the previous state (PE_SRC_Ready see Figure 8-70) when:
• The Device Policy Manager has been informed.

8.3.3.5.1.3 PE_SRC_Chunk_Received State

The PE_SRC_Chunk_Received state Shall be entered from the PE_SRC_Ready state either as the result of a Protocol
Error received during an interruptible AMS or as a result of an unsupported Message being received in the

Page 444 USB Power Delivery Specification Revision 3.0, Version 1.1
PE_SRC_Ready state directly where the Message is a Chunk in a multi-Chunk Message (see also Section 6.6.17.1 and
Section 8.3.3.4.1).
On entry to the PE_SRC_Chunk_Received state (from the PE_SRC_Ready state) the Policy Engine Shall initialize and
run the ChunkingNotSupportedTimer.
The Policy Engine Shall transition to PE_SRC_Send_Not_Supported when:
• The ChunkingNotSupportedTimer has timed out.

8.3.3.5.2 Sink Port Not Supported Message State Diagram

Figure 8-71 shows the state diagram for a Not_Supported Message sent or received by a Sink Port.

Figure 8-71 Sink Port Not Supported Message State Diagram

PE_SRC_Chunk_Received
ChunkingNotSupportedTimer
timeout Actions on entry:
Start ChunkingNotSupportedTimer

Power = Explicit Contract

PD = connected

Protocol Error1 &

Chunk from
a multi-Chunk Message2

Protocol Error1 &

not a Chunk from
PE_SNK_Send_Not_Supported a multi-Chunk Message Not_Supported Message
received1 PE_SNK_Not_Supported_Received
PE_SNK_Ready
Actions on entry: Actions on entry:
Send Not_Supported Message Not_Supported Inform Device Policy Manager of
Message sent DPM informed Not_Supported Message
Power = Explicit Contract
PD = connected Power = Explicit Contract
PD = connected

1Transition can either be the result of a Protocol Error during an interruptible AMS or as a result of an unsupported
Message being received in the PE_SNK_Ready state directly (see also Section 8.3.3.4.2).

8.3.3.5.2.1 PE_SNK_Send_Not_Supported State

The PE_SNK_Send_Not_Supported state Shall be entered from the PE_SNK_Ready state either as the result of a
Protocol Error received during an interruptible AMS or as a result of an unsupported Message being received in the
PE_SNK_Ready state directly except for the first Chunk in a multi-Chunk Message (see also Section 6.11.2.1 and
Section 8.3.3.4.1).
On entry to the PE_SNK_Send_Not_Supported state (from the PE_SNK_Ready state) the Policy Engine Shall request
the Protocol Layer to send a Not_Supported Message.
The Policy Engine Shall transition back to the previous state (PE_SNK_Ready see Figure 8-71) when:
• The Not_Supported Message has been successfully sent.

8.3.3.5.2.2 PE_SNK_Not_Supported_Received State

The PE_SNK_Not_Supported_Received state Shall be entered from the PE_SNK_Ready state when a Not_Supported
Message is received.
On entry to the PE_SNK_Not_Supported_Received state the Policy Engine Shall inform the Device Policy Manager.
The Policy Engine Shall transition back to the previous state (PE_SNK_Ready see Figure 8-71) when:
• The Device Policy Manager has been informed.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 445
 8.3.3.5.2.1 PE_SNK_Chunk_Received State
The PE_SNK_Chunk_Received state Shall be entered from the PE_SNK_Ready state either as the result of a Protocol
Error received during an interruptible AMS or as a result of an unsupported Message being received in the
PE_SNK_Ready state directly where the Message is a Chunk in a multi-Chunk Message (see also Section 6.6.17.1 and
Section 8.3.3.4.1).
On entry to the PE_SNK_Chunk_Received state (from the PE_SNK_Ready state) the Policy Engine Shall initialize and
run the ChunkingNotSupportedTimer.
The Policy Engine Shall transition to PE_SNK_Send_Not_Supported when:
• The ChunkingNotSupportedTimer has timed out.

8.3.3.6 Source Port Ping State Diagram

Figure 8-70 shows the state diagram for a Ping Message from a Source Port.

Figure 8-72 Source Port Ping State Diagram

Send Ping request

PE_SRC_Ping from DPM

Actions on entry:
PE_SRC_Ready
Send Ping message
Ping message sent
Power = Explicit Contract
PD = connected

8.3.3.6.1 PE_SRC_Ping State

On entry to the PE_SRC_Ping state (from the PE_SRC_Ready state) the Policy Engine Shall request the Protocol Layer
to send a Ping Message.
The Policy Engine Shall transition back to the previous state (PE_SRC_Ready) (see Figure 8-66) when:
 The Ping Message has been successfully sent.

8.3.3.7 Source Alert State Diagrams

8.3.3.7.1 Source Port Source Alert State Diagram

Figure 8-73 shows the state diagram for an Alert Message sent by a Source Port.

Figure 8-73 Source Port Source Alert State Diagram

DPM indicates Source

PE_SRC_Send_Source_Alert alert condition

Actions on entry:
PE_SRC_Ready
Send Alert Message Alert
Message sent
Power = Explicit Contract
PD = connected

8.3.3.7.1.1 PE_SRC_Send_Source_Alert State

The PE_SRC_Send_Source_Alert state Shall be entered from the PE_SRC_Ready state when the Device Policy Manager
indicates that there is a Source alert condition to be reported.
On entry to the PE_SRC_Send_Source_Alert state the Policy Engine Shall request the Protocol Layer to send an Alert
Message.
The Policy Engine Shall transition back to PE_SRC_Ready (see Figure 8-66) when:

Page 446 USB Power Delivery Specification Revision 3.0, Version 1.1
 The Alert Message has been successfully sent.

8.3.3.7.2 Sink Port Source Alert State Diagram

Figure 8-74 shows the state diagram for an Alert Message received by a Sink Port.

Figure 8-74 Sink Port Source Alert State Diagram

Source Alert Message

PE_SNK_Source_Alert_Received received

Actions on entry:
PE_SNK_Ready
Inform DPM of the detail of the alert
DPM Informed
Power = Explicit Contract
PD = connected

8.3.3.7.2.1 PE_SNK_Source_Alert_Received State

The PE_SNK_Source_Alert_Received state Shall be entered from the PE_SNK_Ready state when an Alert Message is
received.
On entry to the PE_SNK_Source_Alert_Received state the Policy Engine Shall inform the Device Policy Manager of the
details of the Source alert.
The Policy Engine Shall transition back to PE_SNK_Ready (see Figure 8-67) when:
 The DPM has been informed.

8.3.3.7.3 Sink Port Sink Alert State Diagram

Figure 8-75 shows the state diagram for an Alert Message sent by a Sink Port.

Figure 8-75 Sink Port Sink Alert State Diagram

DPM indicates Sink

PE_SNK_Send_Sink_Alert alert condition

Actions on entry:
PE_SNK_Ready
Send Alert Message Alert
Message sent
Power = Explicit Contract
PD = connected

8.3.3.7.3.1 PE_SNK_Send_Sink_Alert State

The PE_SNK_Send_Sink_Alert state Shall be entered from the PE_SNK_Ready state when the Device Policy Manager
indicates that there is a Source alert condition to be reported.
On entry to the PE_SNK_Send_Sink_Alert state the Policy Engine Shall request the Protocol Layer to send an Alert
Message.
The Policy Engine Shall transition back to PE_SNK_Ready (see Figure 8-67) when:
 The Alert Message has been successfully sent.

8.3.3.7.4 Source Port Sink Alert State Diagram

Figure 8-76 shows the state diagram for an Alert Message received by a Source Port.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 447
 Figure 8-76 Source Port Sink Alert State Diagram

Sink Alert Message

PE_SRC_Sink_Alert_Received received

Actions on entry:
PE_SRC_Ready
Inform DPM of the detail of the alert
DPM Informed
Power = Explicit Contract
PD = connected

8.3.3.7.4.1 PE_SRC_Sink_Alert_Received State

The PE_SRC_Sink_Alert_Received state Shall be entered from the PE_SRC_Ready state when an Alert Message is
received.
On entry to the PE_SRC_Sink_Alert_Received state the Policy Engine Shall inform the Device Policy Manager of the
details of the Source alert.
The Policy Engine Shall transition back to PE_SRC_Ready (see Figure 8-66) when:
 The DPM has been informed.

8.3.3.8 Source Capabilities Extended State Diagrams

8.3.3.8.1 Sink Port Get Source Capabilities Extended State Diagram

Figure 8-77 shows the state diagram for a Sink on receiving a request from the Device Policy Manager to get the Port
Partner’s extended Source capabilities. See also Section 6.5.1.

Figure 8-77 Sink Port Get Source Capabilities Extended State Diagram

get extended source capabilities

request PE_SNK_Get_Source_Cap_Ext
from Device Policy Manager
PE_SNK_Ready Actions on entry:
Send Get_Source_Cap_Extended Message
Initialize and run SenderResponseTimer
Source_Capabilities_Extended
Message received | Actions on exit:
SenderResponseTimer Pass source extended capabilities/
Timeout outcome to Device Policy Manager
Power = Explicit Contract
PD = Connected

8.3.3.8.1.1 PE_SNK_Get_Source_Cap_Ext State

The Policy Engine Shall transition to the PE_SNK_Get_Source_Cap_Ext state, from the PE_SNK_Ready state, due to a
request to get the remote extended source capabilities from the Device Policy Manager.
On entry to the PE_SNK_Get_Source_Cap_Ext state the Policy Engine Shall send a Get_Source_Cap_Extended Message
and initialize and run the SenderResponseTimer.
On exit from the PE_SNK_Get_Source_Cap_Ext state the Policy Engine Shall inform the Device Policy Manager of the
outcome (capabilities or response timeout).
The Policy Engine Shall transition back to the PE_SNK_Ready state (see Figure 8-67) when:
 A Source_Capabilities_Extended Message is received
 Or SenderResponseTimer times out.

8.3.3.8.2 Source Give Source Capabilities Extended State Diagram

Figure 8-78 shows the state diagram for a Source on receiving a Get_Source_Cap_Extended Message. See also Section
6.5.1.

Page 448 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-78 Source Give Source Capabilities Extended State Diagram

Get_Source_Cap_Extended message
received PE_SRC_Give_Source_Cap_Ext
PE_SRC_Ready
Actions on entry:
Get present extended source capabilities from Device
Source_Capabilities_Extended Policy Manager
Message sent Send Source_Capabilities_Extended message (based on
Device Policy Manager response)
Power = Explicit Contract
PD = Connected

8.3.3.8.2.1 PE_SRC_Give_Source_Cap_Ext State

The Policy Engine Shall transition to the PE_SRC_Give_Source_Cap_Ext state, from the PE_SRC_Ready state, when a
Get_Source_Cap_Extended Message is received.
On entry to the PE_SRC_Give_Source_Cap_Ext state the Policy Engine Shall request the present extended Source
capabilities from the Device Policy Manager and then send a Source_Capabilities_Extended Message based on these
capabilities.
The Policy Engine Shall transition back to the PE_SRC_Ready state (see Figure 8-66) when:
 The Source_Capabilities_Extended Message has been successfully sent.

8.3.3.9 Status State Diagrams

8.3.3.9.1 Sink Port Get Source Status State Diagram

Figure 8-79 shows the state diagram for a Sink on receiving a request from the Device Policy Manager to get the Port
Partner’s Source status. See also Section 6.5.2.

Figure 8-79 Sink Port Get Source Status State Diagram

get source status request

from Device Policy Manager PE_SNK_Get_Source_Status
PE_SNK_Ready Actions on entry:
Send Get_Status Message
Initialize and run SenderResponseTimer
Status
Message received | Actions on exit:
SenderResponseTimer Pass Source status/outcome to Device
Timeout Policy Manager
Power = Explicit Contract
PD = Connected

8.3.3.9.1.1 PE_SNK_Get_Source_Status State

The Policy Engine Shall transition to the PE_SNK_Get_Source_Status state, from the PE_SNK_Ready state, due to a
request to get the remote source status from the Device Policy Manager.
On entry to the PE_SNK_Get_Source_Status state the Policy Engine Shall send a Get_Status Message and initialize and
run the SenderResponseTimer.
On exit from the PE_SNK_Get_Source_Status state the Policy Engine Shall inform the Device Policy Manager of the
outcome (status or response timeout).
The Policy Engine Shall transition back to the PE_SNK_Ready state (see Figure 8-67) when:
 A Status Message is received
 Or SenderResponseTimer times out.

8.3.3.9.2 Source Give Source Status State Diagram

Figure 8-80 shows the state diagram for a Source on receiving a Get_Status Message. See also Section 6.5.1.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 449
 Figure 8-80 Source Give Source Status State Diagram

Get_Status message
received PE_SRC_Give_Source_Status
PE_SRC_Ready
Actions on entry:
Get present Source status from Device Policy Manager
Status Send Status message (based on Device Policy Manager
Message sent response)

Power = Explicit Contract

PD = Connected

8.3.3.9.2.1 PE_SRC_Give_Source_Status State

The Policy Engine Shall transition to the PE_SRC_Give_Source_Status state, from the PE_SRC_Ready state, when a
Get_Status Message is received.
On entry to the PE_SRC_Give_Source_Status state the Policy Engine Shall request the present Source status from the
Device Policy Manager and then send a Status Message based on these capabilities.
The Policy Engine Shall transition back to the PE_SRC_Ready state (see Figure 8-66) when:
 The Status Message has been successfully sent.

8.3.3.9.3 Source Port Get Sink Status State Diagram

Figure 8-81 shows the state diagram for a Source on receiving a request from the Device Policy Manager to get the
Port Partner’s Sink status. See also Section 6.5.2.

Figure 8-81 Source Port Get Sink Status State Diagram

get sink status request

from Device Policy Manager PE_SRC_Get_Sink_Status
PE_SRC_Ready Actions on entry:
Send Get_Status Message
Initialize and run SenderResponseTimer
Status
Message received | Actions on exit:
SenderResponseTimer Pass Sink status/outcome to Device
Timeout Policy Manager
Power = Explicit Contract
PD = Connected

8.3.3.9.3.1 PE_SRC_Get_Sink_Status State

The Policy Engine Shall transition to the PE_SRC_Get_Sink_Status state, from the PE_SRC_Ready state, due to a
request to get the remote source status from the Device Policy Manager.
On entry to the PE_SRC_Get_Sink_Status state the Policy Engine Shall send a Status Message and initialize and run the
SenderResponseTimer.
On exit from the PE_SRC_Get_Sink_Status state the Policy Engine Shall inform the Device Policy Manager of the
outcome (status or response timeout).
The Policy Engine Shall transition back to the PE_SRC_Ready state (see Figure 8-66) when:
 A Status Message is received
 Or SenderResponseTimer times out.

8.3.3.9.4 Sink Give Sink Status State Diagram

Figure 8-82 shows the state diagram for a Source on receiving a Get_Status Message. See also Section 6.5.1.

Page 450 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-82 Sink Give Sink Status State Diagram

Get_Status message
received PE_SNK_Give_Sink_Status
PE_SNK_Ready
Actions on entry:
Get present Sink status from Device Policy Manager
Status Send Status message (based on Device Policy Manager
Message sent response)

Power = Explicit Contract

PD = Connected

8.3.3.9.4.1 PE_SNK_Give_Sink_Status State

The Policy Engine Shall transition to the PE_SNK_Give_Sink_Status state, from the PE_SNK_Ready state, when a
Get_Status Message is received.
On entry to the PE_SNK_Give_Sink_Status state the Policy Engine Shall request the present extended Source
capabilities from the Device Policy Manager and then send a Status Message based on these capabilities.
The Policy Engine Shall transition back to the PE_SNK_Ready state (see Figure 8-67) when:
 The Status Message has been successfully sent.

8.3.3.9.5 Sink Port Get Source PPS Status State Diagram

Figure 8-83 shows the state diagram for a Sink on receiving a request from the Device Policy Manager to get the Port
Partner’s Source status when operating as a PPS. See also Section 6.5.10.

Figure 8-83 Sink Port Get Source PPS Status State Diagram

get PPS status request

from Device Policy Manager PE_SNK_Get_PPS_Status
PE_SNK_Ready Actions on entry:
Send Get_PPS_Status Message
Initialize and run SenderResponseTimer
PPS_Status
Message received | Actions on exit:
SenderResponseTimer Pass Source status/outcome to Device
Timeout Policy Manager
Power = Explicit Contract
PD = Connected

8.3.3.9.5.1 PE_SNK_Get_PPS_Status State

The Policy Engine Shall transition to the PE_SNK_Get_PPS_Status state, from the PE_SNK_Ready state, due to a
request to get the remote source PPS status from the Device Policy Manager.
On entry to the PE_SNK_Get_PPS_Status state the Policy Engine Shall send a Get_PPS_Status Message and initialize
and run the SenderResponseTimer.
On exit from the PE_SNK_Get_PPS_Status state the Policy Engine Shall inform the Device Policy Manager of the
outcome (status or response timeout).
The Policy Engine Shall transition back to the PE_SNK_Ready state (see Figure 8-67) when:
 A PPS_Status Message is received
 Or SenderResponseTimer times out.

8.3.3.9.6 Source Give Source PPS Status State Diagram

Figure 8-84 shows the state diagram for a Source on receiving a Get_PPS_Status Message. See also Section 6.5.1.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 451
 Figure 8-84 Source Give Source PPS Status State Diagram

Get_PPS_Status message
received PE_SRC_Give_PPS_Status
PE_SRC_Ready
Actions on entry:
Get present Source PPS status from Device Policy
PPS_Status Manager
Message sent Send PPS_Status message (based on Device Policy
Manager response)
Power = Explicit Contract
PD = Connected

8.3.3.9.6.1 PE_SRC_Give_PPS_Status State

The Policy Engine Shall transition to the PE_SRC_Give_PPS_Status state, from the PE_SRC_Ready state, when a
Get_PPS_Status Message is received.
On entry to the PE_SRC_Give_PPS_Status state the Policy Engine Shall request the present Source PPS status from the
Device Policy Manager and then send a PPS_Status Message based on these capabilities.
The Policy Engine Shall transition back to the PE_SRC_Ready state (see Figure 8-66) when:
 The PPS_Status Message has been successfully sent.

8.3.3.10 Battery Capabilities State Diagrams

8.3.3.10.1 Get Battery Capabilities State Diagram

Figure 8-85 shows the state diagram for a Source or Sink on receiving a request from the Device Policy Manager to get
the Port Partner’s Battery capabilities for a specified Battery. See also Section 6.5.5.

Figure 8-85 Get Battery Capabilities State Diagram

get Battery capabilities

request PE_Get_Battery_Cap
from Device Policy Manager
PE_SRC_Ready or Actions on entry:
PE_SNK_Ready Send Get_Battery_Cap Message
Initialize and run SenderResponseTimer
Battery_Capabilities
Message received | Actions on exit:
SenderResponseTimer Pass Battery capabilities/outcome to
Timeout Device Policy Manager
Power = Explicit Contract
PD = Connected

8.3.3.10.1.1 PE_Get_Battery_Cap State

The Policy Engine Shall transition to the PE_Get_Battery_Cap state, from either the PE_SRC_Ready or PE_SNK_Ready
state, due to a request to get the remote Battery capabilities, for a specified Battery, from the Device Policy Manager.
On entry to the PE_Get_Battery_Cap state the Policy Engine Shall send a Get_Battery_Cap Message and initialize and
run the SenderResponseTimer.
On exit from the PE_Get_Battery_Cap state the Policy Engine Shall inform the Device Policy Manager of the outcome
(capabilities or response timeout).
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state as appropriate (see Figure
8-66 and Figure 8-67) when:
 A Battery_Capabilities Message is received
 Or SenderResponseTimer times out.

8.3.3.10.2 Give Battery Capabilities State Diagram

Figure 8-86 shows the state diagram for a Source or Sink on receiving a Get_Battery_Cap Message. See also Section
6.5.5.

Page 452 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-86 Give Battery Capabilities State Diagram

Get_Battery_Cap Message
received PE_Give_Battery_Cap
PE_SRC_Ready or
PE_SNK_Ready Actions on entry:
Get present Battery capabilities from Device Policy
Battery_Capabilities Manager
Message sent Send Battery_Capabilities Message (based on Device
Policy Manager response)
Power = Explicit Contract
PD = Connected

8.3.3.10.2.1 PE_Give_Battery_Cap State

The Policy Engine Shall transition to the PE_Give_Battery_Cap state, from either the PE_SRC_Ready or PE_SNK_Ready
state, when a Get_Battery_Cap Message is received.
On entry to the PE_Give_Battery_Cap state the Policy Engine Shall request the present Battery capabilities, for the
requested Battery, from the Device Policy Manager and then send a Source_Capabilities_Extended Message based on
these capabilities.
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state as appropriate (see Figure
8-66 and Figure 8-67) when:
 The Battery_Capabilities Message has been successfully sent.

8.3.3.11 Battery Status State Diagrams

8.3.3.11.1 Get Battery Status State Diagram

Figure 8-87 shows the state diagram for a Source or Sink on receiving a request from the Device Policy Manager to get
the Port Partner’s Battery status for a specified Battery. See also Section 6.5.4.

Figure 8-87 Get Battery Status State Diagram

get Battery status

request PE_Get_Battery_Status
from Device Policy Manager
PE_SRC_Ready or Actions on entry:
PE_SNK_Ready Send Get_Battery_Status Message
Initialize and run SenderResponseTimer
Battery_Status
Message received | Actions on exit:
SenderResponseTimer Pass Battery status/outcome to Device
Timeout Policy Manager
Power = Explicit Contract
PD = Connected

8.3.3.11.1.1 PE_Get_Battery_Status State

The Policy Engine Shall transition to the PE_Get_Battery_Status state, from either the PE_SRC_Ready or
PE_SNK_Ready state, due to a request to get the remote Battery status, for a specified Battery, from the Device Policy
Manager.
On entry to the PE_Get_Battery_Status state the Policy Engine Shall send a Get_Battery_Status Message and initialize
and run the SenderResponseTimer.
On exit from the PE_Get_Battery_Status state the Policy Engine Shall inform the Device Policy Manager of the
outcome (status or response timeout).
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state as appropriate (see Figure
8-66 and Figure 8-67) when:
 A Battery_Status Message is received
 Or SenderResponseTimer times out.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 453
 8.3.3.11.2 Give Battery Status State Diagram
Figure 8-88 shows the state diagram for a Source or Sink on receiving a Get_Battery_Status Message. See also Section
6.5.4.

Figure 8-88 Give Battery Status State Diagram

Get_Battery_Status Message
received PE_Give_Battery_Status
PE_SRC_Ready or
PE_SNK_Ready Actions on entry:
Get present Battery status from Device Policy Manager
Battery_Status Send Battery_Status Message (based on Device Policy
Message sent Manager response)

Power = Explicit Contract

PD = Connected

8.3.3.11.2.1 PE_Give_Battery_Status State

The Policy Engine Shall transition to the PE_Give_Battery_Status state, from either the PE_SRC_Ready or
PE_SNK_Ready state, when a Get_Battery_Status Message is received.
On entry to the PE_Give_Battery_Status state the Policy Engine Shall request the present Battery status, for the
requested Battery, from the Device Policy Manager and then send a Battery_Status Message based on this status.
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state as appropriate (see Figure
8-66 and Figure 8-67) when:
 The Battery_Status Message has been successfully sent.

8.3.3.12 Manufacturer Information State Diagrams

8.3.3.12.1 Get Manufacturer Information State Diagram

Figure 8-89 shows the state diagram for a Source or Sink on receiving a request from the Device Policy Manager to get
the Port Partner’s Manufacturer Information. See also Section 6.5.6.

Figure 8-89 Get Manufacturer Information State Diagram

get manufacturer information

request PE_Get_Manfacturer_Info
from Device Policy Manager
PE_SRC_Ready or Actions on entry:
PE_SNK_Ready Send Get_Manfacturer_Info Message
Initialize and run SenderResponseTimer
Manufacturer_Info
Message received | Actions on exit:
SenderResponseTimer Pass Manufacturer Information/
Timeout outcome to Device Policy Manager
Power = Explicit Contract
PD = Connected

8.3.3.12.1.1 PE_Get_Manufacturer_Info State

The Policy Engine Shall transition to the PE_Get_Manufacturer_Info state, from either the PE_SRC_Ready or
PE_SNK_Ready state, due to a request to get the remote Manufacturer Information from the Device Policy Manager.
On entry to the PE_Get_Manufacturer_Info state the Policy Engine Shall send a Get_Manufacturer_Info Message and
initialize and run the SenderResponseTimer.
On exit from the PE_Get_Manufacturer_Info state the Policy Engine Shall inform the Device Policy Manager of the
outcome (status or response timeout).
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state as appropriate (see Figure
8-66 and Figure 8-67) when:

Page 454 USB Power Delivery Specification Revision 3.0, Version 1.1
 A Manufacturer_Info Message is received
 Or SenderResponseTimer times out.

8.3.3.12.2 Give Manufacturer Information State Diagram

Figure 8-90 shows the state diagram for a Source, Sink or Cable Plug on receiving a Get_Manufacturer_Info Message.
See also Section 6.5.6.

Figure 8-90 Give Manufacturer Information State Diagram

Get_Manufacturer_Info Message
received PE_Give_Manufacturer_Info
PE_SRC_Ready,
PE_SNK_Ready or Actions on entry:
PE_CBL_Ready Get present Manufacturer Information from Device Policy
Manufacturer_Info Manager
Message sent Send Manufacturer_Info Message (based on Device Policy
Manager response)
Power = Explicit Contract
PD = Connected

8.3.3.12.2.1 PE_Give_Manufacturer_Info State

The Policy Engine Shall transition to the PE_Give_Manufacturer_Info state, from either the PE_SRC_Ready,
PE_SNK_Ready or PE_CBL_Ready state, when a Get_Manufacturer_Info Message is received.
On entry to the PE_Give_Manufacturer_Info state the Policy Engine Shall request the manufacturer information from
the Device Policy Manager and then send a Manufacturer_Info Message based on this status.
The Policy Engine Shall transition back to either the PE_SRC_Ready, PE_SNK_Ready or PE_CBL_Ready state as
appropriate (see Figure 8-66, Figure 8-67and Figure 8-126) when:
 The Manufacturer_Info Message has been successfully sent.

8.3.3.13 Country Codes and Information State Diagrams

8.3.3.13.1 Get Country Codes State Diagram

Figure 8-91 shows the state diagram for a Source or Sink on receiving a request from the Device Policy Manager to get
the Port Partner’s Manufacturer Information. See also Section 6.5.11.

Figure 8-91 Get Country Codes State Diagram

get country codes request

from Device Policy Manager PE_Get_Country_Codes
PE_SRC_Ready or Actions on entry:
PE_SNK_Ready Send Get_Country_Codes Message
Initialize and run SenderResponseTimer
Country_Codes
Message received | Actions on exit:
SenderResponseTimer Pass Country Codes/outcome to Device
Timeout Policy Manager
Power = Explicit Contract
PD = Connected

8.3.3.13.1.1 PE_Get_Country_Codes State

The Policy Engine Shall transition to the PE_Get_Country_Codes state, from either the PE_SRC_Ready or
PE_SNK_Ready state, due to a request to get the remote Manufacturer Information from the Device Policy Manager.
On entry to the PE_Get_Country_Codes state the Policy Engine Shall send a Get_Country_Codes Message and initialize
and run the SenderResponseTimer.
On exit from the PE_Get_Country_Codes state the Policy Engine Shall inform the Device Policy Manager of the
outcome (status or response timeout).

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 455
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state as appropriate (see Figure
8-66 and Figure 8-67) when:
 A Country_Codes Message is received
 Or SenderResponseTimer times out.

8.3.3.13.2 Give Country Codes State Diagram

Figure 8-92 shows the state diagram for a Source, Sink or Cable Plug on receiving a Get_Country_Codes Message. See
also Section 6.5.11.

Figure 8-92 Give Country Codes State Diagram

Get_Country_Codes Message
received PE_Give_Country_Codes
PE_SRC_Ready,
PE_SNK_Ready or Actions on entry:
PE_CBL_Ready Get present Country Codes from Device Policy Manager
Country_Codes Send Country_Codes Message (based on Device Policy
Message sent Manager response)

Power = Explicit Contract

PD = Connected

8.3.3.13.2.1 PE_Give_Country_Codes State

The Policy Engine Shall transition to the PE_Give_Country_Codes state, from either the PE_SRC_Ready, PE_SNK_Ready
or PE_CBL_Ready state, when a Get_Country_Codes Message is received.
On entry to the PE_Give_Country_Codes state the Policy Engine Shall request the country codes from the Device Policy
Manager and then send a Country_Codes Message containing these codes.
The Policy Engine Shall transition back to either the PE_SRC_Ready, PE_SNK_Ready or PE_CBL_Ready state as
appropriate (see Figure 8-66, Figure 8-67and Figure 8-126) when:
 The Country_Codes Message has been successfully sent.

8.3.3.13.3 Get Country Information State Diagram

Figure 8-93 shows the state diagram for a Source or Sink on receiving a request from the Device Policy Manager to get
the Port Partner’s Country Information. See also Section 6.5.12.

Figure 8-93 Get Country Information State Diagram

get country information

request PE_Get_Country_Info
from Device Policy Manager
PE_SRC_Ready or Actions on entry:
PE_SNK_Ready Send Get_Country_Info Message
Initialize and run SenderResponseTimer
Country_Info
Message received | Actions on exit:
SenderResponseTimer Pass Country Information/outcome to
Timeout Device Policy Manager
Power = Explicit Contract
PD = Connected

8.3.3.13.3.1 PE_Get_Country_Info State

The Policy Engine Shall transition to the PE_Get_Country_Info state, from either the PE_SRC_Ready or PE_SNK_Ready
state, due to a request to get the remote Manufacturer Information from the Device Policy Manager.
On entry to the PE_Get_Country_Info state the Policy Engine Shall send a Get_Manufacturer_Info Message and
initialize and run the SenderResponseTimer.
On exit from the PE_Get_Country_Info state the Policy Engine Shall inform the Device Policy Manager of the outcome
(country information or response timeout).

Page 456 USB Power Delivery Specification Revision 3.0, Version 1.1
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state as appropriate (see Figure
8-66 and Figure 8-67) when:
 A Country_Info Message is received
 Or SenderResponseTimer times out.

8.3.3.13.4 Give Country Information State Diagram

Figure 8-90 shows the state diagram for a Source, Sink or Cable Plug on receiving a Get_Country_Info Message. See
also Section 6.5.12.

Figure 8-94 Give Country Information State Diagram

Get_Country_Info Message
received PE_Give_Country_Info
PE_SRC_Ready,
PE_SNK_Ready or Actions on entry:
PE_CBL_Ready Get present Country Information from Device Policy
Country_Info Manager
Message sent Send Country_Info Message (based on Device Policy
Manager response)
Power = Explicit Contract
PD = Connected

8.3.3.13.4.1 PE_Give_Country_Info State

The Policy Engine Shall transition to the PE_Give_Country_Info state, from either the PE_SRC_Ready, PE_SNK_Ready
or PE_CBL_Ready state, when a Get_Country_Info Message is received.
On entry to the PE_Give_Country_Info state the Policy Engine Shall request the country information from the Device
Policy Manager and then send a Country_Info Message containing this country information.
The Policy Engine Shall transition back to either the PE_SRC_Ready, PE_SNK_Ready or PE_CBL_Ready state as
appropriate (see Figure 8-66, Figure 8-67and Figure 8-126) when:
 The Country_Info Message has been successfully sent.

8.3.3.14 Security State Diagrams

8.3.3.14.1 Send Security Request State Diagram

Figure 8-95 shows the state diagram for a Source or Sink on receiving a request from the Device Policy Manager to
send a security request. See also Section 6.5.8.

Figure 8-95 Send security request State Diagram

Send security request

from Device Policy Manager PE_Send_Security_Request
PE_SRC_Ready or
Actions on entry:
PE_SNK_Ready Send Security_Request Message
Security_Request
Message sent
Power = Explicit Contract
PD = Connected

8.3.3.14.1.1 PE_Send_Security_Request State

The Policy Engine Shall transition to the PE_Send_Security_Request state, from either the PE_SRC_Ready or
PE_SNK_Ready state, due to a request to send a security request from the Device Policy Manager.
On entry to the PE_Send_Security_Request state the Policy Engine Shall send a Security_Request Message.
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state as appropriate (see Figure
8-66 and Figure 8-67) when:

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 457
 The Security_Request Message has been sent.

8.3.3.14.2 Send Security Response State Diagram

Figure 8-96 shows the state diagram for a Source, Sink or Cable Plug on receiving a Security_Request Message. See
also Section 6.5.8.

Figure 8-96 Send security response State Diagram

Security_Request Message
received PE_Send_Security_Response
PE_SRC_Ready,
PE_SNK_Ready or Actions on entry:
PE_CBL_Ready Get present Security response from Device Policy
Security_Response Manager
Message sent Send Security_Response Message (based on Device
Policy Manager response)
Power = Explicit Contract
PD = Connected

8.3.3.14.2.1 PE_Send_Security_Response State

The Policy Engine Shall transition to the PE_Send_Security_Response state, from either the PE_SRC_Ready,
PE_SNK_Ready or PE_CBL_Ready state, when a Security_Request Message is received.
On entry to the PE_Send_Security_Response state the Policy Engine Shall request the appropriate response from the
Device Policy Manager and then send a Security_Response Message based on this status.
The Policy Engine Shall transition back to either the PE_SRC_Ready, PE_SNK_Ready or PE_CBL_Ready state as
appropriate (see Figure 8-66, Figure 8-67and Figure 8-126) when:
 The Security_Response Message has been successfully sent.

8.3.3.14.3 Security Response Received State Diagram

Figure 8-97 shows the state diagram for a Source or Sink on receiving a Security_Response Message. See also Section
6.5.8.

Figure 8-97 Security response received State Diagram

Security_Response Message
received PE_Security_Response_Received
PE_SRC_Ready or
PE_SNK_Ready Actions on entry:
Inform Device Policy Manager of the security response
details.
DPM informed

Power = Explicit Contract

PD = Connected

8.3.3.14.3.1 PE_Security_Response_Received State

The Policy Engine Shall transition to the PE_Security_Response_Received state, from either the PE_SRC_Ready or
PE_SNK_Ready when a Security_Response Message is received.
On entry to the PE_Security_Response_Received state the Policy Engine Shall inform the Device Policy Manager of the
details of the security response.
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state as appropriate (see Figure
8-66, Figure 8-67 and Figure 8-126) when:
 The Device Policy Manager has been informed.

Page 458 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.3.15 Firmware Update State Diagrams

8.3.3.15.1 Send Firmware Update Request State Diagram

Figure 8-98 shows the state diagram for a Source or Sink on receiving a request from the Device Policy Manager to
send a firmware update request. See also Section 6.5.9.

Figure 8-98 Send firmware update request State Diagram

Send firmware update request

from Device Policy Manager PE_Send_Firmware_Update_Request
PE_SRC_Ready or
Actions on entry:
PE_SNK_Ready Send Firmware_Update_Request Message
Firmware_Update_Request
Message sent
Power = Explicit Contract
PD = Connected

8.3.3.15.1.1 PE_Send_Firmware_Update_Request State

The Policy Engine Shall transition to the PE_Send_Firmware_Update_Request state, from either the PE_SRC_Ready or
PE_SNK_Ready state, due to a request to send a firmware update request from the Device Policy Manager.
On entry to the PE_Send_Firmware_Update_Request state the Policy Engine Shall send a Firmware_Update_Request
Message.
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state as appropriate (see Figure
8-66 and Figure 8-67) when:
 The Firmware_Update_Request Message has been sent.

8.3.3.15.2 Send Firmware Update Response State Diagram

Figure 8-99 shows the state diagram for a Source, Sink or Cable Plug on receiving a Firmware_Update_Request
Message. See also Section 6.5.9.

Figure 8-99 Send firmware update response State Diagram

Firmware_Update_Request
Message received PE_Send_Firmware_Update_Response
PE_SRC_Ready,
PE_SNK_Ready or Actions on entry:
PE_CBL_Ready Get present firmware update response from Device Policy
Firmware_Update_Response Manager
Message sent Send Firmware_Update_Response Message (based on
Device Policy Manager response)
Power = Explicit Contract
PD = Connected

8.3.3.15.2.1 PE_Send_Firmware_Update_Response State

The Policy Engine Shall transition to the PE_Send_Firmware_Update_Response state, from either the PE_SRC_Ready,
PE_SNK_Ready or PE_CBL_Ready state, when a Firmware_Update_Request Message is received.
On entry to the PE_Send_Firmware_Update_Response state the Policy Engine Shall request the appropriate response
from the Device Policy Manager and then send a Firmware_Update_Response Message based on this status.
The Policy Engine Shall transition back to either the PE_SRC_Ready, PE_SNK_Ready or PE_CBL_Ready state as
appropriate (see Figure 8-66, Figure 8-67and Figure 8-126) when:
 The Firmware_Update_Response Message has been successfully sent.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 459
 8.3.3.15.3 Firmware Update Response Received State Diagram
Figure 8-100 shows the state diagram for a Source or Sink on receiving a Firmware_Update_Response Message. See
also Section 6.5.9.

Figure 8-100 Firmware update response received State Diagram

Firmware_Update_Response
Message received PE_Firmware_Update_Response_Received
PE_SRC_Ready or
PE_SNK_Ready Actions on entry:
Inform Device Policy Manager of the firmware update
response details.
DPM informed

Power = Explicit Contract

PD = Connected

8.3.3.15.3.1 PE_Firmware_Update_Response_Received State

The Policy Engine Shall transition to the PE_Firmware_Update_Response_Received state, from either the
PE_SRC_Ready or PE_SNK_Ready when a Firmware_Update_Response Message is received.
On entry to the PE_Firmware_Update_Response_Received state the Policy Engine Shall inform the Device Policy
Manager of the details of the firmware update response.
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state as appropriate (see Figure
8-66, Figure 8-67 and Figure 8-126) when:
 The Device Policy Manager has been informed.

8.3.3.16 Dual-Role Port State Diagrams

Dual-Role Ports that combine Source and Sink capabilities Shall comprise Source and Sink Policy Engine state
machines. In addition they Shall have the capability to perform a Power Role Swap from the PE_SRC_Ready or
PE_SNK_Ready states and Shall return to USB Default Operation on a Hard Reset.
The State Diagrams in this section Shall apply to every [USB Type-C 1.2] DRP.

Page 460 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.3.16.1 DFP to UFP Data Role Swap State Diagram
Figure 8-101 shows the additional state diagram required to perform a Data Role Swap from DFP to UFP operation
and the changes that Shall be followed for error and Hard Reset handling.

Figure 8-101: DFP to UFP Data Role Swap State Diagram

DR_Swap message received &

in Modal Operation
PE_SRC_Hard_Reset or
PE_SNK_Hard_Reset PE_SRC_Ready or
PE_SNK_Ready
(DFP)

Data Role Swap required

(indication from Reject message received |
Message sent Device Policy Manager)Wait message received |
DR_Swap message received & SenderResponseTimer
not in Modal Operation timeout

PE_DRS_DFP_UFP_ PE_DRS_DFP_UFP_
Reject_Swap Data Role Swap not ok | PE_DRS_DFP_UFP_
Further evaluation
Evaluate_Swap Send_Swap
Actions on entry: required Actions on entry:
Send Reject or Wait message Get evaluation of Data Role Swap Actions on entry:
as appropriate request from Device Policy Manager Send Swap DR message
Initialize and run
Power = Explicit Contract SenderResponseTimer
Power = Explicit Contract
PD = Connected
PD = Connected Power = Explicit Contract
PD = Connected
Data Role Swap ok
Accept received
PE_DRS_DFP_UFP_
Accept_Swap
Actions on entry:
Send Accept message

Power = Explicit Contract

PD = Connected

Accept message
sent

PE_DRS_DFP_UFP_
Change_to_UFP
Actions on entry:
Request Device Policy Manager to
change port to UFP
Power = Explicit Contract
PD = Connected

Port changed to UFP

PE_SRC_Ready or
PE_SNK_Ready
(UFP)

8.3.3.16.1.1 PE_SRC_Ready or PE_SNK_Ready State

The Data Role Swap process Shall start only from either the PE_SRC_Ready or PE_SNK_Ready state where power is
stable.
The Policy Engine Shall transition to the PE_DRS_DFP_UFP_Evaluate_Swap state when:
 A DR_Swap Message is received and
 There are no Active Modes (not in Modal Operation).
The Policy Engine Shall transition to either the PE_SRC_Hard_Reset or PE_SNK_Hard_Reset states when:
 A DR_Swap Message is received and

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 461
 There are one or more Active Modes (Modal Operation).
The Policy Engine Shall transition to the PE_DRS_DFP_UFP_Send_Swap state when:
 The Device Policy Manager indicates that a Data Role Swap is required.

8.3.3.16.1.2 PE_DRS_DFP_UFP_Evaluate_Swap State

On entry to the PE_DRS_DFP_UFP_Evaluate_Swap state the Policy Engine Shall ask the Device Policy Manager
whether a Data Role Swap can be made.
The Policy Engine Shall transition to the PE_DRS_DFP_UFP_Accept_Swap state when:
 The Device Policy Manager indicates that a Data Role Swap is ok.
The Policy Engine Shall transition to the PE_DRS_DFP_UFP_Reject_Swap state when:
 The Device Policy Manager indicates that a Data Role Swap is not ok.
 Or further evaluation of the Data Role Swap request is needed.

8.3.3.16.1.3 PE_DRS_DFP_UFP_Accept_Swap State

On entry to the PE_DRS_DFP_UFP_Accept_Swap state the Policy Engine Shall request the Protocol Layer to send an
Accept Message.
The Policy Engine Shall transition to the PE_DRS_DFP_UFP_Change_to_UFP state when:
 The Accept Message has been sent.

8.3.3.16.1.4 PE_DRS_DFP_UFP_Change_to_UFP State

On entry to the PE_DRS_DFP_UFP_Change_to_UFP state the Policy Engine Shall request the Device Policy Manager to
change the Port from a DFP to a UFP.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state when:
 The Device Policy Manager indicates that the Port has been changed to a UFP.

8.3.3.16.1.5 PE_DRS_DFP_UFP_Send_Swap State

On entry to the PE_DRS_DFP_UFP_Send_Swap state the Policy Engine Shall request the Protocol Layer to send a
DR_Swap Message and Shall start the SenderResponseTimer.
On exit from the PE_DRS_DFP_UFP_Send_Swap state the Policy Engine Shall stop the SenderResponseTimer.
The Policy Engine Shall continue as a DFP and Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state
when:
 A Reject Message is received.
 Or a Wait Message is received.
 Or the SenderResponseTimer times out.
The Policy Engine Shall transition to the PE_DRS_DFP_UFP_Change_to_UFP state when:
 An Accept Message is received.

8.3.3.16.1.6 PE_DRS_DFP_UFP_Reject_Swap State

On entry to the PE_DRS_DFP_UFP_Reject_Swap state the Policy Engine Shall request the Protocol Layer to send:
 A Reject Message if the device is unable to perform a Data Role Swap at this time.
 A Wait Message if further evaluation of the Data Role Swap request is required. Note: in this case it is expected
that one of the Port Partners will send a DR_Swap Message at a later time (see Section 6.3.12.3).

Page 462 USB Power Delivery Specification Revision 3.0, Version 1.1
The Policy Engine Shall continue as a DFP and Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state
when:
 The Reject or Wait Message has been sent.

8.3.3.16.2 UFP to DFP Data Role Swap State Diagram

Figure 8-102 shows the additional state diagram required to perform a Data Role Swap from DRP UFP to DFP
operation and the changes that Shall be followed for error and Hard Reset handling.

Figure 8-102: UFP to DFP Data Role Swap State Diagram

DR_Swap message received &

PE_SRC_Hard_Reset or in Modal Operation
PE_SNK_Hard_Reset

PE_SRC_Ready or
PE_SNK_Ready
(UFP)
Reject message received |
Wait message received |
SenderResponseTimer
timeout
DR_Swap message received & Data Role Swap required
not in Modal Operation (indication from
Message sent Device Policy Manager)

PE_DRS_UFP_DFP_ PE_DRS_UFP_DFP_ PE_DRS_UFP_DFP_

Reject_Swap Evaluate_Swap Send_Swap
Data Role Swap not ok |
Further evaluation Actions on entry:
Actions on entry: Actions on entry:
required Get evaluation of Data Role Swap
Send Reject or Wait message Send Swap DR message
request from Device Policy Manager
as appropriate Initialize and run
SenderResponseTimer
Power = Explicit Contract
Power = Explicit Contract
PD = Connected Power = Explicit Contract
PD = Connected
PD = Connected
Data Role Swap ok

PE_DRS_UFP_DFP_ Accept received

Accept_Swap
Actions on entry:
Send Accept message

Power = Explicit Contract

PD = Connected

Accept message
sent

PE_DRS_UFP_DFP_
Change_to_DFP
Actions on entry:
Request Device Policy Manager to
change port to DFP

Power = Explicit Contract

PD = Connected

Port changed to DFP

PE_SRC_Ready or
PE_SNK_Ready
(DFP)

8.3.3.16.2.1 PE_SRC_Ready or PE_SNK_Ready State

The Data Role Swap process Shall start only from the either the PE_SRC_Ready or PE_SNK_Ready state where power
is stable.
The Policy Engine Shall transition to the PE_DRS_UFP_DFP_Evaluate_Swap state when:

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 463
 A DR_Swap Message is received and
 There are no Active Modes (not in Modal Operation).
The Policy Engine Shall transition to either the PE_SRC_Hard_Reset or PE_SNK_Hard_Reset states when:
 A DR_Swap Message is received and
 There are one or more Active Modes (Modal Operation).
The Policy Engine Shall transition to the PE_DRS_UFP_DFP_Send_Swap state when:
 The Device Policy Manager indicates that a Data Role Swap is required.

8.3.3.16.2.2 PE_DRS_UFP_DFP_Evaluate_Swap State

On entry to the PE_DRS_UFP_DFP_Evaluate_Swap state the Policy Engine Shall ask the Device Policy Manager
whether a Data Role Swap can be made.
The Policy Engine Shall transition to the PE_DRS_UFP_DFP_Accept_Swap state when:
 The Device Policy Manager indicates that a Data Role Swap is ok.
The Policy Engine Shall transition to the PE_DRS_UFP_DFP_Reject_Swap state when:
 The Device Policy Manager indicates that a Data Role Swap is not ok.
 Or further evaluation of the Data Role Swap request is needed.

8.3.3.16.2.3 PE_DRS_UFP_DFP_Accept_Swap State

On entry to the PE_DRS_UFP_DFP_Accept_Swap state the Policy Engine Shall request the Protocol Layer to send an
Accept Message.
The Policy Engine Shall transition to the PE_DRS_UFP_DFP_Change_to_DFP state when:
 The Accept Message has been sent.

8.3.3.16.2.4 PE_DRS_UFP_DFP_Change_to_DFP State

On entry to the PE_DRS_UFP_DFP_Change_to_DFP state the Policy Engine Shall request the Device Policy Manager to
change the Port from a UFP to a DFP.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state when:
 The Device Policy Manager indicates that the Port has been changed to a DFP.

8.3.3.16.2.5 PE_DRS_UFP_DFP_Send_Swap State

On entry to the PE_DRS_UFP_DFP_Send_Swap state the Policy Engine Shall request the Protocol Layer to send a
DR_Swap Message and Shall start the SenderResponseTimer.
On exit from the PE_DRS_UFP_DFP_Send_Swap state the Policy Engine Shall stop the SenderResponseTimer.
The Policy Engine Shall continue as a UFP and Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state
when:
 A Reject Message is received.
 Or a Wait Message is received.
 Or the SenderResponseTimer times out.
The Policy Engine Shall transition to the PE_DRS_UFP_DFP_Change_to_DFP state when:
 An Accept Message is received.

Page 464 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.3.16.2.6 PE_DRS_UFP_DFP_Reject_Swap State
On entry to the PE_DRS_UFP_DFP_Reject_Swap state the Policy Engine Shall request the Protocol Layer to send:
 A Reject Message if the device is unable to perform a Data Role Swap at this time.
 A Wait Message if further evaluation of the Data Role Swap request is required. Note: in this case it is expected
that one of the Port Partners will send a DR_Swap Message at a later time (see Section 6.3.12.3).
The Policy Engine Shall continue as a UFP and Shall transition to the either the PE_SRC_Ready or PE_SNK_Ready state
when:
 The Reject or Wait Message has been sent.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 465
 8.3.3.16.3 Policy Engine in Source to Sink Power Role Swap State Diagram
Dual-Role Ports that combine Source and Sink capabilities Shall comprise Source and Sink Policy Engine state
machines. In addition they Shall have the capability to do a Power Role Swap from the PE_SRC_Ready state and Shall
return to USB Default Operation on a Hard Reset.
Figure 8-103 shows the additional state diagram required to perform a Power Role Swap from Source to Sink roles
and the changes that Shall be followed for error handling.

Figure 8-103: Dual-Role Port in Source to Sink Power Role Swap State Diagram

Message sent
PE_SRC_Ready
Reject message received |
Wait message received |
PR_Swap message received Power Role Swap required SenderResponseTimer
(indication from timeout
Device Policy Manager)
PE_PRS_SRC_SNK_ PE_PRS_SRC_SNK_
Reject_PR_Swap Power Role Swap not ok | Evaluate_Swap
Further evaluation
Actions on entry: required Actions on entry: PE_PRS_SRC_SNK_
Send Reject or Wait message Get evaluation of swap request from Send_Swap
as appropriate Device Policy Manager
Actions on entry:
Power = Explicit Contract Power = Explicit Contract Send PR_Swap message
PD = Connected PD = Connected Initialize and run
SenderResponseTimer
Power Role Swap ok
Power = Explicit Contract
PD = Connected
PE_PRS_SRC_SNK_
Accept_Swap
Actions on entry:
Accept received
Send Accept message
Power = Explicit Contract
PD = Connected

Accept message
sent

PE_PRS_SRC_SNK_
Transition_to_off
Actions on entry:
Tell Device Policy Manager to turn off
power supply

Power = Transition to stop sourcing

PD = Connected

Source turned off

PE_PRS_SRC_SNK_
Assert_Rd
Actions on entry:
Request DPM to assert Rd

Power = Source off

PD = Connected

Rd asserted

PSSourceOnTimer Timeout |
PS_RDY message not sent after retries (no GoodCRC received)
PE_PRS_SRC_SNK_
Wait_Source_on
Actions on entry:
Send PS_RDY message
Initialize and run PSSourceOnTimer

Power = Source off

PD = Connected

PS_RDY message
received

ErrorRecovery PE_SNK_Startup

8.3.3.16.3.1 PE_SRC_Ready State

The Power Role Swap process Shall start only from the PE_SRC_Ready state where power is stable.

Page 466 USB Power Delivery Specification Revision 3.0, Version 1.1
The Policy Engine Shall transition to the PE_PRS_SRC_SNK_Evaluate_Swap state when:
 A PR_Swap Message is received.
The Policy Engine Shall transition to the PE_PRS_SRC_SNK_Send_Swap state when:
 The Device Policy Manager indicates that a Power Role Swap is required.

8.3.3.16.3.2 PE_PRS_SRC_SNK_Evaluate_Swap State

On entry to the PE_PRS_SRC_SNK_Evaluate_Swap state the Policy Engine Shall ask the Device Policy Manager
whether a Power Role Swap can be made.
The Policy Engine Shall transition to the PE_PRS_SRC_SNK_Accept_Swap state when:
 The Device Policy Manager indicates that a Power Role Swap is ok.
The Policy Engine Shall transition to the PE_PRS_SRC_SNK_Reject_Swap state when:
 The Device Policy Manager indicates that a Power Role Swap is not ok.
 Or further evaluation of the Power Role Swap request is needed.

8.3.3.16.3.3 PE_PRS_SRC_SNK_Accept_Swap State

On entry to the PE_PRS_SRC_SNK_Accept_Swap state the Policy Engine Shall request the Protocol Layer to send an
Accept Message.
The Policy Engine Shall transition to the PE_PRS_SRC_SNK_Transition_to_off state when:
 The Accept Message has been sent.

8.3.3.16.3.4 PE_PRS_SRC_SNK_Transition_to_off State

On entry to the PE_PRS_SRC_SNK_Transition_to_off state the Policy Engine Shall request the Device Policy Manager to
turn off the Source.
The Policy Engine Shall transition to the PE_PRS_SRC_SNK_Assert_Rd state when:
 The Device Policy Manager indicates that the Source has been turned off.

8.3.3.16.3.5 PE_PRS_SRC_SNK_Assert_Rd State

On entry to the PE_PRS_SRC_SNK_Assert_Rd state the Policy Engine Shall request the Device Policy Manager to
change the resistor asserted on the CC wire from Rp to Rd.
The Policy Engine Shall transition to the PE_PRS_SRC_SNK_Wait_Source_on state when:
 The Device Policy Manager indicates that Rd is asserted.

8.3.3.16.3.6 PE_PRS_SRC_SNK_Wait_Source_on State

On entry to the PE_PRS_SRC_SNK_Wait_Source_on state the Policy Engine Shall request the Protocol Layer to send a
PS_RDY Message and Shall start the PSSourceOnTimer.
On exit from the Source off state the Policy Engine Shall stop the PSSourceOnTimer.
The Policy Engine Shall transition to the PE_SNK_Startup when:
 A PS_RDY Message is received indicating that the remote Source is now supplying power.
The Policy Engine Shall transition to the ErrorRecovery state when:
 The PSSourceOnTimer times out or

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 467
 The PS_RDY Message is not sent after retries (a GoodCRC Message has not been received). Note: a soft reset Shall
Not be initiated in this case.

8.3.3.16.3.7 PE_PRS_SRC_SNK_Send_Swap State

On entry to the PE_PRS_SRC_SNK_Send_Swap state the Policy Engine Shall request the Protocol Layer to send a
PR_Swap Message and Shall start the SenderResponseTimer.
On exit from the PE_PRS_SRC_SNK_Send_Swap state the Policy Engine Shall stop the SenderResponseTimer.
The Policy Engine Shall transition to the PE_SRC_Ready state when:
 A Reject Message is received.
 Or a Wait Message is received.
 Or the SenderResponseTimer times out.
The Policy Engine Shall transition to the PE_PRS_SRC_SNK_Transition_to_off state when:
 An Accept Message is received.

8.3.3.16.3.8 PE_PRS_SRC_SNK_Reject_Swap State

On entry to the PE_PRS_SRC_SNK_Reject_Swap state the Policy Engine Shall request the Protocol Layer to send:
 A Reject Message if the device is unable to perform a Power Role Swap at this time.
 A Wait Message if further evaluation of the Power Role Swap request is required. Note: in this case it is expected
that one of the Port Partners will send a PR_Swap Message at a later time (see Section 6.3.12.2).
The Policy Engine Shall transition to the PE_SRC_Ready when:
 The Reject or Wait Message has been sent.

8.3.3.16.4 Policy Engine in Sink to Source Power Role Swap State Diagram
Dual-Role Ports that combine Sink and Source capabilities Shall comprise Sink and Source Policy Engine state
machines. In addition they Shall have the capability to do a Power Role Swap from the PE_SNK_Ready state and Shall
return to USB Default Operation on a Hard Reset.
Figure 8-104 shows the additional state diagram required to perform a Power Role Swap from Sink to Source roles
and the changes that Shall be followed for error handling.

Page 468 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-104: Dual-role Port in Sink to Source Power Role Swap State Diagram

Message sent
PE_SNK_Ready
Reject message received |
Power Role Swap required Wait message received |
PR_Swap message received SenderResponseTimer
(indication from
Device Policy Manager) timeout

PE_PRS_SNK_SRC_ PE_PRS_SNK_SRC_
Reject_Swap Power Role Swap not ok |
Evaluate_Swap
Further evaluation PE_PRS_SNK_SRC_
Actions on entry: required Actions on entry: Send_Swap
Send Reject or Wait message Get evaluation of swap request from
as appropriate Device Policy Manager Actions on entry:
Send PR_Swap message
Power = Explicit Contract Power = Explicit Contract Initialize and run
PD = Connected PD = Connected SenderResponseTimer

Power Role Swap ok Power = Explicit Contract

PD = Connected

PE_PRS_SNK_SRC_
Accept_Swap
Actions on entry:
Send Accept message Accept message
received
Power = Explicit Contract
PD = Connected

Accept message sent

PE_PRS_SNK_SRC_
Transition_to_off
Actions on entry:
PSSourceOffTimer timeout Initialize and run PSSourceOffTimer
Tell Device Policy Manager to turn off
Power Sink.
Power = Transition to stop sinking
PD = Connected

PS_RDY message received

PE_PRS_SNK_SRC_
Assert_Rp
Actions on entry:
ErrorRecovery Request DPM to assert Rp

Power = Source off

PD = Connected

Rp asserted

PE_PRS_SNK_SRC_
Source_on
Actions on entry:
Tell Device Policy Manager to turn on
PS_RDY message not sent Source
after retries (no GoodCRC received)
Actions on exit:
Send PS_RDY message

Power = Transition to source on

PD = Connected

Source is on

PE_SRC_Startup

8.3.3.16.4.1 PE_SNK_Ready State

The Power Role Swap process Shall start only from the PE_SNK_Ready state where power is stable.
The Policy Engine Shall transition to the PE_PRS_SNK_SRC_Evaluate_Swap state when:
 A PR_Swap Message is received.
The Policy Engine Shall transition to the PE_PRS_SNK_SRC_Send_Swap state when:
 The Device Policy Manager indicates that a Power Role Swap is required.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 469
 8.3.3.16.4.2 PE_PRS_SNK_SRC_Evaluate_Swap State
On entry to the PE_PRS_SNK_SRC_Send_Swap state the Policy Engine Shall ask the Device Policy Manager whether a
Power Role Swap can be made.
The Policy Engine Shall transition to the PE_PRS_SNK_SRC_Accept_Swap state when:
 The Device Policy Manager indicates that a Power Role Swap is ok.
The Policy Engine Shall transition to the PE_PRS_SNK_SRC_Reject_Swap state when:
 The Device Policy Manager indicates that a Power Role Swap is not ok.

8.3.3.16.4.3 PE_PRS_SNK_SRC_Accept_Swap State

On entry to the PE_PRS_SNK_SRC_Accept_Swap state the Policy Engine Shall request the Protocol Layer to send an
Accept Message.
The Policy Engine Shall transition to the PE_PRS_SNK_SRC_Transition_to_off state when:
 The Accept Message has been sent.

8.3.3.16.4.4 PE_PRS_SNK_SRC_Transition_to_off State

On entry to the PE_PRS_SNK_SRC_Transition_to_off state the Policy Engine Shall initialize and run the
PSSourceOffTimer and then request the Device Policy Manager to turn off the Sink.
The Policy Engine Shall transition to the ErrorRecovery state when:
 The PSSourceOffTimer times out.
The Policy Engine Shall transition to the PE_PRS_SNK_SRC_Assert_Rp state when:
 A PS_RDY Message is received.

8.3.3.16.4.5 PE_PRS_SNK_SRC_Assert_Rp State

On entry to the PE_PRS_SNK_SRC_Assert_Rp state the Policy Engine Shall request the Device Policy Manager to
change the resistor asserted on the CC wire from Rd to Rp.
The Policy Engine Shall transition to the PE_PRS_SNK_SRC_Source_on state when:
 The Device Policy Manager indicates that Rd is asserted.

8.3.3.16.4.6 PE_PRS_SNK_SRC_Source_on State

On entry to the PE_PRS_SNK_SRC_Source_on state the Policy Engine Shall request the Device Policy Manager to turn
on the Source.
On exit from the PE_PRS_SNK_SRC_Source_on state the Policy Engine Shall send a PS_RDY Message.
The Policy Engine Shall transition to the PE_SRC_Startup state when:
 The Source Port has been turned on.
The Policy Engine Shall transition to the ErrorRecovery state when:
 The PS_RDY Message is not sent after retries (a GoodCRC Message has not been received). A soft reset Shall Not
be initiated in this case.

8.3.3.16.4.7 PE_PRS_SNK_SRC_Send_Swap State

On entry to the PE_PRS_SNK_SRC_Send_Swap state the Policy Engine Shall request the Protocol Layer to send a
PR_Swap Message and Shall initialize and run the SenderResponseTimer.

Page 470 USB Power Delivery Specification Revision 3.0, Version 1.1
The Policy Engine Shall transition to the PE_SNK_Ready state when:
 A Reject Message is received.
 Or a Wait Message is received.
 Or the SenderResponseTimer times out.
The Policy Engine Shall transition to the PE_PRS_SNK_SRC_Transition_to_off state when:
 An Accept Message is received.

8.3.3.16.4.8 PE_PRS_SNK_SRC_Reject_Swap State

On entry to the PE_PRS_SNK_SRC_Reject_Swap state the Policy Engine Shall request the Protocol Layer to send:
 A Reject Message if the device is unable to perform a Power Role Swap at this time.
 A Wait Message if further evaluation of the Power Role Swap request is required. Note: in this case it is expected
that one of the Port Partners will send a PR_Swap Message at a later time (see Section 6.3.12.2).
The Policy Engine Shall transition to the PE_SNK_Ready state when:
 The Reject or Wait Message has been sent.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 471
 8.3.3.16.5 Policy Engine in Source to Sink Fast Role Swap State Diagram
Dual-Role Ports that combine Source and Sink capabilities Shall comprise Source and Sink Policy Engine state
machines. In addition they Should have the capability to do a Fast Role Swap from the PE_SRC_Ready state and Shall
return to USB Default Operation on a Hard Reset.
Figure 8-103 shows the additional state diagram required to perform a Fast Role Swap from Source to Sink roles and
the changes that Shall be followed for error handling.

Figure 8-105: Dual-Role Port in Source to Sink Fast Role Swap State Diagram

FR_Swap Message received

PE_SRC_Ready

PE_FRS_SRC_SNK_
CC_Signal DPM indicates Fast Role Swap
Actions on entry: is being signaled
CC signaled on CC Wire
Power = Implicit Contract
PD = Connected

FR_Swap Message received

PE_FRS_SRC_SNK_
Evaluate_Swap
Actions on entry:
Power Role Swap not ok | Get evaluation of swap request from
Fast Role Swap not signaled Device Policy Manager

Power = Implicit Contract

PD = Connected

Power Role Swap ok

PE_FRS_SRC_SNK_
Accept_Swap
Actions on entry:
Send Accept message
Power = Implicit Contract
PD = Connected

Accept message
PS_RDY message not sent after sent
retries (no GoodCRC received)

PE_FRS_SRC_SNK_
Transition_to_off
Actions on entry:
PE_SRC_Hard_Reset Wait for VBUS to reach vSafe5V

Power = Implicit contract

PD = Connected

VBUS at vSafe5V

PE_FRS_SRC_SNK_
Assert_Rd
Actions on entry:
Request DPM to assert Rd

Power = Implicit contract

PD = Connected

Rd asserted

PE_FRS_SRC_SNK_
PSSourceOnTimer Timeout | Wait_Source_on
PS_RDY message not sent after
retries (no GoodCRC received) Actions on entry:
Send PS_RDY message
Initialize and run PSSourceOnTimer

Power = Implicit contract

PD = Connected

PS_RDY message
received

ErrorRecovery PE_SNK_Startup

Page 472 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.3.16.5.1 PE_SRC_Ready State
The Fast Role Swap process Shall start only from the PE_SRC_Ready state where power is stable.
The Policy Engine Shall transition to the PE_FRS_SRC_SNK_Evaluate_Swap state when:
 An FR_Swap Message is received.

8.3.3.16.5.2 PE_FRS_SRC_SNK_CC_Signal State

The Policy Engine Shall transition to the PE_FRS_SRC_SNK_CC_Signal state from any other state provided there is an
Explicit Contract in place when:
 The Device Policy Manager indicates that Fast Role Swap signaling is being applied to the CC Wire.
In the PE_FRS_SRC_SNK_CC_Signal state the Policy Engine waits for an FR_Swap Message from the new Source.
The Policy Engine Shall transition to the PE_FRS_SRC_SNK_Evaluate_Swap state when:
 An FR_Swap Message is received.

8.3.3.16.5.3 PE_FRS_SRC_SNK_Evaluate_Swap State

On entry to the PE_FRS_SRC_SNK_Evaluate_Swap state the Policy Engine Shall ask the Device Policy Manager whether
a Fast Role Swap can be made.
The Policy Engine Shall transition to the PE_FRS_SRC_SNK_Accept_Swap state when:
 The Device Policy Manager indicates that a Fast Role Swap is ok.
The Policy Engine Shall transition to the PE_SRC_Hard_Reset state when:
 The Device Policy Manager indicates that a Fast Role Swap is not ok or
 The Device Policy Manager indicates that a Fast Role Swap is not being signaled.

8.3.3.16.5.4 PE_FRS_SRC_SNK_Accept_Swap State

On entry to the PE_FRS_SRC_SNK_Accept_Swap state the Policy Engine Shall request the Protocol Layer to send an
Accept Message.
The Policy Engine Shall transition to the PE_FRS_SNK_SRC_Transition_to_off state when:
 The Accept Message has been sent.
The Policy Engine Shall transition to the PE_SRC_Hard_Reset state when:
 The Accept Message is not sent after retries (a GoodCRC Message has not been received). Note: a soft reset Shall
Not be initiated in this case.

8.3.3.16.5.5 PE_FRS_SRC_SNK_Transition_to_off State

On entry to the PE_FRS_SNK_SRC_Transition_to_off state the Policy Engine Shall until VBUS has discharged to vSafe5V.
The Policy Engine Shall transition to the PE_PRS_SRC_SNK_Assert_Rd state when:
 The Device Policy Manager indicates that VBUS has discharged to vSafe5V.

8.3.3.16.5.6 PE_FRS_SRC_SNK_Assert_Rd State

On entry to the PE_PRS_SRC_SNK_Assert_Rd state the Policy Engine Shall request the Device Policy Manager to
change the resistor asserted on the CC wire from Rp to Rd.
The Policy Engine Shall transition to the PE_PRS_SRC_SNK_Wait_Source_on state when:
 The Device Policy Manager indicates that Rd is asserted.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 473
 8.3.3.16.5.7 PE_FRS_SRC_SNK_Wait_Source_on State
On entry to the PE_PRS_SRC_SNK_Wait_Source_on state the Policy Engine Shall request the Protocol Layer to send a
PS_RDY Message and Shall start the PSSourceOnTimer.
On exit from the Source off state the Policy Engine Shall stop the PSSourceOnTimer.
The Policy Engine Shall transition to the PE_SNK_Startup when:
 A PS_RDY Message is received indicating that the new Source is now applying Rp.
The Policy Engine Shall transition to the ErrorRecovery state when:
 The PSSourceOnTimer times out or
 The PS_RDY Message is not sent after retries (a GoodCRC Message has not been received). Note: a soft reset Shall
Not be initiated in this case.

8.3.3.16.6 Policy Engine in Sink to Source Fast Role Swap State Diagram
Dual-Role Ports that combine Sink and Source capabilities Shall comprise Sink and Source Policy Engine state
machines. In addition they Should have the capability to do a Fast Role Swap from the PE_SNK_Ready state and Shall
return to USB Default Operation on a Hard Reset.
Figure 8-104 shows the additional state diagram required to perform a Fast Role Swap from Sink to Source roles and
the changes that Shall be followed for error handling.

Page 474 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-106: Dual-role Port in Sink to Source Fast Role Swap State Diagram

Fast Swap signal detected on CC Wire and vSafe5V applied

From Device Policy Manager

PE_FRS_SNK_SRC_
Start_AMS
Actions on entry:
Notify the Protocol Layer that
the first Message in the AMS
will follow.

Power = Implicit Contract

PD = Connected

Protocol Layer notified

PE_FRS_SNK_SRC_
SenderResponseTimer timeout | Send_Swap
FR_Swap message not sent Actions on entry:
after retries (no GoodCRC received) Send FR_Swap message
Initialize and run
SenderResponseTimer

Power = Implicit Contract

PD = Connected

Accept message
received

PE_FRS_SNK_SRC_
Transition_to_off
PSSourceOffTimer timeout Actions on entry:
Initialize and run PSSourceOffTimer

Power = Implicit Contract

PD = Connected

PS_RDY message received

PE_FRS_SNK_SRC_Vbus_Applied
Actions on entry:
Request Device Policy Manager to notify
when vSafe5v is being applied by the local
power source.

Power = Implicit Contract

PD = Connected

New Source is applying vSafe5V

PE_FRS_SNK_SRC_
Assert_Rp
Actions on entry:
Request DPM to assert Rp

Power = Implicit Contract

PD = Connected

Rp asserted

PE_FRS_SNK_SRC_
Source_on
PS_RDY message not sent Actions on entry:
after retries (no GoodCRC received) Send PS_RDY Message

Power = Transition to source on

PD = Connected

PS_RDY Message sent

ErrorRecovery PE_SRC_Startup

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 475
 8.3.3.16.6.1 PE_FRS_SNK_SRC_Start_AMS State
The Policy Engine Shall transition to the PE_FRS_SNK_SRC_Send_Swap state from any other state provided there is an
Explicit Contract in place when:
 The Device Policy Manager indicates that a Fast Role Swap signal has been detected on the CC Wire and vSafe5V
has been applied to VBUS.
On entry to the PE_FRS_SNK_SRC_Start_AMS state the Policy Engine Shall notify the Protocol Layer that the first
Message in an AMS will follow.
The Policy Engine Shall transition to the PE_FRS_SNK_SRC_Send_Swap state when:
 The Protocol Layer has been notified.

8.3.3.16.6.2 PE_FRS_SNK_SRC_Send_Swap State

On entry to the PE_FRS_SNK_SRC_Send_Swap state the Policy Engine Shall request the Protocol Layer to send an
FR_Swap Message and Shall initialize and run the SenderResponseTimer.
The Policy Engine Shall transition to the PE_FRS_SNK_SRC_Transition_to_off state when:
 An Accept Message is received.
The Policy Engine Shall transition to the ErrorRecovery state when:
 The SenderResponseTimer times out or
 The FR_Swap Message is not sent after retries (a GoodCRC Message has not been received). A soft reset Shall Not
be initiated in this case.

8.3.3.16.6.3 PE_FRS_SNK_SRC_Transition_to_off State

On entry to the PE_FRS_SNK_SRC_Transition_to_off state the Policy Engine Shall initialize and run the
PSSourceOffTimer and then request the Device Policy Manager to turn off the Sink.
The Policy Engine Shall transition to the ErrorRecovery state when:
 The PSSourceOffTimer times out.
The Policy Engine Shall transition to the PE_FRS_SNK_SRC_Vbus_Applied state when:
 A PS_RDY Message is received.

8.3.3.16.6.4 PE_FRS_SNK_SRC_Vbus_Applied State

On entry to the PE_FRS_SNK_SRC_Vbus_Applied state the Policy Engine waits for a notification from the Device Policy
Manager that the local power source has applied vSafe5V to VBUS (see Section5.8.6.3). Note this could have already
been applied prior to entering this state or could be applied while waiting in this state.
The Policy Engine Shall transition to the PE_FRS_SNK_SRC_Assert_Rp state when:
 The Device Policy Manager indicates that vSafe5V is being applied.

8.3.3.16.6.5 PE_FRS_SNK_SRC_Assert_Rp State

On entry to the PE_FRS_SNK_SRC_Assert_Rp state the Policy Engine Shall request the Device Policy Manager to change
the resistor asserted on the CC wire from Rd to Rp.
The Policy Engine Shall transition to the PE_FRS_SNK_SRC_Source_on state when:
 The Device Policy Manager indicates that Rp is asserted.

Page 476 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.3.16.6.6 PE_FRS_SNK_SRC_Source_on State
On entry to the PE_FRS_SNK_SRC_Source_on state the Policy Engine Shall request the Device Policy Manager to turn
on the Source.
On exit from the PE_FRS_SNK_SRC_Source_on state (except if the exit is to send a Ping Message) the Policy Engine
Shall send a PS_RDY Message.
The Policy Engine Shall transition to the PE_SRC_Startup state when:
 The PS_RDY Message has been sent.
The Policy Engine Shall transition to the ErrorRecovery state when:
 The PS_RDY Message is not sent after retries (a GoodCRC Message has not been received). A soft reset Shall Not
be initiated in this case.

8.3.3.16.7 Dual-Role (Source Port) Get Source Capabilities State Diagram

Figure 8-107 shows the state diagram for a Dual-Role device, presently operating as a Source, on receiving a request
from the Device Policy Manager to get the Port Partner’s Source capabilities. See also Section 6.4.1.1.3.

Figure 8-107 Dual-Role (Source) Get Source Capabilities diagram

get source capabilities request PE_DR_SRC_Get_Source_Cap

from Device Policy Manager
PE_SRC_Ready Actions on entry:
Send Get_Source_Cap message
Source capabilities Initialize and run SenderResponseTimer
message received |
Actions on exit:
SenderResponseTimer
Pass source capabilities/outcome to
Timeout |
Device Policy Manager
Reject message received
Power = Explicit Contract
PD = Connected

8.3.3.16.7.1 PE_DR_SRC_Get_Source_Cap State

The Policy Engine Shall transition to the PE_DR_SRC_Get_Source_Cap state, from the PE_SRC_Ready state, due to a
request to get the remote source capabilities from the Device Policy Manager.
On entry to the PE_DR_SRC_Get_Source_Cap state the Policy Engine Shall send a Get_Source_Cap Message and
initialize and run the SenderResponseTimer.
On exit from the PE_DR_SRC_Get_Source_Cap state the Policy Engine Shall inform the Device Policy Manager of the
outcome (capabilities or response timeout).
The Policy Engine Shall transition back to the PE_SRC_Ready state (see Figure 8-66) when:
 A Source_Capabilities Message is received
 Or SenderResponseTimer times out
 Or a Reject Message is received.

8.3.3.16.8 Dual-Role (Source Port) Give Sink Capabilities State Diagram

Figure 8-108 shows the state diagram for a Dual-Role device, presently operating as a Source, on receiving a
Get_Sink_Cap Message. See also Section 6.4.1.1.3.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 477
 Figure 8-108 Dual-Role (Source) Give Sink Capabilities diagram

Get_Sink_Cap message
received PE_DR_SRC_Give_Sink_Cap
PE_SRC_Ready
Actions on entry:
Get present sink capabilities from Device Policy Manager
Sink Capabilities Send Capabilities message (based on Device Policy
message sent Manager response)
Power = Explicit Contract
PD = Connected

8.3.3.16.8.1 PE_DR_SRC_Give_Sink_Cap State

The Policy Engine Shall transition to the PE_DR_SRC_Give_Sink_Cap state, from the PE_SRC_Ready state, when a
Get_Sink_Cap Message is received.
On entry to the PE_DR_SRC_Give_Sink_Cap state the Policy Engine Shall request the present capabilities from the
Device Policy Manager and then send a Sink_Capabilities Message based on these capabilities.
The Policy Engine Shall transition back to the PE_SRC_Ready state (see Figure 8-66) when:
 The Sink_Capabilities Message has been successfully sent.

8.3.3.16.9 Dual-Role (Sink Port) Get Sink Capabilities State Diagram

Figure 8-109 shows the state diagram for a Dual-Role device, presently operating as a Sink, on receiving a request
from the Device Policy Manager to get the Port Partner’s Sink capabilities. See also Section 6.4.1.1.3.

Figure 8-109 Dual-Role (Sink) Get Sink Capabilities State Diagram

get sink capabilities request PE_DR_SNK_Get_Sink_Cap

from Device Policy Manager
PE_SNK_Ready Actions on entry:
Send Get_Sink_Cap message
Initialize and run
Sink capabilities SenderResponseTimer
message received |
Actions on exit:
SenderResponseTimer
Pass sink capabilities/outcome to
Timeout |
Device Policy Manager
Reject message received
Power = Explicit Contract
PD = Connected

8.3.3.16.9.1 PE_DR_SNK_Get_Sink_Cap State

The Policy Engine Shall transition to the PE_DR_SNK_Get_Sink_Cap state, from the PE_SNK_Ready state, due to a
request to get the remote source capabilities from the Device Policy Manager.
On entry to the PE_DR_SNK_Get_Sink_Cap state the Policy Engine Shall send a Get_Sink_Cap Message and initialize
and run the SenderResponseTimer.
On exit from the PE_DR_SNK_Get_Sink_Cap state the Policy Engine Shall inform the Device Policy Manager of the
outcome (capabilities or response timeout).
The Policy Engine Shall transition back to the PE_SNK_Ready state (see Figure 8-67) when:
 A Source_Capabilities Message is received
 Or SenderResponseTimer times out
 Or a Reject Message is received.

8.3.3.16.10 Dual-Role (Sink Port) Give Source Capabilities State Diagram

Figure 8-110 shows the state diagram for a Dual-Role device, presently operating as a Sink, on receiving a
Get_Source_Cap Message. See also Section 6.4.1.1.3.

Page 478 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-110 Dual-Role (Sink) Give Source Capabilities State Diagram

Get_Source_Cap message
received
PE_SNK_Ready PE_DR_SNK_Give_Source_Cap
Actions on entry:
Request source capabilities from
Source Capabilities Device Policy Manager
message sent Send Capabilities message
Power = Explicit Contract
PD = Connected

8.3.3.16.10.1 PE_DR_SNK_Give_Source_Cap State

The Policy Engine Shall transition to the PE_DR_SNK_Give_Source_Cap state, from the PE_SNK_Ready state, when a
Get_Source_Cap Message is received.
On entry to the PE_DR_SNK_Give_Source_Cap state the Policy Engine Shall request the present capabilities from the
Device Policy Manager and then send a Source_Capabilities Message based on these capabilities.
The Policy Engine Shall transition back to the PE_SNK_Ready state (see Figure 8-67) when:
 The Source_Capabilities Message has been successfully sent.

8.3.3.16.11 Dual-Role (Source Port) Get Source Capabilities Extended State Diagram
Figure 8-111 shows the state diagram for a Dual-Role device, presently operating as a Source, on receiving a request
from the Device Policy Manager to get the Port Partner’s extended Source capabilities. See also Section 6.5.1.

Figure 8-111 Dual-Role (Source) Get Source Capabilities Extended State Diagram

get extended source capabilities

request PE_DR_SRC_Get_Source_Cap_Ext
from Device Policy Manager
PE_SRC_Ready Actions on entry:
Send Get_Source_Cap_Extended Message
Initialize and run SenderResponseTimer
Source_Capabilities_Extended
Message received | Actions on exit:
SenderResponseTimer Pass source extended capabilities/
Timeout outcome to Device Policy Manager
Power = Explicit Contract
PD = Connected

8.3.3.16.11.1 PE_DR_SRC_Get_Source_Cap_Ext State

The Policy Engine Shall transition to the PE_DR_SRC_Get_Source_Cap_Ext state, from the PE_SRC_Ready state, due to a
request to get the remote extended source capabilities from the Device Policy Manager.
On entry to the PE_DR_SRC_Get_Source_Cap_Ext state the Policy Engine Shall send a Get_Source_Cap_Extended
Message and initialize and run the SenderResponseTimer.
On exit from the PE_DR_SRC_Get_Source_Cap_Ext state the Policy Engine Shall inform the Device Policy Manager of
the outcome (capabilities or response timeout).
The Policy Engine Shall transition back to the PE_SRC_Ready state (see Figure 8-66) when:
 A Source_Capabilities_Extended Message is received
 Or SenderResponseTimer times out.

8.3.3.16.12 Dual-Role (Sink Port) Give Source Capabilities Extended State Diagram
Figure 8-112 shows the state diagram for a Dual-Role device, presently operating as a Sink, on receiving a
Get_Source_Cap_Extended Message. See also Section 6.5.1.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 479
 Figure 8-112 Dual-Role (Source) Give Sink Capabilities diagram

Get_Source_Cap_Extended message
received PE_DR_SNK_Give_Source_Cap_Ext
PE_SNK_Ready
Actions on entry:
Get present extended source capabilities from Device
Source_Capabilities_Extended Policy Manager
Message sent Send Source_Capabilities_Extended message (based on
Device Policy Manager response)
Power = Explicit Contract
PD = Connected

8.3.3.16.12.1 PE_DR_SNK_Give_Source_Cap_Ext State

The Policy Engine Shall transition to the PE_DR_SNK_Give_Source_Cap_Ext state, from the PE_SNK_Ready state, when
a Get_Source_Cap_Extended Message is received.
On entry to the PE_DR_SNK_Give_Source_Cap_Ext state the Policy Engine Shall request the present extended Source
capabilities from the Device Policy Manager and then send a Source_Capabilities_Extended Message based on these
capabilities.
The Policy Engine Shall transition back to the PE_SNK_Ready state (see Figure 8-67) when:
 The Source_Capabilities_Extended Message has been successfully sent.

8.3.3.17 VCONN Swap State Diagram

The State Diagram in this section Shall apply to Ports that supply VCONN. Figure 8-113 shows the state operation for a
Port on sending or receiving a VCONN Swap request.

Page 480 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-113 VCONN Swap State Diagram

VCONN Swap required

(indication from
Device Policy Manager)

PE_SRC_Ready or
PE_SNK_Ready

Reject message received |

Message sent Wait message received |
VCONN_Swap message received SenderResponseTimer
timeout

Not presently VCONN Source &

PE_VCS_Reject_VCONN_Swap (VCONN Swap not ok | PE_VCS_Evaluate_Swap PE_VCS_Send_Swap
Further evaluation
Actions on entry: Required) Actions on entry: Actions on entry:
Send Reject or Wait message as Get evaluation of VCONN swap Send VCONN_Swap message
appropriate request from Device Policy Manager Initialize and run
SenderResponseTimer
Power = Explicit Contract Power = Explicit Contract
PD = Connected PD = Connected Power = Explicit Contract
PD = Connected

VCONN Swap ok Accept received &

Presently VCONN Source1
Accept received &
Not presently VCONN Source1
PE_VCS_Accept_Swap
Actions on entry:
Send Accept message
Power = Explicit Contract
PD = Connected
Accept message sent &
Not presently VCONN Source1
Accept message sent &
Presently VCONN Source1

PE_VCS_Wait_for_VCONN PE_VCS_Turn_On_VCONN
VCONNOnTimer Timeout Actions on entry: Actions on entry:
Start VCONNOnTimer Tell Device Policy Manager to turn on
VCONN
Power = Explicit Contract
PD = Connected Power = Explicit Contract
PD = Connected

PS_RDY message
received VCONN turned on

PE_VCS_Turn_Off_VCONN
PE_VCS_Send_PS_Rdy
Actions on entry:
Tell Device Policy Manager to turn off Actions on entry:
VCONN Send PS_RDY message

Power = Explicit Contract Power = Explicit Contract

PD = Connected PD = Connected

UFP VCONN is off

Hard Reset: PS_RDY message
sent

 Consumer/Provider ->
PE_SNK_Hard_Reset
PE_SRC_Ready or
 Provider/Consumer ->
PE_SNK_Ready
PE_SRC_Hard_Reset

1A Port is presently the VCONN Source if it has the responsibility for supplying VCONN even if VCONN has been turned
off.

8.3.3.17.1.1 PE_VCS_Send_Swap State

The PE_VCS_Send_Swap state is entered from either the PE_SRC_Ready or PE_SNK_Ready state when the Policy
Engine receives a request from the Device Policy Manager to perform a VCONN Swap.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 481
On entry to the PE_VCS_Send_Swap state the Policy Engine Shall send a VCONN_Swap Message and start the
SenderResponseTimer.
The Policy Engine Shall transition to the PE_VCS_Wait_For_VCONN state when:
 An Accept Message is received and
 DFP current has VCONN turned on.
The Policy Engine Shall transition to the PE_VCS_Turn_On_VCONN state when:
 An Accept Message is received and
 DFP current has VCONN turned off.
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state for a DFP when:
 A Reject Message is received or
 A Wait Message is received or
 The SenderResponseTimer times out.

8.3.3.17.1.2 PE_VCS_Evaluate_Swap State

The PE_VCS_Evaluate_Swap state is entered from either the PE_SRC_Ready or PE_SNK_Ready state when the Policy
Engine receives a VCONN_Swap Message.
On entry to the PE_VCS_Evaluate_Swap state the Policy Engine Shall request the Device Policy Manager for an
evaluation of the VCONN Swap request. Note: Ports that are presently the VCONN Source must always accept a VCONN
swap request (see Section 6.3.11).
The Policy Engine Shall transition to the PE_VCS_Accept_Swap state when:
 The Device Policy Manager indicates that a VCONN Swap is ok.
The Policy Engine Shall transition to the PE_VCS_Reject_Swap state when:
 The Port is not presently the VCONN Source and
 The Device Policy Manager indicates that a VCONN Swap is not ok or
 The Device Policy Manager indicates that a VCONN Swap cannot be done at this time.

8.3.3.17.1.3 PE_VCS_Accept_Swap State

On entry to the PE_VCS_Accept_Swap state the Policy Engine Shall send an Accept Message.
The Policy Engine Shall transition to the PE_VCS_Wait_For_VCONN state when:
 The Accept Message has been sent and
 The UFP’s VCONN is on.
The Policy Engine Shall transition to the PE_VCS_Turn_On_VCONN state when:
 The Accept Message has been sent and
 The UFP’s VCONN is off.

8.3.3.17.1.4 PE_VCS_Reject_Swap State

On entry to the PE_VCS_Reject_Swap state the Policy Engine Shall request the Protocol Layer to send:
 A Reject Message if the device is unable to perform a VCONN Swap at this time.
 A Wait Message if further evaluation of the VCONN Swap request is required. Note: in this case it is expected that
the DFP will send a VCONN_Swap Message at a later time.
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state when:

Page 482 USB Power Delivery Specification Revision 3.0, Version 1.1
 The Reject or Wait Message has been sent.

8.3.3.17.1.5 PE_VCS_UFP_Wait_for_VCONN State

On entry to the PE_VCS_Wait_For_VCONN state the Policy Engine Shall start the VCONNOnTimer.
The Policy Engine Shall transition to the PE_VCS_Turn_Off_VCONN state when:
 A PS_RDY Message is received.
The Policy Engine Shall transition to either the PE_SRC_Hard_Reset or PE_SNK_Hard_Reset state when:
 The VCONNOnTimer times out.

8.3.3.17.1.6 PE_VCS_Turn_Off_VCONN State

On entry to the PE_VCS_Turn_Off_VCONN state the Policy Engine Shall tell the Device Policy Manager to turn off
VCONN.
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state for a UFP when:
 The UFP’s VCONN is off.

8.3.3.17.1.7 PE_VCS_Turn_On_VCONN State

On entry to the PE_VCS_Turn_On_VCONN state the Policy Engine Shall tell the Device Policy Manager to turn on
VCONN.
The Policy Engine Shall transition to the PE_VCS_Send_Ps_Rdy state when:
 The UFP’s VCONN is on.

8.3.3.17.1.8 PE_VCS_Send_PS_Rdy State

On entry to the PE_VCS_Send_Ps_Rdy state the Policy Engine Shall send a PS_RDY Message.
The Policy Engine Shall transition back to either the PE_SRC_Ready or PE_SNK_Ready state for a UFP when:
 The PS_RDY Message has been sent.

8.3.3.18 Initiator Structured VDM State Diagrams

The State Diagrams in this section Shall apply to all Initiators.

8.3.3.18.1 Initiator Structured VDM Discover Identity State Diagram

Figure 8-114 shows the state diagram for an Initiator when discovering the identity of its Port Partner or Cable Plug.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 483
 Figure 8-114 Initiator to Port VDM Discover Identity State Diagram

PE_INIT_PORT_VDM_Identity_ACKed PE_INIT_PORT_VDM_Identity_NAKed
Actions on entry: Actions on entry:
Inform DPM of identity Inform DPM of result
Power = Explicit Contract Power = Explicit Contract
PD = Connected PD = Connected

DPM informed
Discover Identity ACK
received Discover Identity NAK/BUSY |
VDMResponseTimer Timeout

PE_INIT_PORT_VDM_Identity_Request
Actions on entry:
Send Discover Identity request DPM informed
Start VDMResponseTimer

Power = Explicit Contract

PD = Connected

DPM requests
identity discovery

PE_SRC_Ready or PE_SNK_Ready

8.3.3.18.1.1 PE_INIT_PORT_VDM_Identity_Request State

The Policy Engine transitions to the PE_INIT_PORT_VDM_Identity_Request state from either the PE_SRC_Ready or
PE_SNK_Ready state when:
 The Device Policy Manager requests the discovery of the identity of the Port Partner.
On entry to the PE_INIT_PORT_VDM_Identity_Request state the Policy Engine Shall send a Structured VDM Discover
Identity Command request and Shall start the VDMResponseTimer.
The Policy Engine Shall transition to the PE_INIT_PORT_VDM_Identity_ACKed state when:
 A Structured VDM Discover Identity ACK Command response is received.
The Policy Engine Shall transition to the PE_INIT_PORT_VDM_Identity_NAKed state when:
 A Structured VDM Discover Identity NAK or BUSY Command response is received or
 The VDMResponseTimer times out.

8.3.3.18.1.2 PE_INIT_PORT_VDM_Identity_ACKed State

On entry to the PE_INIT_PORT_VDM_Identity_ACKed state the Policy Engine Shall inform the Device Policy Manager
of the Identity information.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state when:
 The Device Policy Manager has been informed.

8.3.3.18.1.3 PE_INIT_PORT_VDM_Identity_NAKed State

On entry to the PE_INIT_PORT_VDM_Identity_NAKed state the Policy Engine Shall inform the Device Policy Manager
of the result (NAK, BUSY or timeout).
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state when:
 The Device Policy Manager has been informed.

Page 484 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.3.18.2 Initiator Structured VDM Discover SVIDs State Diagram
Figure 8-115 shows the state diagram for an Initiator when discovering SVIDs of its Port Partner or Cable Plug.

Figure 8-115 Initiator VDM Discover SVIDs State Diagram

PE_INIT_VDM_SVIDs_ACKed PE_INIT_VDM_SVIDs_NAKed
Actions on entry: Actions on entry:
Inform DPM of SVIDs Inform DPM of result
Power = Explicit Contract Power = Explicit Contract
PD = Connected PD = Connected

DPM informed
Discover SVIDs ACK Discover SVIDs NAK/BUSY |
received VDMResponseTimer Timeout

PE_INIT_VDM_SVIDs_Request
Actions on entry:
Send Discover SVIDs request DPM informed
Start VDMResponseTimer

Power = Explicit Contract

PD = Connected

DPM requests
SVIDs discovery

PE_SRC_Ready or PE_SNK_Ready

8.3.3.18.2.1 PE_INIT_VDM_SVIDs_Request State

The Policy Engine transitions to the PE_INIT_VDM_SVIDs_Request state from either the PE_SRC_Ready or
PE_SNK_Ready state when:
 The Device Policy Manager requests the discovery of the SVIDs of the Port Partner or a Cable Plug.
On entry to the PE_INIT_VDM_SVIDs_Request state the Policy Engine Shall send a Structured VDM Discover SVIDs
Command request and Shall start the VDMResponseTimer.
The Policy Engine Shall transition to the PE_INIT_VDM_SVIDs_ACKed state when:
 A Structured VDM Discover SVIDs ACK Command response is received.
The Policy Engine Shall transition to the PE_INIT_VDM_SVIDs_NAKed state when:
 A Structured VDM Discover SVIDs NAK or BUSY Command response is received or
 The VDMResponseTimer times out.

8.3.3.18.2.2 PE_INIT_VDM_SVIDs_ACKed State

On entry to the PE_INIT_VDM_SVIDs_ACKed state the Policy Engine Shall inform the Device Policy Manager of the
SVIDs information.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state when:
 The Device Policy Manager has been informed.

8.3.3.18.2.3 PE_INIT_VDM_SVIDs_NAKed State

On entry to the PE_INIT_VDM_SVIDs_NAKed state the Policy Engine Shall inform the Device Policy Manager of the
result (NAK, BUSY or timeout).

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 485
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state when:
 The Device Policy Manager has been informed.

8.3.3.18.3 Initiator Structured VDM Discover Modes State Diagram

Figure 8-116 shows the state diagram for an Initiator when discovering Modes of its Port Partner or Cable Plug.

Figure 8-116 Initiator VDM Discover Modes State Diagram

PE_INIT_VDM_Modes_ACKed PE_INIT_VDM_Modes_NAKed
Actions on entry: Actions on entry:
Inform DPM of Modes Inform DPM of result
Power = Explicit Contract Power = Explicit Contract
PD = Connected PD = Connected

DPM informed
Discover Modes ACK Discover Modes NAK/BUSY |
received VDMResponseTimer Timeout

PE_INIT_VDM_Modes_Request
Actions on entry:
Send Discover Modes request DPM informed
Start VDMResponseTimer

Power = Explicit Contract

PD = Connected

DPM requests
Modes discovery

PE_SRC_Ready or PE_SNK_Ready

8.3.3.18.3.1 PE_INIT_VDM_Modes_Request State

The Policy Engine transitions to the PE_INIT_VDM_Modes_Request state from either the PE_SRC_Ready or
PE_SNK_Ready state when:
 The Device Policy Manager requests the discovery of the Modes of the Port Partner or a Cable Plug.
On entry to the PE_INIT_VDM_Modes_Request state the Policy Engine Shall send a Structured VDM Discover Modes
Command request and Shall start the VDMResponseTimer.
The Policy Engine Shall transition to the PE_INIT_VDM_Modes_ACKed state when:
 A Structured VDM Discover Modes ACK Command response is received.
The Policy Engine Shall transition to the PE_INIT_VDM_Modes_NAKed state when:
 A Structured VDM Discover Modes NAK or BUSY Command response is received or
 The VDMResponseTimer times out.

8.3.3.18.3.2 PE_INIT_VDM_Modes_ACKed State

On entry to the PE_INIT_VDM_Modes_ACKed state the Policy Engine Shall inform the Device Policy Manager of the
Modes information.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state for a DFP when:
 The Device Policy Manager has been informed.

Page 486 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.3.18.3.3 PE_INIT_VDM_Modes_NAKed State
On entry to the PE_INIT_VDM_Modes_NAKed state the Policy Engine Shall inform the Device Policy Manager of the
result (NAK, BUSY or timeout).
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state for a DFP when:
 The Device Policy Manager has been informed.

8.3.3.18.4 Initiator Structured VDM Attention State Diagram

Figure 8-121 shows the state diagram for an Initiator when sending an Attention Command request.

Figure 8-117 Initiator VDM Attention State Diagram

PE_SRC_Ready or PE_SNK_Ready

Attention request Attention Command

from DPM request sent

PE_INIT_VDM_Attention_Request

Actions on entry:
Send Attention Command request

Power = Explicit Contract

PD = Connected

8.3.3.18.4.1 PE_INIT_VDM_Attention_Request State

The Policy Engine transitions to the PE_INIT_VDM_Attention_Request state from either the PE_SRC_Ready or
PE_SNK_Ready state when:
 When the Device Policy Manager requests attention from its Port Partner.
On entry to the PE_INIT_VDM_Attention_Request state the Policy Engine Shall send an Attention Command request.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state when:
 The Attention Command request has been sent.

8.3.3.19 Responder Structured VDM State Diagrams

The State Diagrams in this section Shall apply to all Responders that are not Cable Plugs.

8.3.3.19.1 Responder Structured VDM Discover Identity State Diagram

Figure 8-118 shows the state diagram for a Responder receiving a Discover Identity Command request.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 487
 Figure 8-118 Responder Structured VDM Discover Identity State Diagram

PE_RESP_VDM__Get_Identity_NAK PE_RESP_VDM__Get_Identity PE_RESP_VDM__Send_Identity

Actions on entry: DPM says Actions on entry: Identity information Actions on entry:
Send Discover Identity NAK/BUSY Command NAK/BUSY Request Identity information from DPM from DPM Send Discover Identity ACK
response as requested
Power = Explicit Contract Power = Explicit Contract
Power = Explicit Contract PD = Connected PD = Connected
PD = Connected

Discover Identity ACK

Discover Identity NAK/BUSY Discover Identity
sent
sent request

PE_SRC_Ready, PE_SNK_Ready or PE_CBL_Ready

8.3.3.19.1.1 PE_RESP_VDM_Get_Identity State

The Policy Engine transitions to the PE_RESP_VDM_Get_Identity state from either the PE_SRC_Ready, PE_SNK_Ready
or PE_CBL_Ready state when:
 A Structured VDM Discover Identity Command request is received.
On entry to the PE_RESP_VDM_Get_Identity state the Responder Shall request identity information from the Device
Policy Manager.
The Policy Engine Shall transition to the PE_RESP_VDM_Send_Identity state when:
 Identity information is received from the Device Policy Manager.
The Policy Engine Shall transition to the PE_RESP_VDM_Get_Identity_NAK state when:
 The Device Policy Manager indicates that the response to the Discover Identity Command request is NAK or
BUSY.

8.3.3.19.1.2 PE_RESP_VDM_Send_Identity State

On entry to the PE_RESP_VDM_Send_Identity state the Responder Shall send the Structured VDM Discover Identity
ACK Command response.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state for a UFP when:
 The Structured VDM Discover Identity ACK Command response has been sent.

8.3.3.19.1.3 PE_RESP_VDM_Get_Identity_NAK State

On entry to the PE_RESP_VDM_Get_Identity_NAK state the Policy Engine Shall send a Structured VDM Discover
Identity NAK or BUSY Command response as indicated by the Device Policy Manager.
The Policy Engine Shall transition to either the PE_SRC_Ready, PE_SNK_Ready or PE_CBL_Ready state when:
 The Structured VDM Discover Identity NAK or BUSY Command response has been sent.

8.3.3.19.2 Responder Structured VDM Discover SVIDs State Diagram

Figure 8-119 shows the state diagram for a Responder when receiving a Discover SVIDs Command.

Page 488 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-119 Responder Structured VDM Discover SVIDs State Diagram

PE_RESP_VDM__Get_SVIDs_NAK PE_RESP_VDM__Get_SVIDs PE_RESP_VDM__Send_SVID

Actions on entry: DPM says Actions on entry: SVIDs information
s
Actions on entry:
Send Discover SVIDs NAK/BUSY Command NAK/BUSY Request SVIDs information from DPM from DPM Send Discover SVIDs ACK
response as requested
Power = Explicit Contract Power = Explicit Contract
Power = Explicit Contract PD = Connected PD = Connected
PD = Connected

Discover SVIDs ACK

Discover SVIDs NAK/BUSY Discover SVIDs
sent
sent request

PE_SRC_Ready, PE_SNK_Ready or PE_CBL_Ready

8.3.3.19.2.1 PE_RESP_VDM_Get_SVIDs State

The Policy Engine transitions to the PE_RESP_VDM_Get_SVIDs state from either the PE_SRC_Ready, PE_SNK_Ready or
PE_CBL_Ready state when:
 A Structured VDM Discover SVIDs Command request is received.
On entry to the PE_RESP_VDM_Get_SVIDs state the Responder Shall request SVIDs information from the Device Policy
Manager.
The Policy Engine Shall transition to the PE_RESP_VDM_Send_SVIDs state when:
 SVIDs information is received from the Device Policy Manager.
The Policy Engine Shall transition to the PE_RESP_VDM_Get_SVIDs_NAK state when:
 The Device Policy Manager indicates that the response to the Discover SVIDs Command request is NAK or BUSY.

8.3.3.19.2.2 PE_UFP_VDM_Send_SVIDs State

On entry to the PE_RESP_VDM_Send_SVIDs state the Responder Shall send the Structured VDM Discover SVIDs ACK
Command response.
The Policy Engine Shall transition to either the PE_SRC_Ready, PE_SNK_Ready or PE_CBL_Ready state when:
 The Structured VDM Discover SVIDs ACK Command response has been sent.

8.3.3.19.2.3 PE_UFP_VDM_Get_SVIDs_NAK State

On entry to the PE_RESP_VDM_Get_SVIDs_NAK state the Policy Engine Shall send a Structured VDM Discover SVIDs
NAK or BUSY Command response as indicated by the Device Policy Manager.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state when:
 The Structured VDM Discover SVIDs NAK or BUSY Command response has been sent.

8.3.3.19.3 Responder Structured VDM Discover Modes State Diagram

Figure 8-120 shows the state diagram for a Responder on receiving a Discover Modes Command.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 489
 Figure 8-120 Responder Structured VDM Discover Modes State Diagram

PE_RESP_VDM__Get_Modes PE_RESP_VDM__Get_Modes PE_RESP_VDM__Send_Mod

Actions on entry: _NAK DPM says Actions on entry: Modes information
es
Actions on entry:
Send Discover Modes NAK/BUSY Command NAK/BUSY Request Modes information from DPM from DPM Send Discover Modes ACK
response as requested
Power = Explicit Contract Power = Explicit Contract
Power = Explicit Contract PD = Connected PD = Connected
PD = Connected

Discover Modes ACK

Discover Modes NAK/BUSY Discover Modes
sent
sent request

PE_SRC_Ready, PE_SNK_Ready or PE_CBL_Ready

8.3.3.19.3.1 PE_RESP_VDM_Get_Modes State

The Policy Engine transitions to the PE_RESP_VDM_Get_Modes state from either the PE_SRC_Ready, PE_SNK_Ready or
PE_CBL_Ready state when:
 A Structured VDM Discover Modes Command request is received.
On entry to the PE_RESP_VDM_Get_Modes state the Responder Shall request Modes information from the Device
Policy Manager.
The Policy Engine Shall transition to the PE_RESP_VDM_Send_Modes state when:
 Modes information is received from the Device Policy Manager.
The Policy Engine Shall transition to the PE_RESP_VDM_Get_Modes_NAK state when:
 The Device Policy Manager indicates that the response to the Discover Modes Command request is NAK or BUSY.

8.3.3.19.3.2 PE_RESP_VDM_Send_Modes State

On entry to the PE_RESP_VDM_Send_Modes state the Responder Shall send the Structured VDM Discover Modes ACK
Command response.
The Policy Engine Shall transition to either the PE_SRC_Ready, PE_SNK_Ready or PE_CBL_Ready state when:
 The Structured VDM Discover Modes ACK Command response has been sent.

8.3.3.19.3.3 PE_RESP_VDM_Get_Modes_NAK State

On entry to the PE_RESP_VDM_Get_Modes_NAK state the Policy Engine Shall send a Structured VDM Discover Modes
NAK or BUSY Command response as indicated by the Device Policy Manager.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state when:
 The Structured VDM Discover Modes NAK or BUSY Command response has been sent.

8.3.3.19.4 Receiving a Structured VDM Attention State Diagram

Figure 8-121 shows the state diagram when receiving an Attention Command request.

Page 490 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-121 Receiving a Structured VDM Attention State Diagram

PE_SRC_Ready or PE_SNK_Ready

Attention Command
request received DPM informed

PE_RCV_VDM_Attention_Request

Actions on entry:
Inform Device Policy Manager of Attention Command request

Power = Explicit Contract

PD = Connected

8.3.3.19.4.1 PE_RCV_VDM_Attention_Request State

The Policy Engine transitions to the PE_RCV_VDM_Attention_Request state from either the PE_SRC_Ready or
PE_SNK_Ready state when:
 An Attention Command request is received.
On entry to the PE_RCV_VDM_Attention_Request state the Policy Engine Shall inform the Device Policy Manager of
the Attention Command request.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state when:
 The Device Policy Manager has been informed.

8.3.3.20 DFP Structured VDM State Diagrams

The State Diagrams in this section Shall apply to all DFPs that support Structured VDMs.

8.3.3.20.1 DFP Structured VDM Mode Entry State Diagram

Figure 8-122 shows the state operation for a DFP when entering a Mode.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 491
 Figure 8-122 DFP VDM Mode Entry State Diagram

PE_DFP_VDM_Mode_Entry_ACKed PE_DFP_VDM_Mode_Entry_NAKed

Actions on entry: Actions on entry:

Request DPM to enter the mode Inform DPM of reason for failure

Power = Explicit Contract Power = Explicit Contract

PD = Connected PD = Connected

Mode Entry ACK

received Mode Entry NAK/BUSY
Received |
Mode entered VDMModeEntryTimer timeout |
PE_DFP_VDM_Mode_Entry_Request Protocol Error3

Actions on entry:
Send Mode Entry request DPM informed2
Start VDMModeEntryTimer

Power = Explicit Contract

PD = Connected

DPM requests
Mode entry1

PE_SRC_Ready or PE_SNK_Ready
(DFP)

1The Device Policy Manager Shall have placed the system into USB Safe State before issuing this request when
entering Modal operation.
2 The Device Policy Manager Shall have returned the system to USB operation if not in Modal operation at this point.
3Protocol Errors are handled by informing the DPM, returning to USB Safe State and then processing the Message
once the PE_SRC_Ready or PE_SNK_Ready state has been entered.

8.3.3.20.1.1 PE_DFP_VDM_Mode_Entry_Request State

The Policy Engine transitions to the PE_DFP_VDM_Mode_Entry_Request state from either the PE_SRC_Ready or
PE_SNK_Ready state for a DFP when:
 The Device Policy Manager requests that the Port Partner or a Cable Plug enter a Mode.
On entry to the PE_DFP_VDM_Mode_Entry_Request state the Policy Engine Shall send a Structured VDM Enter Mode
Command request and Shall start the VDMModeEntryTimer.
The Policy Engine Shall transition to the PE_DFP_VDM_Mode_Entry_ACKed state when:
 A Structured VDM Enter Mode ACK Command response is received.
The Policy Engine Shall transition to the PE_DFP_VDM_Mode_Entry_NAKed state when:
 A Structured VDM Enter Mode NAK or BUSY Command response is received or
 The VDMModeEntryTimer times out.

8.3.3.20.1.2 PE_DFP_VDM_Mode_Entry_ACKed State

On entry to the PE_DFP_VDM_Mode_Entry_ACKed state the Policy Engine Shall request the Device Policy Manager to
enter the Mode.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state for a DFP when:
 The Mode has been entered.

Page 492 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.3.20.1.3 PE_DFP_VDM_Mode_Entry_NAKed State
On entry to the PE_DFP_VDM_Mode_Entry_NAKed state the Policy Engine Shall inform the Device Policy Manager of
the reason for failure (NAK, BUSY, timeout or Protocol Error).
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state for a DFP when:
 The Device Policy Manager has been informed.

8.3.3.20.2 DFP Structured VDM Mode Exit State Diagram

Figure 8-123 shows the state diagram for a DFP when exiting a Mode.

Figure 8-123 DFP VDM Mode Exit State Diagram

PE_SRC_Ready or PE_SNK_Ready
(DFP)

DPM indicates DPM informed1

Mode exit

PE_DFP_VDM_Mode_Exit_Request

Actions on entry:
Send Exit Mode request
Start VDMModeExitTimer
Exit Mode BUSY Received | Power = Explicit Contract
VDMModeExitTimer Timeout PD = Connected

Exit Mode ACK/NAK

received

PE_DFP_VDM_Exit_Mode_ACKed
PE_SRC_Hard_Reset or Actions on entry:
PE_SNK_Hard_Reset Inform DPM of ACK or NAK
(DFP)
Power = Explicit Contract
PD = Connected

1The Device Policy Manager is required to return the system to USB operation at this point when exiting Modal
Operation.

8.3.3.20.2.1 PE_DFP_VDM_Mode_Exit_Request State

The Policy Engine transitions to the PE_DFP_VDM_Mode_Exit_Request state from either the PE_SRC_Ready or
PE_SNK_Ready state for a DFP when:
 The Device Policy Manager requests that the Port Partner or a Cable Plug exit a Mode.
On entry to the PE_DFP_VDM_Mode_Exit_Request state the Policy Engine Shall send a Structured VDM Exit Mode
Command request and Shall start the VDMModeExitTimer.
The Policy Engine Shall transition to the PE_DFP_VDM_Mode_Exit_ACKed state when:
 A Structured VDM Exit Mode ACK or NAK Command response is received.
The Policy Engine Shall transition to either the PE_SRC_Hard_Reset or PE_SNK_Hard_Reset state depending on the
present Power Role when:
 A Structured VDM Exit Mode BUSY Command response is received or

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 493
 The VDMModeExitTimer times out.

8.3.3.20.2.2 PE_DFP_VDM_DFP_Mode_Exit_ACKed State

On Exit to the PE_DFP_VDM_Mode_Exit_ACKed state the Policy Engine Shall inform the Device Policy Manager Of the
result: ACK or NAK.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state for a DFP when:
 The Device Policy Manager has been informed.

8.3.3.21 UFP Structured VDM State Diagrams

The State Diagrams in this section Shall apply to all UFPs that support Structured VDMs.

8.3.3.21.1 UFP Structured VDM Enter Mode State Diagram

Figure 8-124 shows the state diagram for a UFP in response to an Enter Mode Command.

Figure 8-124 UFP Structured VDM Enter Mode State Diagram

PE_SRC_Ready or PE_SNK_Ready (UFP)

Actions on entry:

Power = Explicit Contract

PD = Connected

Enter Modes
request1

Enter Mode NAK sent PE_UFP_VDM__Evaluate_Mode_Entry

DPM says Actions on entry:
NAK Request DPM to evaluate request to enter a Mode

Cable = Awake
PD = Connected
Enter Mode ACK
sent
DPM says
Mode entered

PE_UFP_VDM__Mode_Entry PE_UFP_VDM__Mode_Entry_ACK
Actions on entry: _NAK
Actions on entry:
Send Enter Mode NAK Command response as
Send Enter Mode ACK Command
requested
Cable = Awake
Cable = Awake
PD = Connected
PD = Connected

1 The UFP is required to be in USB operation or USB Safe State at this point.

8.3.3.21.1.1 PE_UFP_VDM_Evaluate_Mode_Entry State

The Policy Engine transitions to the PE_UFP_VDM_Evaluate_Mode_Entry state from either the PE_SRC_Ready or
PE_SNK_Ready state for a UFP when:
 A Structured VDM Enter Mode Command request is received from the DFP.
On Entry to the PE_UFP_VDM_Evaluate_Mode_Entry state the Policy Engine Shall request the Device Policy Manager
to evaluate the Enter Mode Command request and enter the Mode indicated in the Command request if the request is
acceptable.
The Policy Engine Shall transition to the PE_UFP_VDM_Mode_Entry_ACK state when:
 The Device Policy Manager indicates that the Mode has been entered.
The Policy Engine Shall transition to the PE_UFP_VDM_Mode_Entry_NAK state when:

Page 494 USB Power Delivery Specification Revision 3.0, Version 1.1
 The Device Policy Manager indicates that the response to the Mode request is NAK.

8.3.3.21.1.2 PE_UFP_VDM_Mode_Entry_ACK State

On entry to the PE_UFP_VDM_Mode_Entry_ACK state the Policy Engine Shall send a Structured VDM Enter Mode ACK
Command response.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state for a UFP when:
 The Structured VDM Enter Mode ACK Command response has been sent.

8.3.3.21.1.3 PE_UFP_VDM_Mode_Entry_NAK State

On entry to the PE_UFP_VDM_Mode_Entry_NAK state the Policy Engine Shall send a Structured VDM Enter Mode NAK
Command response as indicated by the Device Policy Manager.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state for a UFP when:
 The Structured VDM Enter Mode NAK Command response has been sent.

8.3.3.21.2 UFP Structured VDM Exit Mode State Diagram

Figure 8-125 shows the state diagram for a UFP in response to an Exit Mode Command.

Figure 8-125 UFP Structured VDM Exit Mode State Diagram

PE_SRC_Ready or PE_SNK_Ready (UFP)

Actions on entry:

Power = Explicit Contract

PD = Connected

Exit Mode request

received

PE_UFP_VDM__Mode_Exit
Actions on entry:
Request DPM to evaluate request to exit the
requested Mode Exit Mode
NAK sent
Power = Explicit Contract DPM says NAK
PD = Connected
Exit Mode ACK
sent1

Mode exited

PE_UFP_VDM__Mode_Exit_ PE_UFP_VDM__Mode_Exit_
Actions on entry: ACK Actions on entry: NAK
Send Exit Mode ACK Command Send Exit Mode NAK Command

Power = Explicit Contract Power = Explicit Contract

PD = Connected PD = Connected

1 The UFP is required to be in USB operation or USB Safe State at this point.

8.3.3.21.2.1 PE_UFP_VDM_Mode_Exit State

The Policy Engine transitions to the PE_UFP_VDM_Mode_Exit state from either the PE_SRC_Ready or PE_SNK_Ready
state for a UFP when:
 A Structured VDM Exit Mode Command request is received from the DFP.
On entry to the PE_UFP_VDM_Mode_Exit state the Policy Engine Shall request the Device Policy Manager to exit the
Mode indicated in the Command.
The Policy Engine Shall transition to the PE_UFP_VDM_Mode_Exit_ACK state when:

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 495
 The Device Policy Manger indicates that the Mode has been exited.
The Policy Engine Shall transition to the PE_UFP_VDM_Mode_Exit_NAK state when:
 The Device Policy Manager indicates that the Command response to the Exit Mode Command request is NAK.

8.3.3.21.2.2 PE_CBL_Mode_Exit_ACK State

On entry to the PE_UFP_VDM_Mode_Exit_ACK state the Policy Engine Shall send a Structured VDM Exit Mode ACK
Command response.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state for a UFP when:
 The Structured VDM Exit Mode ACK Command response has been sent.

8.3.3.21.2.3 PE_UFP_VDM_Mode_Exit_NAK State

On entry to the PE_UFP_VDM_Mode_Exit_NAK state the Policy Engine Shall send a Structured VDM Exit Mode NAK
Command response as indicated by the Device Policy Manager.
The Policy Engine Shall transition to either the either the PE_SRC_Ready or PE_SNK_Ready state for a UFP when:
 The Structured VDM Exit Mode NAK Command response has been sent.

8.3.3.22 Cable Plug Specific State Diagrams

The State Diagrams in this section Shall apply to all Cable Plugs that support Structured VDMs.

8.3.3.22.1 Cable Plug Cable Ready State Diagram

Figure 8-126 shows the Cable Ready state diagram for a Cable Plug.

Figure 8-126 Cable Ready VDM State Diagram

Power up |
Hard Reset Complete |
Cable Reset Complete

PE_CBL__Ready
Actions on entry:

Cable = Awake/Asleep
PD = Not Connected/Connected

8.3.3.22.1.1 PE_CBL_Ready State

The PE_CBL_Ready state shown in the following sections is the normal operational state for a Cable Plug and where it
starts after power up or a Hard/Cable Reset.

8.3.3.22.2 Soft/Hard/Cable Reset

8.3.3.22.2.1 Cable Plug Soft Reset State Diagram

Figure 8-127 shows the Cable Plug state diagram on reception of a Soft_Reset Message.

Page 496 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 8-127 Cable Plug Soft Reset State Diagram

PE_CBL_Ready

Accept message
sent

PE_CBL_Soft_Reset Transmission
Error indication
Actions on entry: from Protocol Layer
Reset Protocol Layer PE_CBL_Hard_Reset
Send Accept message
Cable = Awake
PD = Connected

Soft Reset message

received

8.3.3.22.2.1.1 PE_CBL_Soft_Reset State

The PE_CBL_Soft_Reset state Shall be entered from any state when a Reset Message is received from the Protocol
Layer.
On entry to the PE_CBL_Soft_Reset state the Policy Engine Shall reset the Protocol Layer in the Cable Plug and Shall
then request the Protocol Layer to send an Accept Message.
The Policy Engine Shall transition to the PE_CBL_Ready state when:
 The Accept Message has been sent.
The Policy Engine Shall transition to the PE_CBL_Hard_Reset state when:
 The Protocol Layer indicates that a transmission error has occurred.

8.3.3.22.2.2 Cable Plug Hard Reset State Diagram

Figure 8-128 shows the Cable Plug state diagram for a Hard Reset or Cable Reset.

Figure 8-128 Cable Plug Hard Reset State Diagram

Hard Reset signalling

Received |
Cable Reset Command

PE_CBL_Hard_Reset

Actions on entry:
Reset Cable Plug

Cable = Awake/Asleep
PD = Not Connected

Cable reset complete

PE_CBL_Ready

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 497
 8.3.3.22.2.2.1 PE_CBL_Hard_Reset State
The PE_CBL_Hard_Reset state Shall be entered from any state when either Hard Reset Signaling or Cable Reset
Signaling is detected.
On entry to the PE_CBL_Hard_Reset state the Policy Engine Shall reset the Cable Plug (equivalent to a power cycle).
The Policy Engine Shall transition to the PE_CBL_Ready state when:
 The Cable Plug reset is complete.

8.3.3.22.2.3 DFP Soft Reset or Cable Reset of a Cable Plug State Diagram
Figure 8-129 below shows the state diagram for the Policy Engine in a DFP when performing a Soft Reset or Cable
Reset of a Cable Plug. The following sections describe operation in each of the states.

Figure 8-129 DFP Soft Reset or Cable Reset of a Cable Plug State Diagram

Accept message
PE_SRC_Ready or PE_SNK_Ready received
(DFP)

Cable Reset sent

SenderResponseTimer
Timeout | PE_DFP_CBL_Send_Soft_Reset
PE_DFP_CBL_Send_Cable_Reset Transmission
Error indication Actions on entry:
Actions on entry: from Protocol Layer Reset Protocol Layer
Turn on VCONN
Send Soft Reset message
Send Cable Reset message
Initialize and run SenderResponseTimer
Power = DefauIt/Implicit or Explicit Contract
PD = Connected Power = DefauIt/Implicit or Explicit Contract
PD = Connected

Cable Reset Request

Message not sent after retries (no GoodCRC received)1 |
from Device Policy Manager
Protocol error detected

1 Excludes the Soft_Reset Message itself.

8.3.3.22.2.3.1 PE_DFP_CBL_Send_Soft_Reset State
The PE_DFP_CBL_Send_Soft_Reset state Shall be entered from any state when a Protocol Error is detected by the
Protocol Layer (see Section 6.8.1) when a Message has not been sent after retries while communicating with a Cable
Plug or whenever the Device Policy Manager directs a Soft Reset.
On entry to the PE_DFP_CBL_Send_Soft_Reset state the Policy Engine Shall request the Protocol Layer to perform a
Soft Reset, then Shall send a Soft_Reset Message to the Cable Plug, and initialize and run the SenderResponseTimer.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state, depending on the DFP’s Power
Role, when:
 An Accept Message has been received.
The Policy Engine Shall transition to the PE_DFP_CBL_Send_Cable_Reset state when:
 A SenderResponseTimer timeout occurs
 Or the Protocol Layer indicates that a transmission error has occurred.

Page 498 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.3.22.2.3.2 PE_DFP_CBL_Send_Cable_Reset State
The PE_DFP_CBL_Send_Cable_Reset state Shall be entered from any state when the Device Policy Manager requests a
Cable Reset.
On entry to the PE_DFP_CBL_Send_Cable_Reset state the Policy Engine Shall request the Protocol Layer to send Cable
Reset Signaling.
The Policy Engine Shall transition to either the PE_SRC_Ready or PE_SNK_Ready state, depending on the DFP’s Power
Role, when:
 Cable Reset Signaling has been sent.

8.3.3.22.2.4 UFP Source Soft Reset of a Cable Plug State Diagram

Figure 8-130 below shows the state diagram for the Policy Engine in a UFP Source, prior to an Explicit Contract, when
performing a Soft Reset of a Cable Plug. The following sections describe operation in each of the states.

Figure 8-130 UFP Source Soft Reset of a Cable Plug State Diagram

PE_SRC_Ready (UFP)

Accept message Received |

SenderResponseTimer Timeout |
Transmission Error indication
from Protocol Layer

PE_UFP_CBL_Send_Soft_Reset
Actions on entry:
Reset Protocol Layer
Send Soft Reset message
Initialize and run SenderResponseTimer

Power = DefauIt/Implicit or Explicit Contract

PD = Connected

Message not sent after retries (no GoodCRC received)1 |

Protocol error detected

1 Excludes the Soft_Reset Message itself.

8.3.3.22.2.4.1 PE_UFP_CBL_Send_Soft_Reset State
The PE_UFP_CBL_Send_Soft_Reset state Shall be entered from any state when a Protocol Error is detected by the
Protocol Layer, when a Message has not been sent after retries while communicating with a Cable Plug or whenever
the Device Policy Manager directs a Soft Reset.
Note that there are corner cases that are not shown in the defined state diagrams that could be handled without
generating a Protocol Error.
On entry to the PE_UFP_CBL_Send_Soft_Reset state the Policy Engine Shall request the Protocol Layer to perform a
Soft Reset, then Shall send a Soft_Reset Message to the Cable Plug, and initialize and run the SenderResponseTimer.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 499
The Policy Engine Shall transition to the PE_SRC_Ready state when:
 An Accept Message has been received
 Or a SenderResponseTimer timeout occurs
 Or the Protocol Layer indicates that a transmission error has occurred.

8.3.3.22.3 Source Startup Structured VDM Discover Identity of a Cable Plug State Diagram
Figure 8-131 shows the state diagram for Source discovery of identity information from a Cable Plug during the
startup sequence.

Figure 8-131 Source Startup Structured VDM Discover Identity State Diagram

PE_SRC_Startup

DPM requests identity discovery &

Protocol Layer Reset Complete

PE_SRC_VDM_Identity_Request
Actions on entry:
Send Discover Identity request
Increment the DiscoverIdentityCounter
Start VDMResponseTimer

Power = No or Implicit Contract Discover Identity NAK/BUSY |

DPM requests identity discovery & Cable Plug = Not PD Connected VDMResponseTimer Timeout |
DiscoverIdentityCounter < nDiscoverIdentityCount2 Discover Identity request sending
failure (without GoodCRC)
Discover Identity ACK
received

PE_SRC_VDM_Identity_ACKed PE_SRC_VDM_Identity_NAKed
Actions on entry: Actions on entry:
Inform DPM of identity Inform DPM of result
Power = No or Implicit Contract Power =No or Implicit Contract
Cable Plug = PD Connected Cable Plug = PD Connected

DPM informed
DPM informed

PE_SRC_Discovery PE_SRC_Send_Capabilities or
PE_SRC_Discovery1

1If the Discover Identity Command is being sent at startup then the Policy Engine will subsequently transition to the
PE_SRC_Send_Capabilities state as normal. Otherwise the Policy Engine will transition to the PE_SRC_Discovery state.
2The SourceCapabilityTimer continues to run during the states defined in this diagram even though there has been
an exit from the PE_SRC_Discovery state. This ensures that Source_Capabilities Messages are sent out at a regular
rate.

8.3.3.22.3.1 PE_SRC_VDM_Identity_Request State

The Policy Engine Shall transition to the PE_SRC_VDM_Identity_Request state from the PE_SRC_Startup state when:

Page 500 USB Power Delivery Specification Revision 3.0, Version 1.1
 The Device Policy Manager requests the discovery of the identity of the Cable Plug.
The Policy Engine Shall transition to the PE_SRC_VDM_Identity_Request state from the PE_SRC_Discovery state when:
 The Device Policy Manager requests the discovery of the identity of the Cable Plug and
 The DiscoverIdentityCounter < nDiscoverIdentityCount.
Even though there has been a transition out of the PE_SRC_Discovery state the SourceCapabilityTimer Shall continue
to run during the states shown in Figure 8-131 and Shall Not be initialized on re-entry to PE_SRC_Discovery.
On entry to the PE_SRC_VDM_Identity_Request state the Policy Engine Shall send a Structured VDM Discover Identity
Command request, Shall increment the DiscoverIdentityCounter and Shall start the VDMResponseTimer.
The Policy Engine Shall transition to the PE_SRC_VDM_Identity_ACKed state when:
 A Structured VDM Discover Identity ACK Command response is received.
The Policy Engine Shall transition to the PE_SRC_VDM_Identity_NAKed state when:
 A Structured VDM Discover Identity NAK or BUSY Command response is received or
 The VDMResponseTimer times out or
 The Structured VDM Discover Identity Command request Message sending fails (no GoodCRC Message received
after retries).

8.3.3.22.3.2 PE_SRC_VDM_Identity_ACKed State

On entry to the PE_SRC_VDM_Identity_ACKed state the Policy Engine Shall inform the Device Policy Manager of the
Identity information.
The Policy Engine Shall transition back to either the PE_SRC_Send_Capabilities or PE_SRC_Discovery state when:
 The Device Policy Manager has been informed.

8.3.3.22.3.3 PE_SRC_VDM_Identity_NAKed State

On entry to the PE_SRC_VDM_Identity_NAKed state the Policy Engine Shall inform the Device Policy Manager of the
result (NAK, BUSY or timeout).
The Policy Engine Shall transition back to either the PE_SRC_Send_Capabilities or PE_SRC_Discovery state when:
 The Device Policy Manager has been informed.

8.3.3.22.4 Cable Plug Mode Entry/Exit

8.3.3.22.4.1 Cable Plug Structured VDM Enter Mode State Diagram

Figure 8-132 shows the state diagram for a Cable Plug in response to an Enter Mode Command.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 501
 Figure 8-132 Cable Plug Structured VDM Enter Mode State Diagram

PE_CBL__Ready
Actions on entry:

Cable = Awake/Asleep
PD = Not Connected/Connected

Enter Modes
request1

Enter Mode NAK sent PE_CBL__Evaluate_Mode_Entry

DPM says Actions on entry:
NAK Request DPM to evaluate request to enter a
Mode
Cable = Awake
PD = Connected
Enter Mode ACK
sent
DPM says
Mode entered

PE_CBL__Mode_Entry_NAK PE_CBL__Mode_Entry_ACK
Actions on entry:
Actions on entry:
Send Enter Mode NAK Command response as
Send Enter Mode ACK Command
requested
Cable = Awake
Cable = Awake
PD = Connected
PD = Connected

1 The Cable is required to be in USB operation or USB Safe State at this point.
8.3.3.22.4.1.1 PE_CBL_Evaluate_Mode_Entry State
The Policy Engine transitions to the PE_CBL_Evaluate_Mode_Entry state from the PE_CBL_Ready state when:
 A Structured VDM Enter Mode Command request is received from the DFP.
On Entry to the PE_CBL_Evaluate_Mode_Entry state the Policy Engine Shall request the Device Policy Manager to
evaluate the Enter Mode Command request and enter the Mode indicated in the Command request if the request is
acceptable.
The Policy Engine Shall transition to the PE_CBL_Mode_Entry_ACK state when:
 The Device Policy Manager indicates that the Mode has been entered.
The Policy Engine Shall transition to the PE_CBL_Mode_Entry_NAK state when:
 The Device Policy Manager indicates that the response to the Mode request is NAK.
8.3.3.22.4.1.2 PE_CBL_Mode_Entry_ACK State
On entry to the PE_CBL_Mode_Entry_ACK state the Policy Engine Shall send a Structured VDM Enter Mode ACK
Command response.
The Policy Engine Shall transition to the PE_CBL_Ready state when:
 The Structured VDM Enter Mode ACK Command response has been sent.
8.3.3.22.4.1.3 PE_CBL_Mode_Entry_NAK State
On entry to the PE_CBL_Mode_Entry_NAK state the Policy Engine Shall send a Structured VDM Enter Mode NAK
Command response as indicated by the Device Policy Manager.
The Policy Engine Shall transition to the PE_CBL_Ready state when:
 The Structured VDM Enter Mode NAK Command response has been sent.

Page 502 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.3.22.4.2 Cable Plug Structured VDM Exit Mode State Diagram
Figure 8-133 shows the state diagram for a Cable Plug in response to an Exit Mode Command.

Figure 8-133 Cable Plug Structured VDM Exit Mode State Diagram

PE_CBL__Ready
Actions on entry:

Cable = Awake/Asleep
PD = Not Connected/Connected

Exit Mode request

received

PE_CBL__Mode_Exit
Actions on entry:
Request DPM to evaluate request to exit the
requested Mode Exit Mode
NAK sent
Cable = Awake DPM says NAK
PD = Connected
Exit Mode ACK
sent1

Mode exited

PE_CBL__Mode_Exit_ACK PE_CBL__Mode_Exit_NAK
Actions on entry: Actions on entry:
Send Exit Mode ACK Command Send Exit Mode NAK Command

Cable = Awake Cable = Awake

PD = Connected PD = Connected

1 The Cable is required to be in USB operation or USB Safe State at this point.
8.3.3.22.4.2.1 PE_CBL_Mode_Exit State
The Policy Engine transitions to the PE_CBL_Mode_Exit state from the PE_CBL_Ready state when:
 A Structured VDM Exit Mode Command request is received from the DFP.
On entry to the PE_CBL_Mode_Exit state the Policy Engine Shall request the Device Policy Manager to exit the Mode
indicated in the Command.
The Policy Engine Shall transition to the PE_CBL_Mode_Exit_ACK state when:
 The Device Policy Manger indicates that the Mode has been exited.
The Policy Engine Shall transition to the PE_CBL_Mode_Exit_NAK state when:
 The Device Policy Manager indicates that the Command response to the Exit Mode Command request is NAK.
8.3.3.22.4.2.2 PE_CBL_Mode_Exit_ACK State
On entry to the PE_CBL_Mode_Exit_ACK state the Policy Engine Shall send a Structured VDM Exit Mode ACK
Command response.
The Policy Engine Shall transition to the PE_CBL_Ready state when:
 The Structured VDM Exit Mode ACK Command response has been sent.
8.3.3.22.4.2.3 PE_CBL_Mode_Exit_NAK State
On entry to the PE_CBL_Mode_Exit_NAK state the Policy Engine Shall send a Structured VDM Exit Mode NAK
Command response as indicated by the Device Policy Manager.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 503
The Policy Engine Shall transition to the PE_CBL_Ready state when:
 The Structured VDM Exit Mode NAK Command response has been sent.

8.3.3.23 BIST State diagrams

8.3.3.23.1 BIST Carrier Mode State Diagram

Figure 8-134 shows the state diagram required by a UUT, which can be either a Source, Sink or Cable Plug, when
operating in BIST Carrier Mode. Transitions Shall be from either the PE_SRC_Ready, PE_SNK_Ready or
PE_CBL_Ready states.

Figure 8-134 BIST Carrier Mode State Diagram

PE_SRC_Ready or
PE_SNK_Ready or
PE_CBL_Ready

BIST message received

with Data Object BIST Carrier Mode &
VBUS = vSafe5V

PE_BIST_Carrier_Mode
Actions on entry:
Tell Protocol Layer to go to BIST
Carrier Mode
Initialize and run BISTContModeTimer

VBUS = vSafe5V
PD = Connected

BISTContModeTimer
timeout

PE_SRC_Transition_to_default or
PE_SNK_Transition_to_default or
PE_CBL_Ready

8.3.3.23.1.1 PE_BIST_Carrier_Mode State

The Source, Sink or Cable Plug Shall enter the PE_BIST_Carrier_Mode state from either the PE_SRC_Ready,
PE_SNK_Ready or PE_CBL_Ready state when:
 A BIST Message is received with a BIST Carrier Mode BIST Data Object and
 VBUS is at vSafe5V.
On entry to the PE_BIST_Carrier_Mode state the Policy Engine Shall tell the Protocol Layer to go to BIST Carrier Mode
and Shall initialize and run the BISTContModeTimer.
The Policy Engine Shall transition to either the PE_SRC_Transition_to_default state, PE_SNK_Transition_to_default
state or PE_CBL_Ready state (as appropriate) when:
 The BISTContModeTimer times out.

Page 504 USB Power Delivery Specification Revision 3.0, Version 1.1
 8.3.3.24 USB Type-C Referenced States
This section contains states cross-referenced from the [USB Type-C 1.2] specification.

8.3.3.24.1 ErrorRecovery state

The ErrorRecovery state is used to electronically disconnect Port Partners using the USB Type-C connector. The
ErrorRecovery state Shall be entered when there are errors on USB Type-C Ports which cannot be recovered by Hard
Reset. The ErrorRecovery state Shall map to USB Type-C ErrorRecovery state operation as defined in the [USB Type-
C 1.2] specification, including any other state transitions mandated in cases where USB Type-C ErrorRecovery is not
supported.
On entry to the ErrorRecovery state the Contract and PD Connection Shall be ended.
On exit from the ErrorRecovery state a new Explicit Contract Should be established once the Port Partners have re-
connected over the CC wire.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 505
 8.3.3.25 Policy Engine States
Table 8-62 lists the states used by the various state machines.

Table 8-62 Policy Engine States

State name Reference

Source Port
PE_SRC_Startup Section 8.3.3.2.1

PE_SRC_Discovery Section 8.3.3.2.2

PE_SRC_Send_Capabilities Section 8.3.3.2.3

PE_SRC_Negotiate_Capability Section 8.3.3.2.4

PE_SRC_Transition_Supply Section 8.3.3.2.5

PE_SRC_Ready Section 8.3.3.2.6

PE_SRC_Disabled Section 8.3.3.2.7

PE_SRC_Capability_Response Section 8.3.3.2.8

PE_SRC_Hard_Reset Section 8.3.3.2.9

PE_SRC_Hard_Reset_Received Section 8.3.3.2.10

PE_SRC_Transition_to_default Section 8.3.3.2.11

PE_SRC_Get_Sink_Cap Section 8.3.3.2.12

PE_SRC_Wait_New_Capabilities Section 8.3.3.2.13

Sink Port
PE_SNK_Startup Section 8.3.3.3.1

PE_SNK_Discovery Section 8.3.3.3.2

PE_SNK_Wait_for_Capabilities Section 8.3.3.3.3

PE_SNK_Evaluate_Capability Section 8.3.3.3.4

PE_SNK_Select_Capability Section 8.3.3.3.5

PE_SNK_Transition_Sink Section 8.3.3.3.6

PE_SNK_Ready Section 8.3.3.3.7

PE_SNK_Hard_Reset Section 8.3.3.3.8

PE_SNK_Transition_to_default Section 8.3.3.3.9

PE_SNK_Give_Sink_Cap Section 8.3.3.3.10

PE_SNK_Get_Source_Cap Section 8.3.3.3.11

Soft Reset and Protocol Error
Source Port Soft Reset
PE_SRC_Send_Soft_Reset Section 8.3.3.4.1.1

PE_SRC_Soft_Reset Section 8.3.3.4.1.2

Sink Port Soft Reset
PE_SNK_Send_Soft_Reset Section 8.3.3.4.2.1

PE_SNK_Soft_Reset Section 8.3.3.4.2.2

Not Supported Message
Source Port Not Supported
PE_SRC_Send_Not_Supported Section 8.3.3.5.1.1

Page 506 USB Power Delivery Specification Revision 3.0, Version 1.1
 State name Reference
PE_SRC_Not_Supported_Received Section 8.3.3.5.1.2

PE_SRC_Chunk_Received Section 8.3.3.5.1.3

Sink Port Not Supported
PE_SNK_Send_Not_Supported Section 8.3.3.5.2.1

PE_SNK_Not_Supported_Received Section 8.3.3.5.2.2

PE_SNK_Chunk_Received Section 8.3.3.5.2.1

Source Port Ping
PE_SRC_Ping Section 8.3.3.6.1
Source Alert
Source Port Source Alert
PE_SRC_Send_Source_Alert Section 8.3.3.7.1.1
Sink Port Source Alert
PE_SNK_Source_Alert_Received Section 8.3.3.7.2.1
Sink Port Sink Alert
PE_SNK_Send_Sink_Alert Section 8.3.3.7.3.1
Source Port Sink Alert
PE_SRC_Sink_Alert_Received Section 8.3.3.7.4.1
Source Extended Capabilities
Sink Port Get Source Capabilities Extended
PE_SNK_Get_Source_Cap_Ext Section 8.3.3.8.1.1
Source Port Give Source Capabilities Extended
PE_SRC_Give_Source_Cap_Ext Section 8.3.3.8.2.1
Source Status
Sink Port Get Source Status
PE_SNK_Get_Source_Status Section 8.3.3.9.1.1
Source Port Give Source Status
PE_SRC_Give_Source_Status Section 8.3.3.9.2.1
Source Port Get Sink Status
PE_SRC_Get_Sink_Status Section 8.3.3.9.3.1
Sink Port Give Sink Status
PE_SNK_Give_Sink_Status Section 8.3.3.9.4.1
Sink Port Get PPS Status
PE_SNK_Get_PPS_Status Section 8.3.3.9.5.1
Source Port Give PPS Status
PE_SRC_Give_PPS_Status Section 8.3.3.9.6.1
Battery Capabilities
Get Battery Capabilities
PE_Get_Battery_Cap Section 8.3.3.10.1.1
Give Battery Capabilities
PE_Give_Battery_Cap Section 8.3.3.10.2.1
Battery Status
Get Battery Status
PE_Get_Battery_Status Section 8.3.3.11.1.1

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 507
 State name Reference
Give Battery Status
PE_Give_Battery_Status Section 8.3.3.11.2.1
Manufacturer Information
Get Manufacturer Information
PE_Get_Manufacturer_Info Section 8.3.3.12.1
Give Manufacturer Information
PE_Give_Manufacturer_Info Section 8.3.3.12.2
Country Codes and Information
Get Country Codes
PE_Get_Country_Codes Section 8.3.3.13.1.1
Give Country Codes
PE_Give_Country_Codes Section 8.3.3.13.2.1
Get Country Information
PE_Get_Country_Info Section 8.3.3.13.3.1
Give Country Information
PE_Give_Country_Info Section 8.3.3.13.4.1
Security Request/Response
Send Security Request
PE_Send_Security_Request Section 8.3.3.14.1
Send Security Response
PE_Send_Security_Response Section 8.3.3.14.2
Security Response Received
PE_Security_Response_Received Section 8.3.3.14.3
Firmware Update Request/Response
Send Firmware Update Request
PE_Send_Firmware_Update_Request Section 8.3.3.15.1.1
Send Firmware Update Response
PE_Send_Firmware_Update_Response Section 8.3.3.15.2.1
Firmware Update Response Received
PE_Firmware_Update_Response_Received Section 8.3.3.15.3.1
Dual-Role Port
DFP to UFP Data Role Swap
PE_DRS_DFP_UFP_Evaluate_Swap Section 8.3.3.16.1.2

PE_DRS_DFP_UFP_Accept_Swap Section 8.3.3.16.1.3

PE_DRS_DFP_UFP_Change_to_UFP Section 8.3.3.16.1.4

PE_DRS_DFP_UFP_Send_Swap Section 8.3.3.16.1.5

PE_DRS_DFP_UFP_Reject_Swap Section 8.3.3.16.1.6

UFP to DFP Data Role Swap
PE_DRS_UFP_DFP_Evaluate_Swap Section 8.3.3.16.2.2

PE_DRS_UFP_DFP_Accept_Swap Section 8.3.3.16.2.3

PE_DRS_UFP_DFP_Change_to_DFP Section 8.3.3.16.2.4

PE_DRS_UFP_DFP_Send_Swap Section 8.3.3.16.2.5

Page 508 USB Power Delivery Specification Revision 3.0, Version 1.1
 State name Reference
PE_DRS_UFP_DFP_Reject_Swap Section 8.3.3.16.2.6
Source to Sink Power Role Swap
PE_PRS_SRC_SNK_Evaluate_Swap Section 8.3.3.16.3.2

PE_PRS_SRC_SNK_Accept_Swap Section 8.3.3.16.3.3

PE_PRS_SRC_SNK_Transition_to_off Section 8.3.3.16.3.4

PE_PRS_SRC_SNK_Assert_Rd Section 8.3.3.16.3.5

PE_PRS_SRC_SNK_Wait_Source_on Section 8.3.3.16.3.6

PE_PRS_SRC_SNK_Send_Swap Section 8.3.3.16.3.7

PE_PRS_SRC_SNK_Reject_Swap Section 8.3.3.16.3.8

Sink to Source Power Role Swap
PE_PRS_SNK_SRC_Evaluate_Swap Section 8.3.3.16.4.2

PE_PRS_SNK_SRC_Accept_Swap Section 8.3.3.16.4.3

PE_PRS_SNK_SRC_Transition_to_off Section 8.3.3.16.4.4

PE_PRS_SNK_SRC_Assert_Rp
PE_PRS_SNK_SRC_Source_on Section 8.3.3.16.4.5

PE_PRS_SNK_SRC_Send_Swap Section 8.3.3.16.4.7

PE_PRS_SNK_SRC_Reject_Swap Section 8.3.3.16.4.8

Source to Sink Fast Role Swap
PE_FRS_SRC_SNK_CC_Signal Section 8.3.3.16.5.2

PE_FRS_SRC_SNK_Evaluate_Swap Section 8.3.3.16.5.3

PE_FRS_SRC_SNK_Accept_Swap Section 8.3.3.16.5.4

PE_FRS_SRC_SNK_Transition_to_off Section 8.3.3.16.5.5

PE_FRS_SRC_SNK_Assert_Rd Section 8.3.3.16.5.6

PE_FRS_SRC_SNK_Wait_Source_on Section 8.3.3.16.5.7

Sink to Source Fast Role Swap
PE_FRS_SNK_SRC_Start_AMS Section 8.3.3.16.6.1

PE_FRS_SNK_SRC_Send_Swap Section 8.3.3.16.6.2

PE_FRS_SNK_SRC_Transition_to_off Section 8.3.3.16.6.3

PE_FRS_SNK_SRC_Vbus_Applied Section 8.3.3.16.6.4

PE_FRS_SNK_SRC_Assert_Rp Section 8.3.3.16.6.5

PE_FRS_SNK_SRC_Source_on Section 8.3.3.16.6.6

Dual-Role Source Port Get Source Capabilities
PE_DR_SRC_Get_Source_Cap Section 8.3.3.16.7.1
Dual-Role Source Port Give Sink Capabilities
PE_DR_SRC_Give_Sink_Cap Section 8.3.3.16.8.1
Dual-Role Sink Port Get Sink Capabilities
PE_DR_SNK_Get_Sink_Cap Section 8.3.3.16.9.1
Dual-Role Sink Port Give Source Capabilities
PE_DR_SNK_Give_Source_Cap Section 8.3.3.16.10.1

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 509
 State name Reference
Dual-Role Source Port Get Source Capabilities Extended
PE_DR_SRC_Get_Source_Cap_Ext Section 8.3.3.16.11.1
Dual-Role Sink Port Give Source Capabilities Extended
PE_DR_SNK_Give_Source_Cap_Ext Section 8.3.3.16.12.1
USB Type-C VCONN Swap
PE_VCS_Send_Swap Section 8.3.3.17.1.1

PE_VCS_Evaluate_Swap Section 8.3.3.17.1.2

PE_VCS_Accept_Swap Section 8.3.3.17.1.3

PE_VCS_Reject_Swap Section 8.3.3.17.1.4

PE_VCS_Wait_For_VCONN Section 8.3.3.17.1.5

PE_VCS_Turn_Off_VCONN Section 8.3.3.17.1.6

PE_VCS_Turn_On_VCONN Section 8.3.3.17.1.7

PE_VCS_Send_Ps_Rdy Section 8.3.3.17.1.8
Initiator Structured VDM
Initiator to Port Structured VDM Discover Identity
PE_INIT_PORT_VDM_Identity_Request Section 8.3.3.18.1.1

PE_INIT_PORT_VDM_Identity_ACKed Section 8.3.3.18.1.2

PE_INIT_PORT_VDM_Identity_NAKed Section 8.3.3.18.1.3

Initiator Structured VDM Discover SVIDs
PE_INIT_VDM_SVIDs_Request Section 8.3.3.18.2.1

PE_INIT_VDM_SVIDs_ACKed Section 8.3.3.18.2.2

PE_INIT_VDM_SVIDs_NAKed Section 8.3.3.18.2.3

Initiator Structured VDM Discover Modes
PE_INIT_VDM_Modes_Request Section 8.3.3.18.3.1

PE_INIT_VDM_Modes_ACKed Section 8.3.3.18.3.2

PE_INIT_VDM_Modes_NAKed Section 8.3.3.18.3.3

Initiator Structured VDM Attention
PE_INIT_VDM_Attention_Request Section 8.3.3.18.4.1
Responder Structured VDM
Responder Structured VDM Discovery Identity
PE_RESP_VDM_Get_Identity Section 8.3.3.19.1.1

PE_RESP_VDM_Send_Identity Section 8.3.3.19.1.2

PE_RESP_VDM_Get_Identity_NAK Section 8.3.3.19.1.3

Responder Structured VDM Discovery SVIDs
PE_RESP_VDM_Get_SVIDs Section 8.3.3.19.2.1

PE_RESP_VDM_Send_SVIDs Section 8.3.3.19.2.2

PE_RESP_VDM_Get_SVIDs_NAK Section 8.3.3.19.2.3

Responder Structured VDM Discovery Modes
PE_RESP_VDM_Get_Modes Section 8.3.3.19.3.1

PE_RESP_VDM_Send_Modes Section 8.3.3.19.3.2

PE_RESP_VDM_Get_Modes_NAK Section 8.3.3.19.3.3

Page 510 USB Power Delivery Specification Revision 3.0, Version 1.1
 State name Reference
Receiving a Structured VDM Attention
PE_RCV_VDM_Attention_Request Section 8.3.3.19.4.1
DFP Structured VDM
DFP Structured VDM Mode Entry
PE_DFP_VDM_Mode_Entry_Request Section 8.3.3.20.1.1

PE_DFP_VDM_Mode_Entry_ACKed Section 8.3.3.20.1.2

PE_DFP_VDM_Mode_Entry_NAKed Section 8.3.3.20.1.3

DFP Structured VDM Mode Exit
PE_DFP_VDM_Mode_Exit_Request Section 8.3.3.20.2.1

PE_DFP_VDM_Mode_Exit_ACKed Section 8.3.3.20.2.2

UFP Structure VDM
UFP Structured VDM Enter Mode
PE_UFP_VDM_Evaluate_Mode_Entry Section 8.3.3.21.1.1
PE_UFP_VDM_Mode_Entry_ACK Section 8.3.3.21.1.2

PE_UFP_VDM_Mode_Entry_NAK Section 8.3.3.21.1.3

UFP Structured VDM Exit Mode
PE_UFP_VDM_Mode_Exit Section 8.3.3.21.2.1

PE_UFP_VDM_Mode_Exit_ACK Section 8.3.3.21.2.2

PE_UFP_VDM_Mode_Exit_NAK Section 8.3.3.21.2.3

Cable Plug Specific
Cable Ready
PE_CBL_Ready Section 8.3.3.22.1.1
Mode Entry
PE_CBL_Evaluate_Mode_Entry Section 8.3.3.22.4.1.1

PE_CBL_Mode_Entry_ACK Section 8.3.3.22.4.1.2

PE_CBL_Mode_Entry_NAK Section 8.3.3.22.4.1.3

Mode Exit
PE_CBL_Mode_Exit Section 8.3.3.22.4.2.1

PE_CBL_Mode_Exit_ACK Section 8.3.3.22.4.2.2

PE_CBL_Mode_Exit_NAK Section 8.3.3.22.4.2.3

Cable Soft Reset
PE_CBL_Soft_Reset Section 8.3.3.22.2.1.1
Cable Hard Reset
PE_CBL_Hard_Reset Section 8.3.3.22.2.2.1
DFP Soft Reset or Cable Reset
PE_DFP_CBL_Send_Soft_Reset Section 8.3.3.22.2.3.1

PE_DFP_CBL_Send_Cable_Reset Section 8.3.3.22.2.3.2

UFP Source Soft Reset
PE_UFP_CBL_Send_Soft_Reset Section 8.3.3.22.2.4
Source Startup Structured VDM Discover Identity
PE_SRC_VDM_Identity_Request Section 8.3.3.22.3.1

PE_SRC_VDM_Identity_ACKed Section 8.3.3.22.3.2

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 511
 State name Reference
PE_SRC_VDM_Identity_NAKed Section 8.3.3.22.3.3
BIST Carrier Mode
PE_BIST_Carrier_Mode Section 8.3.3.23.1.1
USB Type-C referenced states
ErrorRecovery Section 8.3.3.24.1

Page 512 USB Power Delivery Specification Revision 3.0, Version 1.1
9. States and Status Reporting
9.1 Overview
This chapter describes the Status reporting mechanisms for devices with data connections (e.g. D+/D- and or SSTx+/-
and SSRx+/-). It also describes the corresponding USB state a device that supports USB PD Shall transition to as a
result of changes to the USB PD state that the device is in.
This chapter does not define the System Policy or the System Policy Manager. That is defined in [USBTypeCBridge
1.0]. In addition the Policies themselves are not described here; these are left to the implementers of the relevant
products and systems to define.
All PD Capable USB (PDUSB) Devices Shall report themselves as self-powered devices (over USB) when plugged into a
PD capable Port even if they are entirely powered from VBUS. However, there are some differences between PD and
[USB 2.0] / [USB 3.1]; for example, the presence of VBUS alone does not mean that the device (Consumer) moves from
the USB Attached state to the USB Powered state. Similarly the removal of VBUS alone does not move the device
(Consumer) from any of the USB states to the Attached state. See Section 9.1.2 for details.
PDUSB Devices Shall follow the PD requirements when it comes to suspend (see Section 6.4.1.2.2.2), configured, and
operational power. The PD requirements when the device is configured or operational are defined in this section (see
Table 9-4). Note that the power requirements reported in the PD Consumer Port descriptor of the device Shall
override the power draw reported in the bMaxPower field in the configuration descriptor. A PDUSB Device Shall
report zero in the bMaxPower field after successfully negotiating a mutually agreeable Contract and Shall disconnect
and re-enumerate when it switches operation back to operating in standard [USB 2.0], [USB 3.1], [USB Type-C 1.2] or
[USBBC 1.2] When operating in [USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2] mode it Shall report its power
draw via the bMaxPower field.
As shown in Figure 9-1, each Provider and Consumer will have their own Local Policies which operate between
directly connected ports. An example of a typical PD system is shown in Figure 9-1. This example consists of a
Provider, Consumer/Providers and Consumers connected together in a tree topology. Between directly connected
devices there is both a flow of Power and also Communication consisting of both Status and Control information.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 513
 Figure 9-1 Example PD Topology

AC/Battery

Power

Provider
Communication

P/C Provider/Consumer

Consumer/
Provider
P/C P/C P/C

Consumer/ AC/Battery
Consumer Consumer
Provider

Figure 9-2 shows how this same topology can be mapped to USB. In a USB based system, policy is managed by the
host and communication of system level policy information is via standard USB data line communication. This is a
separate mechanism to the USB Power Delivery VBUS protocol which is used to manage Local Policy. When USB data
line communication is used, status information and control requests are passed directly between the System Policy
Manager (SPM) on the host and the Provider or Consumer.
Status information comes from a Provider or Consumer to the SPM so it can better manage the resources on the host
and provide feedback to the end user.
Real systems will be a mixture of devices which in terms of power management support might have implemented PD,
[USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2] or they might even just be non-compliant Power Sucking
Devices. The level of communication of system status to the SPM will therefore not necessarily be comprehensive.
The aim of the status mechanisms described here is to provide a mechanism whereby each connected entity in the
system provides as much information as possible on the status of itself.

Page 514 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 9-2 Mapping of PD Topology to USB

AC/Battery

Power

Root Hub
Communication

Hub

AC/Battery
Device Device Device

Information described in this section that is communicated to the SPM is as follows:

 Versions of USB Type-C Current, PD and BC supported.
 Capabilities as a Provider/Consumer.
 Current operational state of each Port e.g. Standard, USB Type-C Current, BC, PD and negotiated power level.
 Status of AC or Battery Power for each PDUSB Device in the system.
The SPM can negotiate with Providers or Consumers in the system in order to request a different Local Policy, or to
request the amount of power to be delivered by the Provider to the Consumer. Any change in Local Policy could
trigger a renegotiation of the Contract, using USB Power Delivery protocols, between a directly connected Provider
and Consumer. A change in how much power is to be delivered will, for example, cause a renegotiation.

9.1.1 PDUSB Device and Hub Requirements

All PDUSB Devices Shall return all relevant descriptors mentioned in this chapter. PDUSB Hubs Shall also support a
PD bridge as defined in [USBTypeCBridge 1.0].

9.1.2 Mapping to USB Device States

As mentioned in Section 9.1 a PDUSB Device reports itself as a self-powered device. However, the device Shall
determine whether or not it is in the USB Attached or USB Powered states as described in Figure 9-3, Figure 9-4 and
Figure 9-5. All other USB states of the PDUSB Device Shall be as described in Chapter 9 of [USB 2.0] and [USB 3.1].

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 515
Figure 9-3 shows how a PDUSB Device determines when to transition from the USB Attached to the USB Powered
state. USB Type-C Dead Battery operation does not require special handling since the default state at Attach or after a
Hard Reset is that the USB Device is a Sink.

Figure 9-3 USB Attached to USB Powered State Transition

Negotiate
enough
No Power? Yes
Hard
Reset
No

USB VBUS Yes Can Yes USB

Attached Present enumerate? Powered

Device
in Sink
Mode
No
Device in
Source
Mode (5V)

Device is a Yes Attached Yes

Source? Sink?

No No

Figure 9-4 shows how a PDUSB Device determines when to transition from the USB Powered state to the USB
Attached state when the device is a Consumer. A PDUSB Device determines that it is performing a Power Role Swap
as described in Section 8.3.3.16.3 and Section 8.3.3.16.4. See Section 7.1.5 for additional information on device
behavior during Hard Resets.

Page 516 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure 9-4 Any USB State to USB Attached State Transition (When operating as a Consumer)

Hard Reset Hard Reset

and and
Can Operate Can’t Operate

Swapping
Any USB VBUS No Power
No USB
State Present Attached
Roles?

Yes Yes
Hard Reset
and
Bus Powered
Figure 9-5 shows how a PDUSB Device determines when to transition from the USB Powered state to the USB
Attached state when the device is a Provider.

Figure 9-5 Any USB State to USB Attached State Transition (When operating as a Provider)

Local Power Source Lost

Hard
Reset
Any USB Lack of PD Yes USB
State comms? Attached

No

Figure 9-6 shows how a PDUSB Device using the USB Type-C connector determines when to transition from the USB
Powered state to the USB Attached state after a Data Role Swap has been performed i.e. it has just changed from
operation as a PDUSB Host to operation as a PDUSB Device. The Data Role Swap is described in Section 6.3.9. A Hard
Reset will also return a Sink acting as a PDUSB Host to PDUSB Device operation as described in Section 6.8.2. See
Section 7.1.5 for additional information on device behavior during Hard Resets.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 517
 Figure 9-6 Any USB State to USB Attached State Transition (After a USB Type-C Data Role Swap)

Hard Reset
No Changes Data
Role

Swapping
Any USB VBUS Yes Data
Yes USB
State Present Attached
Roles?

9.1.3 PD Software Stack

Figure 9-7 gives an example of the software stack on a PD aware OS. In this stack we are using the example of a
system with an xHCI based controller. The USB Power Delivery hardware May or May Not be a part of the xHC.

Figure 9-7 Software stack on a PD aware OS

9.1.4 PDUSB Device Enumeration

As described earlier, a PDUSB Device acts as a self-powered device with some caveats with respect to how it
transitions from the USB Attached state to USB Powered state. Figure 9-8 gives a high level overview of the
enumeration steps involved due to this change. A PDUSB Device will first (Step1) interact with the Power Delivery
Page 518 USB Power Delivery Specification Revision 3.0, Version 1.1
hardware and the Local Policy manager to determine whether or not it can get sufficient power to
enumerate/operate. Note: PD is likely to have established a Contract prior to enumeration. The SPM will be notified
(Step 2) of the result of this negotiation between the Power Delivery hardware and the PDUSB Device. After
successfully negotiating a mutually agreeable Contract the device will signal a connect to the xHC. The standard USB
enumeration process (Steps 3, 4 and 5) is then followed to load the appropriate driver for the function(s) that the
PDUSB Device exposes.

Figure 9-8 Enumeration of a PDUSB Device

If a PDUSB Device cannot perform its intended function with the amount of power that it can get from the Port it is
connected to then the host system Should display a Message (on a PD aware OS) about the failure to provide sufficient
power to the device. In addition the device Shall follow the requirements listed in Section 8.2.5.2.1.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 519
 9.2 PD Specific Descriptors
A PDUSB Device Shall return all relevant descriptors mentioned in this section.
The device Shall return its capability descriptors as part of the device’s Binary Object Store (BOS) descriptor set.
Table 9-1 lists the type of PD device capabilities.

Table 9-1 USB Power Delivery Type Codes

Capability Code Value Description

POWER_DELIVERY_CAPABILITY 06H Defines the various PD Capabilities of this device

BATTERY_INFO_CAPABILITY 07H Provides information on each Battery supported by the device

PD_CONSUMER_PORT_CAPABILITY 08H The Consumer characteristics of a Port on the device

PD_PROVIDER_PORT_CAPABILITY 09H The provider characteristics of a Port on the device

9.2.1 USB Power Delivery Capability Descriptor

Table 9-2 USB Power Delivery Capability Descriptor

Offset Field Size Value Description

0 bLength 1 Number Size of descriptor
1 bDescriptorType 1 Constant DEVICE CAPABILITY Descriptor type
2 bDevCapabilityType 1 Constant Capability type: POWER_DELIVERY_CAPABILITY
3 bReserved 1 Shall be set to zero.
Reserved

4 bmAttributes 4 Bitmap Bitmap encoding of supported device level features. A

value of one in a bit location indicates a feature is
supported; a value of zero indicates it is not supported.
Encodings are:
Bit Description
0 Reserved. Shall be set to zero.
1 Battery Charging. This bit Shall be set to one
to indicate this device supports the Battery
Charging Specification as per the value
reported in the bcdBCVersion field.
2 USB Power Delivery. This bit Shall be set to
one to indicate this device supports the USB
Power Delivery Specification as per the value
reported in the bcdPDVersion field.
3 Provider. This bit Shall be set to one to
indicate this device is capable of providing
power. This field is only Valid if Bit 2 is set to
one.
4 Consumer. This bit Shall be set to one to
indicate that this device is a consumer of
power. This field is only Valid if Bit 2 is set to
one.
5 This bit Shall be set to 1 to indicate that this
device supports the feature CHARGING_POLICY.
Note that supporting the CHARGING_POLICY
feature does not require a BC or PD
mechanism to be implemented.
6 USB Type-C Current. This bit Shall be set to
one to indicate this device supports power

Page 520 USB Power Delivery Specification Revision 3.0, Version 1.1
 Offset Field Size Value Description
capabilities defined in the USB Type-C
Specification as per the value reported in the
bcdUSBTypeCVersion field
7 Reserved. Shall be set to zero.
15:8 bmPowerSource. At least one of the following
bits 8, 9 and 14 Shall be set to indicate which
power sources are supported.
Bit Description
8 AC Supply
9 Battery
10 Other
13:11 NumBatteries. This
field Shall only be Valid
when the Battery field is
set to one and Shall be
used to report the
number of batteries in
the device.
14 Uses VBUS
15 Reserved and Shall be
set to zero.
31:16 Reserved and Shall be set to zero.
8 bcdBCVersion 2 BCD Battery Charging Specification Release Number in Binary-
Coded Decimal (e.g., V1.20 is 120H). This field Shall only be
Valid if the device indicates that it supports BC in the
bmAttributes field.
10 bcdPDVersion 2 BCD USB Power Delivery Specification Release Number in
Binary-Coded Decimal. This field Shall only be Valid if the
device indicates that it supports PD in the bmAttributes
field.
12 bcdUSBTypeCVersion 2 BCD USB Type-C Specification Release Number in Binary-Coded
Decimal. This field Shall only be Valid if the device
indicates that it supports USB Type-C in the bmAttributes
field.

9.2.2 Battery Info Capability Descriptor

A PDUSB Device Shall support this capability descriptor if it reported that one of its power sources was a Battery in
the bmPowerSource field in its Power Deliver Capability Descriptor. It Shall return one Battery Info Descriptor per
Battery it supports.

Table 9-3 Battery Info Capability Descriptor

Offset Field Size Value Description

0 bLength 1 Number Size of descriptor
1 bDescriptorType 1 Constant DEVICE CAPABILITY Descriptor type
2 bDevCapabilityType 1 Constant Capability type: BATTERY_INFO_CAPABILITY
3 iBattery 1 Index Index of string descriptor Shall contain the user
friendly name for this Battery.
4 iSerial 1 Index Index of string descriptor Shall contain the Serial
Number String for this Battery.
5 iManufacturer 1 Index Index of string descriptor Shall contain the name of the
Manufacturer for this Battery.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 521
 Offset Field Size Value Description
6 bBatteryId 1 Number Value Shall be used to uniquely identify this Battery in
status Messages.
7 bReserved 1 Number Reserved and Shall be set to zero.
8 dwChargedThreshold 4 mWh Shall contain the Battery Charge value above which
this Battery is considered to be fully charged but not
necessarily “topped off.”
12 dwWeakThreshold 4 mWh Shall contain the minimum charge level of this Battery
such that above this threshold, a device can be assured
of being able to power up successfully (see Battery
Charging 1.2).
16 dwBatteryDesignCapacity 4 mWh Shall contain the design capacity of the Battery.
20 dwBatteryLastFullchargeCapacity 4 mWh Shall contain the maximum capacity of the Battery
when fully charged.

9.2.3 PD Consumer Port Capability Descriptor

A PDUSB Device Shall support this capability descriptor if it is a Consumer.

Table 9-4 PD Consumer Port Descriptor

Offset Field Size Value Description

0 bLength 1 Number Size of descriptor
1 bDescriptorType 1 Constant DEVICE CAPABILITY Descriptor type
2 bDevCapabilityType 1 Constant Capability type: PD_CONSUMER_PORT_CAPABILITY
3 bReserved 1 Number Reserved and Shall be set to zero.
4 bmCapabilities 2 Bitmap Capability: This field Shall indicate the specification
the Consumer Port will operate under.
Bit Description
0 Battery Charging (BC)
1 USB Power Delivery (PD)
2 USB Type-C Current
15:3 Reserved and Shall be set to
zero.
6 wMinVoltage 2 Number Shall contain the minimum voltage in 50mV units that
this Consumer is capable of operating at.
8 wMaxVoltage 2 Number Shall contain the maximum voltage in 50mV units that
this Consumer is capable of operating at.
10 wReserved 2 Number Reserved and Shall be set to zero.
12 dwMaxOperatingPower 4 Number Shall contain the maximum power in 10mW units this
Consumer can draw when it is in a steady state
operating mode.
16 dwMaxPeakPower 4 Number Shall contain the maximum power in 10mW units this
Consumer can draw for a short duration of time
(dwMaxPeakPowerTime) before it falls back into a
steady state.
20 dwMaxPeakPowerTime 4 Number Shall contain the time in 100ms units that this
Consumer can draw peak current.
A device Shall set this field to 0xFFFF if this value is
unknown.

9.2.4 PD Provider Port Capability Descriptor

A PDUSB Device Shall support this capability descriptor if it is a Provider.
Page 522 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 9-5 PD Provider Port Descriptor

Offset Field Size Value Description

0 bLength 1 Number Size of descriptor
1 bDescriptorType 1 Constant DEVICE CAPABILITY Descriptor type
2 bDevCapabilityType 1 Constant Capability type: PD_PROVIDER_PORT_CAPABILITY
3 bReserved 1 Number Reserved and Shall be set to zero.
4 bmCapabilities 2 Bitmap This field Shall indicate the specification the Provider
Port will operation under.
Bit Description
0 Battery Charging (BC)
1 USB Power Delivery (PD)
2 USB Type-C Current
15:3 Reserved. Shall be set to zero.
6 bNumOfPDObjects 1 Number Shall indicate the number of Power Data Objects.
7 bReserved 1 Number Reserved and Shall be set to zero.
8 wPowerDataObject1 4 Bitmap Shall contain the first Power Data Object supported by
this Provider Port. See Section 6.4.1 for details of the
Power Data Objects.
… … … … …
N+4 wPowerDataObjectN 4 Bitmap Shall contain the 2nd and subsequent Power Data
Objects supported by this Provider Port. See Section
6.4.1 for details of the Power Data Objects.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 523
 9.3 PD Specific Requests and Events
A PDUSB Device that is compliant to this specification Shall support the Battery related requests if it has a battery.
A PDUSB Hub that is compliant to this specification Shall support a USB PD Bridge as described in [USBTypeCBridge
1.0] irrespective of whether the PDUSB Hub is a Provider, a Consumer, or both.

9.3.1 PD Specific Requests

PD defines requests to which PDUSB Devices Shall respond as outlined in Table 9-6. All Valid requests in Table 9-6
Shall be implemented by PDUSB Devices.

Table 9-6 PD Requests

Request bmRequestType bRequest wValue wIndex wLength Data

GetBatteryStatus 10000000B Get_Battery_Status Zero Battery ID Eight Battery Status
SetPDFeature 00000000B SET_FEATURE Feature Feature Zero None
Selector Specific

Table 9-7 gives the bRequest values for commands that are not listed in the hub/device framework chapters of [USB
2.0], [USB 3.1].

Table 9-7 PD Request Codes

bRequest Value
GET_BATTERY_STATUS 21

Table 9-8 gives the Valid feature selectors for the PD class. Refer to Section 9.4.2.1, and Section 9.4.2.2 for a
description of the features.

Table 9-8 PD Feature Selectors

Feature Selector Recipient Value

BATTERY_WAKE_MASK Device 40

CHARGING_POLICY Device 54

Page 524 USB Power Delivery Specification Revision 3.0, Version 1.1
 9.4 PDUSB Hub and PDUSB Peripheral Device Requests
9.4.1 GetBatteryStatus
This request returns the current status of the Battery in a PDUSB Hub/Peripheral.
bmRequestType bRequest wValue wIndex wLength Data
Battery
10000000B Get_Battery_Status Zero Battery ID Eight
Status

The PDUSB Hub/Peripheral Shall return the Battery Status of the Battery identified by the value of wIndex field.
Every PDUSB Device that has a Battery Shall return its Battery Status when queried with this request. For Providers
or Consumers with multiple batteries, the status of each Battery Shall be reported per Battery.

Table 9-9 Battery Status Structure

Offset Field Size Value Description

0 bBatteryAttributes 1 Number Shall indicate whether a Battery is installed and whether
this is charging or discharging.
Value Description
0 There is no Battery
1 The Battery is charging
2 The Battery is discharging
3 The Battery is neither discharging nor
charging
255-4 Reserved and Shall Not be used
1 bBatterySOC 1 Number Shall indicate the Battery State of Charge given as
percentage value from Battery Remaining Capacity.
2 bBatteryStatus 1 Number If a Battery is present Shall indicate the present status of
the Battery.
Value Meaning
0 No error
1 Battery required and not present
2 Battery non-chargeable/wrong
chemistry
3 Over-temp shutdown
4 Over-voltage shutdown
5 Over-current shutdown
6 Fatigued Battery
7 Unspecified error
255-8 Reserved and Shall Not be used
3 bRemoteWakeCapStatus 1 Bitmap If the device supports remote wake, then the device Shall
support Battery Remote wake events. The default value for
the Remote wake events Shall be turned off (set to zero)
and can be enable/disabled by the host as required. If set
to one the device Shall generate a wake event when a
change of status occurs. See Section 9.4.2 for more details.
Bit Description
0 Battery present event
1 Charging flow
2 Battery error
7:3 Reserved and Shall be set to zero

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 525
 Offset Field Size Value Description
4 wRemainingOperatingTime 2 Number Shall contain the operating time (in minutes) until the
Weak Battery threshold is reached, based on Present
Battery Strength and the device’s present operational
power needs. Note: this value Shall exclude any additional
power received from charging.
A Battery that is not capable of returning this information
Shall return a value of 0xFFFF.
6 wRemainingChargeTime 2 Number Shall contain the remaining time (in minutes) until the
Charged Battery threshold is reached based on Present
Battery Strength, charging power and the device’s present
operational power needs. Value Shall only be Valid if the
Charging Flow is “Charging”.
A Battery that is not capable of returning this information
Shall return a value of 0xFFFF.

If wValue or wLength are not as specified above, then the behavior of the PDUSB Device is not specified.
If wIndex refers to a Battery that does not exist, then the PDUSB Device Shall respond with a Request Error.
If the PDUSB Device is not configured, the PDUSB Hub's response to this request is undefined.
If the PDUSB Hub is not configured, the PDUSB Hub's response to this request is undefined.

9.4.2 SetPDFeature
This request sets the value requested in the PDUSB Hub/Peripheral.
bmRequestType bRequest wValue wIndex wLength Data
00000000B SET_ FEATURE Feature Selector Feature Specific Zero None

Setting a feature enables that feature or starts a process associated with that feature; see Table 9-8 for the feature
selector definitions. Features that May be set with this request are:
 BATTERY_WAKE_MASK.
 CHARGING_POLICY.

9.4.2.1 BATTERY_WAKE_MASK Feature Selector

When the feature selector is set to BATTERY_WAKE_MASK, then the wIndex field is structured as shown in the
following table.

Table 9-10 Battery Wake Mask

Bit Description
0 Battery Present: When this bit is set then
the PDUSB Device Shall generate a wake
event if it detects that a Battery has been
Attached.
1 Charging Flow: When this bit is set then
the PDUSB Device Shall generate a wake
event if it detects that a Battery switched
from charging to discharging or vice versa.
2 Battery Error: When this bit is set then
the PDUSB Device Shall generate a wake
event if the Battery has detected an error
condition.
15:3 Reserved and Shall Not be used.

Page 526 USB Power Delivery Specification Revision 3.0, Version 1.1
The SPM May Enable or Disable the wake events associated with one or more of the above events by using this
feature.
If the PDUSB Hub is not configured, the PDUSB Hub's response to this request is undefined.

9.4.2.2 CHARGING_POLICY Feature Selector

When the feature selector is set to CHARGING_POLICY, the wIndex field Shall be set to one of the values defined in
Table 9-11. If the device is using USB Type-C Current above the default value or is using PD then this feature setting
has no effect and the rules for power levels specified in the [USB Type-C 1.2] or USB PD specifications Shall apply.

Table 9-11 Charging Policy Encoding

Value Description
00H The device Shall follow the default current limits as defined in the USB 2.0 or USB 3.1 specification,
or as negotiated through other USB mechanisms such as BC.
This is the default value.
01H The Device May draw additional power during the unconfigured and suspend states for the
purposes of charging.
For charging the device itself, the device Shall limit its current draw to the higher of these two
values:
ICCHPF as defined in the USB 2.0 or USB 3.1 specification, regardless of its USB state.
Current limit as negotiated through other USB mechanisms such as BC.
02H The Device May draw additional power during the unconfigured and suspend states for the
purposes of charging.
For charging the device itself, the device Shall limit its current draw to the higher of these two
values:
ICCLPF as defined in the USB 2.0 or USB 3.1 specification, regardless of its USB state.
Current limit as negotiated through other USB mechanisms such as BC.
03H The device Shall Not consume any current for charging the device itself regardless of its USB state.
04H-FFFFH Reserved and Shall Not be used

This is a Valid command for the PDUSB Hub/Peripheral in the Address or Configured USB states. Further, it is only
Valid if the device reports a USB PD capability descriptor in its BOS descriptor and Bit 5 of the bmAttributes in that
descriptor is set to 1. The device will go back to the wIndex default value of 0 whenever it is reset.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 527
10. Power Rules
10.1 Introduction
The flexibility of power provision on USB Type-C is expected to lead to adapter re-use and the increasingly
widespread provision of USB power outlets in domestic and public places and in transport of all kinds. Environmental
considerations could result in unbundled adapters. Rules are needed to avoid incompatibility between the Sources
and the Sinks they are used to power, in order to avoid user confusion and to meet user expectations. This section
specifies a set of rules that Sources and Sinks Shall follow. These rules provide a simple and consistent user
experience.

10.2 Source Power Rules

10.2.1 Source Power Rule Considerations
The Source power rules are designed to:
 Ensure the PD Power (PDP) of an adapter specified in watts explicitly defines the voltages and currents at each
voltage the adapter supports
 Ensure that adapters with a large PDP are always capable of providing the power to devices designed for use with
adapters with a smaller PDP
 Enable an ecosystem of adapters that are interoperable with the devices in the ecosystem.
The considerations that lead to the Source power rules are based are summarized in Table 10-1.

Table 10-1 Considerations for Sources

Considerations Rationale Consequence

Simple to identify capability A user going into an electronics retailer Cannot have a complex identification
knows what they need scheme
Higher power Sources are a Bigger is always better in user’s eyes – Higher power Sources do everything
superset of smaller ones don’t want a degradation in performance smaller ones do
Unambiguous Source definitions Sources with the same power rating but To avoid user confusion, any given power
different VI combinations might not rating has a single definition
interoperate
A range of power ratings Users and companies will want freedom to Fixed profiles at specific power levels don’t
pick appropriate Source ratings provide adequate flexibility, e.g. profiles as
defined in previous versions of PD.
5V@3A USB Type-C Source is 5V@3A USB Type-C Source is considered All > 15W adapters must support 5V@3A or
defined by [USB Type-C 1.2] superset consideration is violated
Maximize 3A cable utilization 3A cables will be ubiquitous Increase to maximum voltage (20V) before
increasing current beyond 3A
Optimize voltage rail count More rails are a higher burden for Sources, 5V is a basic USB requirement. 20V
particularly in terms of testing provides the maximum capability.
Some Sources are not able to Some small Battery operated Sources e.g. In addition to the minimal 5V
provide significant power mobile devices, are able to provide more advertisement are able to advertise more
power directly from their Battery than power from their Battery
from a regulated 5V supply
Some Sources share power Hubs have to be supported See Section 10.2.4
between multiple Ports (Hubs)

Page 528 USB Power Delivery Specification Revision 3.0, Version 1.1
 10.2.2 Normative Voltages and Currents
The voltages and currents a Source with a PDP of x Watts Shall support are as defined in Table 10-2.

Table 10-2 Normative Voltages and Currents

PDP (W) Current at 5V (A) Current at 9V (A) Current at 15V (A) Current at 20V (A)
0.5 ≤ x ≤ 15 x÷5
15 < x ≤ 27 3 x÷9
27 < x ≤ 45 3 3 x ÷ 15
45 < x ≤ 60 3 3 3 x ÷ 20
60 < x ≤ 100 3 3 3 x ÷ 201
1 Requires a 5A cable.

Figure 10-1 illustrates the maximum current and power rails that a Source Shall support at each voltage for a given
PDP.

Figure 10-1 Source Power Rule Illustration

4
Current (A)

5 + 9V 5 + 9 + 15V
3

1
7.5W

27W
15W

45W

0
Rp1 Rp2
0 10 20 30 40 50 60 70 80 90 100
Source Power Rating (W)

Figure 10-2 shows an example of an adapter with a rating at 50W. The adapter is required to support 20V at 2.5A,
15V at 3A, 9V at 3A and 5V at 3A.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 529
 Figure 10-2 Source Power Rule Example

4
Current (A)

5 + 9V 5 + 9 + 15V
3

50W
7.5W

27W
15W

45W
0
Rp1 Rp2
0 10 20 30 40 50 60 70 80 90 100
Source Power Rating (W)

Table 10-3, Table 10-4, Table 10-5 and Table 10-6 show the Fixed Supply PDOs that Shall be supported for each of the
Normative voltages defined in Table 10-2.

Table 10-3 Fixed Supply PDO – Source 5V

Bit(s) Description
B31…30 Fixed supply
B29 Dual-Role Power
B28 USB Suspend Supported
B27 Unconstrained Power
B26 USB Communications Capable
B25 Dual-Role Data
B24…22 Reserved – Shall be set to zero.
B21…20 Peak Current
B19…10 5V
B9…0
PDP (x) Current (A)
0.5 ≤ x ≤ 15 x÷5
15 < x ≤ 100 3

Page 530 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 10-4 Fixed Supply PDO – Source 9V

Bit(s) Description
B31…30 Fixed Supply
B29…22 Reserved – Shall be set to zero.
B21…20 Peak Current
B19…10 9V
B9…0
PDP (x) Current (A)
0.5 ≤ x ≤ 15 PDO not required
15 < x ≤ 27 x÷9
27 < x ≤ 100 3

Table 10-5 Fixed Supply PDO – Source 15V

Bit(s) Description
B31…30 Fixed Supply
B29…22 Reserved – Shall be set to zero.
B21…20 Peak Current
B19…10 15V
B9…0
PDP (x) Current (A)
0.5 ≤ x ≤ 27 PDO not required
27 < x ≤ 45 x ÷ 15
45 < x ≤ 100 3

Table 10-6 Fixed Supply PDO – Source 20V

Bit(s) Description
B31…30 Fixed Supply
B29…22 Reserved – Shall be set to zero.
B21…20 Peak Current
B19…10 20V
B9…0
PDP (x) Current (A)
0.5 ≤ x ≤ 45 PDO not required
45 < x ≤ 100 x ÷ 20

More current May be offered in the PDOs when Optional voltages/currents are supported and a 5A cable is being
used (see Section 10.2.3).

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 531
 10.2.3 Optional Voltages/Currents
10.2.3.1 Optional Normative Fixed, Variable and Battery Supply
In addition to the voltages and currents specified in Section 10.2.2 a Source that is optimized for use with a specific
Sink or a specific class of Sinks May Optionally supply additional voltages and increased currents. When Optional
voltages and increased currents are provided, the following requirements Shall apply:
 The Source Shall be able to meet its PDP at the Normative voltages and currents as specified in Section 10.2.2.
 A Source Shall Not advertise Fixed Supply PDO Optional voltages and currents that exceed the PDP.
 A Source Shall Not advertise Variable Supply PDO Optional maximum voltages and currents that exceed the PDP.
 A Source Shall Not advertise a Battery Supply PDO Optional maximum allowable power that exceeds the PDP.

10.2.3.2 Optional Normative Programmable Power Supply

In addition to the voltages and currents specified in Section 10.2.2 a Source that is optimized for use with a specific
Sink or a specific class of Sinks May Optionally offer a Programmable Power Supply. The Programmable Power
Supply’s PDP Shall be calculated as the product of the Nominal Voltage times the Maximum Current.
When Optional Programmable Power Supply APDOs are offered, the following requirements Shall apply:
 A Source that advertises Optional Programmable Power Supply APDOs Shall advertise the PDOs and APDOs
shown in Table 10-7.
 A Source Shall advertise Optional Programmable Power Supply APDOs with Maximum Voltage and Minimum
Voltages for nominal voltage as defined in Table 10-8.
 A Source that advertises Programmable Power Supply APDOs other than the ones listed in Table 10-8 Shall Not
advertise additional APDO's with a Maximum Voltage * Maximum Current that exceeds the adapter's PDP.
 In no case Shall a Source advertise a current that exceeds the attached cable’s current rating.
Table 10-7 shows the Programmable Power Supply APDOs that Shall be offered for a given PDP.

Table 10-7 Programmable Power Supply PDOs and APDOs based on the PDP

PDP (W) 5V fixed 9V fixed 15V fixed 20V fixed 5V Prog 9V Prog 15V Prog 20V Prog
x <= 15W PDP/5 - - - PDP/5 - - -
15 < x <= 27W 3A PDP/9 - - 3A or PDP/9 - -
PDP/52
27 < x <= 45W 3A 3A PDP/15 - PDP/51 3A or PDP/15 -
PDP/92
45 < x <= 100W 3A 3A 3A PDP/20 - PDP/91 3A or PDP/202
PDP/152
Notes:
1. This PPS APDO is Optional.
2. The PPS May offer more than 3A when a 5A cable is present.

10.2.3.2.1 Programmable Power Supply Voltage Ranges

The Programmable Power Supply voltage ranges map to the Fixed Supply Voltages. For each Fixed Voltage there is a
defined voltage range for the matching Programmable Power Supply APDO. Table 10-8 shows the Minimum and
Maximum voltage for the Programmable Power Supply that corresponds to the Fixed nominal voltage.

Page 532 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table 10-8 Programmable Power Supply Voltage Ranges

Fixed Nominal Voltage

5V Prog 9V Prog 15V Prog 20V Prog
Maximum Voltage 5.9V 11V 16V 21V
Minimum Voltage 3V 3V 3V 3V

The voltage output at the Source’s connector Shall be +/-5% for both the Maximum Voltage and the Minimum Voltage.

10.1.2.2 Examples of the use of the Programmable Power Supplies

The following examples illustrate what a power adapter that advertises a particular PDP May offer:
1. PDP 15W
 5V @ 3A and 5V Prog @ 3A is the baseline
2. PDP 25W
 5V @ 3A, 9V @ 2.8A, 5V Prog @ 3A and 9V Prog @ 2.8A is the baseline
 5V @ 3A, 9V @ 2.8A, 5V Prog @ >3A up to 5A and 9V Prog @ 2.8A (with a 5A cable)
3. PDP 27W
 5V @ 3A, 9V @ 3A, 9V Prog @ 3A is the baseline
 5V @ 3A, 9V @ 3A, 5V Prog @ 3A and 9V Prog @ 3A can offer 5V Prog, but it is covered by the 9V Prog
 5V @ 3A, 9V @ 3A, 5V Prog @ >3A up to 5A and 9V Prog @ 3A (with a 5A cable)
4. PDP 36W
 5V @ 3A, 9V @ 3A, 15 @ 2.4A, 9V Prog @ 3 A and 15V Prog @ 2.4A is the baseline
 5V @ 3A, 9V @ 3A, 15 @ 2.4A, 5V Prog @ >3A up to 5A, 9V Prog @ >3A up to 4A and 15V Prog @ 2.4A (with
a 5A cable)
The first example is a simple single output voltage supply. Both the Fixed and Programmable outputs supply 3A.
The second example illustrates that there are multiple ways to meet the requirements. The first sub-bullet is the
power that the power rules require. The second sub-bullet illustrates that the power supply can offer more power at
a particular voltage so long as it does not violate the power rules. In this case it offers 25W at both 5V and 9V.
The third example illustrates that there are multiple ways a 27W PDP power adapter can be implemented and meet
the power rules. The first sub-bullet shows that the 9V Prog @ 3A fully covers the 5V Prog @3A range so it is not
necessary to advertise both. The second and third sub-bullets illustrate that the power adapter can advertise lower
voltages at higher currents than required so long as the power does not exceed the PDP.
The fourth example illustrates as the PDP goes higher there are more possible combinations that meet the power
rules. Although there are multiple ways to meet the power rules, no more than a combination of seven PDO and
APDOs can be offered.

10.2.4 Power sharing between ports

The Source power rules defined in Section 10.2.2 and Section 10.2.3 Shall apply independently to each port on a
system with multiple ports.

10.3 Sink Power Rules

10.3.1 Sink Power Rule Considerations
The Sink power rules are designed to ensure the best possible user experience when a given Sink used with a
compliant Source of arbitrary Output Power Rating that only supplies the Normative voltages and currents.
The Sink Power Rules are based on the following considerations:

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 533
 Low power Sources (e.g., 5V) are expected to be very common and will be used with Sinks designed for a higher
PDP.
 Optimizing the user experience when Sources with a high PDP are used with low power Sinks.
 Preventing Sinks that only function well (or at all) when using Optional voltages and currents.

10.3.2 Normative Sink Rules

Sinks designed to use Sources with a PDP of x W Shall:
 Either operate or charge from Sources that have a PDP ≥ x W.
 Either operate, charge or indicate a capability mismatch (see Section 6.4.2.3) from Sources that have a PDP < x W
and ≥ 0.5W.
A Sink optimized for a Source with Optional voltages and currents or power as described in Section 10.2.3 with a PDP
of x W Shall provide a similar user experience when powered from a Source with a PDP of ≥ x W that supplies only the
Normative voltages and currents as specified in Section 10.2.2.
The following requirements Shall apply to the advertised Sink Capabilities:
 A Sink Shall Not advertise Fixed Supply PDO maximum voltages and currents that exceed the PDP they were
designed to use.
 A Sink Shall Not advertise Variable Supply PDO maximum voltages and currents that exceed the PDP they were
designed to use.
 A Sink Shall Not advertise a Battery Supply PDO maximum allowable power that exceeds the PDP they were
designed to use.

Page 534 USB Power Delivery Specification Revision 3.0, Version 1.1
 A. CRC calculation
A.1 C code example
//
// USB PD CRC Demo Code.
//
#include <stdio.h>

int crc;

//-----------------------------------------------------------------------------

void crcBits(int x, int len) {

const int poly = 0x04C11DB6; //spec 04C1 1DB7h

int newbit, newword, rl_crc;

for(int i=0; i<len; i++) {

newbit = ((crc>>31) ^ ((x>>i)&1)) & 1;

if(newbit) newword=poly; else newword=0;
rl_crc = (crc<<1) | newbit;
crc = rl_crc ^ newword;
printf("%2d newbit=%d, x>>i=0x%x, crc=0x%x\n", i, newbit,(x>>i),crc);
}
}

int crcWrap(int c){

int ret = 0;
int j, bit;

c = ~c;
printf("~crc=0x%x\n", c);

for(int i=0;i<32;i++) {
j = 31-i;

bit = (c>>i) & 1;

ret |= bit<<j;

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 535
 }
return ret;

//-----------------------------------------------------------------------------

int main(){

int txCrc=0,rxCrc=0,residue=0,data;

printf("using packet data 0x%x\n", data=0x0101);

crc = 0xffffffff;
crcBits(data,16);
txCrc = crcWrap(crc);

printf("crc=0x%x, txCrc=0x%x\n", crc, txCrc);

printf("received packet after decode= 0x%x, 0x%x\n", data, txCrc);

crc = 0xffffffff;
crcBits(data,16);
rxCrc = crcWrap(crc);

printf("Crc of the received packet data is (of course) =0x%x\n", rxCrc);

printf("continue by running the transmit crc through the crc\n");

crcBits(rxCrc,32);

printf("Now the crc residue is 0x%x\n", crc);

printf("should be 0xc704dd7b\n");

Page 536 USB Power Delivery Specification Revision 3.0, Version 1.1
 A.2 Table showing the full calculation over one Message
CRC register CRC register CRC register CRC register
Function Nibble Symbol Bits bit nr. Function Nibble Symbol Bits bit nr.
transmitter receiver transmitter receiver
0 FFFFFFFF FFFFFFFF 1 1 FFFFFFFF FFFFFFFF 85
1 FFFFFFFF FFFFFFFF 2 0 FFFFFFFE FFFFFFFF 86
#1
0 FFFFFFFF FFFFFFFF 3 #09 0 FB3EE24B FFFFFFFF 87
1 FFFFFFFF FFFFFFFF 4 1 F2BCD921 FFFFFFFF 88
0 FFFFFFFF FFFFFFFF 5 0 E1B8AFF5 FFFFFFFF 89
1 FFFFFFFF FFFFFFFF 6 0 E1B8AFF5 FFFFFFFF 90
0 FFFFFFFF FFFFFFFF 7 1 C7B0425D FFFFFFFE 91
#0
1 FFFFFFFF FFFFFFFF 8 #1E 1 8BA1990D FB3EE24B 92
0 FFFFFFFF FFFFFFFF 9 1 13822FAD F2BCD921 93
GoodCRC
1 FFFFFFFF FFFFFFFF 10 1 27045F5A E1B8AFF5 94
Header
0 FFFFFFFF FFFFFFFF 11 1 27045F5A E1B8AFF5 95
#0101
1 FFFFFFFF FFFFFFFF 12 0 4AC9A303 C7B0425D 96
#1
0 FFFFFFFF FFFFFFFF 13 #09 0 95934606 8BA1990D 97
1 FFFFFFFF FFFFFFFF 14 1 2FE791BB 13822FAD 98
0 FFFFFFFF FFFFFFFF 15 0 5FCF2376 27045F5A 99
1 FFFFFFFF FFFFFFFF 16 0 5FCF2376 27045F5A 100
0 FFFFFFFF FFFFFFFF 17 1 BF9E46EC 4AC9A303 101
#0
1 FFFFFFFF FFFFFFFF 18 #1E 1 7BFD906F 95934606 102
0 FFFFFFFF FFFFFFFF 19 1 F7FB20DE 2FE791BB 103
1 FFFFFFFF FFFFFFFF 20 1 EB375C0B 5FCF2376 104
0 FFFFFFFF FFFFFFFF 21 0 EB375C0B 5FCF2376 105
1 FFFFFFFF FFFFFFFF 22 1 EB375C0B BF9E46EC 106
#8
0 FFFFFFFF FFFFFFFF 23 #12 0 EB375C0B 7BFD906F 107
1 FFFFFFFF FFFFFFFF 24 0 EB375C0B F7FB20DE 108
0 FFFFFFFF FFFFFFFF 25 1 EB375C0B EB375C0B 109
1 FFFFFFFF FFFFFFFF 26 0 EB375C0B EB375C0B 110
0 FFFFFFFF FFFFFFFF 27 0 EB375C0B D2AFA5A1 111
#2
1 FFFFFFFF FFFFFFFF 28 #14 1 EB375C0B A19E56F5 112
P 0 FFFFFFFF FFFFFFFF 29 0 EB375C0B 47FDB05D 113
r 1 FFFFFFFF FFFFFFFF 30 1 EB375C0B 8B3A7D0D 114
e 0 FFFFFFFF FFFFFFFF 31 1 EB375C0B 8B3A7D0D 115
a 1 FFFFFFFF FFFFFFFF 32 0 EB375C0B 12B5E7AD 116
#3
m 0 FFFFFFFF FFFFFFFF 33 #15 1 EB375C0B 21AAD2ED 117
b 1 FFFFFFFF FFFFFFFF 34 0 EB375C0B 4355A5DA 118
l 0 FFFFFFFF FFFFFFFF 35 1 EB375C0B 86AB4BB4 119
e 1 FFFFFFFF FFFFFFFF 36 1 EB375C0B 86AB4BB4 120
0 FFFFFFFF FFFFFFFF 37 0 EB375C0B 0D569768 121
CRC-32 = #1
1 FFFFFFFF FFFFFFFF 38 #09 0 EB375C0B 1E6C3367 122
swapped
0 FFFFFFFF FFFFFFFF 39 1 EB375C0B 3CD866CE 123
and
1 FFFFFFFF FFFFFFFF 40 0 EB375C0B 79B0CD9C 124
inverted
0 FFFFFFFF FFFFFFFF 41 1 EB375C0B 79B0CD9C 125
EB375C0B
1 FFFFFFFF FFFFFFFF 42 1 EB375C0B F7A0868F 126
= #5
0 FFFFFFFF FFFFFFFF 43 #0B 0 EB375C0B EB8010A9 127
2FC51328
1 FFFFFFFF FFFFFFFF 44 1 EB375C0B D3C13CE5 128
0 FFFFFFFF FFFFFFFF 45 0 EB375C0B A343647D 129
1 FFFFFFFF FFFFFFFF 46 0 EB375C0B A343647D 130
0 FFFFFFFF FFFFFFFF 47 1 EB375C0B 4686C8FA 131
#C
1 FFFFFFFF FFFFFFFF 48 #1A 0 EB375C0B 8D0D91F4 132
0 FFFFFFFF FFFFFFFF 49 1 EB375C0B 1A1B23E8 133
1 FFFFFFFF FFFFFFFF 50 1 EB375C0B 343647D0 134
0 FFFFFFFF FFFFFFFF 51 1 EB375C0B 343647D0 135
1 FFFFFFFF FFFFFFFF 52 0 EB375C0B 686C8FA0 136
#F
0 FFFFFFFF FFFFFFFF 53 #1D 1 EB375C0B D0D91F40 137
1 FFFFFFFF FFFFFFFF 54 1 EB375C0B A1B23E80 138
0 FFFFFFFF FFFFFFFF 55 1 EB375C0B 43647D00 139
1 FFFFFFFF FFFFFFFF 56 0 EB375C0B 43647D00 140
0 FFFFFFFF FFFFFFFF 57 0 EB375C0B 8209E7B7 141
#2
1 FFFFFFFF FFFFFFFF 58 #14 1 EB375C0B 0413CF6E 142
0 FFFFFFFF FFFFFFFF 59 0 EB375C0B 0CE6836B 143
1 FFFFFFFF FFFFFFFF 60 1 EB375C0B 1D0C1B61 144
0 FFFFFFFF FFFFFFFF 61 1 EB375C0B 1D0C1B61 145
1 FFFFFFFF FFFFFFFF 62 0 EB375C0B 3A1836C2 146
0 FFFFFFFF FFFFFFFF 63 EOP #0D 1 EB375C0B 70F17033 147
1 FFFFFFFF FFFFFFFF 64 1 EB375C0B E1E2E066 148
0 FFFFFFFF FFFFFFFF 65 0 EB375C0B C704DD7B 149
0 FFFFFFFF FFFFFFFF 66
Sync1
0 FFFFFFFF FFFFFFFF 67
(#18) Note: CRC transmitter is calculated over data bytes
1 FFFFFFFF FFFFFFFF 68
only, in casu marked nibbles, and calculation results
1 FFFFFFFF FFFFFFFF 69
are available one (bit-) clock later
0 FFFFFFFF FFFFFFFF 70
0 FFFFFFFF FFFFFFFF 71
Sync1
0 FFFFFFFF FFFFFFFF 72
(#18) Note: CRC receiver is calculated over data bytes and
1 FFFFFFFF FFFFFFFF 73
S received CRC bytes, in casu marked nibbles, and
1 FFFFFFFF FFFFFFFF 74
O calculation results are available five (bit-) clocks later
0 FFFFFFFF FFFFFFFF 75
P
0 FFFFFFFF FFFFFFFF 76
Sync1
0 FFFFFFFF FFFFFFFF 77 Fixed residual
(#18)
1 FFFFFFFF FFFFFFFF 78
1 FFFFFFFF FFFFFFFF 79
1 FFFFFFFF FFFFFFFF 80
0 FFFFFFFF FFFFFFFF 81
Sync2
0 FFFFFFFF FFFFFFFF 82
(#11)
0 FFFFFFFF FFFFFFFF 83
1 FFFFFFFF FFFFFFFF 84

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 537
 B. PD Message Sequence Examples
The following examples are intended to show how the Device Policy Manager might operate and the sequence of
Power Delivery messaging which will result. The aim of this section is to inform implementer’s how some of the
mechanisms detailed in this specification might be applied; it does not contain any Normative requirements.
All ports are assumed to be Enhanced SuperSpeed capable, with a default operating voltage of 5V and a unit load of
150mA. This 0.75W is assumed to be enough power to enable an externally powered device to maintain
communication over USB and is enough to allow such a device to enumerate but not operate until more power is
negotiated.
Although the Hubs in these illustrations support Power Delivery on both their UFPs and DFPs this is only one possible
Hub implementation.
HDDs are assumed to spin up immediately after they are Attached. This follows the typical operation of current
systems.
Ideal power transmission is assumed so that there are no power losses through a device; in practice these would need
to be taken into account when requesting power.

B.1 External power is supplied downstream

Figure B-1 External Power supplied downstream

Laptop

AC

Display 1

Display 2

Configuration:
1. Laptop with an AC supply. AC supply provides sufficient power to charge the laptop and, in addition, to provide up to
60W downstream via its Enhanced SuperSpeed Port. According to the Source Power Rules described in Section 10.2
this means that the Port has a PD Power of 60W and so can supply: 5V@3A, 9V@3A, 15V@3A and 20V@3A.
2. Display 1 requires 30W to display and therefore a PD Power of 60W to operate itself plus Display 2 connected
downstream. Display 1 initially uses 15V@2A to operate itself, since this also allows operation with a Source of 30W
PD Power. On connection of Display 2, Display 1 will move to operation at 20V@3A to allow operation of the
additional 30W ganged display. According to the Sink Power Rules described in Section 10.3 this means that Display 1

Page 538 USB Power Delivery Specification Revision 3.0, Version 1.1
 requires a Source with a PD Power of 60W to fully operate. Display 1 contains a Hub allowing Display 2 to be
connected to Display 1.
3. Display 2 requires 30W operate itself and does not support an additional display connected downstream. Display 1 uses
15V@2A to operate itself from a Source of 30W PD Power.
4. In USB suspend Display 1 and Display 2 will power down but can maintain USB connection using the PD power
provided.

Table B-1 External power is supplied downstream

Step Laptop Display 1 Display 2 Device Policy Power (W)

Manager

Display 1

1 Connected to wall Detached Detached 0

supply

2 Display 1 Attached, Attached, drawing Detached 0.75

VBUS powered. 5V@150mA.

3 Set of Source Source Capabilities Detached Laptop determines 0.75

Capabilities sent received its Source
including: 5V@3A Capabilities based
(15W), 9V@3A (27W), on its needs and
15V@3A(45W) and the presence of a
20V@3A (60W). wall supply.
The Unconstrained
Power and USB
suspend bits are set.

4 Request received Requests 15V@2A Detached Display 1 knows it 0.75

(30W) from laptop needs 20v@1.5A
(30W) for its own
operation,
evaluates the
supplied
capabilities and
determines that
this is available.

5 Sends Accept Accept received Detached Waiting for PS_RDY 0.75

before drawing
additional power.

6 Sends PS_RDY PS_RDY received. Detached Laptop evaluates 30

Starts drawing the request, finds
15V@2A. Display 1 that it can meet
turns on and starts this and so sends
operating. an accept.

Display 2

7 Powering Display 1 Detects Attach Attached, no VBUS 30

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 539
Step Laptop Display 1 Display 2 Device Policy Power (W)
Manager

8 Request received Display 1 requests Attached, no VBUS Display 1 detects 30

20V@1.73A (34.6W) Attach and
from Laptop. requests additional
4.5W of power for
USB 3.1 Port.

9 Sends Accept Accept received. Attached, no VBUS 34.6

10 Sends PS_RDY PS_RDY received Attached, no VBUS

11 Powers VBUS Attached, drawing 34.6

5V@150mA.

12 Sends out Source Source Capabilities Display 1 has 4.5W 34.6

Capabilities including: received to allocate to
5V@0.9A to Display 2. Display 1. This is
The Unconstrained offered as a
Power and USB standard USB 3.1
suspend bits are set. Port.

13 Request received Display 2 requests Display 2 decides it 34.6

5V@0.15A but can manage to run
indicates a its USB/PD function
Capability with 1 unit load but
Mismatch. Display 2 needs more power
remains off. to function as a
display.

14 Sends Accept Accept received 34.6

15 Sends PS_RDY PS_RDY received Display 2 indicates 34.6

a capability
mismatch to the
user.

16 Get Sink Capabilities Get Sink Capabilities Display 1 needs to 34.6

sent received assess the
capability
mismatch by first
determining what
Display 2 actually
needs.

17 Sink Capabilities Display 2 returns 34.6

received Sink Capabilities
indicating operation
at 15V@2A.

Page 540 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Laptop Display 1 Display 2 Device Policy Power (W)
Manager

18 Request received Display 1 requests Display1 now 34.6

20V@3A (60W) from knows what
Laptop. Display 2 needs
and requests the
additional power
from the laptop.

19 Sends Accept Accept received. 34.6

20 Sends PS_RDY PS_RDY received An additional 30W 60

is now available to
Display 1 to offer
to Display 2.

21 Sends out Source Source Capabilities Now that Display 1 60

Capabilities including: received can power Display
5V@0.9A and 2 correctly this
20V@1.5A to Display power is offered by
2. The Unconstrained Display 1 via a new
Power and USB capabilities
suspend bits are set. Message.

22 Request received Display 2 requests 60

15V@2A.

23 Sends Accept Accept received Display 1 60

determines that
the request by
Display 2 is within
the offered
capabilities so the
request is
accepted.

24 Sends PS_RDY. PS_RDY received. Display 2 now has 60

Drawing 20V@3A from Starts drawing the power it needs
laptop. 15V@2A, turns on and can start
and starts working.
operating.

USB Suspend

25 Laptop OS goes into Display 1 turns off but Display 2 turns off No changes in 60
suspend (S3), VBUS draws 50mW, 25mW but draws 25mW to Contract. This is a
remains on but USB to maintain PDUSB maintain USB/PD power reduction
bus is also suspended. Hub functions. The functions. purely based on
additional 25mW is the USB state.
used to supply the
Port used by Display 2.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 541
 Step Laptop Display 1 Display 2 Device Policy Power (W)
Manager

26 Laptop OS wakes up. Display 1 turns on and Display 2 turns on No changes in PD 60

USB is woken up. returns to drawing and returns to Contract. This
20V@3A. drawing 15V@2A. purely relates to
USB bus state.

B.2 External power is supplied upstream

Figure B-2 External Power supplied upstream
Tablet

Display 1

Display 2

AC

Configuration:
1. Tablet with no AC supply. Tablet is a USB host and can use 5V@0.2A (1W) during normal operation and up to
5V@2.4A (12W) in order to charge.
2. Display 1 requires 30W to operate and therefore a PD Power of 42W to operate itself and charge the tablet. Display 1
uses 15V@2A to operate itself, since this allows operation with a Source of 30W PD Power and then moves to operation
at 20V@2.1A to allow charging of the laptop. According to the Sink Power Rules described in Section 10.3 this means
that the Display 1 requires a Source with a PD Power of 42W to fully operate.
3. Display 2 has an AC supply connected. AC supply provides sufficient power to power Display 2 and, in addition, to
provide up to 60W PD Power upstream.

Table B-2 External power is supplied upstream

Step Tablet Display 1 Display 2 Device Policy Power (W)

Manager

Display 1 - Dead Battery

1 Detached Detached Connected to the 0

wall supply.

Page 542 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Tablet Display 1 Display 2 Device Policy Power (W)
Manager

2 Attached to Display 2 Display 1 Attached 0

3 USB Type-C Power USB Type-C Power 0

drawn 5V@1.5A advertised
5V@1.5A

4 Attached to Display 2, Providing 1 unit 7.5

drawing 5V@1.5A load to Display 1.
(7.5W)

5 Source Capabilities Display2 sends out Based on the 7.5

received a set of capabilities capabilities of the
including: 5V@3A wall supply and its
(15W), 9V@3A own needs Display
(27W), 15V@3A 2 calculates what it
(45W) and 20V@3A can offer upstream.
(60W). The
Unconstrained
Power and USB
suspend bits are
set.

6 Display 1 requests Request received Display 1 knows it 7.5

15V@2A (30W) from needs 30W to
Display 2. operate so it
requests this
amount.

7 Accept received Sends Accept Display 2 accepts 7.5

the offer since it is
within its
capabilities.

8 PS_RDY received. Sends PS_RDY Display 2 indicates 30

Display 1 starts drawing its power supply is
power and turns on. ready to offer the
power.

Tablet – Power Role Swap

9 Tablet is Attached to Attached, VBUS 30

Display 1. powered.

10 Tablet sends out a set Capabilities received 30

of capabilities
including: 5V@0.5A
(2.5W). The
Unconstrained Power
bit cleared and USB
suspend bit set.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 543
Step Tablet Display 1 Display 2 Device Policy Power (W)
Manager

11 Request received Display 1 requests Display 1 has 30

5V@0A from the external power
Tablet. The providing
Unconstrained Power everything it needs
and Dual-Role Power so it does not
bits are set. request any more.

12 Sends Accept Accept received. No power has been 30

requested from the
Tablet so the tablet
has no reason to
Reject this.

13 Sends PS_RDY PS_RDY received. Table completes 30

the Explicit
Contract by sending
PS_RDY.

14 Get Sink Capabilities Sends Get Sink Display 1 has access 30

received. Capabilities to an external
supply so it needs
to check whether
the Tablet
upstream, which
has no external
supply, could use
some power.
Display 1 also
knows that there is
excess capacity,
based on the last
capabilities it
received, which it is
not currently using
from Display 2.

15 The Tablet returns Sink Capabilities 30

Sink Capabilities received
indicating that it is a
Dual-Role and that it
can use 5V@0.2A
(1W) as a Sink.

16 Display 1 requests Request received 30

15V@2.1A (31.5W)
from Display 2.

17 Accept received Sends Accept Request is within 30

the available power
so Display 2 sends
an accept.

Page 544 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Tablet Display 1 Display 2 Device Policy Power (W)
Manager

18 PS_RDY received Sends PS_RDY Display 2 indicates 31.5

that the power
supply is ready to
supply the power.

19 PR_Swap received Requests PR_Swap Display 1 now 31.5

from Tablet. offers to provide
power to the Tablet
by initiating a
Power Role Swap.

20 Accept sent. Tablet Accept received. Tablet is happy to 31.5

turns off its VBUS accept a Power
supply. Role Swap from any
device offering it
power.

21 Send PS_RDY PS_RDY received. Tablet indicates 31.5

Display 1 turns on its that its supply has
VBUS supply been turned off.

22 PS_RDY received. PS_RDY sent. Display 1 indicates 31.5

that its power
supply is ready so
the Tablet starts
drawing power.

23 Source Capabilities Display 1 sends out a 31.5

received set of capabilities to the
Tablet including:
5V@0.48A (2.4W),
12V@0.2A (2.4W) and
20V@0.12 (2.4W). The
Unconstrained Power
and USB suspend bits
are set.

24 The Tablet requests Request received. Tablet can now 31.5

12V@0.2A. request the power
it needs.

25 Accept received Accept sent Power is within the 31.5

capabilities of
Display 1 so it
accepts the
request.

26 PS_RDY received. The PS_RDY sent Display 1 indicates 31.5

Tablet starts drawing that its power
12V@0.2A. supply is ready so
the tablet starts
drawing the power.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 545
Step Tablet Display 1 Display 2 Device Policy Power (W)
Manager

Tablet – Charge

27 Tablet requests Request received. Tablet needs to 31.5

12V@0.2A (2.4W) charge but the
from Display 1. The power offered is
Tablet needs to not sufficient.
charge and so sets the Since Display 1
Capability Mismatch claims to have an
bit and the No USB external supply the
Suspend bit. Tablet will try to get
more power using
the Capability
Mismatch Flag.

28 Accept received Accept sent A Valid request has 31.5

been made so
Display 1 accepts
the request.

29 PS_RDY received PS_RDY received Tablet indicates a 31.5

capability mismatch
to the user.

30 Get Sink Capabilities Get Sink Capabilities Due to the 31.5

received. sent Capability
Mismatch Flag
Display 1 requests
Sink Capabilities
from the Tablet?

31 The Tablet returns Sink Capabilities 31.5

Sink capabilities received
containing: 5V@2.4A
(12W). The
Unconstrained Power
bit is cleared.

Page 546 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Tablet Display 1 Display 2 Device Policy Power (W)
Manager

32 Display 1 requests Request received Since the Tablet 31.5

15V@2.8A (42W) from requires an
Display 2. The No additional 12W of
Suspend Bit is set to power, and Display
reflect the request from 1 knows that this is
the Tablet. available from
Display 2 based on
the last Capabilities
received so it
requests it. In
addition the
Request from the
Tablet indicated
that it wanted No
Suspend so this is
reflected upwards.

33 Accept received Sends Accept Display 2 has 42W 42

available and so
accepts the
request.

34 PS_RDY received Sends PS_RDY Display 2 completes 42

the Explicit
Contract but at this
point has not
accepted that
power can be
drawn during
suspend.

35 Source Capabilities Display2 sends out Based on the 42

received a new set of capabilities of the
capabilities wall supply and its
including: 5V@3A own needs Display
(15W), 9V@3A 2 calculates what it
(27W), 15V@3A can offer upstream.
(45W) and 20V@3A It decides that it
(60W). The can continue to
Unconstrained supply the power
Power and USB even during USB
suspend bits is now suspend and so
set to zero. resets the USB
suspend bit.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 547
Step Tablet Display 1 Display 2 Device Policy Power (W)
Manager

36 Display 1 requests Request received Display 1 repeats its 42

15V@2.8A (42W) from request since a new
Display 2. The No set of Capabilities
Suspend Bit is set to have been sent out.
reflect the request from
the Tablet.

37 Accept received Sends Accept Display 2 has 42W 42

available, even
during suspend,
and so accepts the
request.

38 PS_RDY received Sends PS_RDY Display 2 completes 42

the Explicit
Contract.

39 Capabilities received Display 1 sends out a Display 1 now has 42

set of capabilities to the the additional
Tablet including: power available
5V@2.4A (12W). The and so offers this to
Unconstrained Power the Tablet.
bit is set and USB
suspend bit is cleared.

40 Tablet requests Request received. Tablet is being 42

5V@2.4A (12W) from offered the power
Display 1. it needs to charge
and so the Tablet
requests this from
Display 1.

41 Accept received Sends Accept Request is within 42

the available
Display 1's available
power and so it
accepts the
request.

42 PS_RDY received. Sends PS_RDY Display 1 indicates 42

Tablet starts drawing its supply is ready
5V@2.4A (12W) to supply power.
Display 1 and starts to
charge.

Page 548 USB Power Delivery Specification Revision 3.0, Version 1.1
 B.3 Giving back power
Figure B-3 Giving Back Power

Laptop

AC

Hub

Hard Hard
Disk Disk Phone
Drive 1 Drive 2

Configuration:
1. Laptop with an AC supply. AC supply provides sufficient power to charge the laptop and, in addition, to provide up to
60W PD Power downstream.
2. A Hub with 4 downstream ports which initially provides 1 unit load (150mA) per Port plus 1 unit load for its internal
functions.
3. Two Hard Disk Drives both of which require 5V@2A (10W) to spin up and 5V@1A (5W) while being accessed.
4. A phone which uses 5V@2A (10W) to charge and can give back all of this power when requested.

Table B-3 Giving back power

Step Laptop Hub Peripherals Device Policy Hub Power

Manager (W)

Connect Hub

1 Connected to wall Detached Detached Default

supply

2 Hub is Attached Attached, VBUS Default

powered

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 549
 Step Laptop Hub Peripherals Device Policy Hub Power
Manager (W)

3 Laptop sends out a Source Capabilities Laptop sends out Default

set of capabilities received details of all
including: 5V@3A available power via
(15W), 12V@3A external supply
(36W), and
20V@3A (60W).
The Unconstrained
Power and USB
suspend bits are
set.

4 The Hub requests Request received Hub needs 1 unit Default

5V@0.15A. This is load for its own
the power for the operation and so
Hubs internal requests this
operation. amount.

5 Send Accept Accept received Laptop evaluates 0.75

request and it is
within its available
power.

6 Send PS_RDY PS_RDY received. Laptop indicates 0.75

Starts to draw that its power
5V@0.15A supply is ready.

Connect Hard Disk Drive 1

7 Attached detected. Hard Disk Drive 1 is 0.75

Attached to one of
the downstream
ports of the Hub.

8 Request received The Hub requests Hub needs 0.75W 0.75

5V@0.3A (1.5W) for its own
from the Laptop. operation plus
0.75W for USB
communication on
one Port.

9 Accept sent Accept received Request is within 1.5

available power so
the laptop accepts.

10 PS_RDY sent PS_RDY received Laptop indicates 1.5

that its power
supply is ready

Page 550 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Laptop Hub Peripherals Device Policy Hub Power
Manager (W)

11 Hub turns on VBUS Source Capabilities 1.5

and sends out a set received
of capabilities to
Hard Disk Drive 1
including:
5V@0.15A. The
Unconstrained
Power and USB
suspend bits are set.

12 Request received Hard Disk Drive 1 Hard Disk Drive 1 1.5

requests only needs one
5V@0.15A from unit load when not
the Hub. operating so
requests this.

13 Accept sent Accept received Request is within 1.5

available power so
the Hub accepts.

14 PS_RDY sent PS_RDY received. Laptop indicates its 1.5

The Hard Disk Drive power supply is
starts drawing 1 ready and the Hard
unit load Disk Drive starts
5V@0.15A. drawing power.

Hard Disk Drive 1 spin up

15 Request received Hard Disk Drive 1 Hard Disk Drive 1 1.5

requests needs 20V@0.5A
5V@0.15A from to spin up but this
the Hub but sets is not available so
the Capability it re-requests the
Mismatch bit. available power
flagging a
capability
mismatch.

16 Accept sent Accept received Request is within 1.5

available power so
the Hub accepts.

17 PS_RDY sent PS_RDY received Hard Disk Drive 1 1.5

indicates a
capability
mismatch to the
user.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 551
 Step Laptop Hub Peripherals Device Policy Hub Power
Manager (W)

18 The Hub requests Get Sink Due to the 1.5

the Sink Capabilities Capabilities Capability
from Hard Disk Drive received Mismatch the Hub
1. needs to
determine what
Hard Disk Drive 1
actually needs

19 Sink Capabilities Hard Disk Drive 1 1.5

received returns capabilities
indicating that it
requires 5V@2A.

20 Request received The Hub requests The Hub evaluates 1.5

5V@2.2A (11W) that it now needs
from the Laptop. 0.75W for the Hub
and 10W for Hard
Disk Drive 1.

21 Accept sent Accept received Power request 11

from the Hub is
within the Laptop's
capabilities so the
Laptop accepts the
request.

22 PS_RDY sent PS_RDY received Laptop completes 11

the Explicit
Contract.

23 Hub sends out a set Source Capabilities Hub now offers 11

of capabilities to received Hard Disk Drive 1
Hard Disk Drive 1 what it needs.
including: 5V@2A.
The Unconstrained
Power and USB
suspend bits are set.

24 Request received Hard Disk Drive 1 Hard Disk Drive 1 is 11

requests 5V@2A operating at its
operating current maximum current
and indicates to spin up so sets
5V@2A maximum operating current =
current. maximum current.

25 Accept sent Accept received Request is within 11

the Hubs
capabilities so it
accepts.

Page 552 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Laptop Hub Peripherals Device Policy Hub Power
Manager (W)

26 PS_RDY sent PS_RDY received. Hub indicates its 11

Hard Disk Drive 1 power supply is
starts to draw ready so Hard Disk
5V@2A and spins Drive 1 starts to
up. draw power.

27 Request received Once spun up Hard Hard Disk Drive 1 is 11

Disk Drive 1 operating at a
requests 5V@1A lower current so
operating current sets operating
and 5V@2A current <
maximum current. maximum current.

28 Accept sent Accept received The Hub will 11

maintain a Power
Reserve of 5V@1A
(5W) for Hard Disk
Drive 1 in addition
to the 5V@1A
(5W) it is currently
using.

29 PS_RDY sent PS_RDY received Hub completes the 11

Explicit Contract.

Hard Disk Drive 2 spin up

30 Attach detected Hard Disk Drive 2 is 11

Attached to one of
the downstream
ports of the Hub.

31 Request received The Hub requests The Hub needs 11

5V@2.3A (11.5W) 0.75W for itself,
from the Laptop. 0.75W for USB
communication on
one Port, 5W for
Hard Disk Drive 1
operation and 5W
for the Power
Reserve.

32 Accept sent Accept received Power request 11

from the Hub is
within the Laptop's
capabilities so it
accepts the
request.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 553
 Step Laptop Hub Peripherals Device Policy Hub Power
Manager (W)

33 PS_RDY sent PS_RDY received Laptop indicates its 11.5

power supply is
ready.

34 Hub sends out a set Source Capabilities Hub offers Hard 11.5
of capabilities to received by Hard Disk Drive 2
Hard Disk Drive 2 Disk Drive 2 enough power to
including: enumerate.
5V@0.15A. The
Unconstrained
Power and USB
suspend bits are set.

35 Request received Hard Disk Drive 2 11.5

requests
5V@0.15A from
the Hub.

36 Accept sent to Hard Accept received by Request is within 11.5

Disk Drive 2 Hard Disk Drive 2 available
capabilities so the
Hub accepts

37 PS_RDY sent to Hard PS_RDY received. Hard Disk Drive 2 11.5

Disk Drive 2. Hard Disk Drive 2 takes the power
starts drawing that it needs
5V@0.15A.

Phone charge

38 Attach detected The phone is 11.5

Attached to one of
the downstream
ports of the Hub.

39 Request received The Hub Requests The Hub needs 11.5

5V@2.5A (12.5W) 0.75W for itself,
from the Laptop. 1.5W for USB
communications
on two ports (Hard
Disk Drive 1 and
the Phone), 5W for
Hard Disk Drive 1
operation and 5W
for the Power
Reserve.

Page 554 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Laptop Hub Peripherals Device Policy Hub Power
Manager (W)

40 Accept sent Accept received Request is within 12.5

available
capabilities so the
Laptop accepts

41 PS_RDY sent PS_RDY received Laptop indicates 12.5

that its power
supply is ready.

42 The Hub powers VBUS Source Capabilities The Hub offers the 12.5
and sends out a set received by the Phone 1 unit load
of capabilities to the Phone to enumerate.
Phone including:
5V@0.15A. The
Unconstrained
Power and USB
suspend bits are set.

43 Request received The Phone The Phone would 12.5

from the Phone requests like to charge and
5V@0.15A from so indicates this
the Hub but sets fact through the
the Capability Capability
Mismatch bit. Mismatch bit.

44 Accept sent Accept received Request is within 12.5

available
capabilities so the
Hub accepts

45 PS_RDY sent PS_RDY received Hub indicates that 12.5

its power supply is
ready

46 The Hub requests Get Sink Due to the 12.5

the Sink Capabilities Capabilities Capability
from the phone. received by the Mismatch the Hub
Phone needs to
determine what
the Phone actually
needs

47 Sink Capabilities The Phone returns Phone returns the 12.5

received from the capabilities Capabilities it
Phone indicating that it needs to charge
requires 5V@2A.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 555
 Step Laptop Hub Peripherals Device Policy Hub Power
Manager (W)

48 Request received The Hub Requests The Hub needs 12.5

9V@2.4A (21.6W) 0.75W for itself,
from the Laptop. 0.75W for Hard
Disk Drive 2, 10W
for the phone, 5W
for Hard Disk Drive
1 operation and
5W for the Power
Reserve.

49 Accept sent Accept received Request is within 12.5

available
capabilities so the
Laptop accepts

50 PS_RDY sent PS_RDY received Laptop indicates 21.6

that its power
supply is ready.

51 The Hub sends out a Source Capabilities The Hub now has 21.6
set of capabilities to received by the the power that the
the Phone including: Phone Phone needs and
5V@2A. The so sends out a new
Unconstrained set of Capabilities.
Power and USB
suspend bits are set.

52 Request received The Phone The Phone 21.6

from the Phone requests 5V@2A requests the power
from the Hub and it needs to charge.
sets the No USB It asks for the USB
Suspend bit since it Suspend
needs to charge requirement to be
constantly. It sets removed.
the GiveBack flag
and sets the
Minimum
Operating Current
to 5V@0A.

53 Accept sent to the Accept received by 21.6

Phone the Phone

54 PS_RDY sent to the PS_RDY received by 21.6

phone. the phone. Phone
starts to charge
5V@2A but has to
follow USB
Suspend rules

Page 556 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Laptop Hub Peripherals Device Policy Hub Power
Manager (W)

55 Request received The Hub Requests The Hub needs 21.6

9V@1.9A (17.1W) 0.75W for itself,
from the Laptop but 0.75W for Hard
sets the No USB Disk Drive 2, 10W
Suspend bit. for the phone
(includes the
Power Reserve of
5W), and 5W for
Hard Disk Drive 1
operation. It
requests for USB
Suspend rule to be
removed.

56 Accept sent Accept received Request is within 21.6

available
capabilities so the
Laptop accepts.
Note that the
request for No
Suspend has not
been acted on by
the Laptop. USB
Suspend rules
apply until the
Laptop sends out
new Source
Capabilities with
the USB Suspend
bit cleared.

57 PS_RDY sent PS_RDY received Laptop indicates 17.1

that its power
supply is ready.

Hard Disk Drive 2 spin up

58 Request received Hard Disk Drive 2 Hard Disk Drive 2 17.1

from Hard Disk Drive requests needs more power
2 5V@0.15A from to spin up and so
the Hub but sets indicates a
the Capability Capability
Mismatch bit. Mismatch

59 Accept sent Accept received The request is 17.1

within its
capabilities so the
Hub accepts.

60 PS_RDY sent PS_RDY received The Hub indicates 17.1

that its power
supply is ready.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 557
 Step Laptop Hub Peripherals Device Policy Hub Power
Manager (W)

61 The Hub requests Get Sink Due to the 17.1

the Sink Capabilities Capabilities Capability
from Hard Disk Drive received by Hard Mismatch the Hub
2. Disk Drive 2 has to determine
what Hard Disk
Drive 2 needs

62 Sink Capabilities Hard Disk Drive 2 17.1

received returns capabilities
indicating that it
requires 20V@0.5A
maximum current.

63 The Hub instructs Goto Min received Hub assess that 17.1
the Phone to Goto by the Phone there is additional
Minimum operation. power available
from the Phone
and so tells it to
Goto Min. In this
case it is
reallocating the
Phone’s Charging
power as the
Power Reserve for
the Hard Disk
Drives.

64 The Phone drops to 17.1

zero current draw.

65 PD_RDY sent PS_RDY received. Hub indicates that 17.1

its power supply
has changed to the
new level.

66 Request received The Hub Requests The Hub has an 17.1

9V@2.4A (21.6W) additional 10W
from the Laptop from the Phone
but needs 5W
more to maintain
its Power Reserve.
The Hub needs
0.75W for itself,
10W for Hard Disk
Drive 2, 5W for the
Power Reserve, 5W
for Hard Disk Drive
1 operation.

Page 558 USB Power Delivery Specification Revision 3.0, Version 1.1
 Step Laptop Hub Peripherals Device Policy Hub Power
Manager (W)

67 Accept sent Accept received Request is within 17.1

available
capabilities so the
Laptop accepts.

68 PS_RDY sent PS_RDY received Laptop indicates 21.6

that its power
supply is ready.

69 Hub sends out a set Source Capabilities The Hub now has 21.6
of capabilities to received by Hard the power that
Hard Disk Drive 2 Disk Drive 2 Hard Disk Drive 2
including: 5V@0.5A needs so it sends
and 20V@0.5A. The out new
Unconstrained Capabilities.
Power and USB
suspend bits are set.

70 Request received Hard Disk Drive 2 Hard Disk Drive 2 21.6

from Hard Disk Drive requests requests what it
2 20V@0.5A needs to spin up.
operating current
and 20V@0.5A.

71 Accept sent to Hard Accept received by The Hub assesses 21.6

Disk Drive 2 Hard Disk Drive 2 that the request is
within its
Capabilities so it
accepts.

72 PS_RDY sent. PS_RDY sent. Hard 21.6

Disk Drive 2 starts
to draw 20V@0.5A
and spins up.

73 Request received Once spun up Hard Hard Disk Drive 2 21.6

from Hard Disk Drive Disk Drive 2 no longer needs
2 requests the additional
20V@0.25A power so it gives
operating current back what it does
and 20V@0.5A not need.
maximum current.

74 Accept sent to Hard Accept received by The Hub assesses 21.6

Disk Drive 2 Hard Disk Drive 2 that the request is
within its
Capabilities so it
accepts.

75 PS_RDY sent to Hard PS_RDY received by The Hub indicates 21.6

Disk Drive 2. Hard Disk Drive 2. that its power
supply is ready.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 559
 Step Laptop Hub Peripherals Device Policy Hub Power
Manager (W)

76 The Hub sends out a Source Capabilities The Hub now has 21.6
set of capabilities to received by the the power
the Phone including: Phone available to charge
5V@2A. The the phone so it
Unconstrained sends out new
Power bit is set and Capabilities
the USB suspend bit
is set.

77 Request received The Phone The Phone 21.6

from the Phone requests 5V@2A requests the power
operating current it needs to charge.
from the Hub and It asks for the USB
sets the No USB Suspend
Suspend bit since it requirement to be
needs to charge removed.
constantly. It sets
the GiveBack flag
and sets the
Minimum
Operating Current
to 5V@0A.

78 Accept sent to the Accept received by The Hub assesses 21.6

Phone the Phone that the request is
within its
Capabilities so it
accepts but
maintains USB
Suspend rules.

79 PS_RDY sent to the PS_RDY received by The Hub has 21.6

Phone. the Phone. The allocated 0.75W
phone starts to for itself, 5W for
draw 5V@2A but Hard Disk Drive 2,
has to follow USB 10W for the Phone
Suspend. (including 5W for
the Power
Reserve), and 5W
for Hard Disk Drive
1 operation.

Page 560 USB Power Delivery Specification Revision 3.0, Version 1.1
 C. VDM Command Examples
C.1 Discover Identity Example
C.1.1 Discover Identity Command request
Table C-1 below shows the contents of the key fields in the Message Header and VDM header for an Initiator sending a
Discover Identity Command request.

Table C-1 Discover Identity Command request from Initiator Example

Bit(s) Field Value

Message Header
15 Reserved 0
14…12 Number of Data Objects 1 (VDM Header)
11…9 MessageID 0…7
8 Port Power Role 0 or 1
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0
3…0 Message Type 1111b (Vendor Defined Message)
VDM Header
B31…16 Standard or Vendor ID (SVID) 0xFF00 (PD SID)
B15 VDM Type 1 (Structured VDM)
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b
B10…8 Object Position 000b
B7…6 Command Type 00b (Initiator)
B5 Reserved 0
B4…0 Command1 1 (Discover Identity)

C.1.2 Discover Identity Command response – Active Cable

Table C-2 shows the contents of the key fields in the Message Header and VDM header for a Responder returning
VDOs in response to a Discover SVIDs Command request. In this illustration, the responder is an active Gen2 cable
which supports Modal Operation.

Table C-2 Discover Identity Command response from Active Cable Responder Example

Bit(s) Field Value

Message Header
15 Reserved 0
14…12 Number of Data Objects 5 (VDM Header + ID Header VDO + Cert Stat VDO
+ Product VDO + Cable VDO)
11…9 MessageID 0…7
8 Cable Plug 1
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0
3…0 Message Type 1111b (Vendor Defined Message)

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 561
Bit(s) Field Value
VDM Header
B31…16 Standard or Vendor ID (SVID) 0xFF00 (PD SID)
B15 VDM Type 1 (Structured VDM)
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b
B10…8 Object Position 000b
B7…6 Command Type 01b (Responder ACK)
B5 Reserved 0
B4…0 Command 2 (Discover Identity)
ID Header VDO
B31 Data Capable as USB Host 0 (not data capable as a Host)
B30 Data Capable as a USB Device 0 (not data capable as a Device)
B29…27 Product Type 100b (Active Cable)
B26 Modal Operation Supported 1 (supports Modes)
B25…16 Reserved. Shall be set to zero. 0
B15…0 16-bit unsigned integer. USB Vendor ID USB-IF assigned VID for this cable vendor
Cert Stat VDO
B31…0 32-bit unsigned integer USB-IF assigned XID for this cable
Product VDO
B31…16 16-bit unsigned integer. USB Product ID Product ID assigned by the cable vendor
B15…0 16-bit unsigned integer. bcdDevice Device version assigned by the cable vendor
Cable VDO returned for Product Type “Active Cable”
B31…28 HW Version Cable HW version number (vendor defined)
B27…24 Firmware Version Cable FW version number (vendor defined)
B23…21 VDO Version 00b (Version 1.0)
B20 Reserved 0
B19…18 USB Type-C plug to USB Type-C/Captive 10b (USB Type-C)
B17 Reserved 0
B16…13 Cable Latency 0001b ( <10ns (~1m))
B12…11 Cable Termination Type 11b (Both ends Active, VCONN required)
B10…9 Maximum VBUS Voltage 00b (20V)
B8…7 Reserved 0
B6…5 VBUS Current Handling Capability 01b (3A)
B4 VBUS through cable 1 (Yes)
B3 SOP” controller present? 1 (SOP” controller present)
B2…0 USB SuperSpeed Signaling Support 010b ([USB 3.1] Gen1 and Gen2)

C.1.3 Discover Identity Command response – Hub

Table C-2 shows the contents of the key fields in the Message Header and VDM header for a Responder returning
VDOs in response to a Discover SVIDs Command request. In this illustration, the responder is a Hub

Page 562 USB Power Delivery Specification Revision 3.0, Version 1.1
 Table C-3 Discover Identity Command response from Hub Responder Example

Bit(s) Field Value

Message Header
15 Reserved 0
14…12 Number of Data Objects 4 (VDM Header + ID Header VDO + Cert Stat VDO +
Product VDO)
11…9 MessageID 0…7
8 Port Power Role 0 or 1
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0
3…0 Message Type 1111b (Vendor Defined Message)
VDM Header
B31…16 Standard or Vendor ID (SVID) 0xFF00 (PD SID)
B15 VDM Type 1 (Structured VDM)
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b
B10…8 Object Position 000b
B7…6 Command Type 01b (Responder ACK)
B5 Reserved 0
B4…0 Command 2 (Discover Identity)
ID Header VDO
B31 Data Capable as USB Host 0 (not data capable as a Host)
B30 Data Capable as a USB Device 1 (data capable as a Device)
B29…27 Product Type 001b (Hub)
B26 Modal Operation Supported 0 (doesn’t support Modes)
B25…16 Reserved. Shall be set to zero. 0
B15…0 16-bit unsigned integer. USB Vendor ID USB-IF assigned VID for this hub vendor
Cert Stat VDO
B31…0 32-bit unsigned integer USB-IF assigned XID for this hub
Product VDO
B31…16 16-bit unsigned integer. USB Product ID Product ID assigned by the hub vendor
B15…0 16-bit unsigned integer. bcdDevice Device version assigned by the hub vendor

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 563
 C.2 Discover SVIDs Example
C.2.1 Discover SVIDs Command request
Table C-4 below shows the contents of the key fields in the Message Header and VDM header for an Initiator sending a
Discover SVIDs Command request.

Table C-4 Discover SVIDs Command request from Initiator Example

Bit(s) Field Value

Message Header
15 Reserved 0
14…12 Number of Data Objects 1 (VDM Header)
11…9 MessageID 0…7
8 Port Power Role 0 or 1
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0
3…0 Message Type 1111b (Vendor Defined Message)
VDM Header
B31…16 Standard or Vendor ID (SVID) 0xFF00 (PD SID)
B15 VDM Type 1 (Structured VDM)
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b
B10…8 Object Position 000b
B7…6 Command Type 00b (Initiator)
B5 Reserved 0
B4…0 Command1 2 (Discover SVIDs)

C.2.1 Discover SVIDs Command response

Table C-5 shows the contents of the key fields in the Message Header and VDM Header for a Responder returning
VDOs in response to a Discover SVIDs Command request. In this illustration, the value 3 in the Message Header
indicates that one VDO containing the supported SVIDs would be returned followed by a terminating VDO. Note that
the last VDO returned (the terminator of the transmission) contains zero value SVIDs. If a SVID value is zero, it is not
used.

Table C-5 Discover SVIDs Command response from Responder Example

Bit(s) Field Value
Message Header
15 Reserved 0
14…12 Number of Data Objects 3 (VDM Header + 2*VDO)
11…9 MessageID 0…7
8 Port Power Role 0 or 1
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0
3…0 Message Type 1111b (Vendor Defined Message)
VDM Header
B31…16 Standard or Vendor ID (SVID) 0xFF00 (PD SID)
B15 VDM Type 1 (Structured VDM)

Page 564 USB Power Delivery Specification Revision 3.0, Version 1.1
Bit(s) Field Value
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b (Reserved)
B10…8 Object Position 000b
B7…6 Command Type 01b (Responder ACK)
B5 Reserved 0
B4…0 Command 2 (Discover SVIDs)
VDO 1
B31…16 SVID 0 SVID value
B15…0 SVID 1 SVID value
VDO 2
B31…16 SVID 2 0x0000
B15…0 SVID 3 0x0000

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 565
 C.3 Discover Modes Example
C.3.1 Discover Modes Command request
Table C-6 shows the contents of the key fields in the Message Header and VDM header for an Initiator sending a
Discover Modes Command request. The Initiator of the Discover Modes Command sequence sends a Message Header
with the Number of Data Objects field set to 1 followed by a VDM Header with the Command Type (B7…6) set to zero
indicating the Command is from an Initiator and the Command (B4…0) is set to 3 indicating Mode discovery.

Table C-6 Discover Modes Command request from Initiator Example

Bit(s) Field Value

Message Header
15 Reserved 0
14…12 Number of Data Objects 1 (VDM Header)
11…9 MessageID 0…7
8 Port Power Role 0 or 1
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0
3…0 Message Type 1111b (Vendor Defined Message)
VDM Header
B31…16 Standard or Vendor ID (SVID) SVID for which Modes are being requested
B15 VDM Type 1 (Structured VDM)
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b
B10…8 Object Position 000b
B7…6 Command Type 00b (Initiator)
B5 Reserved 0
B4…0 Command1 3 (Discover Modes)

C.3.2 Discover Modes Command response

The Responder to the Discover Modes Command request returns a Message Header with the Number of Data Objects
field set to a value of 1 to 7 (the actual value is the number of Mode objects plus one) followed by a VDM Header with
the Message Source (B5) set to 1 indicating the Command is from a Responder and the Command (B4…0) set to 2
indicating the following objects describe the Modes the device supports. If the ID is a VID, the structure and content of
the VDO is left to the vendor. If the ID is a SID, the structure and content of the VDO is defined by the Standard.
Table C-7 shows the contents of the key fields in the Message Header and VDM Header for a Responder returning
VDOs in response to a Discover Modes Command request. In this illustration, the value 2 in the Message Header
indicates that the device is returning one VDO describing the Mode it supports. It is possible for a Responder to report
up to six different Modes.

Table C-7 Discover Modes Command response from Responder Example

Bit(s) Field Value

Message Header
15 Reserved 0
14…12 Number of Data Objects 2 (VDM Header + 1 Mode VDO)
11…9 MessageID 0…7
8 Port Power Role 0 or 1

Page 566 USB Power Delivery Specification Revision 3.0, Version 1.1
Bit(s) Field Value
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0
3…0 Message Type 1111b (Vendor Defined Message)
VDM Header
B31…16 Standard or Vendor ID (SVID) SVID for which Modes were requested
B15 VDM Type 1 (Structured VDM)
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b
B10…8 Object Position 000b
B7…6 Command Type 01b (Responder ACK)
B5 Reserved 0
B4…0 Command 3 (Discover Modes)
Mode VDO
B31…0 Mode 1 Standard or Vendor defined Mode value

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 567
 C.4 Enter Mode Example
C.4.1 Enter Mode Command request
The Initiator of the Enter Mode Command request sends a Message Header with the Number of Data Objects field set
to 1 followed by a VDM Header with the Message Source (B5) set to zero indicating the Command is from an Initiator
and the Command (B4…0) set to 4 to request the Responder to enter its mode of operation and sets the Object
Position field to the desired functional VDO based on its offset as received during Discovery.
Table C-8 shows the contents of the key fields in the Message Header and VDM Header for an Initiator sending an
Enter Mode Command request.

Table C-8 Enter Mode Command request from Initiator Example

Bit(s) Field Value

Message Header
15 Reserved 0
14…12 Number of Data Objects 1 (VDM Header)
11…9 MessageID 0…7
8 Port Power Role 0 or 1
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0
3…0 Message Type 1111b (Vendor Defined Message)
VDM Header
B31…16 Standard or Vendor ID (SVID) SVID for the Mode being entered
B15 VDM Type 1 (Structured VDM)
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b
B10…8 Object Position 001b (a one in this field indicates a request to enter
the first Mode in list returned by Discover Modes)
B7…6 Command Type 00b (Initiator)
B5 Reserved 0
B4…0 Command 4 (Enter Mode)

C.4.2 Enter Mode Command response

The Responder that is the target of the Enter Mode Command request sends a Message Header with the Number of
Data Objects field set to a value of 1 followed by a VDM Header with the Command Source (B5) set to 1 indicating the
response is from a Responder and the Command (B4…0) set to 4 indicating the Responder has entered the Mode and
is ready to operate.
Table C-9 shows the contents of the key fields in the Message Header and VDM Header for a Responder sending an
Enter Mode Command response with an ACK.

Table C-9 Enter Mode Command response from Responder Example

Bit(s) Field Value

Message Header
15 Reserved 0
14…12 Number of Data Objects 1 (VDM Header)
11…9 MessageID 0…7
8 Port Power Role 0 or 1

Page 568 USB Power Delivery Specification Revision 3.0, Version 1.1
Bit(s) Field Value
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0
3…0 Message Type 1111b (Vendor Defined Message)
VDM Header
B31…16 Standard or Vendor ID (SVID) SVID for the Mode entered
B15 VDM Type 1 (Structured VDM)
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b
B10…8 Object Position 001b (offset of the Mode entered)
B7…6 Command Type 01b (Responder ACK)
B5 Reserved 0
B4…0 Command 4 (Enter Mode)

C.4.1 Enter Mode Command request with additional VDO

The Initiator of the Enter Mode Command request sends a Message Header with the Number of Data Objects field set
to 2 indicating an additional VDO followed by a VDM Header with the Message Source (B5) set to zero indicating the
Command is from an Initiator and the Command (B4…0) set to 4 to request the Responder to enter its mode of
operation and sets the Object Position field to the desired functional VDO based on its offset as received during
Discovery.
Table C-8 shows the contents of the key fields in the Message Header and VDM Header for an Initiator sending an
Enter Mode Command request with an additional VDO.

Table C-10 Enter Mode Command request from Initiator Example

Bit(s) Field Value

Message Header
15 Reserved 0
14…12 Number of Data Objects 1 (VDM Header)
11…9 MessageID 0…7
8 Port Power Role 0 or 1
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0
3…0 Message Type 1111b (Vendor Defined Message)
VDM Header
B31…16 Standard or Vendor ID (SVID) SVID for the Mode being entered
B15 VDM Type 1 (Structured VDM)
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b
B10…8 Object Position 001b (a one in this field indicates a request to enter
the first Mode in list returned by Discover Modes)
B7…6 Command Type 00b (Initiator)
B5 Reserved 0
B4…0 Command 4 (Enter Mode)
Including Optional Mode specific VDO
B31…0 Mode specific

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 569
 C.5 Exit Mode Example
C.5.1 Exit Mode Command request
The Initiator of the Exit Mode Command request sends a Message Header with the Number of Data Objects field set
to 1 followed by a VDM Header with the Message Source (B5) set to zero indicating the Command is from an Initiator
and the Command (B4…0) set to 5 to request the Responder to exit its Mode of operation.
Table C-11 shows the contents of the key fields in the Message Header and VDM header for an Initiator sending an
Exit Mode Command request.

Table C-11 Exit Mode Command request from Initiator Example

Bit(s) Field Value

Message Header
15 Reserved 0
14…12 Number of Data Objects 1 (VDM Header)
11…9 MessageID 0…7
8 Port Power Role 0 or 1
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0
3…0 Message Type 1111b (Vendor Defined Message)
VDM Header
B31…16 Standard or Vendor ID (SVID) SVID for the Mode being exited
B15 VDM Type 1 (Structured VDM)
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b
B10…8 Object Position 001b (identifies the previously entered Mode by its
Object Position that is to be exited)
B7…6 Command Type 00b (Initiator)
B5 Reserved 0
B4…0 Command 5 (Exit Mode)

C.5.2 Exit Mode Command response

The Responder that receives the Exit Mode Command request sends a Message Header with the Number of Data
Objects field set to a value of 1 followed by a VDM Header with the Message Source (B5) set to 1 indicating the
Command is from a Responder and the Command (B4…0) set to 5 indicating the Responder has exited the Mode and
has returned to normal USB operation.
Table C-12 shows the contents of the key fields in the Message Header and VDM header for a Responder sending an
Exit Mode Command ACK response.

Table C-12 Exit Mode Command response from Responder Example

Bit(s) Field Value

Message Header
15 Reserved 0
14…12 Number of Data Objects 1 (VDM Header)
11…9 MessageID 0…7
8 Port Power Role 0 or 1

Page 570 USB Power Delivery Specification Revision 3.0, Version 1.1
Bit(s) Field Value
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0
3…0 Message Type 1111b (Vendor Defined Message)
VDM Header
B31…16 Standard or Vendor ID (SVID) SVID for the Mode exited
B15 VDM Type 1 (Structured VDM)
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b
B10…8 Object Position 001b (offset of the Mode to be exited)
B7…6 Command Type 01b (Responder ACK)
B5 Reserved 0
B4…0 Command 5 (Exit Mode)

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 571
 C.6 Attention Example
C.6.1 Attention Command request
The Initiator of the Attention Command request sends a Message Header with the Number of Data Objects field set to
1 followed by a VDM Header with the Message Source (B5) set to zero indicating the Command is from an Initiator
and the Command (B4…0) set to 6 to request attention from the Responder.
Table C-11 shows the contents of the key fields in the Message Header and VDM header for an Initiator sending an
Attention Command request.

Table C-13 Attention Command request from Initiator Example

Bit(s) Field Value

Message Header
15 Reserved 0
14…12 Number of Data Objects 1 (VDM Header)
11…9 MessageID 0…7
8 Port Power Role 0 or 1
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0
3…0 Message Type 1111b (Vendor Defined Message)
VDM Header
B31…16 Standard or Vendor ID (SVID) SVID for which attention is being requested
B15 VDM Type 1 (Structured VDM)
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b
B10…8 Object Position 001b (offset of the Mode requesting attention)
B7…6 Command Type 000b (Initiator)
B5 Reserved 0
B4…0 Command 6 (Attention)

C.6.2 Attention Command request with additional VDO

The Initiator of the Attention Command request sends a Message Header with the Number of Data Objects field set to
2 indicating an additional VDO followed by a VDM Header with the Message Source (B5) set to zero indicating the
Command is from an Initiator and the Command (B4…0) set to 6 to request attention from the Responder.
Table C-11 shows the contents of the key fields in the Message Header and VDM header for an Initiator sending an
Attention Command request with an additional VDO.

Table C-14 Attention Command request from Initiator with additional VDO Example

Bit(s) Field Value

Message Header
15 Reserved 0
14…12 Number of Data Objects 2 (VDM Header + VDO)
11…9 MessageID 0…7
8 Port Power Role 0 or 1
7…6 Specification Revision 10b (Revision 3.0)
5…4 Reserved 0

Page 572 USB Power Delivery Specification Revision 3.0, Version 1.1
Bit(s) Field Value
3…0 Message Type 1111b (Vendor Defined Message)
VDM Header
B31…16 Standard or Vendor ID (SVID) SVID for which attention is being requested
B15 VDM Type 1 (Structured VDM)
B14…13 Structured VDM Version 01b (Version 2.0)
B12…11 Reserved 00b
B10…8 Object Position 001b (offset of the Mode requesting attention)
B7…6 Command Type 000b (Initiator)
B5 Reserved 0
B4…0 Command 6 (Attention)
Including Optional Mode specific VDO
B31…0 Mode specific

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 573
D. BMC Receiver Design Examples
The BMC signal is DC-coupled so that the voltage level is affected by the ground IR drop. The DC offset of the BMC
signal at Power Source and Power Sink are in the opposite directions. When the VBUS current is increased from 0A, the
BMC signal waveform shifts downward at Power Sink and shifts upward at Power Source. This section introduces two
sample BMC receiver circuit implementations, which are immune from DC offset and high current load step. They can
be used in Power Source, Power Sink and inside cables.

D.1 Finite Difference Scheme

D.1.1 Sample Circuitry
The sample Finite Difference BMC receiver shown in Figure D-1 consists of the Rx bandwidth limiting filter with the
time constant tRxFilter, a sampler with the sampling step DtS, 50ns, a Finite Difference Calculator which calculates the
voltage difference between the time interval of DtFD, 300ns, an edge detector controlled by two voltage thresholds, Vth,
H and Vth, L and a logic block for bit recognition.

Figure D-1 Circuit Block of BMC Finite Difference Receiver

D.1.2 Theory
This section describes the fundamental theory of Finite Difference Scheme to recover the received BMC signal with
the input and output signal waveforms of the circuit blocks shown in Figure D-1. To illustrate the robustness of the
implementation, the VBUS current load step rate is intentionally increased to 2A/µs at the sink load. In Figure D-2(a),
the red curve represents the VBUS current measured at the Power Sink when the current is increased at 9 µs from 0A to
5A and the blue dash curve represents the VBUS current measured at the USB Type-C connector of the power sink. In
this example, the peak current overshoot with larger load step rate is increased to 518 mA which exceeds iOvershoot.
Figure D-2(b) shows the total BMC noise at Power Sink, coupled from VBUS and D+/D- through the worst [USB Type-C
1.2] compliant cable, after the Rx bandwidth limiting filter with the time constant tRxFilter is applied. The noise can
be decomposed into 3 components. The first is the DC offset, IVBUS(t)*RGND, while IVBUS is the VBUS current and RGND is the
ground DC resistance of the cable. The offset is negative in Power Sink and positive at Power Source. The second
noise component is the inductive VBUS noise, M*d IVBUS(t)/dt, while M is the mutual inductance between the VBUS and CC
wires in the cable and d IVBUS(t)/dt is the load step rate. The third component is [USB 2.0] Full Speed SE0 coupling
noise which would normally occur randomly but was assumed to occur periodically in the simulation to account for
the crosstalk in any phase between the BMC and [USB 2.0] signals. In Figure D-3, the blue dash curve represents the
BMC signal when there is no VBUS current and the red solid curve represents the BMC signal affected by the VBUS
coupling noise shown in Figure D-2(b). The green solid curve is the sample [USB 2.0] noise, after the Rx bandwidth
limiting filter with the time constant tRxFilter is applied.

Page 574 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure D-2 BMC AC and DC noise from VBUS at Power Sink

Figure D-3 Sample BMC Signals (a) without [USB 2.0] SE0 Noise (b) with [USB 2.0] SE0 Noise

(a) (b)
The BMC signals shown in Figure D-3 are sampled every 50ns and the scaled derivative waveforms, Vcc(t) - Vcc(t -
50ns), without and with [USB 2.0] noise are shown in Figure D-4(a) and D-4(b), respectively. In Figure D-4(a), if there
is no [USB 2.0] noise, the derivative waveform just changes slightly before and after the VBUS current transition. That
means, the slope of the BMC waveform is not sensitive to the DC offset and is very useful to be used to design a robust
receiver against a large DC offset. However, the derivative waveforms with [USB 2.0] noise have large perturbation as
shown in Figure D-4(b).

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 575
 Figure D-4 Scaled BMC Signal Derivative with 50ns Sampling Rate

(a) without [USB 2.0] Noise (b) with [USB 2.0] Noise

(a) (b)
To remove the high frequency content of the [USB 2.0] noise, Finite Difference technique with the proper time interval
is applied to the BMC waveform with [USB 2.0] noise in Figure D-3(b). Using Backward Finite Difference Calculator,
DVcc = Vcc (t) - Vcc(t-Dt), Figure D-5 shows the Finite Difference Output while Dt = 500ns. The larger the time interval
Dt is, the larger the peak-to-peak magnitude of the Finite Difference Output will be. However, the time interval is
bounded by the rise time of the BMC signal so that 300ns to 500ns is a good range of the time interval.

Figure D-5 BMC Signal and Finite Difference Output with Various Time Steps

D.1.3 Data Recovery

The edge detection is followed by the Finite Difference Calculation. At the input of the edge detector, if the voltage is
larger than Vth, H at the rising edge, the output will become high voltage level, V H, if the voltage is smaller than Vth, L at
the falling edge, the output will become low voltage level, V L. In this example, Vth, H and Vth, L are 0.2V and -0.2V,
respectively. The solid curve in Figure D-6 represents the output of the edge detector, where VH is 0.5V and VL is -0.5V.

Page 576 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure D-6 Output of Finite Difference in dash line and Edge Detector in solid line

The duty cycle of the output signal from the edge detector varies depending on the thresholds, V th, H and Vth, L, as well
as jitter and noise from silicon and channel. The techniques such as integrating receiver can be used to recover the
BMC signal.

D.1.4 Noise Zone and Detection Zone

Figure D-7 shows the output of Finite Difference when the time interval of Finite Difference is set to 300ns. The noise
Zone is defined in between +Vnoise and –Vnoise, in which the noise glitches occur. The detect zone is defined in
between +Vdetect and –Vdetect, excluding the noise zone. The thresholds of the edge detectors, Vth, H and Vth, L, Shall
be properly set within the detect zone so that the data can be recovered successfully.
In this example, Vdetect is 250mV and Vnoise is 50mV. It is highly recommended that the product implemented with
the similar techniques indicates the performance with the range of Vnoise and Vdetect in the electrical specification.

Figure D-7 Noise Zone and Detect Zone of BMC Receiver

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 577
 D.2 Subtraction Scheme
D.2.1 Sample Circuitry
The sample Subtraction BMC receiver shown in Figure D-8 consists of the two Low Pass Filters (LPF1 and LPF2), a
Subtractor, an Edge Detector and a logic block for bit recognition. The time constant of the first and second LPF are
200ns and 300ns, respectively. The Subtractor subtracts the LPF1 output from the LPF2 output. The Edge Detector
controlled by two voltage thresholds, Vth, H and Vth, L to recover the data.

Figure D-8 Circuit Block of BMC Subtraction Receiver

D.2.2 Output of Each Circuit Block

Figure D-9(a) shows the output of LPF1 as the red solid line and LPF2 as the blue dash line as well as the [USB 2.0]
noise in green solid line. Figure D-9(b) shows the voltage difference between the two output filters, Vdiff =
Vcc_afterLPF1 – Vcc_afterLPF2. The Vdiff waveform looks very similar to the Finite Difference output waveform
shown in Figure D-6 so that the data recovery method through the edge detector is the same as described in Section
D.1.3.

Figure D-9 (a) Output of LPF1 and LPF2 (b) Subtraction of LPF1 and LPF2 Output

(a) (b)

D.2.3 Subtractor Output at Power Source and Power Sink

The following figures shows the example when the VBUS current increases from 0A to 5A and then decreases to 0A
with high load step rate. The output of the LPF1 and the Subtractor at Power Source and Power Sink are shown in
Figure D-10 (a) and (b), respectively. Although the BMC signals at Power Source and Power Sink shift toward the
opposite direction, the Subtractor outputs at Power Source and Power Sink are almost identical disregard of the
opposite direction of the DC offset.

Page 578 USB Power Delivery Specification Revision 3.0, Version 1.1
 Figure D-10 Output of the BMC LPF1 in blue dash curve and the Subtractor in red solid curve

(a) at Power Source (b) at Power Sink

(a)

(b)

D.2.4 Noise Zone and Detection Zone

The zone definition is the same as defined in Section D.1.7. The sizes of the noise zone and detection zone of the
Subtraction Scheme are dependent on the filter time constant. When the time constant of the first and second LPF are
200ns and 300ns, respectively, Vdetect is 250mV and Vnoise is 50mV. It is highly recommended that the product
implemented with the similar techniques indicates the performance with the range of Vnoise and Vdetect in the
electrical specification.

USB Power Delivery Specification Revision 3.0, Version 1.1 Page 579