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Introduction to USB Type-C™

Author: Andrew Rogers

Microchip Technology Inc.

INTRODUCTION
The USB-IF has secured the ubiquitous nature of USB for years to come with the radically updated USB Type-C™ con-
nector. While the sleek new reversible form factor has been significant for generating buzz and excitement from the gen-
eral consumer market, the significantly expanded feature-set is what will eventually transform the desktop and
entertainment environment.
The USB Type-C cable is now poised to become the “universal” cable, as it is capable of supplying blazing fast data
transfer speeds of up to 10Gb/s, 100W of continuous power flow, and ultra high bandwidth video capabilities made avail-
able through Alternate Modes all in parallel with a single connection.
This document is intended for those already familiar with USB2.0/USB3.0/USB3.1 who are interested in the high level
details of the expanded feature set that the USB Type-C cable brings to USB.

SECTIONS
Section 1.0, General Information
Section 2.0, USB Type-C Cables
Section 3.0, CC Pins
Section 4.0, VCONN Supply
Section 5.0, USB Power Delivery 2.0
Section 6.0, Alternate Modes

REFERENCES
This document is an introduction to USB Type-C™ and is not intended to be a replacement to the official specification.
Consult the following specifications for technical details not described in this document.
• USB Type-C™ Specification
• USB Power Delivery 2.0 Specification
• USB 2.0 Specification
• USB 3.0 Specification
• USB 3.1 Specification
• USB Battery Charging BC1.2

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1.0 GENERAL INFORMATION
The USB Type-C™ cable is a reversible 24-pin interconnect created by the USB-IF. The USB Type-C™ specification
was first released in August 2014.
The USB Type-C cable is a universal cable that addresses the needs for a wide range of computing, display, and
charging applications. The long-term objective of the USB Type-C cable is to replace all previous iterations of the USB
cable while greatly expanding the overall capabilities. The recent introduction of the USB Power Delivery and Alternate
Mode capabilities further expand the raw potential for even greater adoption of the USB standard in a wider range of
applications.

FIGURE 1: USB CABLE PLUG FORM FACTORS

1 2
5 6 7 8 9

B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12

A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12

4 3 2 1 4 3 4 3 2 1
USB2.0 Type-A USB2.0 Type-B USB3.0 Type-A
56789

54321 54321
1 2
4 3
USB2.0 Mini-A USB2.0 Mini-B
USB3.0 Type-B

12345 12345 12345 6 7 8 9 10

USB2.0 Micro-A USB2.0 Micro-B USB3.0 Micro-B

USB Type-C

1.1 Port Behavior

Prior to the introduction of USB Type-C™ and USB Power Delivery, data and power roles were typically fixed. The shape
of the receptacle/plug dictated both its data role and power role. USB Type-C connections are much more flexible; ports
may be host-mode only, device-mode only, or dual-role and both the data and power roles can be independently and
dynamically swapped using USB Power Delivery protocol. Because of this, there is some new terminology that is used
to describe USB Type-C systems.
• Downstream Facing Port (DFP) - A host or downstream hub port. Typical of a legacy standard Type-A port.
• Upstream Facing Port (UFP) - A device or upstream hub port. Typical of a legacy standard Type-B port.
• Dual-Role Port (DRP) - A port that transitions between DFP and UFP port states until an attach event occurs.
DRPs may be dynamically swapped using USB Power Delivery Protocol Negotiation after an initial attach event.
• Power Source or Provider - A source of 5V-20V up to 5A. Typical of a legacy standard Type-A port.
• Power Sink or Consumer - A sink of 5V-20V up to 5A. Typical of a legacy standard Type-B port.

1.2 Features
1.2.1 MINIMUM FEATURE SET
A basic USB Type-C application can still be cost-effective.USB Type-C ports are not required to implement all of the
advanced features that are defined in the specification. The minimum required feature set includes the following:
• USB2.0 Connection
• Cable attach and detach detection
• VCONN active cable supply

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1.2.2 BATTERY CHARGING
While BC1.2 is still supported over USB Type-C because it depends on the USB2.0 lane, a significantly simplified and
higher power current capability mechanism is also implemented. This simplified approach involves resistor pull-down/
pull-up relationships. These pull-down/pull-up resistors are connected to the CC wire and the upstream facing port
(UFP) must monitor the voltage on the CC1 and CC2 pins in order to detect the current sourcing capability of the down-
stream facing port (DFP) it is connected to. This is a substantial improvement over the complicated handshake mech-
anisms involved with USB BC1.2.
The basic USB Type-C current capabilities are Default USB (500mA for USB2.0 and 900mA for USB3.0), 1.5A@5V,
and 3A@5V.
For additional details see Section 3.0, CC Pins.

1.2.3 USB2.0, USB3.0, USB3.1, AND BEYOND

The USB Type-C cable is designed to support current generation USB2.0 (480 Mb/s), USB3.0 (5Gb/s), USB3.1 (10Gb/
s), and future USB specifications reaching up to 20Gb/s data rates.
For additional details see please refer to the individual specifications as published by the USB-IF.

1.2.4 POWER DELIVERY 2.0

USB Power Delivery protocol is a singled-ended, 1-wire protocol created by the USB-IF which specifies the methods
for serial communication over the USB Type-C CC wire. USB Power Delivery is required for implementation of the fol-
lowing advanced features:
• Communicating with an electronically marked/active cable
• Elevating the VBUS voltage above 5.5V
• Increasing current sourcing/sinking above 3A
• Changing default power roles (Provider or Consumer)
• Using Alternate Modes (see section 1.2.5)
The Power Delivery 2.0 is a port-to-port and port-to-cable communication protocol. The communication can not propa-
gate throughout an entire device tree like standard USB protocols.
For additional details see Section 5.0, USB Power Delivery 2.0.

1.2.5 ALTERNATE MODES (THIRD PARTY PROTOCOLS)

The USB Type-C cable allows for any third party protocol to be used as long as the cable can support it. Alternate Modes
are negotiated and entered on a port-to-port basis using the USB Power Delivery protocol. The following signals may
be reassigned when entering an Alternate Mode.
• TX1+/-
• RX1+/-
• TX2+/-
• RX2+/-
• SBU1/SBU2
Separate specifications define the rules for each Alternate Mode. Currently, specifications exist for DisplayPort
(authored by VESA) and ThunderBolt (authored by Intel). For additional details see Section 6.0, Alternate Modes.

1.3 Connector/Receptacle Pins

FIGURE 2: USB TYPE-C RECEPTACLE

A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12

GND TX1+ TX1- VBUS CC1 D+ D- SBU1 VBUS RX2- RX2+ GND

GND RX1+ RX1- VBUS SBU2 D- D+ CC2 VBUS TX2- TX2+ GND
B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1

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FIGURE 3: USB TYPE-C PLUG

A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1

GND RX2+ RX2- VBUS SBU1 D- D+ CC VBUS TX1- TX1+ GND

GND TX2+ TX2- VBUS VCONN SBU2 VBUS RX1- RX1+ GND
B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12

The USB Type-C connector has 24 pins. Because of its reversibility, the pins are arranged in a mirrored configuration.
There are a total of 6 differential pairs in a full-featured cable assembly. There are also 4 pins that serve functions new
to USB: CC1, CC2, SBU1, SBU2.

1.3.1 USB2.0 DIFFERENTIAL PAIRS

The 2 sets of USB2.0 differential pairs in the connector pinout only connect to a single differential pair in standard
USB2.0 or Full Featured USB Type-C cables. In a typical design, the D+ and D- pins are simply shorted on the PCB so
that a multiplexer or switch is not required.
The second set of pins (B6/B7) may only be re-purposed in docking type applications where only 1 orientation is possi-
ble.

1.3.2 USB3.1 DIFFERENTIAL PAIRS

By default, only one set of TX/RX differential pairs are used for USB3.0/USB3.1 communication, depending on cable
insertion orientation. Because of the cable reversibility, the USB3.0/USB3.1 lanes must be rerouted upon orientation
connection. A typical application may use a 2:1 multiplexer to achieve this.
USB Power Delivery protocol and Alternate Modes allow some or all of the TX/RX differential pairs to be reassigned.

1.3.3 CC1/CC2 PINS

The CC1 and CC2 pins are used to connect to the either the CC or VCONN wire in a USB Type-C cable. Both CC1 and
CC2 pins must be able to support both CC and VCONN functions. The function is detected upon cable insertion.
The CC wire is used to cable orientation detection, USB Type-C current capability advertisement and detection, and
USB2.0 BMC communication. See Section 3.0, CC Pins for additional details.
The VCONN wire is used to power active or electronically marked cables. See Section 4.0, VCONN Supply for addi-
tional details.

1.3.4 SBU1/SBU2
The SBU wires are lower speed signal wires that is allocated for Alternate Mode use only. USB Power Delivery is
required for Alternate Mode negotiation before these pins may be used for any purpose.
TABLE 1: USB TYPE-C™ RECEPTACLE PINOUT
Pin Name Function Note
A1 GND Power Support for 60W minimum (combined with all VBUS pins)
A2 TX1+ USB3.1 or Alternate Mode 10Gb/s differential pair with TX1-
A3 TX1- USB3.1 or Alternate Mode 10Gb/s differential pair with TX1+
A4 VBUS Power Support for 60W minimum (combined with all VBUS pins)
A5 CC1 CC or VCONN —
A6 D+ USB2.0 —
A7 D- USB2.0 —
A8 SBU1 Alternate Mode Lower speed side band signal
A9 VBUS Power Support for 60W minimum (combined with all VBUS pins)
A10 RX2- USB3.1 or Alternate Mode 10Gb/s differential pair with RX2+
A11 RX2+ USB3.1 or Alternate Mode 10Gb/s differential pair with RX2-
A12 GND Power Support for 60W minimum (combined with all VBUS pins)

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TABLE 1: USB TYPE-C™ RECEPTACLE PINOUT (CONTINUED)
Pin Name Function Note
B1 GND Power Support for 60W minimum (combined with all VBUS pins)
B2 TX2+ USB3.1 or Alternate Mode 10Gb/s differential pair with TX2-
B3 TX2- USB3.1 or Alternate Mode 10Gb/s differential pair with TX2+
B4 VBUS Power Support for 60W minimum (combined with all VBUS pins)
B5 CC2 CC or VCONN —
B6 D+ USB2.0 —
B7 D- USB2.0 —
B8 SBU2 Alternate Mode Lower speed side band signal
B9 VBUS Power Support for 60W minimum
B10 RX1- USB3.1 or Alternate Mode 10Gb/s differential pair with RX1+
B11 RX1+ USB3.1 or Alternate Mode 10Gb/s differential pair with RX1-
B12 GND Power Support for 60W minimum

1.4 Power Supply Options

The USB Type-C Interconnect introduces two new native charging options, but is also compatible with legacy charging
options. USB Power Delivery is also supported but optional.
TABLE 2: USB TYPE-C™ POWER SUPPLY OPTIONS
Mode Nominal Voltage Maximum Current
USB2.0 5V 500mA
USB3.0/USB3.1 5V 900mA
USB BC1.2 5V 1.5A
USB Type-C Current @ 1.5A 5V 1.5A
USB Type-C Current @ 2.0A 5V 3.0A
USB Power Delivery Up to 20V Up to 5A

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2.0 USB TYPE-C CABLES

2.1 Physical Specifications

2.1.1 SIZE
The USB Type-C receptacle opening is 8.34mm x 2.56mm. For comparison, the Type-A receptacle opening is 12.50mm
x 5.12mm while the USB3.0 micro-AB receptacle opening is 12.25mm x 1.85mm

2.1.2 DURABILITY
The USB Type-C cable must minimally support 10,000 mating cycles.

2.1.3 WIRE GAUGE

Signal wire gauge is not explicitly specified in the USB Type-C™ specifications, but wires must be appropriately sized
for the length and capabilities of the cable such that:
• Signal integrity on the USB2.0 and USB3.0 wires is preserved
• ~50Ω impedance on the CC and SBU1/SBU2 wires
• Maximum IR drop of 250mV on GND return
• Maximum IR drop of 500mV on VBUS

2.1.4 CABLE LENGTH

Cable lengths are not explicitly specified in the USB Type-C™ specifications. However, the electrical requirements cre-
ate some practical limits. USB3.1 Type-C to Type-C cable assemblies are allocated -6 dB loss at 5GHz, effectively lim-
iting cable lengths to 1 meter. USB3.0 Type-C to Type-C cable assembly are allocated -7 dB loss at 5GHz, effectively
limiting cable lengths to 2 meters.
TABLE 3: USB TYPE-C CABLE LENGTH SUMMARY
USB Version Cable Length Current Rating USB Electronically Marked
USB2.0 ≤ 4 meters 3A Supported Optional
5A Required
USB3.0 ≤ 2 meters 3A Supported Optional
5A Required
USB3.1 ≤ 1 meter 3A Supported Required
5A

2.2 USB2.0
A standard USB2.0 Type-C cable assembly is shown in Figure 4 and Table 4.

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FIGURE 4: USB2.0 TYPE-C PLUG PIN-OUT

GND GND GND GND

RX1+ TX1+
RX1- TX1-
VBUS VBUS VBUS VBUS
SBU2 CC1 CC
D- D+ D+
PCB D+ D- D- Cable
CC2 SBU1 VCONN
VBUS VBUS VBUS VBUS
RX1+ TX1+
RX1- TX1-
GND GND GND GND

Receptacle Cable Plug

TABLE 4: USB TYPE-C™ USB2.0 CABLE ASSEMBLY WIRING

USB Type-C Plug 1 Wire USB Type-C Plug 2

Signal Wire
Pin Signal Name Pin Signal Name
Name Number
A1, B1, A12, B12 GND 1 GND_PWRrt1 [GND_PWRrt2]* A1, B1, A12, B12 GND
A4, B4, A9, B9 VBUS 2 PWR_VBUS1 [PWR_VBUS2]* A4, B4, A9, B9 VBUS
A5 CC 3 CC A5 CC
B5 VCONN [18] [PWR_VCONN]* B5 VCONN
A6 DP 4 UTP_Dp A6 DP
A7 DM 5 UTP_Dm A7 DM
Shell Shield Braid Shield Shell Shield
* Optional wires

2.3 Full Featured

A standard full-featured USB Type-C cable assembly is shown in Figure 5 and Table 5.

FIGURE 5: USB TYPE-C RECEPTACLE AND CABLE PLUG

GND GND GND GND

RX1+ TX1+ RX1+ TX1+
RX1- TX1- RX1- TX1-
VBUS VBUS VBUS VBUS
SBU2 CC1 SBU2 CC
D- D+ D+
PCB D+ D- D- Cable
CC2 SBU1 VCONN SBU1
VBUS VBUS VBUS VBUS
RX1+ TX1+ RX1+ TX1+
RX1- TX1- RX1- TX1-
GND GND GND GND

Receptacle Cable Plug

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TABLE 5: USB TYPE-C™ FULL FEATURED CABLE ASSEMBLY WIRING

USB Type-C Plug 1 Wire USB Type-C Plug 2

Signal Wire
Pin Signal Name Pin Signal Name
Name Number
A1, B1, A12, B12 GND 1[16]* GND_PWRrt1 [GND_PWRrt2]* A1, B1, A12, B12 GND
A4, B4, A9, B9 VBUS 2[17]* PWR_VBUS1 [PWR_VBUS2]* A4, B4, A9, B9 VBUS
A5 CC 3 CC A5 CC
B5 VCONN 18 PWR_VCONN B5 VCONN
A6 DP 4 UTP_Dp A6 DP
A7 DM 5 UTP_Dm A7 DM
A2 SSTX1+ 6 SDPp1 B11 SSRX1+
A3 SSTX1- 7 SDPn2 B10 SSRX1-
B11 SSRX1+ 8 SDPp2 A2 SSTX1+
B10 SSRX1- 9 SDPn2 A3 SSTX1-
B2 SSTX2+ 10 SDPp3 A11 SSRX2+
B3 SSTX2- 11 SDPn3 A10 SSRX2-
A11 SSRX2+ 12 SDPp4 B2 SSTX2+
A10 SSRX2- 13 SDPn4 B3 SSTX2-
A8 SBU1 14 SBU_A B8 SBU2
B8 SBU2 15 SBU_B A8 SBU1
Shell Shield Braid Shield Shell Shield
* Optional wires

2.4 Passive Cables

A passive USB Type-C cable does not have embedded powered electronics. All passive cables must minimally support
USB2.0, and it can support USB Power Delivery up to 60W of power.

2.5 Powered Cable: Electronically Marked

An electronically marked cable has embedded electronics that can communicate with the USB ports via USB Power
Delivery 2.0 BMC protocol. An electronically marked cable may be powered from the VCONN supply or directly from
VBUS and may draw up to 70mW of total power.
Use-case Example 1: All USB3.1 compatible USB Type-C cables must be electronically marked.
Use-case Example 2: A 100W Power Delivery cable. Any cable capable of exceeding 60W of power carrying
capability must be electronically marked and communicate is capabilities to the DFP port.
An electronically marked cable will behave identically to a standard passive cable if inserted into a receptacle that does
not support USB Power Delivery 2.0.

2.6 Powered Cable: Managed Active Cable

A managed active cable is an electronically marked cable that also has powered USB data reconditioning circuitry. A
managed active cable may be powered from the VCONN supply or directly from VBUS and may draw up to 1.0W of
total power.
Use-case Example: An active cable that uses repeaters/re-conditioners to extend the maximum cable length.
A managed active cable will behave identically to a standard active cable if inserted into a receptacle that does not sup-
port USB Power Delivery 2.0. It will still be able to power itself from VCONN or VBUS.

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2.7 USB Type-C to Legacy USB Cables
The USB Type-C™ specification also defines the allowable USB Type-C to Legacy USB cable assemblies. The follow-
ing full cable assemblies are supported:
• USB Type-C to Type-A (USB2.0)
• USB Type-C to Type-A (USB3.0/3.1)
• USB Type-C to Type-B (USB2.0)
• USB Type-C to Type-B (USB3.0/3.1)
• USB Type-C to Mini-B (USB2.0)
• USB Type-C to Micro-B (USB2.0)
• USB Type-C to Micro-B (USB3.0/3.1)
Only two USB Type-C to Legacy adapters are defined:
• USB Type-C to Type-A receptacle adapter
• USB Type-C to Micro-B (USB2.0)

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3.0 CC PINS
The CC1 and CC2 pins are critical for basic USB Type-C operation. Resistors are attached to the CC pins in various
configurations depending on whether the application is a downstream facing port (DFP), upstream facing port (UFP), or
an electronically marked/active cable:
- Rp pull-up resistors on downstream facing ports (Section 3.1)
- Rd pull-down resistors on upstream facing ports (Section 3.2)
- Ra pull-down resistor on electronically marked/active cables (Section 3.3)
The CC1 and CC2 pins must be constantly monitored by the port to perform the following functions:
- Cable attach and removal detection (Section 3.4)
- Cable orientation detection (Section 3.5)
- Basic USB Type-C current capability advertisement (Section 3.6)

3.1 DFP Rp Pull-Up Resistors

The Rp pull-up resistors on a downstream facing port must be connected to both CC1 and CC2 pins, and may be pulled
up to either 3.3V or 5.0V (a current source may also be used). The value of the resistor selected advertises the current
supplying capability of the port to the device. The acceptable (per the USB Type-C™ specification) values for the Rp
pull-up resistors and current sources are shown in the table below.

TABLE 6: VALID DFP RP PULL-UP RESISTOR VALUES

Resistor Pull-up to Resistor Pull-up to Current Source to

DFP Current Capability
4.75V - 5.5V 3.3V ± 5% 1.7V - 5.5V

Default USB Power (500mA for 56 kΩ ± 20% 36 kΩ ± 20 80 µA ± 20%

USB2.0, 900mA for USB3.0)

1.5A @ 5V 22 kΩ ± 5% 12 kΩ ± 5% 180 µA ± 8%

3.0A @ 5V 10 kΩ ± 5% 4.7 kΩ ± 5% 330 µA ± 8%

3.2 UFP Rd Pull-Down Resistors.

An upstream facing port must connect a valid Rp pull-down resistor to GND (or optionally, a voltage clamp) to both CC1
and CC2 pins. A 5.1kΩ ± 10% is the only acceptable resistor if USB Type-C charging of 1.5A@5V or 3.0A@5V is to be
used. The details are shown in the table below.

TABLE 7: VALID UFP RD PULL-DOWN RESISTOR VALUES

Detect Power Current Source to

Rd Implementation Nominal Value
Capability? 1.7V - 5.5V

± 20% voltage clamp 1.1V No 1.32V

± 20% resistor to GND 5.1kΩ No 2.18V

± 10% resistor to GND 5.1kΩ Yes 2.04V

3.3 Active Cable Ra Pull-Down Resistors

An active cable must connect an Ra resistor from the VCONN pin to GND. The Ra resistor may range from 800Ω to
1.2kΩ.

3.4 Cable Attach and Removal Detection

A cable attach is detected when either of the CC1 or CC2 pins detects a valid Rp/Rd connection. For a standard USB
connection, only one of the CC1/CC2 pins may detect a valid Rp/Rd connection, not both.

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5V to VBUS may only be applied when a valid cable attachment is detected. This prevents two downstream facing
ports from back-driving current into each other.
TABLE 8: CONNECTION STATES (FROM DFP PERSPECTIVE)
CC1 CC2 State Position
Open Open Nothing Connected* —
Rd Open UFP Connected Unflipped
Open Rd UFP Connected Flipped
Open Ra Powered Cable/No UFP connected Unflipped
Ra Open Powered Cable/No UFP connected Flipped
Rd Ra Powered Cable/UFP connected Unflipped
Ra Rd Powered Cable/UFP connected Flipped
Rd Rd Debug Accessory Mode connected —
Ra Ra Audio Adapter Mode connected —

Note: *DFP-to-DFP and UFP-to-UFP are undetectable states.

3.5 Cable Orientation Detection

The cable orientation is detected in the following way:
- If the CC1 pin detects a valid Rp/Rd connection, then the cable is in the “Unflipped” orientation at that recep-
tacle.
- If the CC2 pin detects a valid Rp/Rd connection, then the cable is in the “Flipped” orientation at that recepta-
cle.

FIGURE 6: CABLE ORIENTATION DETECTION

DFP 5V
UFP
“Unflipped”
Rp Rp USB Type-C Cable
CC1 CC Wire CC1
CC2 CC2

Rd Rd

“Unflipped”

DFP 5V
UFP
“Unflipped”
Rp Rp USB Type-C Cable
CC1 CC1
CC Wire
CC2 CC2

Rd Rd

“Flipped”

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3.6 USB Type-C Current Advertisement
Both the upstream facing port and the downstream facing port must monitor the voltage on the CC1 and CC2 pins to
determine if a valid Rp/Rd or Rp/Ra connection has been made. The USB Type-C™ specification defines the following
voltage ranges:
TABLE 9: USB TYPE-C VOLTAGE RANGES
No Connection
Current Advertisement Rp / Rd Connection Rp / Ra Connection
(Detached)
3A >2.75V 2.60V - 0.85V 0.80V - 0.00V
1.5A >1.65V 1.60V - 0.45V 0.40V - 0.00V
Default USB (500mA/900mA) >1.65V 1.60V - 0.25V 0.20V - 0.00V
Once a valid connection is established, the upstream facing port (device) may is responsible for drawing the appropriate
amount of maximum current.

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4.0 VCONN SUPPLY
VCONN is a 5V(4.75V - 5.5V allowable range) 1.0W power supply used to power circuits within the plug that are needed
to implement electronically marked cables and VCONN-powered accessories. The DFP is responsible for supplying
VCONN by default. If two Dual-Role ports with USB Power Delivery support are connected to each other, the VCONN
supplier can be swapped via USB PD negotiation.
VCONN is required for PD-enabled port and USB3 support. The VCONN power supply can be supplied in one of two
ways:
a) If a valid Rp/Rd connection is detected on one of the CC pins, the VCONN supply can be blindly routed to the
opposite CC pin
b) After a valid Rp/Rd connection is detected on one of the CC pins, the opposite CC pin can be monitored for a
valid Rp/Ra connection before routing the VCONN supply to the pin.
Because of the reversible nature of the USB Type-C cable, both CC1 and CC2 pins must be able to assume the role of
CC and VCONN upon cable insertion. A typical solution is presented in fig xx below.

FIGURE 7: VCONN SUPPLY AND ACTIVE CABLE

DFP 5V VCONN
UFP
Rp Rp USB Type-C Cable
CC1 CC Wire CC1

CC2 CC2
VCONN Active Cable
Control IC Rd
Ra Ra Rd

Note: While all USB Type-C ports are required to source VCONN to active cables, active cables are permitted to
source power from either VCONN or VBUS.

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5.0 USB POWER DELIVERY 2.0
USB Power Delivery 2.0 refers to a single wire protocol (on CC wire) created by the USB-IF. The name “USB Power
Delivery” can be somewhat misleading as it allows for much more than just power negotiations; it unlocks the advanced
capabilities of the USB Type-C cable. The PD messaging occurs completely independently of USB2.0 or USB3.0/
USB3.1 data and is used for port-to-port negotiation of power roles, voltage level, maximum supplying current capability,
data roles, and Alternate Modes. Port-to-powered cable communication is also handled by USB PD.

5.1 Protocol Details

• All communication occurs over CC wire.
• The DFP is the Bus Master and initiates all communication.
• All messages are 32-bit 4b/5b encoded Bi-phase mark coded (BMC).
• 300k Baud rate
• CRC32 error detection + message retries
• Terminology:
- SOP: DFP to DFP messaging
- SOP’: DFP to active cable plug messaging
- SOP’’: DFP to active cable plug messaging

FIGURE 8: SOP SIGNALING

DFP ELECTRONICALLY MARKED CABLE UFP

CABLE PLUG CABLE PLUG

SOP’
SOP’’
SOP

Note: SOP’ is assigned to one plug of the cable while SOP’’ is assigned to the other. The cable plugs cannot tell
which side that they are connected to, just that one end may respond to SOP’ addressed messages and
the other may respond SOP’’ addressed messages.

5.2 Power Delivery Negotiation

USB Power Delivery allows power configuration of a USB connection to be dynamically modified. The default 5V voltage
on VBUS can be reconfigured up to any level up to 20V. The maximum current supplying capability can also be raised
to a maximum of 5A with a 100W compatible electronically marked USB PD Type-C cable.
The default roles (Provider or Consumer) can also be dynamically swapped at any time if both ports support dual power
role functionality and the port accepts the swap request.

5.3 Alternate Mode and Data Role Negotiation.

Alternate Modes allow third party protocols to be transmitted over the USB Type-C cable. They are negotiated on port-
to-port basis with Power Delivery protocol. See Section 6.0, Alternate Modes for more information.
Data roles can also be swapped dynamically over USB PD protocol negotiation.

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5.4 Billboard Device
Because of the wide range of capabilities enabled with USB PD, it can become confusing for the end user. There may
be times when a user connects two devices and expects a different result than what actually occurs. To provide some
amount of feedback to the user, a USB2.0 “Billboard” class device connected to the Power Delivery system can provide
messages to the user that can explain errors or compatibility issues.

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6.0 ALTERNATE MODES
Alternate Modes and USB Power Delivery are the two key features that will allow the USB Type-C cable to become a
true “universal” cable. Alternate Modes allow the USB Type-C cable to be reconfigured to support third party protocols.
This feature is enabled only if both ports support the USB Power Delivery protocol and are both compatible with the
specific Alternate Mode.
There are no specific limits on Alternate Modes. As long as the cable can support the third party protocol signaling while
maintaining a USB2.0 connection, then the Alternate Mode can be implemented. The USB Type-C™ specification does
not define any Alternate Modes; Each third party must maintain its own USB Type-C Alternate Mode specification.
Alternate Mode negotiation is performed via USB Power Delivery protocol on a port-to-port basis.

6.1 Reconfigurable Pins

All Alternate Modes must minimally maintain a USB2.0 and USB Power Delivery connection. The following pins/wires
may be reconfigured for the use with the Alternate Mode.

FIGURE 9: RECONFIGURABLE PINS ON A FULL FEATURED CABLE

A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1

GND RX2+ RX2- VBUS SBU1 D- D+ CC VBUS TX1- TX1+ GND

GND TX2+ TX2- VBUS VCONN SBU2 VBUS RX1- RX1+ GND
B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12

FIGURE 10: RECONFIGURABLE PINS ON A DIRECT CONNECT APPLICATION

A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1

GND RX2+ RX2- VBUS SBU1 D- D+ CC VBUS TX1- TX1+ GND

GND TX2+ TX2- VBUS VCONN SBU2 VBUS RX1- RX1+ GND
B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12

6.2 Example: DisplayPort

DisplayPort was one of the first 3rd part protocols to be specified as a USB Type-C™ Alternate Mode. The DisplayPort
Alternate mode supports the following modes of operation:
• (2) Display Port lanes + (1) USB3.1 lane
• (4) Display Port lanes

FIGURE 11: (2) DISPLAY PORT LANES + (1) USB3.1 LANE EXAMPLE

A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1

GND DP1- DP0+ VBUS AUX+ D- D+ CC VBUS TX1- TX1+ GND

GND DP1+ DP0- VBUS VCONN AUX- VBUS RX1- RX1+ GND
B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12

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APPENDIX A: APPLICATION NOTE REVISION HISTORY
TABLE A-1: REVISION HISTORY

Revision Level & Date Section/Figure/Entry Correction

A (2-9-15) Unfinished Pre-Release

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THE MICROCHIP WEB SITE
Microchip provides online support via our WWW site at www.microchip.com. This web site is used as a means to make
files and information easily available to customers. Accessible by using your favorite Internet browser, the web site con-
tains the following information:
• Product Support – Data sheets and errata, application notes and sample programs, design resources, user’s
guides and hardware support documents, latest software releases and archived software
• General Technical Support – Frequently Asked Questions (FAQ), technical support requests, online discussion
groups, Microchip consultant program member listing
• Business of Microchip – Product selector and ordering guides, latest Microchip press releases, listing of semi-
nars and events, listings of Microchip sales offices, distributors and factory representatives

CUSTOMER CHANGE NOTIFICATION SERVICE

Microchip’s customer notification service helps keep customers current on Microchip products. Subscribers will receive
e-mail notification whenever there are changes, updates, revisions or errata related to a specified product family or
development tool of interest.
To register, access the Microchip web site at www.microchip.com. Under “Support”, click on “Customer Change Notifi-
cation” and follow the registration instructions.

CUSTOMER SUPPORT
Users of Microchip products can receive assistance through several channels:
• Distributor or Representative
• Local Sales Office
• Field Application Engineer (FAE)
• Technical Support
Customers should contact their distributor, representative or field application engineer (FAE) for support. Local sales
offices are also available to help customers. A listing of sales offices and locations is included in the back of this docu-
ment.
Technical support is available through the web site at: http://microchip.com/support

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 AN1953

Note the following details of the code protection feature on Microchip devices:
• Microchip products meet the specification contained in their particular Microchip Data Sheet.

• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.

• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.

• Microchip is willing to work with the customer who is concerned about the integrity of their code.

• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”

Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.

Information contained in this publication regarding device applications and the like is provided only for your convenience and may be
superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO
REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR
OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE,
MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of
Microchip devices in life support and/or safety applications is entirely at the buyer’s risk, and the buyer agrees to defend, indemnify and
hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implic-
itly or otherwise, under any Microchip intellectual property rights.

Trademarks
The Microchip name and logo, the Microchip logo, dsPIC, FlashFlex, KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro, PICSTART, PIC32
logo, rfPIC, SST, SST Logo, SuperFlash and UNI/O are registered trademarks of Microchip Technology Incorporated in the U.S.A. and
other countries.
FilterLab, Hampshire, HI-TECH C, Linear Active Thermistor, MTP, SEEVAL and The Embedded Control Solutions Company are
registered trademarks of Microchip Technology Incorporated in the U.S.A.
Silicon Storage Technology is a registered trademark of Microchip Technology Inc. in other countries.
Analog-for-the-Digital Age, Application Maestro, BodyCom, chipKIT, chipKIT logo, CodeGuard, dsPICDEM, dsPICDEM.net,
dsPICworks, dsSPEAK, ECAN, ECONOMONITOR, FanSense, HI-TIDE, In-Circuit Serial Programming, ICSP, Mindi, MiWi, MPASM,
MPF, MPLAB Certified logo, MPLIB, MPLINK, mTouch, Omniscient Code Generation, PICC, PICC-18, PICDEM, PICDEM.net, PICkit,
PICtail, REAL ICE, rfLAB, Select Mode, SQI, Serial Quad I/O, Total Endurance, TSHARC, UniWinDriver, WiperLock, ZENA and Z-
Scale are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries.
SQTP is a service mark of Microchip Technology Incorporated in the U.S.A.
GestIC and ULPP are registered trademarks of Microchip Technology Germany II GmbH & Co. KG, a subsidiary of Microchip
Technology Inc., in other countries.
A more complete list of registered trademarks and common law trademarks owned by Standard Microsystems Corporation (“SMSC”)
is available at: www.smsc.com. The absence of a trademark (name, logo, etc.) from the list does not constitute a waiver of any
intellectual property rights that SMSC has established in any of its trademarks.
All other trademarks mentioned herein are property of their respective companies.
© 2015, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved.

ISBN: 978-1-63277-475-0

QUALITY MANAGEMENT SYSTEM Microchip received ISO/TS-16949:2009 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
CERTIFIED BY DNV Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Company’s quality system processes and procedures
are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping
== ISO/TS 16949 == devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.

 2015 Microchip Technology Inc. DS00001953A-page 19

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