KSZ8795CLX

Integrated 5-Port 10/100-Managed Ethernet

Switch with Gigabit GMII/RGMII and MII/
RMII Interfaces
-

Target Applications
- 802.1az EEE Supported
• Industrial Ethernet Applications that Employ IEEE - On-Chip Termination Resistors and Internal
802.3-Compliant MACs. (Ethernet/IP, Profinet, Biasing for Differential Pairs to Reduce
MODBUS TCP, etc.) Power
• VoIP Phone - HP Auto MDI/MDI-X Crossover Support Elim-
• Set-Top/Game Box inates the Need to Differentiate Between
• Automotive Straight or Crossover Cables in Applications
• Industrial Control • MAC and GMAC Ports
• IPTV POF - Four Internal Media Access Control (MAC1 to
MAC4) Units and One Internal Gigabit Media
• SOHO Residential Gateway with Full-Wire Speed
Access Control (GMAC5) Unit
of Four LAN Ports
- GMII, RGMII, MII or RMII Interfaces Support
• Broadband Gateway/Firewall/VPN
for the Port 5 GMAC5 with Uplink
• Integrated DSL/Cable Modem
- 2 KByte Jumbo Packet Support
• Wireless LAN Access Point + Gateway
- Tail Tagging Mode (One Byte Added Before
• Standalone 10/100 Switch FCS) Support on Port 5 to Inform the Proces-
• Networked Measurement and Control Systems sor in which the Ingress Port Receives the
Packet and its Priority
Features - Supports Reduced Media Independent Inter-
face (RMII) with 50 MHz Reference Clock
• Management Capabilities
Output
- The KSZ8795CLX Includes All the Functions
- Supports Media Independent Interface (MII)
of a 10/100BASE-T/TX Switch System Which
in Either PHY Mode or MAC Mode on Port 5
Combines a Switch Engine, Frame Buffer
Management, Address Look-Up Table, - LinkMD® Cable Diagnostic Capabilities for
Queue Management, MIB Counters, Media Determining Cable Opens, Shorts, and
Access Controllers (MAC), and PHY Trans- Length
ceivers • Advanced Switch Capabilities
- Non-Blocking Store-and-Forward Switch - Non-Blocking Store-and-Forward Switch
Fabric Assures Fast Packet Delivery by Uti- Fabric Assures Fast Packet Delivery by Uti-
lizing a 1024-Entries Forwarding Table lizing 1024 Entry Forwarding Table
- Port Mirroring/Monitoring/Sniffing: Ingress - 64 KB Frame Buffer RAM
and/or Egress Traffic to Any Port - IEEE 802.1q VLAN Support for up to 128
- MIB Counters for Fully-Compliant Statistics Active VLAN Groups (Full-Range 4096 of
Gathering (36 Counters per Port) VLAN IDs)
- Support Hardware for Port-Based Flush and - IEEE 802.1p/Q Tag Insertion or Removal on
Freeze Command in MIB Counter. a Per Port Basis (Egress)
- Multiple Loopback of Remote, PHY, and MAC - VLAN ID Tag/Untag Options on Per Port
Modes Support for the Diagnostics Basis
- Rapid Spanning Tree Support (RSTP) for - Fully Compliant with IEEE 802.3/802.3u
Topology Management and Ring/Linear Standards
Recovery - IEEE 802.3x Full-Duplex with Force-Mode
• Robust PHY Ports Option and Half-Duplex Back-Pressure Colli-
- Four Integrated IEEE 802.3/802.3u-Compli- sion Flow Control
ant Ethernet Transceivers Supporting - IEEE 802.1w Rapid Spanning Tree Protocol
10BASE-T and 100BASE-TX Support

 2016-2017 Microchip Technology Inc. DS00002112B-page 1

 KSZ8795CLX
- IGMP v1/v2/v3 Snooping for Multicast Packet - Supports IEEE P802.3az Energy Efficient
Filtering Ethernet (EEE) to Reduce Power Consump-
- QoS/CoS Packets Prioritization Support: tion in Transceivers in LPI State Even
802.1p, DiffServ-Based and Re-Mapping of Though Cables are Not Removed
802.1p Priority Field Per Port Basis on Four - Dynamic Clock Tree Control to Reduce
Priority Levels Clocking in Areas that are Not in Use
- IPv4/IPv6 QoS Support - Low Power Consumption without Extra
- IPV6 Multicast Listener Discovery (MLD) Power Consumption on Transformers
Snooping - Voltages: Using External LDO Power Sup-
- Programmable Rate Limiting at the Ingress plies
and Egress Ports on a Per Port Basis - Analog VDDAT 3.3V or 2.5V
- Jitter-Free Per Packet Based Rate Limiting - VDDIO Support 3.3V, 2.5V, and 1.8V
Support - Low 1.2V Voltage for Analog and Digital Core
- Tail Tag Mode (1 byte Added before FCS) Power
Support on Port 5 to Inform the Processor - WoL Support with Configurable Packet Con-
which Ingress Port Receives the Packet trol
- Broadcast Storm Protection with Percentage • Additional Features
Control (Global and Per Port Basis) - Single 25 MHz +50 ppm Reference Clock
- 1K Entry Forwarding Table with 64 KB Frame Requirement
Buffer - Comprehensive Programmable Two-LED
- 4 Priority Queues with Dynamic Packet Map- Indicator Support for Link, Activity, Full-/Half-
ping for IEEE 802.1P, IPV4 TOS (DIFF- Duplex, and 10/100 Speed
SERV), IPv6 Traffic Class, etc. • Packaging and Environmental
- Supports WoL Using AMD’s Magic Packet - Commercial Temperature Range: 0°C to
- VLAN and Address Filtering +70°C
- Supports 802.1x Port-Based Security, - Industrial Temperature Range: –40°C to
Authentication and MAC-Based Authentica- +85°C
tion via Access Control Lists (ACL) - Package Available in an 80-Pin LQFP, Lead-
- Provides Port-Based and Rule-Based ACLs Free (RoHS-Compliant) Package
to Support Layer 2 MAC SA/DA Address, - Supports Human Body Model (HBM) ESD
Layer 3 IP Address and IP Mask, Layer 4 Rating of 5 kV
TCP/UDP Port Number, IP Protocol, TCP
- 0.065 µm CMOS Technology for Lower
Flag and Compensation for the Port Security
Power Consumption
Filtering
- Ingress and Egress Rate Limit Based on Bit
per Second (bps) and Packet-Based Rate
Limiting (pps)
• Configuration Registers Access
- High-Speed SPI (4-Wire, up to 50 MHz) Inter-
face to Access All Internal Registers
- MII Management (MIIM, MDC/MDIO 2-Wire)
Interface to Access All PHY Registers per
Clause 22.2.4.5 of the IEEE 802.3 Specifica-
tion
- I/O Pin Strapping Facility to Set Certain Reg-
ister Bits from I/O Pins During Reset Time
- Control Registers Configurable On-the-Fly
• Power and Power Management
- Full-Chip Software Power-Down (All Register
Values are Not Saved and Strap-In value Will
Re-Strap after it Releases the Power-Down)
- Per-Port Software Power-Down
- Energy Detect Power-Down (EDPD), which
Disables the PHY Transceiver When Cables
are Removed

 2016-2017 Microchip Technology Inc. DS00002112B-page 2

 KSZ8795CLX

TO OUR VALUED CUSTOMERS

It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip
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The last character of the literature number is the version number, (e.g., DS30000000A is version A of document DS30000000).

Errata
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for cur-
rent devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the
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To determine if an errata sheet exists for a particular device, please check with one of the following:
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When contacting a sales office, please specify which device, revision of silicon and data sheet (include -literature number) you are
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 2016-2017 Microchip Technology Inc. DS00002112B-page 3

KSZ8795CLX
Table of Contents
1.0 Introduction ..................................................................................................................................................................................... 5
2.0 Pin Description and Configuration ................................................................................................................................................... 6
3.0 Functional Description ................................................................................................................................................................... 14
4.0 Device Registers ........................................................................................................................................................................... 47
5.0 Operational Characteristics ......................................................................................................................................................... 113
6.0 Electrical Characteristics ............................................................................................................................................................. 114
7.0 Timing Diagrams ......................................................................................................................................................................... 116
8.0 Reset Circuit ................................................................................................................................................................................ 126
9.0 Selection of Isolation Transformer .............................................................................................................................................. 127
10.0 Selection of Reference Crystal .................................................................................................................................................. 127
11.0 Package Outlines ...................................................................................................................................................................... 128
Appendix A: Data Sheet Revision History ......................................................................................................................................... 129
The Microchip Web Site .................................................................................................................................................................... 130
Customer Change Notification Service ............................................................................................................................................. 130
Customer Support ............................................................................................................................................................................. 130
Product Identification System ............................................................................................................................................................ 131

DS00002112B-page 4  2016-2017 Microchip Technology Inc.

 KSZ8795CLX
1.0 INTRODUCTION

1.1 General Description

The KSZ8795CLX is a highly integrated, Layer 2-managed, 5-port switch with numerous features designed to reduce
system cost. It is intended for cost-sensitive applications requiring four 10/100 Mbps copper ports and one 10/100/
1000 Mbps Gigabit uplink port. The KSZ8795CLX incorporates a small package outline, lowest power consumption with
internal biasing, and on-chip termination. Its extensive features set includes enhanced power management, program-
mable rate limiting and priority ratio, tagged and port-based VLAN, port-based security and ACL rule-based packet fil-
tering technology, quality-of-service (QoS) priority with four queues, management interfaces, enhanced MIB counters,
high-performance memory bandwidth, and a shared memory-based switch fabric with non-blocking support. The
KSZ8795CLX provides support for multiple CPU data interfaces to effectively address both current and emerging fast
Ethernet and Gigabit Ethernet applications where the port 5 GMAC can be configured to any of GMII, RGMII, MII and
RMII modes.
The KSZ8795CLX is built upon industry-leading Ethernet analog and digital technology, with features designed to off-
load host processing and streamline the overall design.
• Four integrated 10/100BASE-T/TX MAC/PHYs
• One integrated 10/100/1000BASE-T/TX GMAC with selectable GMII, RGMII, MII, and RMII interfaces
• Small 80-pin LQFP package
A robust assortment of power-management features including Energy Efficient Ethernet (EEE), PME, and Wake-on-
LAN (WoL) have been designed-in to satisfy energy-efficient environments.
KSZ8795CLX supports two management interface modes of SPI and MIIM only, SPI access all registers, MIIM mode
access all PHYs registers through MDC/MDIO interface.

FIGURE 1-1: FUNCTIONAL BLOCK DIAGRAM

KSZ8795
10/100
10/100 1K LOOK-UP
AUTO MDI/MDIX T/TX
MAC 1 ENGINE
EEE PHY1

10/100
FIFO, FLOW CONTROL, VLAN

AUTO MDI/MDIX 10/100

T/TX
MAC 2 QUEUE
EEE PHY2
MANAGEMENT

10/100
10/100
AUTO MDI/MDIX T/TX
MAC 3
EEE PHY3
BUFFER
MANAGEMENT
10/100
AUTO MDI/MDIX 10/100
T/TX
MAC 4
EEE PHY4
FRAME
10/100/1000 BUFFER
SW5-GMII/RGMII/MII/RMII
GMAC 5
TAGGING, PRIORITY

MDC, MDI/O FOR MIIM

MIB
CONTROL REG SPI I/F SPI COUNTERS

LED0 [4:1]
LED I/F CONTROL
LED1 [4:1] REGISTERS

 2016-2017 Microchip Technology Inc. DS00002112B-page 5

KSZ8795CLX
2.0 PIN DESCRIPTION AND CONFIGURATION

FIGURE 2-1: 80-LQFP PIN ASSIGNMENT (TOP VIEW)

SDA_MDIO
SCL_MDC
VDDAT33

VDD12D

LED1_0
LED1_1
LED2_0
LED2_1
SPIS_N
RST_N

VDDIO
GNDD

GNDD
GNDA

ATST

SPIQ
ISET
XO

NC
XI
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
VDD12A 1 60 RXD5_7
VDDAT33 2 59 RXD5_6
GNDA 3 58 RXD5_5
RXP1 4 57 RXD5_4
RXM1 5 56 PME
TXP1 6 55 REFCLKO
TXM1 7 54 COL5
RXP2 8 53 CRS5
RXM2 9 KSZ8795 52 RXER5
TXP2 10 51 RXDV5/CRSDV5/RXD5_CTL
TXM2 11 (TOP VIEW) 50 RXD5_3
VDDAT33 12 49 RXD5_2
RXP3 13 48 VDDIO
RXM3 14 47 GNDD
TXP3 15 46 RXD5_1
TXM3 16 45 RXD5_0
RXP4 17 44 RXC5/GRXC5
RXM4 18 43 TXC5/REFCLKI5/GTXC5
TXP4 19 42 VDD12D
TXM4 20 41 TXD5_7
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
GNDA

TXEN5/TXDS5_CTL
NC
INTR_N
LED3_1
LED3_0
VDD12D
GNDD
LED4_1

TXD5_0
LED4_0
TXD5_1
GNDD
VDDIO
TXD5_2
TXD5_3
TXER5
TXD5_4
TXD5_5
TXD5_6

DS00002112B-page 6  2016-2017 Microchip Technology Inc.

 KSZ8795CLX
TABLE 2-1: SIGNALS - KSZ8795CLX

Pin Pin Type

Port Description
Number Name Note 2-1

1 VDD12A P — 1.2V Core Power

2 VDDAT P — 3.3V or 2.5V Analog Power.

3 GNDA GND — Analog Ground.

4 RXP1 I 1 Port 1 Physical Receive Signal + (Differential).

5 RXM1 I 1 Port 1 Physical Receive Signal - (Differential).

6 TXP1 O 1 Port 1 Physical Transmit Signal + (Differential).

7 TXM1 O 1 Port 1 Physical Transmit Signal - (Differential).

8 RXP2 I 2 Port 2 Physical Receive Signal + (Differential).

9 RXM2 I 2 Port 2 Physical Receive Signal - (Differential).

10 TXP2 O 2 Port 2 Physical Transmit Signal + (Differential).

11 TXM2 O 2 Port 2 Physical Transmit Signal - (Differential).

12 VDDAT P 3.3V or 2.5V Analog Power.

13 RXP3 I 3 Port 3 Physical Receive Signal + (Differential).

14 RXM3 I 3 Port 3 Physical Receive Signal - (Differential).

15 TXP3 O 3 Port 3 Physical Transmit Signal + (Differential).

16 TXM3 O 3 Port 3 Physical Transmit Signal – (Differential).

17 RXP4 I 4 Port 4 Physical Receive Signal + (Differential).

18 RXM4 I 4 Port 4 Physical Receive Signal - (Differential).

19 TXP4 O 4 Port 4 Physical Transmit Signal + (Differential).

20 TXM4 O 4 Port 4 Physical Transmit Signal - (Differential).

21 GNDA GND — Analog Ground.

22 NC NC — No Connect.

23 INTR_N Opu — Interrupt: Active-Low. This pin is open-drain output pin.

Note: An external pull-up resistor is needed on this pin
when it is in use.

24 LED3_1 Ipu/O 3 Port 3 LED Indicator 1:

See Global Register 11 bits [5:4] for details.
Strap Option: Switch Port 5 GMAC5 interface mode select by
LED3[1:0]
00 = MII for SW5-MII
01 = RMII for SW5-RMII
10 = GMII for SW5-GMII
11 = RGMII for SW5-RGMII (Default)

25 LED3_0 Ipu/O 3 Port 3 LED Indicator 0:

See Global Register 11 bits [5:4] for details.
Strap Option: See LED3_1.

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KSZ8795CLX
TABLE 2-1: SIGNALS - KSZ8795CLX (CONTINUED)

Pin Pin Type

Port Description
Number Name Note 2-1

26 VDD12D P — 1.2V Core Power.

27 GNDD GND — Digital Ground.

28 LED4_1 Ipu/O 4 Port 4 LED Indicator 1:

See Global Register 11 bits [5:4] for details.

29 TXEN5/ Ipd 5 GMII/MII/RMII: Port 5 Switch transmit enable.

TXD5_CTL RGMII: Transmit data control.

30 TXD5_0 Ipd 5 GMII/RGMII/MII/RMII: Port 5 switch transmit Bit[0].

31 LED4_0 Ipu/O 4 Port 4 LED Indicator 0:

See Global Register 11 bits [5:4] for details.

32 TXD5_1 Ipd 5 GMII/RGMII/MII/RMII: Port 5 switch transmit Bit[1].

33 GNDD GND — Digital Ground.

34 VDDIO P — 3.3V, 2.5V, or 1.8V digital VDD for digital I/O circuitry.

35 TXD5_2 Ipd 5 GMII/RGMII/MII: Port 5 switch transmit Bit[2].

RMII: No connection.

36 TXD5_3 Ipd 5 GMII/RGMII/MII: Port 5 switch transmit Bit[3].

RMII: No connection.

37 TXER5 Ipd 5 GMII/MII: Port 5 switch transmit error.

RGMII/RMII: No connection.

38 TXD5_4 Ipd 5 GMII: Port 5 switch transmit Bit[4].

RGMII/MII/RMII: No connection.

39 TXD5_5 Ipd 5 GMII: Port 5 switch transmit Bit[5].

RGMII/MII/RMII: No connection.

40 TXD5_6 Ipd 5 GMII: Port 5 switch transmit Bit[6].

RGMII/MII/RMII: No connection.

41 TXD5_7 Ipd 5 GMII: Port 5 Switch transmit Bit[7].

RGMII/MII/RMII: No connection.

42 VDD12D P — 1.2V Core Power.

43 TXC5/ I/O 5 Port 5 Switch GMAC5 Clock Pin:

REFCLKI/ MII: 2.5/25 MHz clock, PHY mode is output, MAC mode is input.
GTXC5 RMII: Input for receiving 50 MHz clock in normal mode
GMII: Input 125 MHz clock for the transmit
RGMII: Input 125 MHz clock with falling and rising edge to latch
data for the transmit.

44 RXC5/ I/O 5 Port 5 Switch GMAC5 Clock Pin:

GRXC5 MII: 2.5/25 MHz clock, PHY mode is output, MAC mode is input.
RMII: Output 50 MHz reference clock for the receiving/transmit
in the clock mode.
GMII: Output 125 MHz clock for the receiving.
RGMII: Output 125 MHz clock with falling and rising edge to
latch data for the receiving.

DS00002112B-page 8  2016-2017 Microchip Technology Inc.

 KSZ8795CLX
TABLE 2-1: SIGNALS - KSZ8795CLX (CONTINUED)

Pin Pin Type

Port Description
Number Name Note 2-1

45 RXD5_0 Ipd/O 5 GMII/RGMII/MII/RMII: Port 5 Switch receive Bit[0].

46 RXD5_1 Ipd/O 5 GMII/RGMII/MII/RMII: Port 5 Switch receive Bit[1].

47 GNDD GND — Digital Ground.

48 VDDIO P — 3.3V, 2.5V, or 1.8V digital VDD for digital I/O circuitry.

49 RXD5_2 Ipd/O 5 GMII/RGMII/MII: Port 5 Switch receive Bit[2].

RMII: No connection

50 RXD5_3 Ipd/O 5 GMII/RGMII/MII: Port 5 Switch receive Bit[3].

RMII: No connection

51 RXDV5/ Ipd/O 5 GMII/MII: RXDV5 is for Port 5 switch GMII/MII receive data
CRSDV5/ valid.
RXD5_CTL RMII: CRSDV5 is for Port 5 RMII carrier sense/receive data
valid output.
RGMII: RXD5_CTL is for Port 5 RGMII receive data control

52 RXER5 Ipd/O 5 GMII/MII: Port 5 Switch receive error.

RGMII/RMII: No connection.

53 CRS5 Ipd/O 5 GMII/MII: Port 5 Switch MII modes carrier sense.

RGMII/RMII: No connection.

54 COL5 Ipd/O 5 GMII/MII: Port 5 Switch MII collision detect.

RGMII/RMII: No connection.

55 REFCLKO Ipu/O — 25 MHz Clock Output (Option)

Controlled by the strap pin LED2_0 and the Global Register 11
Bit[1]. Default is enabled; it is better to disable it if it’s not being
used.

56 PME_N I/O — Power Management Event

This output signal indicates that a WoL event has been detected
as a result of a wake-up frame being detected. The KSZ8795-
CLX is requesting the system to wake up from low power mode.
Its assertion polarity is programmable with the default polarity to
be active-low.

57 RXD5_4 Ipd/O 5 GMII: Port 5 switch receive Bit[4].

RGMII/MI/RMII: No connection.

58 RXD5_5 Ipd/O 5 GMII: Port 5 switch receive Bit[5].

RGMII/MII/RMII: No connection.

59 RXD5_6 Ipd/O 5 GMII: Port 5 switch receive Bit[6].

RGMII/MII/RMII: No connection.

60 RXD5_7 Ipd/O 5 GMII: Port 5 switch receive Bit[7].

RGMII/MII/RMII: No connection.

61 GNDD GND — Digital Ground.

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KSZ8795CLX
TABLE 2-1: SIGNALS - KSZ8795CLX (CONTINUED)

Pin Pin Type

Port Description
Number Name Note 2-1

62 LED2_1 Ipu/O 2 Port 2 LED Indicator 1:

See Global Register 11 bits [5:4] for details.
Strap Option: Port 5 GMII/MII and RMII mode select
When Port 5 is GMII/MII mode:
PU = GMII/MII is in GMAC/MAC mode. (Default)
PD = GMII/MII is in GPHY/PHY mode.
Note: When set GMAC5 GMII to GPHY mode, the CRS
and COL pins will change from the input to output.
When set MII to PHY mode, the CRS, COL, RXC
and TXC pins will change from the input to output.

When Port 5 is RMII mode:

PU = Clock mode in RMII, using 25MHz OSC clock and provide
50 MHz RMII clock from pin RXC5.
PD = Normal mode in RMII, the TXC5/REFCLKI5 pin on the
port 5 RMII will receive an external 50 MHz clock
Note: Port 5 also can use either an internal or external
clock in RMII mode based on this strap pin or the set-
ting of the Register 86 (0x56) bit[7].

63 LED2_0 Ipu/O 2 Port 2 LED Indicator 0:

See Global Register 11 bits [5:4] for details.
Strap Option: REFCLKO enable
PU = REFCLK_O (25 MHz) is enabled. (Default)
PD = REFCLK_O is disabled.
Note: It is better to disable this 25 MHz clock if not provid-
ing an extra 25 MHz clock for the system.

64 LED1_1 Ipu/O 1 Port 1 LED Indicator 1:

See Global Register 11 bits [5:4] for details.
Strap Option: PLL Clock source select
PU = Still use 25 MHz clock from XI/XO pin even though it is in
Port 5 RMII normal mode.
PD = Use external clock from pin TXC5 in Port 5 RMII normal
mode.
Note: If received clock in Port 5 RMII normal mode has
large clock jitter, one can select the 25 MHz crystal/
oscillator as the switch’s clock source.

65 LED1_0 Ipu/O 1 Port 1 LED Indicator 0:

See Global Register 11 bits [5:4] for details.
Strap Option: Speed select in GMII/RGMII
PU = 1Gbps in GMII/RGMII.(Default)
PD = 10/100Mbps in GMII/RGMII.
Note: Programmable through internal registers also.

66 SPIQ Ipd/O All SPI Serial Data Output in SPI Slave Mode:
Strap Option: Serial bus configuration.
PD = SPI slave mode.
PU = MDC/MDIO mode.
Note: An external pull-up or pull-down resistor is required.

DS00002112B-page 10  2016-2017 Microchip Technology Inc.

 KSZ8795CLX
TABLE 2-1: SIGNALS - KSZ8795CLX (CONTINUED)

Pin Pin Type

Port Description
Number Name Note 2-1

67 SCL_MDC Ipu All Clock Input for SPI or MDC/MDIO Interface:

Input clock up to 50 MHz in SPI slave mode.
Input clock up to 25 MHz in MDC/MDIO for MIIM access.

68 SDA_MDIO Ipu/O All Data for SPI or MDC/MDIO Interface:

Serial data input in SPI slave mode.
MDC/MDIO interface data input/output.

69 SPIS_N Ipu All SPI Slave Mode Chip Select (Active-Low):

SPI data transfer start in SPI slave mode. When SPIS_N is
high, the KSZ8795CLX is deselected and SPIQ is held in the
high impedance state. A high-to-low transition initiates the SPI
data transfer. This pin is active-low.

70 VDDIO P — 3.3V, 2.5V or 1.8V digital VDD for digital I/O circuitry.

71 GNDD GND — Digital Ground.

72 RST_N Ipu — Reset: This active-low signal resets the hardware in the device.
See the timing requirements in this section.

73 VDD12D P — 1.2V Core Power.

74 NC NC — No Connect.

75 ATST NC — No Connect. Factory test pin.

76 VDDAT P — 3.3V or 2.5V Analog Power.

77 ISET — Transmit Output Current Set:

This pin configures the physical transmit output current. It
should be connected to GND through a 12.4 kΩ 1% resistor.

78 GNDA GND — Analog Ground.

79 XI I — Crystal Clock Input/Oscillator Input:

When using a 25 MHz crystal, this input is connected to one end
of the crystal circuit. When using a 3.3V oscillator, this is the
input from the oscillator.
The crystal or oscillator should have a tolerance of ±50 ppm.

80 XO O — Crystal Clock Output:

When using a 25 MHz crystal, this output is connected to one
end of the crystal circuit.
Note 2-1 P = power supply; GND = ground; I = input; O = output
I/O = bi-directional
Ipu = Input w/internal pull-up.
Ipd = Input w/internal pull-down.
Ipd/O = Input w/internal pull-down during reset, output pin otherwise.
Ipu/O = Input w/internal pull-up during reset, output pin otherwise.
OTRI = Output tri-stated.
PU = Strap pin pull-up.
PD = Strap pin pull-down.
NC = No connect or tie-to-ground for this product.

 2016-2017 Microchip Technology Inc. DS00002112B-page 11

KSZ8795CLX
The KSZ8795CLX can function as a managed switch and utilizes strap-in pins to configure the device for different
modes. The strap-in pins are configured by using external pull-up/down resistors to create a high or low state on the
pins which are sampled during the power-down reset or warm reset. The functions are described in following table.

TABLE 2-2: STRAP-IN OPTIONS - KSZ8795CLX

Type
Pin Number Pin Name Description
(Note 2-2)
Switch Port 5 GMAC5 Interface Mode Select:
Strap Option:
00 = MII for SW5-MII
24, 25 LED3[1,0] Ipu/O
01 = RMII for SW5-RMII
10 = GMII for SW5-GMII
11 = RGMII for SW5-RGMII (Default)
Port 5 GMII/MII and RMII Mode Select:
Strap Option:
When Port 5 is GMII/MII mode:
PU = GMII/MII is in GMAC/MAC mode. (Default)
PD = GMII/MII is in GPHY/PHY mode.
Note: When set GMAC5 GMII to GPHY mode, the CRS and
COL pins will change from the input to output. When set
MII to PHY mode, the CRS, COL, RXC and TXC pins will
change from the input to output.
62 LED2_1 Ipu/O

When Port 5 is RMII mode:

PU = Clock mode in RMII, using 25 MHz OSC clock and provide
50 MHz RMII clock from pin RXC5.
PD = Normal mode in RMII, the TXC5/REFCLKI5 pin on the Port 5
RMII will receive an external 50 MHz clock
Note: Port 5 also can use either an internal or external clock in
RMII mode based on this strap pin or the setting of the
Register 86 (0x56) bit[7].
63 LED2_0 Ipu/O REFCLKO Enable:
Strap Option:
PU = REFCLK_O (25 MHz) is enabled. (Default)
PD = REFCLK_O is disabled.
64 LED1_1 Ipu/O PLL Clock Source Select:
Strap Option:
PU = Still use 25 MHz clock from XI/XO pin even though it is in Port
5 RMII normal mode.
PD = Use external clock from TXC5 pin in Port 5 RMII normal mode.
Note: If received clock in Port 5 RMII normal mode with bigger
clock jitter, still can select to use the 25 MHz crystal/oscil-
lator as switch’s clock source.
65 LED1_0 Ipu/O Port 5 Gigabit Select:
Strap Option:
PU = 1 Gbps in GMII/RGMII mode (Default)
PD = 10/100 Mbps in GMII/RGMII mode.
Note: Programmable through internal register also

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 KSZ8795CLX
TABLE 2-2: STRAP-IN OPTIONS - KSZ8795CLX (CONTINUED)
Type
Pin Number Pin Name Description
(Note 2-2)
66 SPIQ Ipd/O Serial Bus Configuration
Strap Option:
PD = SPI slave mode. (Default)
PU = MDC/MDIO mode.
Note: An external pull-up or pull-down resistor is requested. If
the uplink port is used for the RGMII interface, SPI mode
is recommend for setting register 86 (0x56) bits [4:3] for
RGMII v2.0; MDC/MDIO mode can’t set this feature.
Note 2-2 Ipd/O = Input w/internal pull-down during reset, output pin otherwise.
Ipu/O = Input w/internal pull-up during reset, output pin otherwise.

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KSZ8795CLX
3.0 FUNCTIONAL DESCRIPTION
The KSZ8795CLX contains four 10/100 physical layer transceivers, four media access control (MAC) units, and one
Gigabit media access control (GMAC) unit with an integrated Layer 2-managed switch. The device runs in two modes.
The first mode is as a four-port standalone switch and the second is as a five-port switch with fifth port that is provided
through a Gigabit media independent interface that supports GMII, RGMII, MII, and RMII. This is useful for implementing
an integrated broadband router.
The KSZ8795CLX has the flexibility to reside in a managed mode. In a managed mode, a host processor has complete
control of the KSZ8795CLX via the SPI bus, or the MDC/MDIO interface.
On the media side, the KSZ8795CLX supports IEEE 802.3 10BASE-T, 100BASE-TX on all copper ports with Auto- MDI/
MDI-X. The KSZ8795CLX can be used as a fully-managed five-port switch or hooked up to a microprocessor via its SW-
GMII/RGMII/MII/RMII interfaces to allow for integrating into a variety of environments.
Physical signal transmission and reception are enhanced through the use of patented analog circuitry and DSP tech-
nology that makes the design more efficient and allows for reduced power consumption and smaller die size.
Major enhancements from the KSZ8995 and KS8895 to the KSZ8795CLX include more host interface options such as
the GMII and RGMII interfaces, power-saving features such as IEEE 802.1az Energy Efficient Ethernet (EEE), MLD
snooping, Wake-on-LAN (WoL), port-based ACL filtering for the port security, enhanced quality-of-service (QoS) priority,
rapid spanning tree, IGMP snooping, port mirroring support, and flexible rate limiting.

3.1 Physical Layer (PHY)

3.1.1 100BASE-TX TRANSMIT
The 100BASE-TX transmit function performs parallel-to-serial conversion, 4B/5B coding, scrambling, NRZ-to-NRZI con-
version, and MLT3 encoding and transmission. The circuit starts with a parallel-to-serial conversion, which converts the
MII data from the MAC into a 125 MHz serial bit stream. The data and control stream is then converted into 4B/5B coding
followed by a scrambler. The serialized data is further converted from NRZ-to-NRZI format, and then transmitted in
MLT3 current output. The output current is set by an external 1% 12.4 kΩ resistor for the 1:1 transformer ratio. It has a
typical rise/fall time of 4 ns and complies with the ANSI TP-PMD standard regarding amplitude balance, overshoot, and
timing jitter. The wave-shaped 10BASE-T output is also incorporated into the 100BASE-TX transmitter.

3.1.2 100BASE-TX RECEIVE

The 100BASE-TX receiver function performs adaptive equalization, DC restoration, MLT3-to-NRZI conversion, data and
clock recovery, NRZI-to-NRZ conversion, descrambling, 4B/5B decoding, and serial-to-parallel conversion. The receiv-
ing side starts with the equalization filter to compensate for inter-symbol interference (ISI) over the twisted pair cable.
Since the amplitude loss and phase distortion is a function of the length of the cable, the equalizer has to adjust its char-
acteristics to optimize the performance. In this design, the variable equalizer will make an initial estimation based on
comparisons of incoming signal strength against some known cable characteristics, then tunes itself for optimization.
This is an ongoing process and can self-adjust against environmental changes such as temperature variations.
The equalized signal then goes through a DC restoration and data conversion block. The DC restoration circuit is used
to compensate for the effect of baseline wander and improve the dynamic range. The differential data conversion circuit
converts the MLT3 format back to NRZI. The slicing threshold is also adaptive.
The clock recovery circuit extracts the 125 MHz clock from the edges of the NRZI signal. This recovered clock is then
used to convert the NRZI signal into the NRZ format. The signal is then sent through the descrambler followed by the
4B/5B decoder. Finally, the NRZ serial data is converted to the MII format and provided as the input data to the MAC.

3.1.3 PLL CLOCK SYNTHESIZER

The KSZ8795CLX generates 125 MHz, 83 MHz, 41 MHz, 25 MHz, and 10 MHz clocks for system timing. Internal clocks
are generated from an external 25 MHz crystal or oscillator.

3.1.4 SCRAMBLER/DE-SCRAMBLER (100BASE-TX ONLY)

The purpose of the scrambler is to spread the power spectrum of the signal in order to reduce EMI and baseline wander.
The data is scrambled through the use of an 11-bit wide linear feedback shift register (LFSR). This can generate a 2047-
bit non-repetitive sequence. The receiver will then descramble the incoming data stream with the same sequence at the
transmitter.

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 KSZ8795CLX
3.1.5 10BASE-T TRANSMIT
The 10BASE-T output driver is incorporated into the 100BASE-T driver to allow transmission with the same magnetics.
They are internally wave-shaped and pre-emphasized into outputs with a typical 2.3V amplitude. The harmonic contents
are at least 27 dB below the fundamental when driven by an all-ones Manchester-encoded signal.

3.1.6 10BASE-T RECEIVE

On the receive side, input buffers and level detecting squelch circuits are employed. A differential input receiver circuit
and a PLL perform the decoding function. The Manchester-encoded data stream is separated into a clock signal and
NRZ data. A squelch circuit rejects signals with levels less than 400 mV or with short pulse widths in order to prevent
noises at the RXP or RXM input from falsely triggering the decoder. When the input exceeds the squelch limit, the PLL
locks onto the incoming signal and the KSZ8795CLX decodes a data frame. The receiver clock is maintained active
during idle periods in between data reception.

3.1.7 MDI/MDI-X AUTO CROSSOVER

To eliminate the need for crossover cables between similar devices, the KSZ8795CLX supports HP Auto-MDI/MDI-X
and IEEE 802.3u standard MDI/MDI-X auto crossover. Note that HP Auto-MDI/MDI-X is the default.
The auto-sense function detects remote transmit and receive pairs and correctly assigns transmit and receive pairs for
the KSZ8795CLX device. This feature is extremely useful when end users are unaware of cable types, and also, saves
on an additional uplink configuration connection. The auto-crossover feature can be disabled through the port control
registers, or MIIM PHY registers. The IEEE 802.3u standard MDI and MDI-X definitions are illustrated in Table 3-1.

TABLE 3-1: MDI/MDI-X PIN DEFINITIONS

MDI MDI-X

RJ-45 Pins Signals RJ-45 Pins Signals

1 TD+ 1 RD+
2 TD– 2 RD–
3 RD+ 3 TD+
6 RD– 6 TD–
3.1.7.1 Straight Cable
A straight cable connects an MDI device to an MDI-X device, or an MDI-X device to an MDI device. Figure 3-1 depicts
a typical straight cable connection between a NIC card (MDI) and a switch, or hub (MDI-X).

FIGURE 3-1: TYPICAL STRAIGHT CABLE CONNECTION

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KSZ8795CLX
3.1.7.2 Crossover Cable
A crossover cable connects an MDI device to another MDI device, or an MDI-X device to another MDI-X device. The
following diagram shows a typical crossover cable connection between two switches or hubs (two MDI-X devices).

FIGURE 3-2: TYPICAL CROSSOVER CABLE CONNECTION

10/100 ETHERNET 10/100 ETHERNET

MEDIA DEPENDENT INTERFACE MEDIA DEPENDENT INTERFACE

1 CROSSOVER 1
RECEIVE PAIR CABLE RECEIVE PAIR
2 2

3 3

4 4
TRANSMIT PAIR TRANSMIT PAIR
5 5

6 6

7 7

8 8

MODULAR CONNECTOR (RJ-45) MODULAR CONNECTOR (RJ-45)

HUB HUB
(REPEATER OR SWITCH) (REPEATER OR SWITCH)

3.1.8 AUTO-NEGOTIATION
The KSZ8795CLX conforms to the auto-negotiation protocol as described by the 802.3 committee. Auto-negotiation
allows unshielded twisted pair (UTP) link partners to select the highest common mode-of-operation. Link partners adver-
tise their capabilities to each other and then compare their own capabilities with those they received from their link part-
ners. The highest speed and duplex setting that is common to the two link partners is selected as the mode-of-operation.
Auto-negotiation is supported for the copper ports only.
The following list shows the speed and duplex operation mode (highest to lowest):
• 100BASE-TX, full-duplex
• 100BASE-TX, half-duplex
• 10BASE-T, full-duplex
• 10BASE-T, half-duplex
If auto-negotiation is not supported or the KSZ8795CLX link partner is forced to bypass auto-negotiation, the KSZ8795-
CLX sets its operating mode by observing the signal at its receiver. This is known as parallel detection, and allows the
KSZ8795CLX to establish link by listening for a fixed-signal protocol in the absence of auto-negotiation advertisement
protocol. The auto-negotiation link up process is shown in Figure 3-3.

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 KSZ8795CLX

FIGURE 3-3: AUTO-NEGOTIATION AND PARALLEL OPERATION

3.1.9 LINKMD® CABLE DIAGNOSTICS

The LinkMD feature utilizes time-domain reflectometry (TDR) to analyze the cabling plant for common cabling problems
such as open circuits, short circuits, and impedance mismatches.
LinkMD works by sending a pulse of known amplitude and duration down the MDI and MDI-X pairs and then analyzes
the shape of the reflected signal. Timing the pulse duration gives an indication of the distance to the cabling fault with
maximum distance of 200m and accuracy of ±2m. Internal circuitry displays the TDR information in a user-readable dig-
ital format.
Note: Cable diagnostics are only valid for copper connections only.

3.1.9.1 Access
LinkMD is initiated by accessing the PHY special control/status Registers 26, 42, 58, 74 and the LinkMD result Registers
27, 43, 59, and 75 for Ports 1, 2, 3, and 4 respectively; and in conjunction with the Port Control 10 Register for Ports 1,
2, 3, and 4 respectively to disable Auto-MDI/MDI-X.
Alternatively, the MIIM PHY Registers 0 and 1d can also be used for LinkMD access.

3.1.9.2 Usage
The following is a sample procedure for using LinkMD with Registers {26, 27, and 29} on Port 1:
1. Disable auto MDI/MDI-X by writing a ‘1’ to Register 29, Bit[2] to enable manual control over the differential pair
used to transmit the LinkMD pulse.
2. Start cable diagnostic test by writing a ‘1’ to Register 26, Bit[4]. This enable bit is self-clearing.
3. Wait (poll) for Register 26, Bit[4] to return a ‘0’, and indicating cable diagnostic test is completed.
4. Read cable diagnostic test results in Register 26, bits [6:5]. The results are as follows:

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KSZ8795CLX
00 = normal condition (valid test)
01 = open condition detected in cable (valid test)
10 = short condition detected in cable (valid test)
11 = cable diagnostic test failed (invalid test)
The ‘11’ case, invalid test, occurs when the KSZ8795CLX is unable to shut down the link partner. In this instance, the
test is not run, since it would be impossible for the KSZ8795CLX to determine if the detected signal is a reflection of the
signal generated or a signal from another source.
5. Get distance to fault by concatenating Register 26, bit[0] and Register 27, bits [7:0]; and multiplying the result by
a constant of 0.4. The distance to the cable fault can be determined by the following formula:
D (distance to cable fault, expressed in meters) = 0.4 x (Register 26, Bit[0], Register 27, bits [7:0])
Concatenated value of Registers 26 Bit[0] and 27 bits [7:0] should be converted to decimal before multiplying by 0.4.
The constant (0.4) may be calibrated for different cabling conditions, including cables with a velocity of propagation that
varies significantly from the norm.
For Ports 2, 3, 4, and using the MIIM PHY registers, LinkMD usage is similar.
3.1.9.3 A LinkMD Example
The following is a sample procedure for using LinkMD on Ports 1, 2, 3, and 4 with force MDI-X mode:
//Disable MDI/MDI-X and force to MDI-X mode
//’w’ is WRITE the register. ‘r’ is READ register below
w 1d 04
w 2d 04
w 3d 04
w 4d 04
//Set Internal registers temporary by indirect registers, adjust for LinkMD
w 6e a0
w 6f 4d
w a0 80
//Enable LinkMD Testing with fault cable for Ports 1, 2, 3 and 4
w 1a 10
w 2a 10
w 3a 10
w 4a 10
//Wait until Port Register Control 8 Bit[4] returns a ‘0’ (Self Clear)
//Diagnosis results
r 1a
r 1b
r 2a
r 2b
r 3a
r 3b
r 4a
r 4b
//For example on Port 1, the result analysis based on the values of the register 0x1a and 0x1b
//The register 0x1a Bits[6-5] are for the open or the short detection.
//The register 0x1a Bit[0] + the register 0x1b bits [7-0] = CDT_Fault_Count [8-0]
//The distance to fault is about 0.4 x (CDT_Fault_Count [8-0])

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 KSZ8795CLX
3.1.10 ON-CHIP TERMINATION AND INTERNAL BIASING
The KSZ8795CLX reduces the board cost and simplifies the board layout by using on-chip termination resistors for all
ports and RX/TX differential pairs without the external termination resistors. The combination of the on-chip termination
and the internal biasing will save more PCB spacing and power consumption, compared using external biasing and ter-
mination resistors for multiple switches, because the transformers don’t consume the power anymore. The center taps
of the transformer shouldn’t need to be tied to the analog power.

3.2 Media Access Controller (MAC) Operation

The KSZ8795CLX strictly abides by IEEE 802.3 standards to maximize compatibility.

3.2.1 INTER-PACKET GAP (IPG)

If a frame is successfully transmitted, the 96-bit time IPG is measured between the two consecutive MTXEN. If the cur-
rent packet is experiencing collision, the 96-bit time IPG is measured from MCRS and the next MTXEN.

3.2.2 BACKOFF ALGORITHM

The KSZ8795CLX implements the IEEE Standard 802.3 binary exponential backoff algorithm, and optional “aggressive
mode” backoff. After 16 collisions, the packet will be optionally dropped, depending on the chip configuration in Register
3.

3.2.3 LATE COLLISION

If a transmit packet experiences collisions after 512-bit times of the transmission, the packet will be dropped.

3.2.4 ILLEGAL FRAMES

The KSZ8795CLX discards frames less than 64 bytes and can be programmed to accept frames up to 1536 bytes in
Register 4. For special applications, the KSZ8795CLX can also be programmed to accept frames up to 2K bytes in Reg-
ister 3 Bit[6]. Since the KSZ8795CLX supports VLAN tags, the maximum sizing is adjusted when these tags are present.

3.2.5 FLOW CONTROL

The KSZ8795CLX supports standard 802.3x flow control frames on both transmit and receive sides.
On the receive side, if the KSZ8795CLX receives a pause control frame, the KSZ8795CLX will not transmit the next
normal frame until the timer, specified in the pause control frame, expires. If another pause frame is received before the
current timer expires, the timer will be updated with the new value in the second pause frame. During this period (being
flow controlled), only flow-control packets from the KSZ8795CLX will be transmitted.
On the transmit side, the KSZ8795CLX has intelligent and efficient ways to determine when to invoke flow control. The
flow control is based on availability of the system resources, including available buffers, available transmit queues and
available receive queues.
The KSZ8795CLX flow controls a port that has just received a packet if the destination port resource is busy. The
KSZ8795CLX issues a flow control frame (XOFF), containing the maximum pause time defined in IEEE standard
802.3x. Once the resource is freed up, the KSZ8795CLX sends out the other flow control frame (XON) with zero pause
time to turn off the flow control (turn on transmission to the port). A hysteresis feature is also provided to prevent over-
activation and deactivation of the flow control mechanism.
The KSZ8795CLX flow controls all ports if the receive queue becomes full.

3.2.6 HALF-DUPLEX BACK PRESSURE

The KSZ8795CLX also provides a half-duplex back pressure option (note that this is not in IEEE 802.3 standards). The
activation and deactivation conditions are the same as the ones given for full-duplex mode. If back pressure is required,
the KSZ8795CLX sends preambles to defer the other station's transmission (carrier sense deference). To avoid jabber
and excessive deference as defined in IEEE 802.3 standards, after a certain period of time, the KSZ8795CLX discon-
tinues carrier sense but raises it quickly after it drops packets to inhibit other transmissions. This short silent time (no
carrier sense) is to prevent other stations from sending out packets and keeps other stations in a carrier sense-deferred
state. If the port has packets to send during a back pressure situation, the carrier sense-type back pressure is interrupted
and those packets are transmitted instead. If there are no more packets to send, carrier sense-type back pressure
becomes active again until switch resources are free. If a collision occurs, the binary exponential backoff algorithm is

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KSZ8795CLX
skipped and carrier sense is generated immediately, reducing the chance of further colliding and maintaining carrier
sense to prevent reception of packets. To ensure no packet loss in 10BASE-T or 100BASE-TX half-duplex modes, the
user must enable the following:
• Aggressive backoff (Register 3, Bit[0])
• No excessive collision drop (Register 4, Bit[3])
• Back pressure (Register 4, Bit[5])
These bits are not set as the default because this is not the IEEE standard.

3.2.7 BROADCAST STORM PROTECTION

The KSZ8795CLX has an intelligent option to protect the switch system from receiving too many broadcast packets.
Broadcast packets are normally forwarded to all ports except the source port and thus use too many switch resources
(bandwidth and available space in transmit queues). The KSZ8795CLX has the option to include “multicast packets” for
storm control. The broadcast storm rate parameters are programmed globally and can be enabled or disabled on a per
port basis. The rate is based on a 50 ms (0.05s) interval for 100BT and a 500 ms (0.5s) interval for 10BT. At the begin-
ning of each interval, the counter is cleared to zero and the rate limit mechanism starts to count the number of bytes
during the interval. The rate definition is described in Registers 6 and 7. The default setting for Registers 6 and 7 is 0x4A
(74 decimal). This is equal to a rate of 1%, calculated as follows:
148.80 frames/sec x 50 ms (0.05s)/interval x 1% = 74 frames/interval (approx.) = 0x4A

3.3 Switch Core

3.3.1 ADDRESS LOOK-UP
The internal look-up table stores MAC addresses and their associated information. It contains a 1K unicast address
table plus switching information. The KSZ8795CLX is guaranteed to learn 1K addresses and distinguishes itself from a
hash-based look-up table, which, depending on the operating environment and probabilities, may not guarantee the
absolute number of addresses it can learn.

3.3.2 LEARNING
The internal look-up engine updates its table with a new entry if the following conditions are met:
• The received packet’s source address (SA) does not exist in the look-up table.
• The received packet is good; the packet has no receiving errors and is of legal length.
The look-up engine inserts the qualified SA into the table, along with the port number and time stamp. If the table is full,
the last entry of the table is deleted first to make room for the new entry.

3.3.3 MIGRATION
The internal look-up engine also monitors whether a station is moved. If this occurs, it updates the table accordingly.
Migration happens when the following conditions are met:
• The received packet’s SA is in the table but the associated source port information is different.
• The received packet is good; the packet has no receiving errors and is of legal length.
The look-up engine will update the existing record in the table with the new source port information.

3.3.4 AGING
The look-up engine will update the time stamp information of a record whenever the corresponding SA appears. The
time stamp is used in the aging process. If a record is not updated for a period of time, the look-up engine will remove
the record from the table. The look-up engine constantly performs the aging process and will continuously remove aging
records. The aging period is 300s (±75s). This feature can be enabled or disabled through Register 3 Bit[2].

3.3.5 FORWARDING
The KSZ8795CLX will forward packets using an algorithm that is depicted in the following flowcharts. Figure 3-4 shows
stage one of the forwarding algorithm where the search engine looks up the VLAN ID, static table, and dynamic table
for the destination address, and comes up with “port to forward 1” (PTF1). PTF1 is then further modified by the spanning
tree, IGMP snooping, port mirroring, and port VLAN processes and authentication to come up with “port to forward 2”
(PTF2), as shown in Figure 3-4. The authentication and ACL have highest priority in the forwarding process; ACL result
will overwrite the result of the forwarding process. This is where the packet will be sent.

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 KSZ8795CLX
The KSZ8795CLX will not forward the following packets:
• Error packets. These include framing errors, frame check sequence (FCS) errors, alignment errors, and illegal
size packet errors.
• IEEE802.3x PAUSE frames. KSZ8795CLX intercepts these packets and performs full duplex flow control accord-
ingly.
• "Local" packets. Based on destination address (DA) lookup, if the destination port from the lookup table matches
the port from which the packet originated, the packet is defined as "local."

FIGURE 3-4: DESTINATION ADDRESS LOOKUP AND RESOLUTION FLOW CHART

START PTF 1

- SEARCH VLAN TABLE - CHECK RECEIVING PORT’S RECEIVE ENABLE BIT

- INGRESS VLAN FILTERING - CHECK DESTINATION PORT’S TRANSMIT ENABLE BIT
SPANNING
- DISCARD NPVID CHECK - CHECK WHETHER PACKETS ARE SPECIAL (BPDU)
NO TREE
VLAN ID PROCESS
PTF 1 = NULL VALID?
- APPLIED TO MAC (#1 TO #4)
- MAC #5 IS RESERVED FOR µC
- IGMP WILL BE FORWARDED TO PORT 5
YES IGMP
- SEARCH BASED ON PROCESS

FOUND DA OR DA + FID
GET PTF 1 SEARCH - RX MIRROR
FROM STATIC STATIC - TX MIRROR
ARRAY ARRAY - RX OR TX MIRROR
PORT - RX AND TX MIRROR
MIRROR
NOT FOUND PROCESS

FOUND SEARCH - SEARCH BASED ON

GET PTF 1 DA + FID
FROM ADDRESS ADDRESS PORT VLAN
TABLE LOOK-UP MEMBERSHIP
TABLE CHECK

NOT FOUND

PORT
GET PTF 1 FROM
AUTHENTICATION
VLAN TABLE
AND ACL

PTF 2 PTF 2

3.3.6 SWITCHING ENGINE

The KSZ8795CLX features a high-performance switching engine to move data to and from the MAC’s packet buffers.
It operates in store and forward mode, while the efficient switching mechanism reduces overall latency. The KSZ8795-
CLX has a 64 kB internal frame buffer. This resource is shared between all five ports. There are a total of 512 buffers
available. Each buffer is sized at 128 bytes.

3.4 Power and Power Management

The KSZ8795CLX device requires 3.3V analog power. An external 1.2V LDO provides the necessary 1.2V to power the
analog and digital logic cores. The various I/Os can be operated at 1.8V, 2.5V, and 3.3V. Table 3-2 illustrates the various
voltage options and requirements of the device.

TABLE 3-2: KSZ8795CLX VOLTAGE OPTIONS AND REQUIREMENTS

Power Signal
Device Pin Requirement
Name
VDDAT 2, 12, 76 3.3V or 2.5V input power to the analog blocks of transceiver in the
device.
VDDIO 34, 48, 70 Choice of 1.8V or 2.5V or 3.3V for the I/O circuits. These input power
pins power the I/O circuitry of the device.

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KSZ8795CLX
TABLE 3-2: KSZ8795CLX VOLTAGE OPTIONS AND REQUIREMENTS (CONTINUED)
Power Signal
Device Pin Requirement
Name
VDD12A 1 1.2V core power. Filtered 1.2V input voltage. These pins feed 1.2V to
VDD12D 26, 42, 73 power the internal analog and digital cores.
GNDA 3, 21, 78 Analog ground.
GNDD 27, 33, 47, 61, 71 Digital ground.
The KSZ8795CLX supports enhanced power management in a low power state, with energy detection to ensure low
power dissipation during device idle periods. There are multiple operation modes under the power management function
which are controlled by the Register 14 Bits[4:3] and the Port Control 10 Register Bit[3] as:
• Register 14 Bits[4:3] = 00 Normal Operation Mode
• Register 14 Bits[4:3] = 01 Energy Detect Mode
• Register 14 Bits[4:3] = 10 Soft Power-Down Mode
• Register 14 Bits[4:3] = 11 Reserved
The Port Control 10 Register 29, 45, 61, 77 Bit[3] = 1 are for the port-based power-down mode. Table 3-3 indicates all
internal function blocks’ status under four different power management operation modes.

TABLE 3-3: INTERNAL FUNCTION BLOCK STATUS

KSZ8795CLX Function Power Management Operation Modes
Blocks Normal Mode Energy Detect Mode Soft Power-Down Mode
Internal PLL Clock Enabled Disabled Disabled
TX/RX PHY Enabled Energy Detect at RX Disabled
MAC Enabled Disabled Disabled
Host Interface Enabled Disabled Disabled
3.4.1 NORMAL OPERATION MODE
This is the default setting Bits[4:3] = 00 in Register 14 after chip power-up or hardware reset. When KSZ8795CLX is in
normal operation mode, all PLL clocks are running, PHY and MAC are on, and the host interface is ready for CPU read
or writes.
During normal operation mode, the host CPU can set the Bits [4:3] in Register 14 to change the current normal operation
mode to any one of the other three power management operation modes.

3.4.2 ENERGY DETECT MODE

Energy detect mode provides a mechanism to save more power than in the normal operation mode when the KSZ8795-
CLX port is not connected to an active link partner. In this mode, the device will save more power when the cables are
unplugged. If the cable is not plugged in, the device can automatically enter a low power state: the energy detect mode.
In this mode, the device will keep transmitting 120 ns width pulses at a rate of 1 pulse per second. Once activity resumes
due to plugging a cable in or attempting by the far end to establish link, the device can automatically power up to normal
power state in energy detect mode.
Energy detect mode consists of two states, normal power state and low-power state. While in low power state, the
device reduces power consumption by disabling all circuitry except the energy-detect circuitry of the receiver. The
energy detect mode is entered by setting bits [4:3] = 01 in Register 14. When the KSZ8795CLX is in this mode, it will
monitor the cable energy. If there is no energy on the cable for a time longer than the pre-configured value at bits [7:0]
Go-Sleep time in Register 15, KSZ8795CLX will go into low power state. When KSZ8795CLX is in low power state, it
will keep monitoring the cable energy. Once the energy is detected from the cable, the device will enter normal power
state. When the device is at normal power state, it is able to transmit or receive packet from the cable.

3.4.3 SOFT POWER-DOWN MODE

The soft power-down mode is entered by setting bits [4:3] = 10 in Register 14. When KSZ8795CLX is in this mode, all
PLL clocks are disabled, also all of PHYs and the MACs are off. Any dummy host access will wake-up this device from
current soft power down mode to normal operation mode and internal reset will be issued to make all internal registers
go to the default values.

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 KSZ8795CLX
3.4.4 PORT-BASED POWER-DOWN MODE
In addition, the KSZ8795CLX features a per-port power down mode. To save power, a PHY port that is not in use can
be powered down via the Port Control 10 Register Bit[3], or MIIM PHY Register 0 Bit[11].

3.4.5 ENERGY EFFICIENT ETHERNET (EEE)

Along with supporting different types of power saving modes (H/W power down, S/W power down, and energy detect
mode), the KSZ8795CLX extends the green function capability by supporting Energy Efficient Ethernet (EEE) features
defined in IEEE P802.3az, March 2010. Both 10BASE-T and 100BASE-TX EEE functions are supported in KSZ8795-
CLX. In 100BASE-TX the EEE operation is asymmetric on the same link, which means one direction could be at low-
power idle (LPI) state, in the meanwhile, another direction could exist packet transfer activity. Different from other type
of power saving mode, EEE is able to maintain the link while power saving is achieved. Based on EEE specification, the
energy saving from EEE is done at PHY level. KSZ8795CLX reduces the power consumption not only at PHY level but
also at MAC and switch level by shutting down the unused clocks as much as possible when the device is at low-power
idle phase.
The KSZ8795CLX supports the 802.3az IEEE standard for both 10 Mbps and 100 Mbps interfaces. The EEE capability
combines Switch, MAC, and PHY to support operation in the LPI mode. When the LPI mode is enabled, systems on
both sides of the link can save power during periods of low link utilization.
EEE implementation provides a protocol to coordinate transitions to or from lower power consumption without changing
the link status and without dropping or corrupting frames. The transition time into and out of the lower power consump-
tion is kept small enough to be transparent to upper layer protocols and applications. EEE specifies means to exchange
capabilities between link partners to determine whether EEE is supported and to select the best set of parameters com-
mon to both sides.
Besides supporting the 100BASE-TX PHY EEE, KSZ8795CLX also supports 10BASE-T with reduced transmit ampli-
tude requirements for 10 Mbps mode to allow a reduction in power consumption.

FIGURE 3-5: IEEE TRANSMIT AND RECEIVE SIGNALING PATHS

TRANSMIT PATH

ISSUE OR MAP LPI REQUEST TO

TERMINATE LPI LPI MII PATTERN
REQUEST
PCS
SWITCH MAC (PHY LAYER)
Quite QUIET
Idle
DATA
IDLE
SLEEP
QUIET
SLEEP/REFRESH

QUIET/SLEEP
WAKEUP
IDLE/DATA

RECEIVE PATH

CONTROL/STATUS MAP LPI/P/ AND QUIET

SIGNALS STATE TO LPI MII
PATTERN
CLOCK CONTROL
PCS
STATUS REGISTER MAC (PHY LAYER)
TEST CONTROL
Quite QUIET
Idle
DATA
IDLE
SLEEP
QUIET
SLEEP/REFRESH

QUIET/SLEEP
WAKEUP
IDLE/DATA

LPI STATUS
SIGNALS

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KSZ8795CLX
3.4.5.1 LPI Signaling
LPI signaling allows switch to indicate to the PHY, and to the link partner, that a break in the data stream is expected,
and switch can use this information to enter power-saving modes that require additional time to resume normal opera-
tion. LPI signaling also informs the switch when the link partner has sent such an indication. The definition of LPI sig-
naling uses of the MAC for simplified full duplex operation (with carrier sense deferral). This provides full duplex
operation but uses the carrier sense signal to defer transmission when the PHY is in the LPI mode.
The decision on when to signal LPI (LPI request) to the link partner is made by the switch and communicated to the PHY
through MAC MII interface. The switch is also informed when the link partner is signaling LPI, indication of LPI activation
(LPI indication) on the MAC interface. The conditions under which switch decides to send LPI, and what actions are
taken by switch when it receives LPI from the link partner, are specified in implementation section.

3.4.5.2 LPI Assertion

Without LPI assertion, the normal traffic transition continues on the MII interface. As soon as an LPI request is asserted,
the LPI assert function starts to transmit the “Assert LPI” encoding on the MII and stop the MAC from transmitting normal
traffic. Once the LPI request is de-asserted, the LPI assert function starts to transmit the normal inter-frame encoding
on the MII again. After a delay, the MAC is allowed to start transmitting again. This delay is provided to allow the link
partner to prepare for normal operation. Figure 3-6 illustrates the EEE LPI between two active data idles.

3.4.5.3 LPI Detection

In the absence of “Assert LPI” encoding on the receive MII, the LPI detect function maps the receive MII signals as nor-
mal conditions. At the start of LPI, indicated by the transition from normal inter-frame encoding to the “Assert LPI” encod-
ing on the receive MII, the LPI detect function continues to indicate idle on interface, and asserts LP_IDLE indication.
At the end of LPI, indicated by the transition from the “Assert LPI” encoding to any other encoding on the receive MII,
LP_IDLE indication is de-asserted and the normal decoding operation resumes.

3.4.5.4 PHY LPI Transmit Operation

When the PHY detects the start of “Assert LPI” encoding on the MII, the PHY signals sleep to its link partner to indicate
that the local transmitter is entering LPI mode. The EEE capability requires the PHY transmitter to go quiet after sleep
is signaled. LPI requests are passed from one end of the link to the other and system energy savings can be achieved
even if the PHY link does not go into a low power mode.
The transmit function of the local PHY is periodically enabled in order to transmit refresh signals that are used by the
link partner to update adaptive filters and timing circuits. This maintains link integrity. This quiet-refresh cycle continues
until the reception of the normal inter-frame encoding on the MII. The transmit function in the PHY communicates this
to the link partner by sending a wake signal for a predefined period of time. The PHY then enters the normal operating
state. No data frames are lost or corrupted during the transition to or from the LPI mode.
In 100BT/full-duplex EEE operation, refresh transmission are used to maintain link and the quiet periods are used for
the power saving. Approximately, every 20 ms to 22 ms a refresh of 200 µs to 220 µs is sent to the link partner. The
refresh transmission and quiet periods are shown in Figure 3-6.

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 KSZ8795CLX

FIGURE 3-6: TRAFFIC ACTIVITY AND EEE LPI OPERATIONS

ACTIVE LOW POWER ACTIVE

REFRESH

REFRESH
SLEEP

WAKE
DATA/

DATA/
IDLE

IDLE

IDLE
QUIET QUIET QUIET

Ts Tq Tr Tw_PHY

Tw_SYSTEM

Ts = THE PERIOD OF TIME THAT THE PHY TRANSMITS THE SLEEP SIGNAL BEFORE TURNING ALL TRANSMITTERS OFF, 200 ≤ Ts ≤ 220 USED IN 100BASE-TX.
Tq = THE PERIOD OF TIME THAT THE PHY REMAINS QUIET BEFORE SENDING THE REFRESH SIGNAL, 20_000 ≤ Tq ≤ 22_000 USED IN 100BASE-TX.
Tr = DURATION OF THE REFRESH SIGNAL, 200 ≤ Tr ≤ 220 USED IN 100BASE-TX.

3.4.5.5 PHY LPI Receive Operation

On receive, entering the LPI mode is triggered by the reception of a sleep signal from the link partner, which indicates
that the link partner is about to enter the LPI mode. After sending the sleep signal, the link partner ceases transmission.
When the receiver detects the sleep signal, the local PHY indicates “Assert LPI” on the MII and the local receiver can
disable some functionality to reduce power consumption. The link partner periodically transmits refresh signals that are
used by the local PHY. This quiet-refresh cycle continues until the link partner initiates transition back to normal mode
by transmitting the wake signal for a predetermined period of time controlled by the LPI assert function. This allows the
local receiver to prepare for normal operation and transition from the “Assert LPI” encoding to the normal inter-frame
encoding on the MII. After a system specified recovery time, the link supports the nominal operational data rate.

3.4.5.6 Negotiation with EEE Capability

The EEE capability shall be advertised during the Auto-Negotiation stage. Auto-Negotiation provides a linked device
with the capability to detect the abilities supported by the device at the other end of the link, determine common abilities,
and configure for joint operation. Auto-Negotiation is performed at power up or reset, on command from management,
due to link failure, or due to user intervention.
During Auto-Negotiation, both link partners indicate their EEE capabilities. EEE is supported only if during Auto-Nego-
tiation both the local device and link partner advertise the EEE capability for the resolved PHY type. If EEE is not sup-
ported, all EEE functionality is disabled and the LPI client does not assert LPI. If EEE is supported by both link partners
for the negotiated PHY type, then the EEE function can be used independently in either direction.

3.4.6 WAKE-ON-LAN (WOL)

Wake-on-LAN (WoL) allows a computer to be turned on or woken up by a network message. The message is usually
sent by a program executed on another computer on the same local area network. Wake-up frame events are used to
wake the system whenever meaningful data is presented to the system over the network. Examples of meaningful data
include the reception of a Magic Packet™, a management request from a remote administrator, or simply network traffic
directly targeted to the local system. The KSZ8795CLX can be programmed to notify the host of the wake-up frame
detection with the assertion of the interrupt signal (INTR_N) or assertion of the power management event signal (PME).
The PME control is by PME indirect registers.
KSZ8795CLX MAC supports the detection of the following wake-up events:
• Detection of energy signal over a pre-configured value: Port PME Control Status Register Bit[0] in PME indirect
registers.
• Detection of a link-up in the network link state: Port PME Control Status Register Bit[1] in the PME indirect regis-
ters.
• Receipt of a Magic Packet: Port PME Control Status Register Bit[2] in the PME indirect registers.

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KSZ8795CLX
There are also other types of wake-up events that are not listed here as manufacturers may choose to implement these
in their own ways.

3.4.6.1 Direction of Energy

The energy is detected from the cable and is continuously presented for a time longer than pre-configured value, espe-
cially when this energy change may impact the level at which the system should re-enter to the normal power state.

3.4.6.2 Direction of Link-Up

Link status wake events are useful to indicate a linkup in the network’s connectivity status.

3.4.6.3 Magic Packet

The Magic Packet is a broadcast frame containing anywhere within its payload 6 bytes of all 1s (FF FF FF FF FF FF)
followed by sixteen repetitions of the target computer's 48-bit DA MAC address. Since the magic packet is only scanned
for the above string, and not actually parsed by a full protocol stack, it may be sent as any network- and transport-layer
protocol.
Magic Packet technology is used to remotely wake up a sleeping or powered off PC on a LAN. This is accomplished by
sending a specific packet of information, called a Magic Packet frame, to a node on the network. When a PC capable
of receiving the specific frame goes to sleep, it enables the Magic Packet RX mode in the LAN controller, and when the
LAN controller receives a Magic Packet frame, it will alert the system to wake up. Once the KSZ8795CLX has been
enabled for Magic Packet Detection in Port PME Control Mask Register Bit[2] in the PME indirect register, it scans all
incoming frames addressed to the node for a specific data sequence, which indicates to the controller this is a Magic
Packet frame.
A Magic Packet frame must also meet the basic requirements for the LAN technology chosen, such as source address
(SA), destination address (DA), which may be the receiving station’s IEEE MAC address, or a multicast or broadcast
address and CRC. The specific sequence consists of 16 duplications of the MAC address of this node, with no breaks
or interruptions. This sequence can be located anywhere within the packet, but must be preceded by a synchronization
stream. The synchronization stream is defined as 6 bytes of 0xFF. The device will also accept a broadcast frame, as
long as the 16 duplications of the IEEE address match the address of the machine to be awakened.
Example of Magic Packet:
If the IEEE address for a particular node on a network is 11h 22h, 33h, 44h, 55h, 66h, the LAN controller would be scan-
ning for the data sequence (assuming an Ethernet frame):
DA - SA - TYPE - FF FF FF FF FF FF - 11 22 33 44 55 66 -11 22 33 44 55 66-11 22 33 44 55 66 - 11 22 33 44 55 66 -
11 22 33 44 55 66 - 11 22 33 44 55 66 - 11 22 33 44 55 66 - 11 22 33 44 55 66 - 11 22 33 44 55 66 -11 22 33 44 55 66
- 11 22 33 44 55 66 - 11 22 33 44 55 66 - 11 22 33 44 55 66 - 11 22 3344 55 66 - 11 22 33 44 55 66 - 11 22 33 44 55 66
-MISC-CRC.
There are no further restrictions on a Magic Packet frame. For instance, the sequence could be in a TCP/IP packet or
an IPX packet. The frame may be bridged or routed across the network without affecting its ability to wake-up a node
at the frame’s destination. If the scans do not find the specific sequence shown above, it discards the frame and takes
no further action. If the KSZ8795CLX detects the data sequence, however, it then alerts the PC’s power management
circuitry (assert the PME pin) to wake-up the system.

3.4.7 INTERRUPT (INT_N/PME_N)

INT_N is an interrupt signal that is used to inform the external controller that there has been a status update in the
KSZ8795CLX interrupt status register. Bits [3:0] of Register 125 are the interrupt mask control bits to enable and disable
the conditions for asserting the INT_N signal. Bits [3:0] of Register 124 are the interrupt status bits to indicate which
interrupt conditions have occurred. The interrupt status bits are cleared after reading those bits in the Register 124.
PME_N is an optional PME interrupt signal that is used to inform the external controller that there has been a status
update in the KSZ8795CLX interrupt status register. Bits [4] of Register 125 are the PME mask control bits to enable
and disable the conditions for asserting the PME_N signal. Bits [4] of Register 124 are the PME interrupt status bits to
indicate which PME interrupt conditions have occurred. The PME interrupt status Bit[4] is cleared after reading this bit
of the Register 124.
Additionally, the interrupt pins of INT_N and PME_N eliminate the need for the processor to poll the switch for status
change.

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 KSZ8795CLX
3.5 Interfaces
The KSZ8795CLX device incorporates a number of interfaces to enable it to be designed into a standard network envi-
ronment as well as a vendor unique environment. The available interfaces are summarized in Table 3-4. The detail of
each usage in this table is provided in the sections that follow.

TABLE 3-4: AVAILABLE INTERFACES

Registers
Interface Type Usage
Accessed
SPI Configuration and [As Slave Serial Bus] - External CPU or controller can R/W all All
Register Access internal registers thru this interface.
MIIM Configuration and MDC/MDIO capable CPU or controllers can R/W 4 PHYs reg- PHYs Only
Register Access isters.
GMII Data Flow Interface to the Port 5 GMAC using the standard GMII timing. N/A
MII Data Flow Interface to the Port 5 GMAC using the standard MII timing. N/A
RGMII Data Flow Interface to the Port 5 GMAC using the faster reduced GMII N/A
timing.
RMII Data Flow Interface to the Port 5 GMAC using the faster reduced MII N/A
timing.
3.5.1 CONFIGURATION INTERFACE

3.5.1.1 SPI Slave Serial Bus Configuration

The KSZ8795CLX can also act as an SPI slave device. Through the SPI, the entire feature set can be enabled, including
“VLAN,” “IGMP snooping,” “MIB counters,” etc. The external SPI master device can access any registers randomly in
the data sheet shown. The SPI mode can configure all the desired settings including indirect registers and tables.
KSZ8795 default is in the ‘start switch’ mode with the register 1 bit [0] =’1’, to disable the switch, write a "0" to Register
1 bit [0].
Two standard SPI commands are supported (00000011 for “READ DATA,” and 00000010 for “WRITE DATA”). To speed
configuration time, the KSZ8795CLX also supports multiple reads or writes. After a byte is written to or read from the
KSZ8795CLX, the internal address counter automatically increments if the SPI slave select signal (SPIS_N) continues
to be driven low. If SPIS_N is kept low after the first byte is read, the next byte at the next address will be shifted out on
SPIQ. If SPIS_N is kept low after the first byte is written, bits on the master out slave input (SPID) line will be written to
the next address. Asserting SPIS_N high terminates a read or write operation. This means that the SPIS_N signal must
be asserted high and then low again before issuing another command and address. The address counter wraps back
to zero once it reaches the highest address. Therefore the entire register set can be written to or read from by issuing
a single command and address.
The KSZ8795CLX is able to support SPI bus up to a maximum of 50 MHz. A high-performance SPI master is recom-
mended to prevent internal counter overflow.
To use the KSZ8795CLX SPI:
1. At the board level, connect the KSZ8795CLX pins as detailed in Table 3-5.
2. Configure the serial communication to SPI slave mode by pulling down pin SPIQ with a pull-down resistor.
3. Write configuration data to registers using a typical SPI write data cycle as shown in Figure 3-7 or SPI multiple
write as shown in Figure 3-8. Note that data input on SDA is registered on the rising edge of SCL clock.
4. Registers can be read and the configuration can be verified with a typical SPI read data cycle as shown in
Figure 3-7 or a multiple read as shown in Figure 3-8. Note that read data is registered out of SPIQ on the falling
edge of SCL clock.
TABLE 3-5: SPI CONNECTIONS
KSZ8795CLX Signal Name Microprocessor Signal Description
SPIS_N (S_CS) SPI Slave Select
SCL (S_CLK) SPI Clock
SDA (S_DI) Master Output. Slave Input.
SPIQ (S_DO) Master Input. Slave Output.

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KSZ8795CLX

FIGURE 3-7: SPI ACCESS TIMING

S_CS
S_CS

S_CLK
S_CLK

S_DI
S_DI 0 1 0 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 TR D7 D6 D5 D4 D3 D2 D1 D0

S_DO
S_DO
Write
WRITE WRITE
Write Address WRITE
Write Data
Command
COMMAND ADDRESS DATA

A) SPI Write Cycle

A) SPI WRITE CYCLE

S_CS
S_CS

S_CLK
S_CLK

S_DI
S_DI 0 1 1 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 TR

S_DO D7 D6 D5 D4 D3 D2 D1 D0
S_DO
Read
READ ReadREAD
Address READ
Read Data
Command
COMMAND ADDRESS DATA

B)B)
SPI Read
SPI Cycle
READ CYCLE

FIGURE 3-8: SPI MULTIPLE ACCESS TIMING

S_CS
S_CS

S_CLK

S_DI
S_DI 0 1 0 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 TR D7 D6 D5 D4 D3 D2 D1 D0

S_DO
S_DO
Write
WRITE WRITE
Write Address WRITE
Write Byte 1
Command
COMMAND ADDRESS BYTE 1
S_CS
S_CS

S_CLK

S_DI
S_DI D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0

WRITE
Write Byte 2 WRITE
Write Byte N
BYTE 2 BYTE N
A) SPI Multiple Write Cycle
A) SPI MULTIPLE WRITE CYCLE

S_CS
S_CS

S_CLK

S_DI
S_DI 0 1 1 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 TR

S_DO
S_DO D7 D6 D5 D4 D3 D2 D1 D0
Read ReadREAD
Address ReadREAD
Byte 1
READ
Command
COMMAND ADDRESS BYTE 1
S_CS
S_CS

S_CLK
S_CLK

S_DO
S_DO D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0

Read Byte 2
READ Read Byte N
READ
BYTE 2 BYTE N
B) SPI Multiple Read Cycle
B) SPI MULTIPLE READ CYCLE

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 KSZ8795CLX
3.5.1.2 MII Management Interface (MIIM)
The KSZ8795CLX supports the standard IEEE 802.3 MII management interface, also known as the management data
input/output (MDIO) interface. This interface allows upper-layer devices to monitor and control the states of the
KSZ8795CLX. An external device with MDC/MDIO capability is used to read the PHY status or configure the PHY set-
tings. Further details on the MIIM interface are found in the IEEE 802.3u Specification.
The MIIM interface consists of the following:
• A physical connection that incorporates the data line MDIO and the clock line MDC.
• A specific protocol that operates across the aforementioned physical connection that allows an external controller
to communicate with the KSZ8795CLX device.
• Access to a set of eight 16-bit registers, consisting of 8 standard MIIM Registers [0:5h], 1d and 1f MIIM registers
per port.
The MIIM interface MDC/MDIO can operate up to a maximum clock speed of 25 MHz MDC clock.
Table 3-6 depicts the MII management interface frame format.

TABLE 3-6: MII MANAGEMENT INTERFACE FRAME FORMAT (Note 3-1)

Read/ PHY REG
Start of
Preamble Write Address Address TA Data Bits[15:0] Idle
Frame
OP Code Bits[4:0] Bits[4:0]
Read 32 1s 01 10 AAAAA RRRRR Z0 DDDDDDDD_DDDDDDDD Z
Write 32 1s 01 01 AAAAA RRRRR 10 DDDDDDDD_DDDDDDDD Z
Note 3-1 Preamble – Consists of 32 1s
Start-of-Frame – The start-of-frame is indicated by a “01” pattern. This pattern assures transitions
from the default logic one line state to zero and back to one.
Read/Write OP Code – The operation code for a read transaction is “10”, while the operation code
for a write transaction is 01.
PHY Address Bits[4:0] – The PHY address is five bits, allowing 32 unique PHY addresses. The first
PHY address bit transmitted and received is the MSB of the address.
REG Address Bits[4:0] – The register address is five bits, allowing 32 individual registers to be
addressed within each PHY. The first register address bit transmitted and received is the MSB of the
address.
TA (Turnaround) – The turnaround time is 2-bit time spacing between the register address field and
the data field of a frame to avoid contention during a read transaction. For a read transaction, both
the master and the PHYs shall remain in a high-impedance state for the first bit time of the
turnaround. The PHY shall drive a zero bit during the second bit time of the turnaround of a read
transaction. During a write transaction, the master shall drive a one bit for the first bit time of the
turnaround and a zero bit for the second bit time of the turnaround.
Data Bits[15:0] – The data field is 16 bits. The first data bit transmitted and received shall be Bit[15]
of the register being addressed.
At the beginning of each transaction, the master device shall send a sequence of 32 contiguous logic 1 bits on MDIO
with 32 corresponding cycles on MDC as clock to provide device with a pattern that it can use to establish synchroniza-
tion. Device starts respond to any transaction only after observes a sequence of 32 contiguous one bits on MDIO with
32 corresponding cycles on MDC.
The MIIM interface does not have access to all the configuration registers in the KSZ8795CLX. It can only access the
standard MIIM register (see the MIIM Registers section). The SPI interface, on the other hand, can be used to access
all registers with the entire KSZ8795CLX feature set.

3.5.2 SWITCH PORT 5 GMAC INTERFACE

The KSZ8795CLX GMAC5 interface supports the GMII/MII/RGMII/RMII four interfaces protocols and shares one set of
input/output signals. The purpose of this interface is to provide a simple, inexpensive, and easy-to implement intercon-
nection between the GMAC/MAC sub layer and a GPHY/PHY. Data on these interfaces are framed using the IEEE
Ethernet standard. As such it consists of a preamble, start of frame delimiter, Ethernet headers, protocol-specific data
and a cyclic redundancy check (CRC) checksum.
Transmit and receive signals for GMII/MII/RGMII/RMII interfaces shown in Table 3-7.

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KSZ8795CLX
TABLE 3-7: SIGNALS OF GMII/RGMII/MII/RMII
Direction Type GMII RGMII MII RMII
Input (Output) GTXC GTXC TXC REFCLKI
Input TXER — TXER —
Input TXEN TXD_CTL TXEN TXEN
Input (Output) COL — COL —
Input TXD[7:0] TXD[3:0] TXD[3:0] TXD[1:0]
Input (Output) GRXC GRXC RXC RXC
Output RXER — RXER RXER
Output RXDV RXD_CTL RXDV CRS_DV
Input (Output) CRS — CRS —
Output RXD[7:0] RXD[3:0] RXD[3:0] RXD[1:0]
3.5.2.1 Standard GMII/MII Interface
For MII and GMII, the interface is capable of supporting 10/100 Mbps and 1000 Mbps operation. Data and delimiters
are synchronous to clock references. It provides independent four-/eight-bit-wide transmit and receive data paths and
uses signal levels, two media status signals are provided. The CRS indicates the presence of carrier, and the COL indi-
cates the occurrence of a collision. Both half- and full-duplex operations are provided by MII and full-duplex operation
is used for GMII.
The GMII is based on the MII. MII signal names have been retained and the functions of most signals are the same, but
additional valid combinations of signals have been defined for 1000 Mbps operation. The GMII supports only 1000 Mbps
operation. Operation at 10 Mbps and 100 Mbps is supported by the MII interface.
The MII transfers data using 4-bit words (nibble) in each direction. It is clocked at 2.5/25 MHz to achieve 10/100 Mbps
speed. The GMII transfers data using 8-bit words (nibble) in each direction, clocked at 125 MHz to achieve 1000 Mbps
speed.

3.5.2.2 Reduced Gigabit Media Independent Interface (RGMII)

RGMII is intended to be an alternative to the IEEE802.3u MII and the IEEE802.3z GMII. The principle objective is to
reduce the number of pins required to interconnect the GMAC and the GPHY in a cost effective and technology inde-
pendent manner. In order to accomplish this objective, the data paths and all associated control signals will be reduced
and control signals will be multiplexed together and both edges of the clock will be used. For Gigabit operation, the
clocks will operate at 125 MHz with the rising edge and falling edge to latch the data.

3.5.2.3 Reduced Media Independent Interface (RMII)

The reduced media independent interface (RMII) specifies a low pin count media independent interface (MII). The
KSZ8795CLX supports the RMII interface on the Port 5 GMAC5 and provides the following key characteristics:
• Supports 10 Mbps and 100 Mbps data rates.
• Uses a single 50 MHz clock reference (provided internally or externally): in internal mode, the chip provides a ref-
erence clock from the RXC5 to the opposite clock input pin for RMII interface. In external mode, the chip receives
50 MHz reference clock from an external oscillator or opposite RMII interface.
• Provides independent 2-bit wide (bi-bit) transmit and receive data paths.

3.5.2.4 Port 5 GMAC5 SW5-MII Interface

Table 3-8 shows two connection methods.
1. The first is an external MAC connecting in SW5-MII PHY mode.
2. The second is an external PHY connecting in SW5-MII MAC mode.
The MAC mode or PHY mode setting is determined by the strap pin 62 LED2_1.

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 KSZ8795CLX
TABLE 3-8: PORT 5 SW5-MII CONNECTION
MAC-to-MAC Connection MAC-to-PHY Connection
KSZ8795CLX SW5-MII PHY Mode KSZ8795CLX SW5-MII MAC Mode

KSZ8795CLX Description KSZ8795CLX

External MAC SW5-MII Type External PHY SW5-MII Type
Signals Signals
MTXEN TXEN5 Input Transmit MTXEN RXDV5 Output
Enable
MTXER TXER5 Input Transmit Error MTXER RXER5 Output
MTXD[3:0] TXD5[3:0] Input Transmit Data MTXD[3:0] RXD5[3:0] Output
Bit[3:0]
MTXC TXC5 Output Transmit Clock MTXC RXC5 Input
MCOL COL5 Output Collision MCOL COL5 Input
Detection
MCRS CRS5 Output Carrier Sense MCRS CRS5 Input
MRXDV RXDV5 Output Receive Data MRXDV TXEN5 Input
Valid
MRXER RXER5 Output Receive Error MRXER TXER5 Input
MRXD[3:0] RXD5[3:0] Output Receive Data MRXD[3:0] TXD5[3:0] Input
Bit[3:0]
MRXC RXC5 Output Receive Clock MRXC TXC5 Input
The MII interface operates in either MAC mode or PHY mode. These interfaces are nibble-wide data interfaces, so they
run at one-quarter the network bit rate (not encoded). Additional signals on the transmit side indicate when data is valid
or when an error occurs during transmission. Likewise, the receive side has indicators that convey when the data is valid
and without physical layer errors. For half-duplex operation, there is a COL signal that indicates a collision has occurred
during transmission.
Note: Normally MRXER would indicate a receive error coming from the physical layer device. MTXER would indi-
cate a transmit error from the MAC device. These signals are not appropriate for this configuration. For PHY
mode operation with an external MAC, if the device interfacing with the KSZ8795CLX has an MRXER pin,
it can be tied low. For MAC mode operation with an external PHY, if the device interfacing with the KSZ8795-
CLX has an MTXER pin, it can be tied low.

3.5.2.5 Port 5 GMAC5 SW5-GMII Interface

Table 3-9 shows two GMII connection methods when connected to an external GMAC or GPHY.
• The first is an external GMAC connecting in SW5-GMII GPHY mode.
• The second is an external GPHY connecting in SW5-GMII GMAC mode.
The GMAC mode or GPHY mode setting is determined by the strap Pin 62 LED2_1.

TABLE 3-9: PORT 5 SW5-GMII CONNECTION

GMAC-to-GMAC Connection GMAC-to-GPHY Connection
KSZ8795CLX SW5-GMII GPHY Mode KSZ8795CLX SW5-GMII GMAC Mode

KSZ8795CLX Description KSZ8795CLX

External External
SW5-GMII Type SW5-GMII Type
GMAC GPHY
Signals Signals
MTXEN TXEN5 Input Transmit MTXEN RXDV5 Output
Enable
MTXER TXER5 Input Transmit Error MTXER RXER5 Output
MTXD[7:0] TXD5[7:0] Input Transmit Data MTXD[7:0] RXD5[7:0] Output
Bits[7:0]
MGTXC GTXC5 Input Transmit Clock MGTXC GRXC5 Output

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KSZ8795CLX
TABLE 3-9: PORT 5 SW5-GMII CONNECTION (CONTINUED)
GMAC-to-GMAC Connection GMAC-to-GPHY Connection
KSZ8795CLX SW5-GMII GPHY Mode KSZ8795CLX SW5-GMII GMAC Mode

KSZ8795CLX Description KSZ8795CLX

External External
SW5-GMII Type SW5-GMII Type
GMAC GPHY
Signals Signals
MCOL COL5 Output Collision MCOL COL5 Input
Detection
MCRS CRS5 Output Carrier Sense MCRS CRS5 Input
MRXDV RXDV5 Output Receive Data MRXDV TXEN5 Input
Valid
MRXER RXER5 Output Receive Error MRXER TXER5 Input
MRXD[7:0] RXD5[7:0] Output Receive Data MRXD[7:0] TXD5[7:0] Input
Bits[7:0]
MGRXC GRXC5 Output Receive Clock MGRXC GTXC5 Input

The Port 5 GMAC5 SW5-GMII interface operates at up to 1000 Mbps. In 1Gbps mode, GMII supports the full-duplex
only. The GMII interface is 8-bits data in each direction. Additional signals on the transmit side indicate when data is
valid or when an error occurs during transmission. Likewise, the receive side has indicators that convey when the data
is valid and without physical layer errors. For half-duplex operation in 10/100 Mbps mode, there is a COL signal that
indicates a collision has occurred during transmission.

3.5.2.6 Port 5 GMAC5 SW5-RGMII Interface

Table 3-10 shows the RGMII reduced connections when connecting to an external GMAC or GPHY.

TABLE 3-10: PORT 5 SW5-RGMII CONNECTION

KSZ8795CLX SW5-RGMII Connection

KSZ8795CLX SW5-RGMII Description

External GMAC/GPHY Type
Signals
MRX_CTL TXD5_CTL Input Transmit Control
MRXD[3:0] TXD5[3:0] Input Transmit Data Bit[3:0]
MRX_CLK GTX5_CLK Input Transmit Clock
MTX_CLK RXD5_CTL Output Receive Control
MTXD[3:0] RXD5[3:0] Output Receive Data Bit[3:0]
MGTX_CLK GRXC5 Output Receive Clock
The RGMII interface operates at up to a 1000 Mbps speed rate. Additional transmit and receive signals control the dif-
ferent direction of the data transfer. This RGMII interface supports RGMII Rev 2.0 with adjustable ingress clock and
egress clock delay by the Register 86 (0x56).
For RGMII to correctly configure with the connection partner, Register 86 (0x56) bits [4:3] need to be set up correctly. A
configuration table is found in Table 3-11.

TABLE 3-11: PORT 5 SW5-RGMII CLOCK DELAY CONFIGURATION WITH CONNECTION

PARTNER
Connection Partner
KSZ8795CLX RGMII Clock Mode KSZ8795CLX RGMII
KSZ8795CLX RGMII Clock
Register 86 Bits[4:3] (Receive and Clock Delay/Slew
Register 86 (0x56) Configuration
Configuration Transmit) Configuration
(Note 3-1)
Bit[4:3] = 11 Mode Ingress Clock Input Bit[4] = 1 Delay No Delay
Egress Clock Output Bit[3] = 1 Delay No Delay
Bit[4:3] = 10 Mode Ingress Clock Input Bit[4] = 1 Delay No Delay
Egress Clock Output Bit[3] = 1 No Delay Delay

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TABLE 3-11: PORT 5 SW5-RGMII CLOCK DELAY CONFIGURATION WITH CONNECTION
PARTNER (CONTINUED)
Connection Partner
KSZ8795CLX RGMII Clock Mode KSZ8795CLX RGMII
KSZ8795CLX RGMII Clock
Register 86 Bits[4:3] (Receive and Clock Delay/Slew
Register 86 (0x56) Configuration
Configuration Transmit) Configuration
(Note 3-1)
Bit[4:3] = 01 Mode Ingress Clock Input Bit[4] = 0 (default) No Delay Delay
Egress Clock Output Bit[3] = 0 (default) Delay No Delay
Bit[4:3] = 00 Mode Ingress Clock Input Bit[4] = 0 No Delay Delay
Egress Clock Output Bit[3] = 0 No Delay Delay
Note 3-1 Processor with RGMII, an external GPHY or KSZ8795CLX back-to-back connection.
For example, two KSZ8795 devices are the back-to-back connection. If one device set bit[4:3] =’11’, another one should
set Bit[4:3] = ‘00’. If one device set Bit[4:3] =’01’, another one should set Bit[4:3] = ‘01’ too.
The RGMII mode is configured by the strap-in pin LED3 [1:0] =’11’ (default) or Register 86 (0x56) bits[1:0] = ‘11’ (default).
The speed choice is by the strap-in pin LED1_0 or Register 86 (0x56) Bit[6], the default speed is 1Gbps with bit[6] = 1’,
set bit[6] = ‘0’ is for 10/100 Mbps speed in RGMII mode. KSZ8795CLX provides Register 86 bits[4:3] with the adjustable
clock delay and Register 164 bits[6:4] with the adjustable drive strength for best RGMII timing on board level in 1Gbps
mode.

3.5.2.7 Port 5 GMAC5 SW5-RMII Interface

The RMII specifies a low pin count MII. The KSZ8795CLX supports RMII interface on Port 5 and provides the following
key characteristics:
• Supports 10 Mbps and 100 Mbps data rates.
• Uses a single 50 MHz clock reference (provided internally or externally): In internal mode, the chip provides a ref-
erence clock from the RXC5 pin to the opposite clock input pin for RMII interface when Port 5 RMII is set to clock
mode.
• In external mode, the chip receives 50 MHz reference clock on the TXC5/REFCLKI5 pin from an external oscilla-
tor or opposite RMII interface when the device is set to normal mode.
• Provides independent 2-bit wide (bi-bit) transmit and receive data paths.
For the details of SW5-RMII (Port 5 GMAC5 RMII) signal connection, see Table 3-12.
When the device is strapped to normal mode, the reference clock comes from the TXC5/REFCLKI5 pin and will be used
as the device’s clock source. Set the strap pin LED1_1 can select the device’s clock source either from the TXC5/REF-
CLKI5 pin or from an external 25 MHz crystal/oscillator clock on the XI/XO pin.
In internal mode, when using an internal 50 MHz clock as SW5-RMII reference clock, the KSZ8795CLX port 5 should
be set to clock mode by the strap pin LED2_1 or the port Register 86 bit[7]. The clock mode of the KSZ8795CLX device
will provide the 50 MHz reference clock to the port 5 RMII interface.
In external mode, when using an external 50 MHz clock source as SW5-RMII reference clock, the KSZ8795CLX port 5
should be set to normal mode by the strap pin LED2_1 or the port Register 86 bit[7]. The normal mode of the KSZ8795-
CLX device will start to work when it receives the 50 MHz reference clock on the TXC5/REFCLKI5 pin from an external
50 MHz clock source.

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TABLE 3-12: PORT 5 SW5-RMII CONNECTION
SW5-RMII MAC-to-MAC Connection SW5-RMII MAC-to-PHY Connection
(PHY Mode) (MAC Mode)

KSZ8795CLX Description KSZ8795CLX

External MAC SW5-RMII Type External PHY SW5-RMII Type
Signals Signals
Input 50 MHz
Output 50 MHz Reference
REF_CLKI RXC5 50 MHz REFCLKI5 in Normal
in Clock Mode Clock
Mode
Carrier Sense/
RXDV5/
CRS_DV Output Receive Data CRS_DV TXEN5 Input
CRSDV5
Valid
— — — Receive Error RXER TXER5 Input
Receive Data
RXD[1:0] RXD5[1:0] Output RXD[1:0] TXD5[1:0] Input
Bit[1:0]
Transmit Data RXDV5/
TX_EN TXEN5 Input TX_EN Output
Enable CRSDV5
Transmit Data
TXD[1:0] TXD5[1:0] Input TXD[1:0] RXD[1:0] Output
Bit[1:0]
Input 50 MHz
Reference Output 50 MHz
50 MHz REFCLKI5 in Normal REF_CLKI RXC5
Clock in Clock Mode
Mode

3.6 Advanced Functionality

3.6.1 QOS PRIORITY SUPPORT
The KSZ8795CLX provides quality-of-service (QoS) for applications such as VoIP and video conferencing. The
KSZ8795CLX offers one, two, or four priority queues per port by setting the Port Control 13 Registers Bit[1] and the Port
Control 0 Registers Bit[0], the 1/2/4 queues split as follows:
• [Port Control 9 Registers Bit[1], Control 0 Bit[0]] = 00 Single output queue as default.
• [Port Control 9 Registers Bit[1], Control 0 Bit[0]] = 01 Egress port can be split into two priority transmit queues.
• [Port Control 9 Registers Bit[1], Control 0 Bit[0]] = 10 Egress port can be split into four priority transmit queues.
The four priority transmit queue is a new feature in the KSZ8795CLX. Queue 3 is the highest priority queue and queue
0 is the lowest priority queue. The Port Control 9 Registers Bit[1] and the Port Control 0 Registers Bit[0] are used to
enable split transmit queues for Ports 1, 2, 3, 4 and 5, respectively. If a Port's transmit queue is not split, high priority
and low priority packets have equal priority in the transmit queue.
There is an additional option to either always deliver high priority packets first or to use programmable weighted fair
queuing for the four priority queue scale by the Port Control 14, 15, 16 and 17 Registers (default values are 8, 4, 2, 1
by their bits [6:0]).
Register 130 Bit[7:6] Prio_2Q[1:0] is used when the 2-Queue configuration is selected. These bits are used to map the
2-bit result of IEEE 802.1p from the Registers 128, 129 or TOS/DiffServ mapping from Registers 144-159 (for 4 Queues)
into 2-Queue mode with priority high or low.
Please see the descriptions of Register 130 bits [7:6] for detail.

3.6.1.1 Port-Based Priority

With port-based priority, each ingress port is individually classified as a priority 0-3 receiving port. All packets received
at the priority 3 receiving port are marked as high-priority and are sent to the high-priority transmit queue if the corre-
sponding transmit queue is split. The Port Control 0 Registers bits [4:3] is used to enable port-based priority for ports 1,
2, 3, 4 and 5, respectively.

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3.6.1.2 802.1p-Based Priority
For 802.1p-based priority, the KSZ8795CLX examines the ingress (incoming) packets to determine whether they are
tagged. If tagged, the 3-bit priority field in the VLAN tag is retrieved and compared against the “priority mapping” value,
as specified by the Registers 128 and 129, both Register 128 and 129 can map 3-bit priority field of 0-7 value to 2-bit
result of 0-3 priority levels. The “priority mapping” value is programmable.
Figure 3-9 illustrates how the 802.1p priority field is embedded in the 802.1Q VLAN tag.

FIGURE 3-9: 802.1P PRIORITY FIELD FORMAT

The 802.1p-based priority is enabled by Bit[5] of the Port Control 0 Registers for ports 1, 2, 3, 4 and 5, respectively.
The KSZ8795CLX provides the option to insert or remove the priority tagged frame's header at each individual egress
port. This header, consisting of the two-byte VLAN Protocol ID (VPID) and the two-byte tag control information field
(TCI), is also referred to as the IEEE 802.1Q VLAN tag.
Tag insertion is enabled by bit[2] of the Port Control 0 Registers and the Port Control 8 Registers to select which source
port (ingress port) PVID can be inserted on the egress port for ports 1, 2, 3, 4 and 5, respectively. At the egress port,
untagged packets are tagged with the ingress port’s default tag. The default tags are programmed in the port control 3
and control 4 Registers for ports 1, 2, 3, 4 and 5, respectively. The KSZ8795CLX will not add tags to already tagged
packets.
Tag removal is enabled by Bit[1] of the Port Control 0 Registers for Ports 1, 2, 3, 4 and 5, respectively. At the egress
port, tagged packets will have their 802.1Q VLAN tags removed. The KSZ8795CLX will not modify untagged packets.
The CRC is recalculated for both tag insertion and tag removal.
802.1p priority field re-mapping is a QoS feature that allows the KSZ8795CLX to set the “User Priority Ceiling” at any
ingress port by the Port Control 2 Register Bit[7]. If the ingress packet’s priority field has a higher priority value than the
default tag’s priority field of the ingress port, the packet’s priority field is replaced with the default tag’s priority field.

3.6.1.3 DiffServ-Based Priority

DiffServ-based priority uses the ToS registers (Registers 144 to 159) in the “Advanced Control Registers” sub-section.
The ToS priority control registers implement a fully decoded, 128-bit differentiated services code point (DSCP) register
to determine packet priority from the 6-bit ToS field in the IP header. When the most significant six bits of the ToS field
are fully decoded, 64 code points for DSCP result. These are compared with the corresponding bits in the DSCP register
to determine priority.

3.6.2 SPANNING TREE SUPPORT

Port 5 is the designated port for spanning tree support.
The other ports (Port 1 - Port 4) can be configured in one of the five spanning tree states via the “transmit enable,”
“receive enable,” and “learning disable” register settings in Registers 18, 34, 50, and 66 for Ports 1, 2, 3, and 4, respec-
tively. The following description shows the port setting and software actions taken for each of the five spanning tree
states.

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KSZ8795CLX
The KSZ8795CLX supports common spanning tree (CST). To support spanning tree, the host port (Port 5) is the des-
ignated port for the processor. The other ports can be configured in one of the five spanning tree states via “transmit
enable”, “receive enable” and “learning disable” register settings in: Port Control 2 Registers. Table 3-13 shows the port
setting and software actions taken for each of the five spanning tree states.

TABLE 3-13: PORT SETTING AND SOFTWARE ACTIONS FOR SPANNING TREE
Disable State Port Setting Software Action
The port should not "Transmit enable = 0, The processor should not send any packets to the port. The switch
forward or receive Receive enable = 0, may still send specific packets to the processor (packets that match
any packets. Learn- Learning disable = 1." some entries in the static table with “overriding bit” set) and the pro-
ing is disabled. cessor should discard those packets.
Note: Processor is connected to Port 5 via MII interface. Address
learning is disabled on the port in this state.
Blocking State Port Setting Software Action
Only packets to the "Transmit enable = 0, The processor should not send any packets to the port(s) in this state.
processor are for- Receive enable = 0, The processor should program the static MAC table with the entries
warded. Learning is Learning disable = 1" that it needs to receive (e.g., BPDU packets). The “overriding” bit
disabled. should also be set so that the switch will forward those specific pack-
ets to the processor. Address learning is disabled on the port in this
state.
Listening State Port Setting Software Action
Only packets to and "Transmit enable = 0, The processor should program the static MAC table with the entries
from the processor Receive enable = 0, that it needs to receive (e.g. BPDU packets). The “overriding” bit
are forwarded. Learning disable = 1. should be set so that the switch will forward those specific packets to
Learning is disabled. the processor. The processor may send packets to the port(s) in this
state (see “Tail Tagging Mode” section for details). Address learning is
disabled on the port in this state.
Learning State Port Setting Software Action
Only packets to and “Transmit enable = 0, The processor should program the static MAC table with the entries
from the processor Receive enable = 0, that it needs to receive (e.g., BPDU packets). The “overriding” bit
are forwarded. Learning disable = 0.” should be set so that the switch will forward those specific packets to
Learning is enabled. the processor. The processor may send packets to the port(s) in this
state (see “Tail Tagging Mode” section for details). Address learning is
enabled on the port in this state.
Forwarding State Port Setting Software Action
Packets are for- “Transmit enable = 1, The processor should program the static MAC table with the entries
warded and received Receive enable = 1, that it needs to receive (e.g., BPDU packets). The “overriding” bit
normally. Learning is Learning disable = 0.” should be set so that the switch will forward those specific packets to
enabled. the processor. The processor may send packets to the port(s) in this
state (see “Tail Tagging Mode” section for details). Address learning is
enabled on the port in this state.

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 KSZ8795CLX
3.6.3 RAPID SPANNING TREE SUPPORT
There are three operational states of the discarding, learning, and forwarding assigned to each port for RSTP. Discard-
ing ports do not participate in the active topology and do not learn MAC addresses. Ports in the learning states learn
MAC addresses, but do not forward user traffic. Ports in the forwarding states fully participate in both data forwarding
and MAC learning. RSTP uses only one type of BPDU called RSTP BPDUs. They are similar to STP configuration
BPDUs with the exception of a type field set to “version 2” for RSTP and “version 0” for STP, and flag field carrying addi-
tional information.

TABLE 3-14: PORT SETTING AND SOFTWARE ACTIONS FOR RAPID SPANNING TREE
Disable State Port Setting Software Action
The state includes "Transmit enable = 0, The processor should not send any packets to the port. The switch
three states of the Receive enable = 0, may still send specific packets to the processor (packets that match
disable, blocking and Learning disable = 1." some entries in the static table with “overriding bit” set) and the pro-
listening of STP. cessor should discard those packets. When disable the port’s learning
capability (learning disable = ’1’), set the Register 1 Bit[5] and Bit[4]
will flush rapidly with the port-related entries in the dynamic MAC
table and static MAC table.
Note: Processor is connected to Port 5 via MII interface. Address
learning is disabled on the port in this state.
Learning State Port Setting Software Action
Only packets to and “Transmit enable = 0, The processor should program the static MAC table with the entries
from the processor Receive enable = 0, that it needs to receive (e.g., BPDU packets). The “overriding” bit
are forwarded. Learning disable = 0.” should be set so that the switch will forward those specific packets to
Learning is enabled. the processor. The processor may send packets to the port(s) in this
state (see “Tail Tagging Mode” section for details). Address learning is
enabled on the Port in this state.
Forwarding State Port Setting Software Action
Packets are for- “Transmit enable = 1, The processor should program the static MAC table with the entries
warded and received Receive enable = 1, that it needs to receive (e.g., BPDU packets). The “overriding” bit
normally. Learning is Learning disable = 0.” should be set so that the switch will forward those specific packets to
enabled. the processor. The processor may send packets to the port(s) in this
state (see “Tail Tagging Mode” section for details). Address learning is
enabled on the port in this state.
3.6.4 TAIL TAGGING MODE
The tail tag is only seen and used by the Port 5 interface, which should be connected to a processor by the SW5-GMII,
RGMII, MII, or RMII interfaces. One byte tail tagging is used to indicate the source/destination port on Port 5. Only bits
[3:0] are used for the destination in the tail tagging byte. Other bits are not used. The tail tag feature is enabled by setting
Register 12 Bit[1].

FIGURE 3-10: TAIL TAG FRAME FORMAT

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KSZ8795CLX
TABLE 3-15: TAIL TAG RULES
Ingress to Port 5 (Host to KSZ8795CLX)

Bits[3:0] Destination
0,0,0,0 Reserved
0,0,0,1 Port 1 (Direct forward to Port 1)
0,0,1,0 Port 2 (Direct forward to Port 2)
0,1,0,0 Port 3 (Direct forward to Port 3)
1,0,0,0 Port 4 (Direct forward to Port 4)
1,1,1,1 Port 1, 2, 3, and 4 (direct forward to Port 1, 2, 3, 4)
Bits[7:4] —
0,0,0,0 Queue 0 is used at destination port
0,0,0,1 Queue 1 is used at destination port
0,0,1,0 Queue 2 is used at destination port
0,0,1,1 Queue 3 is used at destination port
0,1,x,x Anyhow send packets to specified port in Bits[3:0]
1,x,x,x Bits[6:0] will be ignored as normal (address look-up)
Egress from Port 5 (KSZ8795CLX to Host)
Bits[1:0] Source
0,0 Port 1 (Packets from Port 1)
0,1 Port 2 (Packets from Port 2)
1,0 Port 3 (Packets from Port 3)
1,1 Port 4 (Packets from Port 4)
3.6.5 IGMP SUPPORT
There are two components involved with the support of the Internet group management protocol (IGMP) in Layer 2. The
first part is IGMP snooping, the second part is this IGMP packet which is sent back to the subscribed port. Those com-
ponents are as follows.

3.6.5.1 IGMP Snooping

The KSZ8795CLX traps IGMP packets and forwards them only to the processor (Port 5 SW5-RGMII/MII/RMII). The
IGMP packets are identified as IP packets (either Ethernet IP packets, or IEEE 802.3 SNAP IP packets) with IP version
= 0x4 and protocol version number = 0x2. Set Register 5 Bit[6] to ‘1’ to enable IGMP snooping.

3.6.5.2 IGMP Send Back to the Subscribed Port

Once the host responds to the received IGMP packet, the host should know the original IGMP ingress port and send
back the IGMP packet to this port only, to avoid this IGMP packet being broadcast to all ports which will downgrade the
performance.
With the tail tag mode enabled, the host will know the port which IGMP packet has been received from tail tag bits [1:0]
and can send back the response IGMP packet to this subscribed port by setting bits [3:0] in the tail tag. Enable tail tag
mode by setting Register 12 Bit[1].

3.6.6 IPV6 MLD SNOOPING

The KSZ8795CLX traps IPv6 multicast listener discovery (MLD) packets and forwards them only to the processor
(Port 5). MLD snooping is controlled by Register 164 Bit[2] (MLD snooping enable) and Register 164 Bit[3] (MLD option).
With MLD snooping enabled, the KSZ8795CLX traps packets that meet all of the following conditions:
• IPv6 multicast packets
• Hop count limit = 1
• IPv6 next header = 1 or 58 (or = 0 with hop-by-hop next header = 1 or 58) If the MLD option bit is set to “1”, the
KSZ8795CLX traps packets with the following additional condition:
- IPv6 next header = 43, 44, 50, 51, or 60 (or = 0 with hop-by-hop next header = 43, 44, 50, 51, or 60)

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 KSZ8795CLX
For MLD snooping, tail tag mode also needs to be enabled, so that the processor knows which port the MLD packet was
received on. This is achieved by setting Register 12 Bit[1].

3.6.7 PORT MIRRORING SUPPORT

The KSZ8795CLX supports “port mirror” as described in the following:

3.6.7.1 “Receive Only” Mirror on a Port

All the packets received on the port will be mirrored on the sniffer port. For example, Port 1 is programmed to be “RX
sniff,” and Port 5 is programmed to be the “sniffer port”. A packet, received on Port 1, is destined to Port 4 after the
internal look-up. The KSZ8795CLX will forward the packet to both Port 4 and Port 5. KSZ8795CLX can optionally for-
ward even “bad” received packets to Port 5.

3.6.7.2 “Transmit Only” Mirror on a Port

All the packets transmitted on the port will be mirrored on the Sniffer Port. For example, Port 1 is programmed to be “TX
sniff,” and Port 5 is programmed to be the “sniffer port”. A packet, received on any of the Ports, is destined to Port 1 after
the internal look-up. The KSZ8795CLX will forward the packet to both Ports 1 and 5.

3.6.7.3 “Receive and Transmit” Mirror on Two Ports

All the packets received on Port A and transmitted on Port B will be mirrored on the sniffer port. To turn on the “AND”
feature, set Register 5 bit[0] to Bit[1]. For example, Port 1 is programmed to be “RX sniff,” Port 2 is programmed to be
“TX sniff,” and Port 5 is programmed to be the “sniffer port”. A packet, received on Port 1, is destined to Port 4 after the
internal look-up. The KSZ8795CLX will forward the packet to Port 4 only because it does not meet the “AND” condition.
A packet, received on Port 1, is destined to Port 2 after the internal look-up. The KSZ8795CLX will forward the packet
to both Port 2 and Port 5.
Multiple ports can be selected to be “RX sniffed” or “TX sniffed.” Any port can be selected to be the “sniffer port.” All
these per port features can be selected through the Port Control 1 Register.

3.6.8 VLAN SUPPORT

The KSZ8795CLX supports 128 active VLANs and 4096 possible VIDs specified in IEEE 802.1q. The KSZ8795CLX
provides a 128-entry VLAN table, which correspond to 4096 possible VIDs and converts to FID (7 bits) for address look-
up max 128 active VLANs. If a non-tagged or null-VID-tagged packet is received, then the ingress port VID is used for
look-up when 802.1q is enabled by the global Register 5 control 3 Bit[7]. In the VLAN mode, the look-up process starts
from VLAN table look-up to determine whether the VID is valid. If the VID is not valid, the packet will then be dropped
and its address will not be learned. If the VID is valid, FID is retrieved for further look-up by the static MAC table or
dynamic MAC table. FID+DA is used to determine the destination port.
Table 3-16 describes the different actions in different situations of DA and FID+DA in the static MAC table and dynamic
MAC table after the VLAN table finishes a look-up action. FID+SA is used for learning purposes. Table 3-17 also
describes learning in the dynamic MAC table when the VLAN table has done a look-up in the static MAC table without
a valid entry.

TABLE 3-16: FID+DA LOOK-UP IN VLAN MODE

DA Found in FID+DA Found in
Static MAC Use FID Flag? FID Match? Dynamic MAC Action
Table? Table?
No Don’t Care Don’t Care No Broadcast to the membership ports
defined in the VLAN Table Bits[11:7].
No Don’t Care Don’t Care Yes Send to the destination port defined in
the Dynamic MAC Address Table
Bits[58:56].
Yes 0 Don’t Care Don’t Care Send to the destination port(s) defined
in the Static MAC Address Table
Bits[52:48].
Yes 1 No No Broadcast to the membership ports
defined in the VLAN Table Bits[11:7].

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KSZ8795CLX
TABLE 3-16: FID+DA LOOK-UP IN VLAN MODE (CONTINUED)
DA Found in FID+DA Found in
Static MAC Use FID Flag? FID Match? Dynamic MAC Action
Table? Table?
Yes 1 No Yes Send to the destination port defined in
the Dynamic MAC Address Table
Bits[58:56].
Yes 1 Yes Don’t Care Send to the destination port(s) defined
in the Static MAC Address Table
bits[52:48].
TABLE 3-17: FID+SA LOOK-UP IN VLAN MODE
FID+SA Found in Dynamic MAC
Action
Table?
No The FID+SA will be learned into the dynamic table.
Yes Time stamp will be updated.
Advanced VLAN features are also supported in KSZ8795CLX, such as “VLAN ingress filtering” and “discard non PVID”
defined in bits [6:5] of the Port Control 2 Register. These features can be controlled on a per port basis.

3.6.9 RATE LIMITING SUPPORT

The KSZ8795CLX provides a fine resolution hardware rate limiting based on both bps (bit per second) and pps (packet
per second).
For bps, the rate step is 64 Kbps when the rate limit is less than 1Mbps rate for 100BT or 10BT, and 640 Kbps for 1000.
The rate step is 1Mbps when the rate limit is more than 1Mbps rate for 100BT or 10BT, 10 Mbps for 1000.
For pps, the rate step is 128 pps (besides the 1st one which is 64 pps) when the rate limit is less than 1Mbps rate for
100BT or 10BT, and 1280 pps (except the 1st one of 640 pps) for 1000. The rate step is 1Mbps when the rate limit is
more than 1.92 Kpps rate for 100BT or 10BT, 19.2 Kpps for 1000 (refer to Table 3-18).
The pps limiting is bounded by the bps rate for each pps setting. The mapping is shown in the 2nd column of Table 3-18.

TABLE 3-18: 10/100/1000 MBPS RATE SELECTION FOR THE RATE LIMIT
Bps Bound
Item of pps 10 Mbps 100 Mbps 1000 Mbps
(Egress Only)
7d’0 7d’0 19.2 Kpps 10 Mbps 19.2 Kpps 100 Mbps 1.92 Mpps 1000 Mbps
7d’1 - 7d’3, 6, (8x)10 1.92 Kpps 1Mbps 1.92 Kpps 1Mbps 19.2 Kpps 10 Mbps
7d’10 x code x code x code x code x code x code
7d’11 - 7d’11 - 7d’100 — 10 Mbps 1.92 Kpps 1Mbps 19.2 Kpps 10 Mbps
7d’100 x code x code x code x code
7d’101 7d’102 64 pps 64 Kbps 64 pps 64 Kbps 640 pps 640 Kbps
7d’102 7d’104 128 pps 128 Kbps 128 pps 128 Kbps 1280 pps 1280 Kbps
7d’103 7d’108 256 pps 192 Kbps 256 pps 192 Kbps 2560 pps 1920 Kbps
7d’104 7d’112 384 pps 256 Kbps 384 pps 256 Kbps 3840 pps 2560 Kbps
7d’105 7d’001 512 pps 320 Kbps 512 pps 320 Kbps 5120 pps 3200 Kbps
7d’106 7d’001 640 pps 384 Kbps 640 pps 384 Kbps 6400 pps 3840 Kbps
7d’107 7d’001 768 pps 448 Kbps 768 pps 448 Kbps 7680 pps 4480 Kbps
7d’108 7d’002 896 pps 512 Kbps 896 pps 512 Kbps 8960 pps 5120 Kbps
7d’109 7d’002 1024 pps 576 Kbps 1024 pps 576 Kbps 10240 pps 5760 Kbps
7d’110 7d’002 1152 pps 640 Kbps 1152 pps 640 Kbps 11520 pps 6400 Kbps
7d’111 7d’002 1280 pps 704 Kbps 1280 pps 704 Kbps 12800 pps 7040 Kbps
7d’112 7d’002 1408 pps 768 Kbps 1408 pps 768 Kbps 14080 pps 7680 Kbps
7d’113 7d’003 1536 pps 832 Kbps 1536 pps 832 Kbps 15360 pps 8320 Kbps

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 KSZ8795CLX
TABLE 3-18: 10/100/1000 MBPS RATE SELECTION FOR THE RATE LIMIT (CONTINUED)
Bps Bound
Item of pps 10 Mbps 100 Mbps 1000 Mbps
(Egress Only)
7d’114 7d’003 1664 pps 896 Kbps 1664 pps 896 Kbps 16640 pps 8960 Kbps
7d’115 7d’003 1792 pps 969 Kbps 1792 pps 969 Kbps 17920 pps 9690 Kbps
The rate limit is independently on the “receive side” and on the “transmit side” on a per port basis. For 10BASE-T, a rate
setting above 10 Mbps means the rate is not limited.
On the receive side, the data receive rate for each priority at each port can be limited by setting up ingress rate control
registers. On the transmit side, the data transmit rate for each queue at each port can be limited by setting up egress
rate control registers. For bps mode, the size of each frame has options to include minimum interframe gap (IFG) or
preamble byte, in addition to the data field (from packet DA to FCS).

3.6.9.1 Ingress Rate Limit

For ingress rate limiting, KSZ8795CLX provides options to selectively choose frames from all types; multicast, broad-
cast, and flooded unicast frames via bits [3:2] of the port rate limit control register. The KSZ8795CLX counts the data
rate from those selected type of frames. Packets are dropped at the ingress port when the data rate exceeds the spec-
ified rate limit or the flow control takes effect without packet dropped when the ingress rate limit flow control is enabled
by the Port Rate Limit Control Register Bit[4]. The ingress rate limiting supports the port-based, 802.1p and DiffServ-
based priorities. The port-based priority is fixed priority 0-3 selection by bits [4:3] of the Port Control 0 register. The
802.1p and DiffServ-based priority can be mapped to priority 0-3 by default of the Register 128 and 129. In the ingress
rate limit, set Register 135 Global Control 19 Bit[3] to enable queue-based rate limit if using 2-queue or 4-queue mode.
All related ingress ports and egress port should be split to two-queue or four-queue mode by the Port Control 9 and
Control 0 registers. The 4-queue mode will use Q0-Q3 for priority 0-3 by bits [6:0] of the Port Register Ingress Limit Con-
trol 1-4. The 2-queue mode will use Q0-Q1 for priority 0-1 by bits [6:0] of the port ingress limit control 1-2 registers. The
priority levels in the packets of the 802.1p and DiffServ can be programmed to priority 0-3 via the Register 128 and 129
for a re-mapping.

3.6.9.2 Egress Rate Limit

For egress rate limiting, the leaky bucket algorithm is applied to each output priority queue for shaping output traffic.
Interframe gap is stretched on a per frame base to generate smooth, non-burst egress traffic. The throughput of each
output priority queue is limited by the egress rate specified by the data rate selection table followed the egress rate limit
control registers.
If any egress queue receives more traffic than the specified egress rate throughput, packets may be accumulated in the
output queue and packet memory. After the memory of the queue or the port is used up, packet dropping or flow control
will be triggered. As a result of congestion, the actual egress rate may be dominated by flow control/dropping at the
ingress end, and may be therefore slightly less than the specified egress rate. The egress rate limiting supports the port-
based, 802.1p and DiffServ-based priorities, the port-based priority is fixed priority 0-3 selection by bits [4:3] of the Port
Control 0 register. The 802.1p and DiffServ-based priority can be mapped to priority 0-3 by default of the Register 128
and 129. In the egress rate limit, set Register 135 Global Control 19 Bit[3] for queue-based rate limit to be enabled if
using two-queue or four-queue mode. All related ingress ports and egress port should be split to 2-queue or 4-queue
mode by the Port Control 9 and Control 0 Registers. The 4-queue mode will use Q0-Q3 for priority 0-3 by bits [6:0] of
the Port Egress Limit Control 1-4 register. The 2-queue mode will use Q0-Q1 for priority 0-1 by bits [6:0] of the Port
Egress Rate Limit Control 1-2 register. The priority levels in the packets of the 802.1p and DiffServ can be programmed
to priority 0-3 by Register 128 and 129 for a re-mapping.
When the egress rate is limited, just use one queue per port for the egress port rate limit. The priority packets will be
based upon the data rate selection table (see Table 3-18). If the egress rate limit uses more than one queue per port for
the egress port rate limit, then the highest priority packets will be based upon the data rate selection table for the rate
limit exact number. Other lower priority packet rates will be limited based upon 8:4:2:1 (default) priority ratio, which is
based on the highest priority rate. The transmit queue priority ratio is programmable.
To reduce congestion, it is good practice to make sure the egress bandwidth exceeds the ingress bandwidth.

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KSZ8795CLX
3.6.9.3 Transmit Queue Ratio Programming
In transmit queues 0-3 of the egress port, the default priority ratio is 8:4:2:1. The priority ratio can be programmed by
the Port Control 10, 11, 12, and 13 registers. When the transmit rate exceeds the ratio limit in the transmit queue, the
transmit rate will be limited by the transmit queue 0-3 ratio of the Port Control 10, 11, 12, and 13 registers. The highest
priority queue will not be limited. Other lower priority queues will be limited based on the transmit queue ratio.

3.6.10 VLAN AND ADDRESS FILTERING

To prevent certain kinds of packets that could degrade the quality of the switch in applications such as voice over internet
protocol (VoIP), the switch provides the mechanism to filter and map the packets with the following MAC addresses and
VLAN IDs.
• Self-address packets
• Unknown unicast packets
• Unknown multicast packets
• Unknown VID packets
• Unknown IP multicast packets
The packets sourced from switch itself can be filtered out by enabling self-address filtering via the Global Control 18
Register Bit[6]. The self-address filtering will filter packets on the egress port; self MAC address is assigned in the Reg-
ister 104-109 MAC Address Registers 0-5.
The unknown unicast packet filtering can be enabled by the Global Control Register 15 Bit[5] and Bits[4:0] specify the
port map for forwarding.
The unknown multicast packet filtering can be enabled by the Global Control Register 16 Bit[5] and forwarding port map
is specified in Bits[4:0].
The unknown VID packet filtering can be enabled by Global Control Register 17 Bit[5] with forwarding port map specified
in Bits[4:0].
The unknown IP multicast packet filtering can be enable by Global Control Register 18 Bit[5] with forwarding port map
specified in Bits[4:0].
Those filtering above are global based.

3.6.11 802.1X PORT-BASED SECURITY

IEEE 802.1x is a port-based authentication protocol. EAPOL is the protocol normally used by the authentication process
as an uncontrolled port. By receiving and extracting special EAPOL frames, the microprocessor (CPU) can control
whether the ingress and egress ports should forward packets or not. If a user port wants service from another port
(authenticator), it must get approved by the authenticator. The KSZ8795CLX detects EAPOL frames by checking the
destination address of the frame. The destination addresses should be either a multicast address as defined in IEEE
802.1x (01-80-C2-00-00-03) or an address used in the programmable reserved multicast address domain with offset -
00-03. Once EAPOL frames are detected, the frames are forwarded to the CPU so it can send the frames to the authen-
ticator server. Eventually, the CPU determines whether the requestor is qualified or not based on its MAC_Source
addresses, and frames are either accepted or dropped.
When the KSZ8795CLX is configured as an authenticator, the ports of the switch must then be configured for authori-
zation. In an authenticator-initiated port authorization, a client is powered up or plugs into the port, and the authenticator
port sends an extensible authentication protocol (EAP) PDU to the supplicant requesting the identification of the suppli-
cant. At this point in the process, the port on the switch is connected from a physical standpoint; however, the 802.1X
process has not authorized the port and no frames are passed from the port on the supplicant into the switching fabric.
If the PC attached to the switch did not understand the EAP PDU that it was receiving from the switch, it would not be
able to send an ID and the port would remain unauthorized. In this state, the port would never pass any user traffic and
would be as good as disabled. If the client PC is running the 802.1X EAP, it would respond to the request with its con-
figured ID. This could be a user name/password combination or a certificate.
After the switch, the authenticator receives the ID from the PC (the supplicant). The KSZ8795CLX then passes the ID
information to an authentication server (RADIUS server) that can verify the identification information. The RADIUS
server responds to the switch with either a success or failure message. If the response is a success, the port will then
be authorized and user traffic will be allowed to pass through the port like any switch port connected to an access device.
If the response is a failure, the port will remain unauthorized and, therefore, unused. If there is no response from the
server, the port will also remain unauthorized and will not pass any traffic.

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 KSZ8795CLX
3.6.11.1 Authentication Register and Programming Model
The port authentication control registers define the control of port-based authentication. The per-port authentication can
be programmed in these registers. KSZ8795CLX provides three modes for implementing the IEEE 802.1x feature. Each
mode can be selected by setting the appropriate bits in the port authentication registers.
When mode control bits AUTHENCIATION_MODE = 00 (pass mode), forced-authorization is enabled and a port is
always authorized and does not require any messages from either the supplicant or the authentication server. This is
typically the case when connecting to another switch, a router, or a server, and also when connecting to clients that do
not support 802.1X. When ACL is enabled, all the packets are passed if they miss ACL rules, otherwise, ACL actions
apply.
The block mode (when AUTHENCIATION_MODE = 01) is the standard port-based authentication mode. A port in this
mode sends EAP packets to the supplicant and will not become authorized unless it receives a positive response from
the authentication server. Traffic is blocked before authentication to all of the incoming packets, upon authentication,
software will switch to pass mode to allow all the incoming packets. In this mode, the source address of incoming pack-
ets is not checked. Including the EAP address, the forwarding map of the entire reserved multicast addresses need to
be configured to be allowed to be forwarded before and after authentication in lookup table. When ACL is enabled, pack-
ets except ACL hit are blocked.
The third mode is trap mode (when AUTHENTICATION_MODE = 11'b). In this mode, all the packets are sent to CPU
port. If ACL is enabled, the missed packets would be forwarded to the CPU rather than dropped. All these per port fea-
tures can be selected through the Port Control 5 register, Bit[2] is used to enable ACL, Bits[1:0] is for the modes
selected.

3.6.12 ACL FILTERING

Access control lists (ACL) can be created to perform the protocol-independent Layer 2 MAC, Layer 3 IP, or Layer 4 TCP/
UDP ACL filtering that filters incoming Ethernet packets based on ACL rule table. The feature allows the switch to filter
customer traffic based on the source MAC address in the Ethernet header, the IP address in the IP header, and the port
number and protocol in the TCP header. This function can be performed through MAC table and ACL rule table. Besides
multicast filtering handled using entries in the static table, ACLs can be configured for all routed network protocols to
filter the packets of those protocols as the packets pass through the switch. ACLs can prevent certain traffic from enter-
ing or exiting a network.

3.6.12.1 Access Control Lists

The KSZ8795CLX offers a rule-based ACL rule table. The ACL rule table is an ordered list of access control entries.
Each entry specifies certain rules (a set of matching conditions and action rules) to permit or deny the packet access to
the switch fabric. The meaning of ‘permit’ or ‘deny’ depends on the context in which the ACL is used. When a packet is
received on an interface, the switch compares the fields in the packet against any applied ACLs to verify that the packet
has the permissions required to be forwarded, based on the conditions specified in the lists.
The filter tests the packets against the ACL entries one-by-one. Usually the first match determines whether the router
accepts or rejects packets. However, it is allowed to cascade the rules to form more robust and/or stringent requirements
for incoming packets. ACLs allow switch filter ingress traffic based on the source, destination MAC address and Ethernet
Type in the Layer 2 header, the source, and destination IP address in Layer 3 header, and port number, protocol in the
Layer 4 header of a packet.
Each list consists of three parts:
• Matching Field
• Action Field
• Processing Field
The matching field specifies the rules that each packet matches against and the action field specifies the action taken
if the test succeeds against the rules. Figure 3-11 shows the format of ACL and a description of the individual fields.

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KSZ8795CLX

FIGURE 3-11: ACL FORMAT

Matching Field
• MD [1:0]: MODE
There are three modes of operation defined in ACL. Mode 0 disables the current rule list, Mode 1 is qualification
rules for Layer 2 MAC header filtering, Mode 2 is used for Layer 3 IP address filtering and Mode 3 performs Layer
4 TCP port number/protocol filtering. While mode 0 is selected, there will be no action taken.
• ENB [1:0]: ENABLE
Enables different rules in the current list.
- When MD = 01
While ENB = 00, the 11 bits of the aggregated bit field from PM, P, RPE, RP, MM in the action field specify a
count value for packets matching the MAC address and TYPE in the matching fields.
The count unit is defined in MSB of FORWARD bit field; while = 0, µs will be used and while = 1, ms will apply.
The 2nd MSB of the FORWARD bit determines the algorithm used to generate an interrupt when the counter
terminates. When = 0, an 11-bit counter will be loaded with the count value from the ACL list and starts count-
ing down every unit of time. An interrupt will be generated when it expires, i.e., the next qualified packet has
not been received within the period specified by the value.
When = 1, the counter is incremented on every matched packet received and an interrupt is generated while
terminal count reach the count value in the ACL list, the count resets thereafter.
When ENB = 01, the MAC address bit field is participating in test; when ENB = 10, the MAC TYPE bit field is
used for test; when ENB = 11, both the MAC address and type are tested against these bit fields in the list.
- When MD = 10

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 KSZ8795CLX
If ENB = 01, the IP address and mask or IP protocol is enabled to be tested accordingly. If ENB = 10, source
and destination addresses are compared. The drop/forward decision is based on the EQ bit setting.
- When MD = 11
If ENB = 00, protocol comparison is enabled.
If ENB = 01, TCP address comparison is selected.
If ENB = 10, UDP address comparison is selected.
If ENB = 11, the sequence number of the TCP is compared.
• S/D: Source or Destination Select
- When = 0, the destination address/port is used to compare; and when = 1, the source is chosen.
• E/Q: Comparison Algorithm
- When = 0, a match if they are not equal. When = 1, a match if they are equal.
• MAC Address [47:0]
- MAC source or destination address
• TYPE [15:0]
- MAC ether type.
• IP Address [31:0]
- IP source or destination address.
• IP Mask [31:0]
- IP address mask for group address filtering.
• MAX Port [15:0], MIN Port [15:0]/Sequence Number [31:0]
- The range of TCP port number or sequence number matching.
• PC [1:0]: Port Comparison
- When = 00, the comparison is disabled; when = 01, matches either one of MAX or MIN; when = 10, a match if
the port number is in the range of MAX to MIN; and when = 11, a match if the port number is out of the range.
• PRO [7:0]
- IP Protocol to be matched.
• FME
- Flag Match Enable – When = 1, enable TCP FLAG matching.
• FLAG [5:0]
- TCP Flag to be matched.
Action Field
• PM [1:0]: Priority Mode
- When = 00, no priority is selected, the priority is determined by the QoS/Classification is used. When = 01, the
priority in P bit field is used if it is greater than QoS result. When = 10, the priority in P bit field is used if it is
smaller than QoS result. When = 11, the P bit field will replace the priority determined by QoS.
• P [2:0]
- Priority.
• RPE: Remark Priority Enable
- When = 0, no remarking is necessary. When = 1, the VLAN priority bits in the tagged packets are replaced by
RP bit field in the list.
• RP [2:0]
- Remarked priority.
• MM [1:0]: Map Mode
- When = 00, no forwarding remapping is necessary. When = 01, the forwarding map in FORWORD is OR’ed
with the Forwarding map from the look-up table. When = 10, the forwarding map in FORWORD is AND’ed
with the Forwarding map from the look-up table. When = 11, the forwarding map in FORWORD replaces the
forwarding map from the look-up table.
• FORWARD Bits[4:0]: Forwarding Port(s) - Each bit indicates the forwarding decision of one port.
Processing Field
• FRN Bits[3:0]: First Rule Number
- Assign which entry with its Action Field in 16 entries is used in the rule set.
• RULESET Bits[15:0]: Rule Set

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KSZ8795CLX
- Group of rules to be qualified, there are 16 entries rule can be assigned to a rule set per port by the two rule-
set registers. The rule table allows the rules to be cascaded. There are 16 entries in the RTB. Each entry can
be a rule on its own, or can be cascaded with other entries to form a rule set. The test result of incoming pack-
ets against rule set will be the AND’ed result of all the test result of incoming packets against the rules
included in this rule set. The action of the rule set will be the action of the first rule specified in FRN field. The
rule with higher priority will have lower index number. Or rule 0 is the highest priority rule and rule 15 is the
lowest priority. ACL rule table entry is disabled when mode bits are set to 2’b00.
A rule set (RULESET) is used to select the match results of different rules against incoming packets. These
selected match results will be AND’ed to determine whether the frame matches or not. The conditions of dif-
ferent rule sets having the same action will be OR’ed for comparison with frame fields, and the CPU will pro-
gram the same action to those rule sets that are to be OR’ed together. For matched rule sets, different rule
sets having different actions will be arbitrated or chosen based upon the first rule number (FRN) of each rule
set. The rule table will be set up with the high priority rule at the top of the table or with the smaller index.
Regardless whether the matched rule sets have the same or different action, the hardware will always com-
pare the first rule number of different rule sets to determine the final rule set and action.

3.6.12.2 DOS Attack Prevention via ACL

The ACL can provide certain detection/protection of the following denial of service (DoS) attack types based on rule
setting, which can be programmed to drop or not to drop each type of DoS packet respectively.
Example 1
When MD = 10, ENABLE = 10, setting EQ bit to 1 can determine the drop or forward packets with identical source and
destination IP addresses in IPv4/IPv6.
Example 2
When MD = 11, ENABLE = 01/10, setting EQ bit to 1 can determine the drop or forward packets with identical source
and destination TCP/UDP Ports in IPv4/IPv6.
Example 3
When MD = 11, ENABLE = 11, Sequence Number = 0, FME = 1, FMSK = 00101001, FLAG = xx1x1xx1, Setting the EQ
bit to 1 will drop/forward the all packets with a TCP sequence number equal to 0, and flag bit URG = 1, PSH = 1 and
FIN = 1.
Example 4
When MD = 11, ENABLE = 01, MAX Port = 1024, MIN Port = 0, FME = 1, FMSK = 00010010, FLAG = xxx0xx1x, Setting
the EQ bit to 1 will drop/forward the all packets with a TCP Port number ≤ 1024, and flag bit URB = 0, SYN = 1.
ACL related registers list as:
• The Register 110 (0x6E), the Register 111 (0x6F) and the ACL rule tables.

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 KSZ8795CLX
4.0 DEVICE REGISTERS
The KSZ8795CLX device has a rich set of registers available to manage the functionality of the device. Access to these
registers is via the MIIM or SPI interfaces. Figure 4-1 provides a global picture of accessibility via the various interfaces
and addressing ranges from the perspective of each interface.

FIGURE 4-1: INTERFACE AND REGISTER MAPPING

MIIM REGISTERS
PHYAD 1, 2, 3, 4
REGAD 0-5, 1D, 1F

PHY BLOCK

SWITCH CONFIG REGISTERS

00 ̢ 0xFF

17h - 4Fh 00h - FFh

SPI

The registers within the linear 0x00-0xFF address space are all accessible via the SPI interface by a CPU attached to
that bus. The mapping of the various functions within that linear address space is summarized in Table 4-1.

TABLE 4-1: MAPPING OF FUNCTIONAL AREAS WITHIN THE ADDRESS SPACE

Register
Device Area Description
Locations
0x00 - 0xFF Switch Control and Configuration Registers which control the overall functionality of the
Switch, MAC, and PHYs
0x6E - 0x6F Indirect Control Registers Registers used to indirectly address and access distinct
areas within the device.
- Management Information Base (MIB) Counters
- Static MAC Address Table
- Dynamic MAC Address Table
- VLAN Table
- PME Indirect Registers
- ACL Indirect Registers
- EEE Indirect Registers
0x70 - 0x78 Indirect Access Registers Registers used to indirectly address and access four
distinct areas within the device.
- Management Information Base (MIB) Counters
- Static MAC Address Table
- Dynamic MAC Address Table
- VLAN Table
0xA0 Indirect Byte Access Registers This indirect byte register is used to access:
- PME Indirect Registers
- ACL Indirect Registers
- EEE Indirect Registers

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KSZ8795CLX
TABLE 4-1: MAPPING OF FUNCTIONAL AREAS WITHIN THE ADDRESS SPACE (CONTINUED)
Register
Device Area Description
Locations
0x17 - 0x4F PHY1 to PHY4 MIIM Registers The same PHY registers as specified in IEEE 802.3
Mapping to Those Port Registers’ specification.
Address Range

4.1 Register Map

TABLE 4-2: DIRECT REGISTERS

Address Contents
0x00-0x01 Family ID, Chip ID, Revision ID, and start switch Registers
0x02-0x0D Global Control Registers 0 – 11
0x0E-0x0F Global Power-Down Management Control Registers
0x10-0x14 Port 1 Control Registers 0 – 4
0x15 Port 1 Authentication Control Register
0x16-0x18 Port 1 Reserved (Factory Test Registers)
0x19-0x1F Port 1 Control/Status Registers
0x20-0x24 Port 2 Control Registers 0 – 4
0x25 Port 2 Authentication Control Register
0x26-0x28 Port 2 Reserved (Factory Test Registers)
0x29-0x2F Port 2 Control/Status Registers
0x30-0x34 Port 3 Control Registers 0 – 4
0x35 Port 3 Authentication Control Register
0x36-0x38 Port 3 Registered (Factory Test Registers)
0x39-0x3F Port 3 Control/Status Registers
0x40-0x44 Port 4 Control Registers 0 – 4
0x45 Port 4 Authentication Control Register
0x46-0x48 Port 4 Reserved (Factory Test Registers)
0x49-0x4F Port 4 Control/Status Registers
0x50-0x54 Port 5 Control Registers 0 – 4
0x56-0x58 Port 5 Reserved (Factory Test Registers)
0x59-0x5F Port 5 Control/Status Registers
0x60-0x67 Reserved (Factory Testing Registers)
0x68-0x6D MAC Address Registers
0x6E-0x6F Indirect Access Control Registers
0x70-0x78 Indirect Data Registers
0x79-0x7B Reserved (Factory Testing Registers)
0x7C-0x7D Global Interrupt and Mask Registers
0x7E-0x7F ACL Interrupt Status and Control Registers
0x80-0x87 Global Control Registers 12 – 19
0x88 Switch Self-Test Control Register
0x89-0x8F QM Global Control Registers
0x90-0x9F Global TOS Priority Control Registers 0 - 15
0xA0 Global Indirect Byte Register
0xA0-0xAF Reserved (Factory Testing Registers)
0xB0-0xBE Port 1 Control Registers

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 KSZ8795CLX
TABLE 4-2: DIRECT REGISTERS (CONTINUED)
Address Contents
0xBF Reserved (Factory Testing Register): Transmit Queue Remap Base Register
0xC0-0xCE Port 2 Control Registers
0xCF Reserved (Factory Testing Register)
0xD0-0xDE Port 3 Control Registers
0xDF Reserved (Factory Testing Register)
0xE0-0xEE Port 4 Control Registers
0xEF Reserved (Factory Testing Register)
0xF0-0xFE Port 5 Control Registers
0xFF Reserved (Factory Testing Register)
TABLE 4-3: GLOBAL REGISTERS
Address Name Description Mode Default
Register 0 (0x00): Chip ID0
70 Family ID Chip family. RO 0x87
Register 1 (0x01): Chip ID1/Start Switch
74 Chip ID 0x9 = 8795 RO 0x9
31 Revision ID — RO 0x0
0 Start Switch 1 = Start the switch function of the chip. R/W 1
0 = Stop the switch function of the chip.
Register 2 (0x02): Global Control 0
7 New Back-Off Enable New Back-off algorithm designed for UNH R/W 0
1 = Enable
0 = Disable
6 Global Soft Reset Enable Global Software Reset R/W 0
1 = Enable to reset all FSM and data path (not con-
figuration).
0 = Disable reset.

Note: This reset will stop to receive packets if

it is being in the traffic. All registers keep
their configuration values.
5 Flush Dynamic MAC Flush the entire dynamic MAC table for RSTP. This R/W 0
Table bit is self- clear (SC). (SC)
1 = Trigger the flush dynamic MAC table operation.
0 = Normal operation.

Note: All the entries associated with a port

that has its learning capability being
turned off (learning disable) will be
flushed. If you want to flush the entire
table, all ports learning capability must
be turned off.

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KSZ8795CLX
TABLE 4-3: GLOBAL REGISTERS (CONTINUED)
Address Name Description Mode Default
4 Flush Static MAC Table Flush the matched entries in static MAC table for R/W 0
RSTP (SC)
1 = Trigger the flush static MAC table operation.
0 = Normal operation.

Note: The matched entry is defined as the

entry in the Forwarding ports field con-
tains a single port and MAC address
with unicast. This port, in turn, has its
learning capability being turned off
(learning disable). Per port, multiple
entries can be qualified as matched
entries.
3 Reserved N/A Don’t change RO 1
2 Reserved N/A Don’t change RO 1
1 UNH Mode 1 = The switch will drop packets with 0x8808 in the R/W 0
T/L filed, or DA = 01-80-C2-00-00-01.
0 = The switch will drop packets qualified as “flow
control” packets.
0 Link Change Age 1 = Link change from “link” to “no link” will cause R/W 0
fast aging (<800 µs) to age address table faster.
After an age cycle is complete, the age logic will
return to normal (300 ±75 seconds).

Note: If any port is unplugged, all addresses

will be automatically aged out.
Register 3 (0x03): Global Control 1
7 Reserved N/A Don’t change. RO 0
6 2KB Packet Support 1 = Enable 2KB packet support. R/W 0
0 = Disable 2KB packet support.
5 IEEE 802.3x Transmit 0 = Enables transmit flow control based on AN R/W 0
Flow Control Disable result.
1 = Will not enable transmit flow control regardless
of the AN result.
4 IEEE 802.3x Receive 0 = Enables receive flow control based on AN R/W 0
Flow Control Disable result.
1 = Will not enable receive flow control regardless
of the AN result.

Note: Bit[5] and Bit[4] default values are con-

trolled by the same pin, but they can be
programmed independently.
3 Frame Length Field 1 = Check frame length field in the IEEE packets. If R/W 0
Check the actual length does not match, the packet will be
dropped (for L/T <1500).
2 Aging Enable 1 = Enable aging function in the chip. R/W 1
0 = Disable aging function.
1 Fast-Age Enable 1 = Turn on fast aging (800 µs). R/W 0
0 Aggressive Back-Off 1 = Enable more aggressive back-off algorithm in R/W 0
Enable half duplex mode to enhance performance. This is
not in the IEEE standard.

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 KSZ8795CLX
TABLE 4-3: GLOBAL REGISTERS (CONTINUED)
Address Name Description Mode Default
Register 4 (0x04): Global Control 2
7 Unicast Port-VLAN This feature is used for port VLAN (described in R/W 1
Mismatch Discard Port Control 1 Register).
1 = All packets cannot cross VLAN boundary.
0 = Unicast packets (excluding unknown/multicast/
broadcast) can cross VLAN boundary.

Note: When mirroring is enabled, the single-

destination packets will be dropped if it’s
mirrored to another port.
6 Multicast Storm 1 = “Broadcast Storm Protection” does not include R/W 1
Protection Disable multicast packets. Only DA = FFFFFFFFFFFF
packets will be regulated.
0 = “Broadcast Storm Protection” includes
DA = FFFFFFFFFFFF and DA[40] = 1 packet.
5 Back 1 = Carrier-sense-based back pressure is selected. R/W 1
Pressure Mode 0 = Collision-based back pressure is selected.
4 Flow Control and Back 1 = Fair mode is selected. In this mode, if a flow R/W 1
Pressure Fair Mode control port and a non-flow control port talk to the
same destination port, then packets from the non-
flow control port may be dropped. This is to prevent
the flow control port from being flow controlled for
an extended period of time.
0 = In this mode, if a flow control port and a non-
flow control port talk to the same destination port,
the flow control port will be flow controlled. This
may not be “fair” to the flow control port.
3 No 1 = The switch will not drop packets when 16 or R/W 0
Excessive Collision Drop more collisions occur.
0 = The switch will drop packets when 16 or more
collisions occur.
2 Reserved N/A Don’t change. RO 0
1 Legal 1 = Enables acceptance of packet sizes up to 1536 R/W 0
Maximum Packet bytes (inclusive).
Size Check Disable 0 = 1522 bytes for tagged packets (not including
packets with STPID from CPU to Ports 1-4), 1518
bytes for untagged packets. Any packets larger
than the specified value will be dropped.
0 Reserved N/A RO 0
Register 5 (0x05): Global Control 3
7 802.1q VLAN Enable 1 = 802.1q VLAN mode is turned on. VLAN table R/W 0
needs to be set up before the operation.
0 = 802.1q VLAN is disabled.
6 IGMP Snoop Enable on 1 = IGMP Snoop enabled. All the IGMP packets will R/W 0
Switch Port 5 SW5-GMII/ be forwarded to the processor via Switch Port 5
RGMII/MII/RMII GMII/RGMII/MII/RMII interface.
Interface 0 = IGMP Snoop disabled.
51 Reserved N/A Don’t change. RO 00000

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KSZ8795CLX
TABLE 4-3: GLOBAL REGISTERS (CONTINUED)
Address Name Description Mode Default
0 Sniff Mode Select 1 = Enables Rx AND Tx sniff (both source port and R/W 0
destination port need to match).
0 = Enables Rx OR Tx sniff (Either source port or
destination port need to match).

Note: Default is used to implement Rx only

sniff.
Register 6 (0x06): Global Control 4
7 Switch SW5-MII/RMII 1 = Enable half-duplex back pressure on the switch R/W 0
Back Pressure Enable MII/RMII interface.
0 = Disable back pressure on the switch MII inter-
face.
6 Switch SW5-MII/RMII 1 = Enable MII/RMII interface half-duplex mode. R/W 0
Half-Duplex Mode 0 = Enable MII/RMII interface full-duplex mode.
5 Switch SW5-MII/RMII 1 = Enable full-duplex flow control on the switch R/W 0
Flow Control Enable MII/RMII interface.
0 = Disable full-duplex flow control on the switch
MII/RMII interface.
4 Switch SW5-MII/RMII 1 = The switch SW5-MII/RMII is in 10 Mbps mode. R/W 0
Speed 0 = The switch SW5-MII/RMII is in 100 Mbps mode.
3 Null VID Replacement 1 = Replace null VID with Port VID (12 bits). R/W 0
0 = No replacement for null VID.
20 Broadcast Storm Protec- This register, along with the next register, deter- R/W 000
tion Rate Bit[10:8] mines how many “64 byte blocks” of packet data
are allowed on an input port in a preset period. The
period is 50 ms for 100BT or 500 ms for 10BT. The
default is 1%.
Register 7 (0x07): Global Control 5
70 Broadcast Storm Protec- This register, along with the previous register, R/W 0x4A
tion Rate Bits[7:0] determines how many “64-byte blocks” of packet
data are allowed on an input port in a preset period.
The period is 50 ms for 100BT or 500 ms for 10BT.
The default is 1%.

Note: 148,800 frames/sec × 50 ms/interval ×

1% = 74 frames/interval (approx.) =
0x4A.
Register 8 (0x08): Global Control 6 MIB Control
7 Flush Counter 1 = All the MIB counter of enabled Port(s) will be R/W (SC) 0
reset to 0. This bit is self-cleared after the operation
finishes.
0 = No reset of the MIB counter.
6 Freeze Counter 1 = Enabled Port(s) will stop counting. R/W 0
0 = Enabled Port(s) will not stop counted.
5 Reserved N/A Don’t change. RO 0
40 Control Enable 1 = Enable flush and freeze for each port. R/W 0
Bit[4] is for Port 5 Flush + Freeze.
Bit[3] is for Port 4 Flush + Freeze.
Bit[2] is for Port 3 Flush + Freeze.
Bit[1] is for Port 2 Flush + Freeze.
Bit[0] is for Port 1 Flush + Freeze.
0 = Disable flush and freeze.

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 KSZ8795CLX
TABLE 4-3: GLOBAL REGISTERS (CONTINUED)
Address Name Description Mode Default
Register 9 (0x09): Global Control 7
7-0 Factory N/A Don’t Change RO 0x40
Testing
Register 10 (0x0A): Global Control 8
7-0 Factory N/A Don’t Change RO 0x00
Testing
Register 11 (0x0B): Global Control 9
7 Reserved N/A Don’t Change RO 0
6 Port 5 SW5- RMII Refer- Select the data sampling edge of the SW5- RMII R/W 0
ence Clock Edge Select reference clock:

1 = Data sampling on the negative edge of REF-

CLK.
0 = Data sampling on the positive edge of REFCLK
(default).
54 LED Mode Programmable LED output to indicate port’s activ- R/W 00
ity/status using 2 bits of the control register. LED is
ON (active) when the output is LOW; the LED is
OFF (inactive) when the output is HIGH.

LINK = LED ON; ACT = LED Blink;

LINK/ACT = LED On/Blink.
Speed = LED ON (100BT); LED OFF (10BT); LED
Blink (1000BT reserved).
Duplex = LED ON (Full duplex); LED OFF (half
duplex).
3 Reserved N/A Don’t change. RO 0
2 Reserved N/A Don’t change. RO 0
1 REFCLKO Enable 1 = Enable REFCLKO pin clock output R/W 0
0 = Disable REFCLKO pin clock output.

Strap-in option: LED2_0

PU = REFCLK_O (25 MHz) is enabled. (Default)
PD = REFCLK_O is disabled

Note: This is an additional clock; this clock

can save an oscillator if system needs
this clock source. If the system doesn’t
need this 25 MHz clock source, which
should be disabled.
0 SPI Read Sampling Select the SPI clock edge for sampling SPI read R/W 0
Clock Edge Select data.

1 = Trigger on the rising edge of SPI clock (for

higher speed SPI)
0 = Trigger on the falling edge of SPI clock.
Register 12 (0x0C): Global Control 10
76 Reserved Reserved RO 01

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KSZ8795CLX
TABLE 4-3: GLOBAL REGISTERS (CONTINUED)
Address Name Description Mode Default
52 Reserved N/A Don’t change. RO 0001
1 Tail Tag Enable Tail Tag feature is applied for Port 5 only. R/W 0

1 = Insert 1 Byte of data right before FCS.

0 = Do not insert.
0 Pass Flow Control 1 = Switch will not filter 802.3x “flow control” pack- R/W 0
Packet ets.
0 = Switch will filter 802.3x “flow control” packets.
Register 13 (0x0D): Global Control 11
7–0 Factory N/A Don’t change. RO 00000000
Testing
Register 14 (0x0E): Power-Down Management Control 1
76 Reserved N/A Don’t change. RO 00
5 PLL Power-Down Pll Power-Down Enable: R/W 0
1 = Enable
0 = Disable

Note: It occurs in the energy detect mode

(EDPD mode)
4–3 Power Management Power Management Mode : R/W 00
Mode Select 00 = Normal mode (D0) (RC)
01 = Energy detection mode (D2)
10 = Soft power-down mode (D3)
11 = Reserved

Note: RC means Read Clear.

20 Reserved N/A Don’t change. RO 000
Register 15 (0x0F): Power-Down Management Control 2
7-0 Go_Sleep_Time [7:0] When the energy-detect mode is on, this value is R/W 01010000
used to control the minimum period that the no
energy event has to be detected consecutively
before the device enters the low power state. The
unit is 20 ms. The default of go_sleep time is 1.6
seconds (80 Dec × 20 ms).

4.2 Port Registers

The following registers are used to enable features that are assigned on a per port basis. The register bit assignments
are the same for all ports, but the address for each port is different, as indicated.

TABLE 4-4: PORT REGISTERS

Address Name Description Mode Default
Register 16 (0x10): Port 1 Control 0
Register 32 (0x20): Port 2 Control 0
Register 48 (0x30): Port 3 Control 0
Register 64 (0x40): Port 4 Control 0
Register 80 (0x50): Port 5 Control 0
7 Broadcast Storm 1 = Enable broadcast storm protection for ingress R/W 0
Protection Enable packets on the port.
0 = Disable broadcast storm protection.

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 KSZ8795CLX
TABLE 4-4: PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
6 DiffServ Priority 1 = Enable DiffServ priority classification for R/W 0
Classification Enable ingress packets on port.
0 = Disable DiffServ function.
5 802.1p Priority 1 = Enable 802.1p priority classification for ingress R/W 0
Classification Enable packets on port.
0 = Disable 802.1p priority classification for ingress
packets on port.
4–3 Port-Based Priority 00 = Ingress packets on Port will be classified as R/W 00
Classification Enable priority 0 queue if “Diffserv” or “802.1p” classifica-
tion is not enabled or fails to classify.
01 = Ingress packets on port will be classified as
priority 1 queue if “Diffserv” or “802.1p” classifica-
tion is not enabled or fails to classify.
10 = Ingress packets on port will be classified as
priority 2 queue if “Diffserv” or “802.1p” classifica-
tion is not enabled or fails to classify.
11 = Ingress packets on port will be classified as
priority 3 queue if “Diffserv” or “802.1p” classifica-
tion is not enabled or fails to classify.

Note: “DiffServ”, “802.1p” and port priority can

be enabled at the same time. The
OR’ed result of 802.1p and DSCP over-
writes the Port priority.
2 Tag insertion 1 = When packets are output on the port, the switch R/W 0
will add 802.1q tags to packets without 802.1q tags
when received. The switch will not add tags to
packets already tagged. The tag inserted is the
ingress port’s “Port VID.”
0 = Disable tag insertion.
1 Tag Removal 1 = When packets are output on the port, the switch R/W 0
will remove 802.1q tags from packets with 802.1q
tags when received. The switch will not modify
packets received without tags.
0 = Disable tag removal.
0 Two Queues Split Enable This Bit[0] in Registers16/32/48/64/80 should be in R/W 0
combination with Registers177/193/209/225/241
Bit[1] for Ports 1  5. This will select the split of 1, 2,
and 4 queues:

For Port 1, Register 177 Bit[1], Register 16 Bit[0]:

11 = Reserved
10 = The port output queue is split into four priority
queues or if map 802.1p to priority 0  3 mode.
01 = The port output queue is split into two priority
queues or if map 802.1p to priority 0  3 mode.
00 = Single output queue on the port. There is no
priority differentiation even though packets are
classified into high or low priority.

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KSZ8795CLX
TABLE 4-4: PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
Register 17 (0x11): Port 1 Control 1
Register 33 (0x21): Port 2 Control 1
Register 49 (0x31): Port 3 Control 1
Register 65 (0x41): Port 4 Control 1
Register 81 (0x51): Port 5 Control 1
7 Sniffer Port 1 = Port is designated as Sniffer port and will trans- R/W 0
mit packets that are monitored.
0 = Port is a normal port.
6 Receive Sniff 1 = All the packets received on the port will be R/W 0
marked as “monitored packets” and forwarded to
the designated “Sniffer port.”
0 = No receive monitoring.
5 Transmit Sniff 1 = All the packets transmitted on the port will be R/W 0
marked as “monitored packets” and forwarded to
the designated “Sniffer port.”
0 = No transmit monitoring.
40 Port VLAN Membership Defines the port’s Port VLAN membership. R/W 0x1f
Bit[4] stands for Port 5,
Bit[3] stands for Port 4,
Bit[2] stands for Port 3,
Bit[1] stands for Port 2,
Bit[0] stands for Port 1.
The port can only communicate within the member-
ship. A ‘1’ includes a port in the membership; a ‘0’
excludes a port in the membership.
Register 18 (0x12): Port 1 Control 2
Register 34 (0x22): Port 2 Control 2
Register 50 (0x32): Port 3 Control 2
Register 66 (0x42): Port 4 Control 2
Register 82 (0x52): Port 5 Control 2
7 User Priority Ceiling 1 = If packet ‘s “user priority field” is greater than R/W 0
the “user priority field” in the port default tag regis-
ter, replace the packet’s “user priority field” with the
“user priority field” in the port default tag Register
Control 3.
0 = No replace packet’s priority filed with port
default tag priority filed of the port Control 3 Regis-
ter Bits[7:5].
6 Ingress VLAN Filtering. 1 = The switch will discard packets whose VID port R/W 0
membership in VLAN table Bits[11:7] does not
include the ingress port.
0 = No ingress VLAN filtering.
5 Discard Non-PVID 1 = The switch will discard packets whose VID R/W 0
Packets does not match ingress port default VID.
0 = No packets will be discarded.
4 Force Flow Control 1 = Enables Rx and Tx flow control on the port, R/W 0
regardless of the AN result.
0 = Flow control is enabled based on the AN result
(Default)
3 Back Pressure Enable 1 = Enable port half-duplex back pressure. R/W 0
0 = Disable port half-duplex back pressure.
2 Transmit Enable 1 = Enable packet transmission on the port. R/W 1
0 = Disable packet transmission on the port.

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 KSZ8795CLX
TABLE 4-4: PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
1 Receive Enable 1 = Enable packet reception on the port. R/W 1
0 = Disable packet reception on the port.
0 Learning Disable 1 = Disable switch address learning capability. R/W 0
0 = Enable switch address learning.
Register 19 (0x13): Port 1 Control 3
Register 35 (0x23): Port 2 Control 3
Register 51 (0x33): Port 3 Control 3
Register 67 (0x43): Port 4 Control 3
Register 83 (0x53): Port 5 Control 3
70 Default Tag [15:8] Port’s default tag, containing: R/W 0
7 5: User priority bits
4: CFI bit
3  0: VID[11:8]
Register 20 (0x14): Port 1 Control 4
Register 36 (0x24): Port 2 Control 4
Register 52 (0x34): Port 3 Control 4
Register 68 (0x44): Port 4 Control 4
Register 84 (0x54): Port 5 Control 4
70 Default Tag [7:0] Default Port 1’s tag, containing: R/W 1
7  0: VID[7:0]
Registers 19 and 20 (and those corresponding to other ports) serve two purposes:
- Associated with the ingress untagged packets and used for egress tagging.
- Default VID for the ingress untagged or null-VID-tagged packets and used for address look-up.
Register 21 (0x15): Port 1 Control 5
Register 37 (0x25): Port 2 Control 5
Register 53 (0x35): Port 3 Control 5
Register 69 (0x45): Port 4 Control 5
Register 85 (0x55): Port 5 Control 5
73 Reserved N/A Don’t change. RO 00000
2 ACL Enable 1 = Enable ACL R/W 0
0 = Disable ACL
10 AUTHENTICATION_- These bits control port-based authentication: R/W 00
MODE 00, 10 = Authentication disable, all traffic is allowed
(forced-authorized), if ACL is enabled, pass all traf-
fic if ACL missed
01 = Authentication enabled, all traffic is blocked, if
ACL is enabled, traffic is blocked if ACL missed
11 = Authentication enabled, all traffic is trapped to
CPU port, if ACL is enabled, traffic is trapped to
port 5 CPU port only if ACL missed.
Register 22 (0x16): Reserved
Register 38 (0x26): Reserved
Register 54 (0x36): Reserved
Register 70 (0x46): Reserved
Register 86 (0x56): Port 5 Interface Control 6
7 RMII_CLK_SEL Port 5 SW5-RMII Mode Select R/W 1
1 = RMII uses internal clock (clock mode)
0 = RMII uses external clock (normal mode)
Strap-in option: LED2_1
PU = SW5-RMII is in the clock mode (Default)
PD = SW5-RMII is in the normal mode.

Note: This pin has an internal pull-up

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KSZ8795CLX
TABLE 4-4: PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
6 Is_1Gbps 1 = 1Gbps is chosen for Port 5 in GMII/RGMII R/W 1
mode.
0 = 10/100 Mbps is chosen for Port 5 in GMII/
RGMII mode.
Strap-in option: LED1_0
PU = 1Gbps in SW5-GMII/RGMII mode (Default)
PD = 10/100 Mbps in SW5-GMII/RGMII mode

Note: This pin has an internal pull-up.

Use Bit[4] of the Register 6, Global Control 4 to set
for 10 or 100 speed in 10/100 Mbps mode.
5 Reserved N/A Don’t change. RO 1
4 RGMII Internal Delay (ID) Enable Ingress RGMII-ID Mode R/W 0
Ingress Enable 1 = Ingress RGMII-ID enabled. An internal
delay is added to ingress clock input.
0 = No delay is added, only clock to data
skew applied.
Note: If RGMII connection partner transmit
data to clock skew is in standard spec
±0.5 ns without delay inserted on PCB,
then set bit [4] =’1’ will enable an
ingress delay to meet the input skew
min 1ns to max 2.6 ns requirement (the
clock trace should be equal length with
data traces in PCB layout).
3 RGMII Internal Delay (ID) Enable Egress RGMII-ID Mode R/W 1
Egress Enable 1 = Egress RGMII-ID enabled. An internal
delay is added to egress clock output.
0 = No delay is added, only clock to data
skew applied.
Note: If setting bit [3] = ‘1’, RGMII transmit
clock adds an internal egress delay to
add min 1 ns data to clock skew to
receive side, then the receiving side
may or may not add any internal delay
to meet its own receiving timing require-
ment. (The clock trace should be equal
length with data traces in PCB layout if
no additional external skew on clock is
needed).

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 KSZ8795CLX
TABLE 4-4: PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
2 GMII/MII Mode Select Port 5 GMAC5 SW5-GMII/MII Mode Select R/W 1
1 = GMII/MII is in GMAC/MAC mode
(Default).
0 = GMII/MII is in GPHY/PHY mode.
Strap-in option: LED2_1
PU = GMII/MII is in GMAC/MAC mode. (Default)
PD = GMII/MII is in GPHY/PHY mode.

Note: When set GMAC5 SW5-GMII to GPHY

mode, the CRS and COL pins will
change from the input to output.
When set SW5-MII to PHY mode, the CRS, COL,
RXC and TXC pins will change from the input to
output.
10 Interface Mode Select These bits select the interface type and mode for R/W 11
Switch Port 5 (SW5).
Note: This is for Port 5 Mode Select:
port 5 SW5- 00 = MII
GMII/RGMII/ 01 = RMII
MII/RMII 10 = GMII
11 = RGMII.
Strap-in option: LED3[1:0]
00 = MII
01 = RMII
10 = GMII
11 = RGMII (Default)

Note: These pins have internal pull-ups.

Register 23 (0x17): Port 1 Control 7 (Note 4-1)
Register 39 (0x27): Port 2 Control 7
Register 55 (0x37): Port 3 Control 7
Register 71 (0x47): Port 4 Control 7
Register 87 (0x57): Reserved
76 Reserved N/A Don’t Change. RO 00
54 Advertised_Flow_Con- These bits indicate that the KSZ8795CLX has R/W 11
trol _Capability implemented both the optional MAC control sub-
layer and the PAUSE function as specified in IEEE
Clause 31 and Annex 31B for full duplex operation
independent of rate and medium.

00 = No pause
01 = Symmetric PAUSE
10 = Asymmetric PAUSE toward link partner
toward link partner
11 = Both Symmetric PAUSE and Asymmetric
PAUSE toward local devices
Bit[5] indicates that asymmetric PAUSE is sup-
ported. The value of Bit[4] when Bit[5] is set indi-
cates the direction of the PAUSE frames that are
supported for flow across the link. Asymmetric
PAUSE configuration results in independent
enabling of the PAUSE receive and PAUSE trans-
mit functions as defined by IEEE Annex 31B.

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KSZ8795CLX
TABLE 4-4: PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
3 Advertised 100BT Full- 1 = Advertise 100BT full-duplex capability. R/W 1
Duplex Capability 0 = Suppress 100BT full-duplex capability from
transmission to link partner.
2 Advertised 100BT Half- 1 = Advertise 100BT half-duplex capability. R/W 1
Duplex Capability 0 = Suppress 100BT half-duplex capability from
transmission to link partner.
1 Advertised 10BT Full- 1 = Advertise 10BT full-duplex capability. R/W 1
Duplex Capability 0 = Suppress 10BT full-duplex capability from
transmission to link partner.
0 Advertised 10BT Half- 1 = Advertise 10BT half-duplex capability. R/W 1
Duplex Capability 0 = Suppress 10BT half-duplex capability from
transmission to link partner.
Register 24 (0x18): Port 1 Status 0
Register 40 (0x28): Port 2 Status 0
Register 56 (0x38): Port 3 Status 0
Register 72 (0x48): Port 4 Status 0
Register 88 (0x58): Reserved
7-6 Reserved N/A Don’t Change. RO 0000
5-4 Partner_Flow_Control_- These bits indicate the partner capability for both RO 00
Capable the optional MAC control sub-layer and the PAUSE
function as specified in IEEE Clause 31 and Annex
31B for full duplex operation independent to rate
and medium.
00 = No pause
01 = Symmetric PAUSE
10 = Asymmetric PAUSE toward link partner
toward link partner
11 = Both Symmetric PAUSE and Asymmetric
PAUSE toward local devices
3 Partner 100BT Full- 1 = Link partner 100BT full-duplex capable. RO 0
Duplex Capability 0 = Link partner not 100BT full-duplex capable.
2 Partner 100BT Half- 1 = Link partner 100BT half-duplex capable. RO 0
Duplex Capability 0 = Link partner not 100BT half-duplex capable.
1 Partner 10BT Full- 1 = Link partner 10BT full-duplex capable. RO 0
Duplex Capability 0 = Link partner not 10BT full-duplex capable.
0 Partner 10BT Half- 1 = Link partner 10BT half-duplex capable. RO 0
Duplex Capability 0 = Link partner not 10BT half-duplex capable.
Register 25 (0x19): Port 1 Status 1 (Note 4-1)
Register 41 (0x29): Port 2 Status 1
Register 57 (0x39): Port 3 Status 1
Register 73 (0x49): Port 4 Status 1
Register 89 (0x59): Reserved
7 HP_MDIX 1 = HP Auto MDI/MDI-X Mode R/W 1
0 = Microchip Auto MDI/MDI-X Mode
6 Factory Testing N/A Don’t Change. RO 0
5 Polrvs 1 = Polarity is reversed RO 0
0 = Polarity is not reversed
4 Transmit Flow Control 1 = Transmit flow control feature is active RO 0
Enable 0 = Transmit flow control feature is inactive
3 Receive Flow Control 1 = Receive flow control feature is active RO 0
Enable 0 = Receive flow control feature is inactive

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 KSZ8795CLX
TABLE 4-4: PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
2 Operation Speed 1 = Link speed is 100 Mbps RO 0
0 = Link speed is 10 Mbps
1 Operation Duplex 1 = Link duplex is full RO 0
0 = Link duplex is half
0 Reserved N/A Don’t Change. RO 0
Register 26 (0x1A): Port 1 PHY (Note 4-1)
Control 8
Register 42 (0x2A): Port 2 PHY
Control 8
Register 58 (0x3A): Port 3 PHY
Control 8
Register 74 (0x4A): Port 4 PHY
Control 8
Register 90 (0x5A): Reserved
7 CDT 10M Short 1 = Less than 10 meter short RO 0

Note: CDT means

Cable Diag-
nostic Test
65 CDT_Result 00 = Normal condition RO 00
01 = Open condition detected in cable
10 = Short condition detected in cable
11 = Cable diagnostic test has failed
4 CDT_Enable 1 = Enable cable diagnostic test. After CDT test R/W 0
has completed, this bit will be self-cleared. (SC)
0 = Indicates that the cable diagnostic test (if
enabled) has Indicate cable diagnostic test.
3 Force_Link 1 = Force link pass R/W 0
0 = Normal Operation
2 Pwrsave 1 = Enable power saving R/W 0
0 = Disable power saving
1 Remote Loopback 1 = Perform Remote loopback, loopback on Port 1 R/W 0
as follows:
Port 1 (Reg. 26, Bit[1] = ‘1’)
Start : RXP1/RXM1 (Port 1)
Loopback: PMD/PMA of Port 1’s PHY
End: TXP1/TXM1 (Port 1)
Setting Reg. 42, 58, 74 Bit[1] = ‘1’ will perform
remote loopback on Ports 2, 3, 4.
0 = Normal Operation.
0 CDT_Fault_Count[8] Bit[8] of CDT Fault Count RO 0
Distance to the fault.
It’s approximately 0.4 × CDT_Fault_Count[8:0].
Register 27 (0x1B): Port 1 LinkMD result
Register 43 (0x2B): Port 2 LinkMD result
Register 59 (0x3B): Port 3 LinkMD result
Register 75 (0x4B): Port 4 LinkMD result
Register 91 (0x5B): Reserved
70 CDT_Fault_Count[7:0] Bits[7:0] of CDT Fault Count RO 0x00

Distance to the fault. It’s approximately 0.4m ×

CDT_Fault_Count[8:0]

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KSZ8795CLX
TABLE 4-4: PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
Register 28 (0x1C): Port 1 Control 9 (Note 4-1)
Register 44 (0x2C): Port 2 Control 9
Register 60 (0x3C): Port 3 Control 9
Register 76 (0x4C): Port 4 Control 9
Register 92 (0x5C): Reserved
7 Disable Auto-Negotiation 1 = Disable Auto-Negotiation. Speed and duplex R/W 0
are decided by bits [6:5] of the same register.
0 = Auto-Negotiation is on.
6 Forced Speed 1 = Forced 100BT if Auto-Negotiation is disabled R/W 1
(Bit[7]).
0 = Forced 10BT if Auto-Negotiation is disabled
(Bit[7]).
5 Forced Duplex 1 = Forced full-duplex if (1) AN is disabled or (2) R/W 0
AN is enabled but failed.
0 = Forced half-duplex if (1) AN is disabled or (2)
AN is enabled but failed (Default).
40 Reserved N/A Don’t Change. RO 0x1f
Register 29 (0x1D): Port 1 Control 10 (Note 4-1)
Register 45 (0x2D): Port 2 Control 10
Register 61 (0x3D): Port 3 Control 10
Register 77 (0x4D): Port 4 Control 10
Register 93 (0x5D): Reserved
7 LED Off 1 = Turn off all port’s LEDs (LEDx_2, LEDx_1, R/W 0
LEDx_0 Pins, where “x” is the port number).
These pins will be driven high if this bit is set to
one.
0 = Normal operation.
6 TXIDS 1 = Disable port’s transmitter. R/W 0
0 = Normal operation.
5 Restart AN 1 = Restart Auto-Negotiation. R/W 0
0 = Normal operation. (SC)
4 Reserved N/A Don’t Change RO 0
3 Power Down 1 = Power-down. R/W 0
0 = Normal operation.
2 Disable Auto MDI/MDI-X 1 = Disable Auto-MDI/MDIX function. R/W 0
0 = Enable Auto-MDI/MDIX function.
1 Forced MDI 1 = If Auto-MDI/MDIX is disabled, force PHY into R/W 0
MDI mode.
0 = MDI-X mode.
0 MAC Loopback 1 = Perform MAC loopback. Loop back path is as R/W 0
follows:
E.g., set Port 1 MAC Loopback (Reg. 29, Bit[0] =
(‘1’), use Port 2 as monitor port. The packets will
transfer.
Start: Port 2 receiving (also can start to receive
packets from Ports 3, 4, 5).
Loop-back: Port 1’s MAC.
End: Port 2 transmitting (also can end at Port 3, 4,
5 respectively).
Setting Reg. 45, 61, 77, 93, Bit[0] = ‘1’ will perform
MAC loopback on Port 2, 3, 4, 5 respectively.
0 = Normal Operation.

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 KSZ8795CLX
TABLE 4-4: PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
Register 30 (0x1E): Port 1 Status 2 (Note 4-1)
Register 46 (0x2E): Port 2 Status 2
Register 62 (0x3E): Port 3 Status 2
Register 78 (0x4E): Port 4 Status 2
Register 94 (0x5E): Reserved
7 MDIX Status 1 = MDI. RO 0
0 = MDI-X.
6 Auto-Negotiation Done 1 = Auto-Negotiation done. RO 0
0 = Auto-Negotiation not done.
5 Link Good 1 = Link good. RO 0
0 = Link not good.
40 Reserved N/A Don’t Change. RO 00000
Register 31 (0x1F): Port 1 Control 11 and Status 3 (Note 4-1)
Register 47 (0x2F): Port 2 Control 11 and Status 3
Register 63 (0x3F): Port 3 Control 11 and Status 3
Register 79 (0x4F): Port 4 Control 11 and Status 3
Register 95 (0x5F): Reserved
7 PHY Loopback 1 = Perform PHY loopback. Loop back path is as R/W 0
follows:
Example 
Set Port 1 PHY Loopback (Reg. 31, Bit[7] = (‘1’)
Use the Port 2 as monitor port. The packets will
transfer.
Start: Port 2 receiving (also can start from Port 3, 4,
5).
Loopback: PMD/PMA of Port 1’s PHY
End: Port 2 transmitting (also can end at Ports 3, 4,
5 respectively).
Setting Reg. 47, 63, 79, 95, Bit[7] = ‘1’ will perform
PHY loopback on Port 2, 3, 4, 5 respectively.
0 = Normal Operation.
6 Reserved N/A Don’t Change RO 0
5 PHY Isolate 1 = Electrical isolation of PHY from the internal MII R/W 0
and TX+/TX.
0 = Normal operation.
4 Soft Reset 1 = PHY soft reset. This bit is self-clearing. R/W 0
0 = Normal operation. (SC)
3 Force Link 1 = Force link in the PHY. R/W 0
0 = Normal operation
20 Port Operation Mode Indicate the current state of port operation mode: RO 001
Indication 000 = Reserved
001 = Still in Auto-Negotiation
010 = 10BASE-T half duplex
011 = 100BASE-TX half duplex
100 = Reserved
101 = 10BASE-T full duplex
110 = 100BASE-TX full duplex
111 = Reserved
Note 4-1 Port Control 7 - 11 and Port Status 1 - 3 contents can be accessed by the MDC/MDIO interface via
the standard MIIM Registers.

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KSZ8795CLX
4.3 Advanced Control Registers
Registers 104 to 109 define the switching engine’s MAC address. This 48-bit address is used as the source address in
MAC pause control frames.

TABLE 4-5: ADVANCED CONTROL REGISTERS 104 - 109

Address Name Description Mode Default
Register 104 (0x68): MAC Address Register 0
7-0 MACA[47:40] — R/W 0x00
Register 105 (0x69): MAC Address Register 1
7-0 MACA[39:32] — R/W 0x10
Register 106 (0x6A): MAC Address Register 2
7-0 MACA[31:24] — R/W 0xA1
Register 107 (0x6B): MAC Address Register 3
7-0 MACA[23:16] — R/W 0xff
Register 108 (0x6C): MAC Address Register 4
7-0 MACA[15:8] — R/W 0xff
Register 109 (0X6D): MAC Address Register 5
7-0 MACA[7:0] — R/W 0xff

Use Registers 110 and 111 to read or write data to the static MAC address table, VLAN table, dynamic address table,
PME registers, ACL tables, EEE registers and the MIB counters.

TABLE 4-6: ADVANCED CONTROL REGISTERS 110 - 111

Address Name Description Mode Default
Register 110 (0x6E): Indirect Access Control 0
7-5 EEE/ACL/ 000 = Indirect mode is used for table select in bits R/W 000
PME Indirect [3:2]. While these bits are not equal 000, bits [3:2]
Register are used for 2 additional MSB address bits.
Function 001 = Global and Port base EEE registers are
Select selected, port count is specified in 4 MSB indirect
address bits and 8 bits register pointer is specified
in 8 LSB indirect address bits.
010 = Port-base ACL registers are selected, Port
count is specified in 4 MSB indirect address bits
and register pointer is specified in 8 LSB indirect
address bits.
011 = Reserved
100 = PME control registers are selected.
101 = Reserved
4 Read High 1 = Read cycle. R/W 0
Write Low 0 = Write cycle.

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 KSZ8795CLX
TABLE 4-6: ADVANCED CONTROL REGISTERS 110 - 111 (CONTINUED)
Address Name Description Mode Default
3-2 Table Select If bits [6:5] = 00, then R/W 00
or 00 = Static MAC Address Table selected.
Indirect 01 = VLAN table selected.
Address 10 = Dynamic Address Table selected.
[11:10] 11 = MIB Counter selected.
If bits [6:5] not equal 00, then These are indirect
address [11:10] that is MSB of indirect address,
Bits[11:8] of the indirect address may be served as
port address, and Bits[7:0] as register address.

Note 1: The Register 110 Bits[3:0] are used for

the indirect address Bits[11:8] 4 MSB
bits, the four bits are used for the port
indirect registers as well.
0000 = Global indirect registers
0001 = Port 1 indirect registers
0010 = Port 2 indirect registers
0011 = Port 3 indirect registers
0100 = Port 4 indirect registers
0101= Port 5 indirect registers
2: The Register 111 Bits[7:0] are used for
the indirect address bits of 8 LSB for
indirect register address spacing.
1-0 Indirect Bits [9:8] of indirect address. R/W 00
Address [9:8]
Register 111 (0x6F): Indirect Access Control 1 (Note 4-2)
7-0 Indirect Bits[7:0] of indirect address. R/W 00000000
Address [7:0]
Note 4-2 Write to Register 111 will trigger a command. Read or write access is decided by Bit[4] of Register
110.
Indirect Data Registers 112-120 are used for table of static, VLAN, dynamic table, PME, EEE, ACL and MIB counter.

TABLE 4-7: ADVANCED CONTROL REGISTERS 112 - 120

Address Name Description Mode Default
Register 112 (0x70): Indirect Data Register 8
7-0 Indirect Data Bits[71:64] of indirect data. R/W 00000000
[71:64]
Register 113 (0x71): Indirect Data Register 7
7-0 Indirect Data Bits[63:56] of indirect data. R/W 00000000
[63:56]
Register 114 (0x72): Indirect Data Register 6
7-0 Indirect Data Bits[55:48] of indirect data. R/W 00000000
[55:48]
Register 115 (0x73): Indirect Data Register 5
7-0 Indirect Data Bits[47:40] of indirect data. R/W 00000000
[47:40]
Register 116 (0x74): Indirect Data Register 4
7-0 Indirect Data Bits[39:32] of indirect data. R/W 00000000
[39:32]

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KSZ8795CLX
TABLE 4-7: ADVANCED CONTROL REGISTERS 112 - 120 (CONTINUED)
Address Name Description Mode Default
Register 117 (0x75): Indirect Data Register 3
7-0 Indirect Data Bits[31:24] of indirect data R/W 00000000
[31:24]
Register 118 (0x76): Indirect Data Register 2
7-0 Indirect Data Bits[23:16] of indirect data. R/W 00000000
[23:6]
Register 119 (0x77): Indirect Data Register 1
7-0 Indirect Data Bits[15:8] of indirect data. R/W 00000000
[15:8]
Register 120 (0x78): Indirect Data Register 0
7-0 Indirect Data Bits[7:0] of indirect data. R/W 00000000
[7:0]

The named indirect byte registers is a direct register which is used for PME/ACL/EEE Indirect Register access only. The
Indirect Byte Register 160 (0XA0) is used for read/write to all PME, EEE, and ACL indirect registers.

TABLE 4-8: ADVANCED CONTROL REGISTERS 160, 124 - 127

Address Name Description Mode Default
Register 160 (0xA0): Indirect Byte Register (for PME, EEE, and ACL Registers)
7-0 Indirect Byte data of indirect access. R/W 00000000
Byte[7:0]
Register 124 (0x7C): Interrupt Status Register
7-5 Reserved N/A Don’t Change. RO 000
4 PME 1 = PME interrupt request RO 0
Interrupt 0 = Normal
Status
Note: This bit reflects PME control registers,
write to PME Control Register to clear
This bit is set when PME is asserted. Write a “1” to
clear this bit (WC)
3 Port 4 1 = Port 4 interrupt request R/WC 0
Interrupt 0 = Normal
Status
Note: This bit is set by Port 4 link change.
Write a “1” to clear this bit (WC)
2 Port 3 1 = Port 3 interrupt request R/WC 0
Interrupt 0 = Normal
Status
Note: This bit is set by a link change on Port
3. Write a “1” to clear this bit (WC)
1 Port 2 1 = Port 2 interrupt request R/WC 0
Interrupt 0 = Normal
Status
Note: This bit is set by a link change on Port
2. Write a “1” to clear this bit (WC)
0 Port 1 1 = Port 1 interrupt request R/WC 0
Interrupt 0 = Normal
Status
Note: This bit is set by link change on Port 1.
Write a “1” to clear this bit (WC)

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 KSZ8795CLX
TABLE 4-8: ADVANCED CONTROL REGISTERS 160, 124 - 127 (CONTINUED)
Address Name Description Mode Default
Register 125 (0x7D): Interrupt Mask Register
7-5 Reserved N/A Don’t Change. RO 000
4 PME 1 = Enable PME interrupt. R/W 0
Interrupt 0 = Normal
Mask
3 Port 4 1 = Enable Port 4 interrupt. R/W 0
Interrupt 0 = Normal
Mask
2 Port 3 1 = Enable Port 3 interrupt. R/W 0
Interrupt 0 = Normal
Mask
1 Port 2 1 = Enable Port 2 interrupt. R/W 0
Interrupt 0 = Normal
Mask
0 Port 1 1 = Enable Port 1 interrupt. R/W 0
Interrupt 0 = Normal
Mask
Register 126 (0x7E): ACL Interrupt Status Register
7-5 Reserved N/A Don’t Change. RO 000
4-0 ACL_INT_ ACL Interrupt Status, one bit per port RO 00000
STATUS 1 = ACL interrupt detected.
0 = No ACL interrupt detected.
Register 127 (0x7F): ACL Interrupt Control Register
7-5 Reserved N/A Don’t Change. RO 000
4-0 ACL_INT_ ACL Interrupt Enable, one bit per port R/W 00000
ENABLE 1 = ACL interrupt enabled.
0 = ACL interrupt disabled.

Registers 128 and 129 can be used to map from 802.1p priority field 0 - 7 to the switch’s four priority queues 0 - 3. 0x3
is the highest priority queues as Priority 3 and 0x0 is the lowest priority queues as Priority 0.

TABLE 4-9: ADVANCED CONTROL REGISTERS 128 - 129

Address Name Description Mode Default
Register 128 (0x80): Global Control 12
7-6 Tag_0x3 IEEE 802.1p mapping. The value in this field is R/W 0x1
used as the frame’s priority when its IEEE 802.1p
tag has a value of 0x3.
5-4 Tag_0x2 IEEE 802.1p mapping. The value in this field is R/W 0x1
used as the frame’s priority when its IEEE 802.1p
tag has a value of 0x2.
3-2 Tag_0x1 IEEE 802.1p mapping. The value in this field is R/W 0x0
used as the frame’s priority when its IEEE 802.1p
tag has a value of 0x1.
1-0 Tag_0x0 IEEE 802.1p mapping. The value in this field is R/W 0x0
used as the frame’s priority when its IEEE 802.1p
tag has a value of 0x0.
Register 129 (0x81): Global Control 13
7-6 Tag_0x7 IEEE 802.1p mapping. The value in this field is R/W 0x3
used as the frame’s priority when its IEEE 802.1p
tag has a value of 0x7.

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KSZ8795CLX
TABLE 4-9: ADVANCED CONTROL REGISTERS 128 - 129 (CONTINUED)
Address Name Description Mode Default
5-4 Tag_0x6 IEEE 802.1p mapping. The value in this field is R/W 0x3
used as the frame’s priority when its IEEE 802.1p
tag has a value of 0x6.
3-2 Tag_0x5 IEEE 802.1p mapping. The value in this field is R/W 0x2
used as the frame’s priority when its IEEE 802.1p
tag has a value of 0x5.
1-0 Tag_0x4 IEEE 802.1p mapping. The value in this field is R/W 0x2
used as the frame’s priority when its IEEE 802.1p
tag has a value of 0x4.

TABLE 4-10: ADVANCED CONTROL REGISTERS 130 - 135

Address Name Description Mode Default
Register 130 (0x82): Global Control 14
7-6 Pri_2Q[1:0] When the 2 Queues configuration is selected, R/W 10
these Pri_2Q[1:0] bits are used to map the 2-bit
result of IEEE 802.1p from Register 128/129 or
TOS/DiffServ from Register 144-159 mapping (for
4 Queues) into two queues low/high priorities.

2-bit result of IEEE 802.1p or TOS/DiffServ

00 (0) = Map to Low priority queue
01 (1) = Prio_2Q[0] map to Low/High priority queue
10 (2) = Prio_2Q[1] map to Low/High priority queue
11 (3) = Map to High priority queue

Pri_2Q[1:0]:
00 = Result 0,1, 2 are low priority. 3 is high priority.
01 = Not supported and should be avoided
10 = Result 0,1 are low priority. 2, 3 are high priority
(default).
11 = Result 0 is low priority. 1, 2, 3 are high priority.
5-0 Reserved N/A Don’t Change. RO 001000
Register 131 (0x83): Global Control 15
7-6 Reserved N/A Don’t Change. RO 10
5 Unknown 1 = Enable supporting unknown unicast packet for- R/W 0
Unicast ward
Packet 0 = Disable
Forward
4-0 Unknown 00000 = Filter unknown unicast packet R/W 00000
Unicast 00001 = Forward unknown unicast packet to Port 1
Packet 00011 = Forward unknown unicast packet to Port 1,
Forward Port Port 2
Pap 00111 = Forward unknown unicast packet to Port 1,
Port 2, and Port 3
01111 = Forward unknown unicast packet to Port 1,
Port 2, Port 3, and Port 4
11111 = Broadcast unknown unicast packet to all
ports
Register 132 (0x84): Global Control 16
7-6 Reserved N/A Don’t Change. RO 01

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 KSZ8795CLX
TABLE 4-10: ADVANCED CONTROL REGISTERS 130 - 135 (CONTINUED)
Address Name Description Mode Default
5 Unknown 1 = Enable supporting unknown multicast packet R/W 0
Multicast forward
Packet 0 = Disable
Forward (not
including IP
multicast
packet)
4 -0 Unknown 00000 = Filter unknown multicast packet R/W 00000
Multicast 00001 = Forward unknown multicast packet to Port
Packet 1
Forward Port 00011 = Forward unknown multicast packet to Port
Map 1, Port 2
00111 = Forward unknown multicast packet to Port
1, Port 2 and Port 3
01111 = Forward unknown multicast packet to Port
1, Port 2, Port 3 and Port 4
11111 = Broadcast unknown multicast packet to all
Ports
Register 133 (0x85): Global Control 17
7-6 Reserved N/A Don’t Change. RO 00
5 Unknown 1 = Enable supporting unknown VID packet for- R/W 0
VID Packet ward
Forward 0 = Disable
4-0 Unknown 00000 = Filter unknown VID packet R/W 00000
VID Packet 00001 = Forward unknown VID packet to Port 1
Forward Port 00011 = Forward unknown VID packet to Port 1,
Map Port 2
00111 = Forward unknown VID packet to Port 1,
Port 2 and Port 3
01111 = Forward unknown VID packet to Port 1,
Port 2, Port 3 and Port 4
11111 = Broadcast unknown VID packet to all Ports
Register 134 (0x86): Global Control 18
7 Reserved N/A Don’t Change. RO 0
6 Self-Address 1 = Enable filtering of self-address unicast and mul- R/W 0
Filter Enable ticast packet
0 = Do not filter self-address packet

Note: The self-address filtering will filter pack-

ets on the egress port, self MAC
address is assigned in the Register 104
- 109.
5 Unknown IP 1 = Enable supporting unknown IP multicast packet R/W 0
Multicast forward
Packet 0 = Disable supporting unknown IP multicast
Forward packet forward

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KSZ8795CLX
TABLE 4-10: ADVANCED CONTROL REGISTERS 130 - 135 (CONTINUED)
Address Name Description Mode Default
4-0 Unknown IP 00000 = Filter unknown IP multicast packet R/W 00000
Multicast 00001 = Forward unknown IP multicast packet to
Packet Port 1
Forward Port 00011 = Forward unknown IP multicast packet to
Map Port 1, Port 2
00111 = Forward unknown IP multicast packet to
Port 1, Port 2, and Port 3
01111 = Forward unknown IP multicast packet to
Port 1, Port 2, Port 3, and Port 4
11111 = Broadcast unknown IP multicast packet to
all ports
Register 135 (0x87): Global Control 19
7-6 Reserved N/A Don’t Change. RO 00
5-4 Ingress Rate The unit period for calculating Ingress Rate Limit: R/W 01
Limit Period 00 = 16 ms
01 = 64 ms
1x = 256 ms
3 Queue- Enable Queue-Based Egress Rate Limit R/W 0
Based 0 = Port-Based Egress Rate Limit (default)
Egress Rate 1 = Queue-Based Egress Rate Limit
Limit
Enabled
2 Insertion 1 = Enable source port PVID tag insertion or non- R/W 0
Source Port insertion option on the egress Port for each source
PVID Tag port PVID-based on the port’s Control 8 Registers.
Selection 0 = Disable, all packets from any ingress port will
Enable be inserted PVID-based on Port Control 0 Register
Bit[2].
1-0 Reserved N/A Don’t Change. RO 00
The Ipv4/Ipv6 TOS priority control registers implement a fully decoded 64-bit differentiated services code point (DSCP)
register used to determine priority from the 6-bit TOS field in the IP header. The most significant 6 bits of the TOS field
are fully decoded into 64 possibilities, and the singular code that results is mapped to the value in the corresponding bit
in the DSCP register.

TABLE 4-11: ADVANCED CONTROL REGISTERS 144 - 159

Address Name Description Mode Default
Register 144 (0x90): TOS Priority Control Register 0
7-6 DSCP[7:6] Ipv4 and Ipv6 Mapping R/W 00
The value in this field is used as the frame’s priority
when bits [7:2] of the frame’s IP OS/DiffServ/Traffic
Class value is 0x03.
5-4 DSCP[5:4] Ipv4 and Ipv6 Mapping R/W 00
The value in this field is used as the frame’s priority
when bits [7:2] of the frame’s IP OS/DiffServ/Traffic
Class value is 0x02.
3-2 DSCP[3:2] Ipv4 and Ipv6 Mapping R/W 00
The value in this field is used as the frame’s priority
when bits [7:2] of the frame’s IP OS/DiffServ/Traffic
Class value is 0x01.

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 KSZ8795CLX
TABLE 4-11: ADVANCED CONTROL REGISTERS 144 - 159 (CONTINUED)
Address Name Description Mode Default
1-0 DSCP[1:0] Ipv4 and Ipv6 Mapping R/W 00
The value in this field is used as the frame’s priority
when bits [7:2] of the frame’s IP OS/DiffServ/Traffic
Class value is 0x00.
Register 145 (0x91): TOS Priority Control Register 1
7-6 DSCP[15:14] Ipv4 and Ipv6 mapping _ for value 0x07 R/W 00
5-4 DSCP[13:12] Ipv4 and Ipv6 mapping _ for value 0x06 R/W 00
3-2 DSCP[11:10] Ipv4 and Ipv6 mapping _ for value 0x05 R/W 00
1-0 DSCP[9:8] Ipv4 and Ipv6 mapping _ for value 0x04 R/W 00
Register 146 (0x92): TOS Priority Control Register 2
7-6 DSCP[23:22] Ipv4 and Ipv6 mapping _ for value 0x0B R/W 00
5-4 DSCP[21:20] Ipv4 and Ipv6 mapping _ for value 0x0A R/W 00
3-2 DSCP[19:18] Ipv4 and Ipv6 mapping _ for value 0x09 R/W 00
1-0 DSCP[17:16] Ipv4 and Ipv6 mapping _ for value 0x08 R/W 00
Register 147 (0x93): TOS Priority Control Register 3
7-6 DSCP[31:30] Ipv4 and Ipv6 mapping _ for value 0x0F R/W 00
5-4 DSCP[29:28] Ipv4 and Ipv6 mapping _ for value 0x0E R/W 00
3-2 DSCP[27:26] Ipv4 and Ipv6 mapping _ for value 0x0D R/W 00
1-0 DSCP[25:24] Ipv4 and Ipv6 mapping _ for value 0x0C R/W 00
Register 148 (0x94): TOS Priority Control Register 4
7-6 DSCP[39:38] Ipv4 and Ipv6 mapping _ for value 0x13 R/W 00
5-4 DSCP[37:36] Ipv4 and Ipv6 mapping _ for value 0x12 R/W 00
3-2 DSCP[35:34] Ipv4 and Ipv6 mapping _ for value 0x11 R/W 00
1-0 DSCP[33:32] Ipv4 and Ipv6 mapping _ for value 0x10 R/W 00
Register 149 (0x95): TOS Priority Control Register 5
7-6 DSCP[47:46] Ipv4 and Ipv6 mapping _ for value 0x17 R/W 00
5-4 DSCP[45:44] Ipv4 and Ipv6 mapping _ for value 0x16 R/W 00
3-2 DSCP[43:42] Ipv4 and Ipv6 mapping _ for value 0x15 R/W 00
1-0 DSCP[41:40] Ipv4 and Ipv6 mapping _ for value 0x14 R/W 00
Register 150 (0x96): TOS Priority Control Register 6
7-6 DSCP[55:54] Ipv4 and Ipv6 mapping _ for value 0x1B R/W 00
5-4 DSCP[53:52] Ipv4 and Ipv6 mapping _ for value 0x1A R/W 00
3-2 DSCP[51:50] Ipv4 and Ipv6 mapping _ for value 0x19 R/W 00
1-0 DSCP[49:48] Ipv4 and Ipv6 mapping _ for value 0x18 R/W 00
Register 151 (0x97): TOS Priority Control Register 7
7-6 DSCP[63:62] Ipv4 and Ipv6 mapping _ for value 0x1F R/W 00
5-4 DSCP[61:60] Ipv4 and Ipv6 mapping _ for value 0x1E R/W 00
3-2 DSCP[59:58] Ipv4 and Ipv6 mapping _ for value 0x1D R/W 00
1-0 DSCP[57:56] Ipv4 and Ipv6 mapping _ for value 0x1C R/W 00
Register 152 (0x98): TOS Priority Control Register 8
7-6 DSCP[71:70] Ipv4 and Ipv6 mapping _ for value 0x23 R/W 00
5-4 DSCP[69:68] Ipv4 and Ipv6 mapping _ for value 0x22 R/W 00
3-2 DSCP[67:66] Ipv4 and Ipv6 mapping _ for value 0x21 R/W 00
1-0 DSCP[65:64] Ipv4 and Ipv6 mapping _ for value 0x20 R/W 00

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KSZ8795CLX
TABLE 4-11: ADVANCED CONTROL REGISTERS 144 - 159 (CONTINUED)
Address Name Description Mode Default
Register 153 (0x99): TOS Priority Control Register 9
7-6 DSCP[79:78] Ipv4 and Ipv6 mapping _ for value 0x27 R/W 00
5-4 DSCP[77:76] Ipv4 and Ipv6 mapping _ for value 0x26 R/W 00
3-2 DSCP[75:74] Ipv4 and Ipv6 mapping _ for value 0x25 R/W 00
1-0 DSCP[73:72] Ipv4 and Ipv6 mapping _ for value 0x24 R/W 00
Register 154 (0x9A): TOS Priority Control Register 10
7-6 DSCP[87:86] Ipv4 and Ipv6 mapping _ for value 0x2B R/W 00
5-4 DSCP[85:84] Ipv4 and Ipv6 mapping _ for value 0x2A R/W 00
3-2 DSCP[83:82] Ipv4 and Ipv6 mapping _ for value 0x29 R/W 00
1-0 DSCP[81:80] Ipv4 and Ipv6 mapping _ for value 0x28 R/W 00
Register 155 (0x9B): TOS Priority Control Register 11
7-6 DSCP[95:94] Ipv4 and Ipv6 mapping _ for value 0x2F R/W 00
5-4 DSCP[93:92] Ipv4 and Ipv6 mapping _ for value 0x2E R/W 00
3-2 DSCP[91:90] Ipv4 and Ipv6 mapping _ for value 0x2D R/W 00
1-0 DSCP[89:88] Ipv4 and Ipv6 mapping _ for value 0x2C R/W 00
Register 156 (0x9C): TOS Priority Control Register 12
7-6 DSCP Ipv4 and Ipv6 mapping _ for value 0x33 R/W 00
[103:102]
5-4 DSCP Ipv4 and Ipv6 mapping _ for value 0x32 R/W 00
[101:100]
3-2 DSCP[99:98] Ipv4 and Ipv6 mapping _ for value 0x31 R/W 00
1-0 DSCP[97:96] Ipv4 and Ipv6 mapping _ for value 0x30 R/W 00
Register 157 (0x9D): TOS Priority Control Register 13
7-6 DSCP Ipv4 and Ipv6 mapping _ for value 0x37 R/W 00
[111:110]
5-4 DSCP Ipv4 and Ipv6 mapping _ for value 0x36 R/W 00
[109:108]
3-2 DSCP Ipv4 and Ipv6 mapping _ for value 0x35 R/W 00
[107:106]
1-0 DSCP Ipv4 and Ipv6 mapping _ for value 0x34 R/W 00
[105:104]
Register 158 (0x9E): TOS Priority Control Register 14
7-6 DSCP Ipv4 and Ipv6 mapping _ for value 0x3B R/W 00
[119:118]
5-4 DSCP Ipv4 and Ipv6 mapping _ for value 0x3A R/W 00
[117:116]
3-2 DSCP Ipv4 and Ipv6 mapping _ for value 0x39 R/W 00
[115:114]
1-0 DSCP Ipv4 and Ipv6 mapping _ for value 0x38 R/W 00
[113:112]
Register 159 (0x9F): TOS Priority Control Register 15
7-6 DSCP Ipv4 and Ipv6 mapping _ for value 0x3F R/W 00
[127:126]
5-4 DSCP Ipv4 and Ipv6 mapping _ for value 0x3E R/W 00
[125:124]
3-2 DSCP Ipv4 and Ipv6 mapping _ for value 0x3D R/W 00
[123:122]

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 KSZ8795CLX
TABLE 4-11: ADVANCED CONTROL REGISTERS 144 - 159 (CONTINUED)
Address Name Description Mode Default
1-0 DSCP Ipv4 and Ipv6 mapping _ for value 0x3C R/W 00
[121:120]

TABLE 4-12: ADVANCED CONTROL REGISTERS 163 - 164

Address Name Description Mode Default
Register 163 (0xA3): Global Control 20
7 Reserved N/A Don’t Change. RO 0
6-4 GMII/RGMI High-Speed Interfaces Drive Strength for GMII and R/W 110
High-Speed RGMI
Drive 000 = 2 mA
Strength 001 = 4 mA
010 = 8 mA
011 = 12 mA
100 = 16 mA
101 = 20 mA
110 = 24 mA (default)
111 = 28 mA
3 Reserved N/A Don’t Change. RO 0
2-0 MII/RMII Low-Speed Interfaces Drive Strength for MII and R/W 010
Low-Speed RMII
Drive 000 = 2 mA
Strength 001 = 4 mA
010 = 8 mA (default)
011 = 12 mA
100 = 16 mA
101 = 20 mA
110 = 24 mA
111 = 28 mA
Register 164 (0xA4): Global Control 21
7-4 Reserved N/A Don’t Change. RO 0x2
3 IPv6 MLD IPv6 MLD Snooping Option R/W 0
Snooping 1 = Enable
Option 0 = Disable
2 IPv6 MLD IPv6 MLD Snooping Enable R/W 0
Snooping 1 = Enable
Enable 0 = Disable
1-0 Reserved N/A Don’t Change. RO 10

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KSZ8795CLX
TABLE 4-13: ADDITIONAL ADVANCED CONTROL REGISTERS (Note 4-1)
Address Name Description Mode Default
Register 176 (0xB0): Port 1 Control 12
Register 192 (0xC0): Port 2 Control 12
Register 208 (0xD0): Port 3 Control 12
Register 224 (0xE0): Port 4 Control 12
Register 240 (0xF0): Port 5 Control 12
7 Reserved — RO 1
6 Pass All Port-based enable to pass all frames R/W 0
Frames 1 = Enable
0 = Disable

Note: This is used in the port mirroring with

RX sniff only.
5 -4 Reserved — RO 00
3 Insert Source Register 176: Insert source Port 1 PVID for R/W 0
Port PVID for untagged frame at egress Port 5
Untagged Register 192: Insert source Port 2 PVID for
Packet Desti- untagged frame at egress Port 5
nation to Register 208: Insert source Port 3 PVID for
Highest untagged frame at egress Port 5
Egress Port Register 224: Insert source Port 4 PVID for
untagged frame at egress Port 5
Register 240: Insert source Port 5 PVID for
untagged frame at egress Port 4

Note: Enabled by the Register 135 Bit[2].

2 Insert Source Register 176: Insert source Port 1 PVID for R/W 0
Port PVID for untagged frame at egress Port 4
Untagged Register 192: Insert source Port 2 PVID for
Packet Desti- untagged frame at egress Port 4
nation to Register 208: Insert source Port 3 PVID for
Second untagged frame at egress Port 4
Highest Register 224: Insert source Port 4 PVID for
Egress Port untagged frame at egress Port 3
Register 240: Insert source Port 5 PVID for
untagged frame at egress Port 3

Note: Enabled by the Register 135 Bit[2].

1 Insert Source Register 176: Insert source Port 1 PVID for R/W 0
Port PVID for untagged frame at egress Port 3
Untagged Register 192: Insert source Port 2 PVID for
Packet Desti- untagged frame at egress Port 3
nation to Register 208: Insert source Port 3 PVID for
Second Low- untagged frame at egress Port 2
est Egress Register 224: Insert source Port 4 PVID for
Port untagged frame at egress Port 2
Register 240: Insert source Port 5 PVID for
untagged frame at egress Port 2

Note: Enabled by the Register 135 Bit[2].

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 KSZ8795CLX
TABLE 4-13: ADDITIONAL ADVANCED CONTROL REGISTERS (Note 4-1) (CONTINUED)
Address Name Description Mode Default
0 Insert Source Register 176: Insert source Port 1 PVID for R/W 0
Port PVID for untagged frame at egress Port 2
Untagged Register 192: Insert source Port 2 PVID for
Packet Desti- untagged frame at egress Port 1
nation to Register 208: Insert source Port 3 PVID for
Lowest untagged frame at egress Port 1
Egress Port Register 224: Insert source Port 4 PVID for
untagged frame at egress Port 1
Register 240: Insert source Port 5 PVID for
untagged frame at egress Port 1

Note: Enabled by the Register 135 Bit[2].

Register 177 (0xB1): Port 1 Control 13
Register 193 (0xC1): Port 2 Control 13
Register 209 (0xD1): Port 3 Control 13
Register 225 (0xE1): Port 4 Control 13
Register 241 (0xF1): Port 5 Control 13
7-2 Reserved — RO 000000
1 4 Queue Split This bit, in combination with Register16/32/48/64/ R/W 0
Enable 80 Bit[0], will select the split of 1, 2, and 4 queues:

{Register 177 Bit[1], Register 16 Bit[0] = }:

11 = Reserved.
10 = The port output queue is split into four priority
queues or if map 802.1p to priority 0-3 mode.
01 = The port output queue is split into two priority
queues or if map 802.1p to priority 0-3 mode.
00 = Single output queue on the port. There is no
priority differentiation even though packets are
classified into high and low priority.
0 Enable Drop- 0 = Disable tagged packets drop R/W 0
ping Tag 1 = Enable tagged packets drop
Register 178 (0xB2): Port 1 Control 14
Register 194 (0xC2): Port 2 Control 14
Register 210 (0xD2): Port 3 Control 14
Register 226 (0xE2): Port 4 Control 14
Register 242 (0xF2): Port 5 Control 14
7 Enable Port 0 = Strict priority, will transmit all the packets from R/W 1
Transmit this priority queue 3 before transmit lower priority
Queue 3 queue.
Ratio 1 = Bits[6:0] reflect the packet number allow to
transmit from this priority queue 3 within a certain
time.
6-0 Port Trans- Packet number for Transmit Queue 3 for highest R/W 0001000
mit Queue 3 priority packets in four queues mode.
Ratio[6:0]

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KSZ8795CLX
TABLE 4-13: ADDITIONAL ADVANCED CONTROL REGISTERS (Note 4-1) (CONTINUED)
Address Name Description Mode Default
Register 179 (0xB3): Port 1 Control 15
Register 195 (0xC3): Port 2 Control 15
Register 211 (0xD3): Port 3 Control 15
Register 227 (0xE3): Port 4 Control 15
Register 243 (0xF3): Port 5 Control 15
7 Enable Port 0 = Strict priority, will transmit all the packets from R/W 1
Transmit this priority queue 2 before transmit lower priority
Queue 2 queue.
Ratio 1 = Bits[6:0] reflect the packet number allow to
transmit from this priority queue 1 within a certain
time.
6-0 Port Trans- Packet number for Transmit Queue 2 for high/low R/W 0000100
mit Queue 2 priority packets in high/low priority packets in four
Ratio[6:0] queues mode.
Register 180 (0xB4): Port 1 Control 16
Register 196 (0xC4): Port 2 Control 16
Register 212 (0xD4): Port 3 Control 16
Register 228 (0xE4): Port 4 Control 16
Register 244 (0xF4): Port 5 Control 16
7 Enable Port 0 = Strict priority, will transmit all the packets from R/W 1
Transmit this priority queue 1 before transmit lower priority
Queue 1 queue.
Rate 1 = Bits[6:0] reflect the packet number allow to
transmit from this priority queue 1 within a certain
time.
6-0 Port Trans- Packet number for Transmit Queue 1 for low-/high- R/W 0000010
mit Queue 1 priority packets in four queues mode and high-pri-
Ratio[6:0] ority packets in two queues mode.
Register 181 (0xB5): Port 1 Control 17
Register 197 (0xC5): Port 2 Control 17
Register 213 (0xD5): Port 3 Control 17
Register 229 (0xE5): Port 4 Control 17
Register 245 (0xF5): Port 5 Control 17
7 Enable Port 0 = Strict priority, will transmit all the packets from R/W 1
Transmit this priority queue 0 before transmit lower priority
Queue 0 queue.
Rate 1 = Bits[6:0] reflect the packet number allow to
transmit from this priority queue 0 within a certain
time.
6-0 Port Trans- Packet number for Transmit Queue 0 for lowest pri- R/W 0000001
mit Queue 0 ority packets in four queues mode and low priority
Ratio[6:0] packets in two queues mode.
Register 182 (0xB6): Port 1 Rate Limit Control
Register 198 (0xC6): Port 2 Rate Limit Control
Register 214 (0xD6): Port 3 Rate Limit Control
Register 230 (0xE6): Port 4 Rate Limit Control
Register 246 (0xF6): Port 5 Rate Limit Control
7 Reserved — RO 0
6 Ingress Limit 1 = Ingress rate limit is port based R/W 0
Port/Priority 0 = Ingress rate limit is priority based
Based Select

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 KSZ8795CLX
TABLE 4-13: ADDITIONAL ADVANCED CONTROL REGISTERS (Note 4-1) (CONTINUED)
Address Name Description Mode Default
5 Ingress Limit 1 = Rate limit is counted based on number of R/W 0
Bit/Packets packet.
Mode Select 0 = Rate limit is counted based on number of bit.
4 Ingress Rate 1 = Flow Control is asserted if the port’s receive R/W 0
Limit Flow rate is exceeded.
Control 0 = Flow Control is not asserted if the port’s receive
Enable rate is exceeded.
3-2 Limit Mode Ingress Limit Mode R/W 00
These bits determine what type of frames are lim-
ited and counted against ingress rate limiting.

00 = Limit and count all frames.

01 = Limit and count Broadcast, Multicast, and
flooded unicast frames.
10 = Limit and count Broadcast and Multicast
frames only.
11 = Limit and count Broadcast frames only.
1 Count IFG Count IFG Bytes R/W 0
1 = Each frame’s minimum inter-frame gap. (IFG)
bytes (12 per frame) are included in Ingress and
Egress rate limiting calculations.
0 = IFG bytes are not counted.
0 Count Pre Count Preamble Bytes R/W 0
1 = Each frame’s preamble bytes (8 per frame) are
included in Ingress and Egress rate limiting calcu-
lations.
0 = Preamble bytes are not counted.
Register 183 (0xB7): Port 1 Priority 0 Ingress Limit Control 1
Register 199 (0xC7): Port 2 Priority 0 Ingress Limit Control 1
Register 215 (0xD7): Port 3 Priority 0 Ingress Limit Control 1
Register 231 (0xE7): Port 4 Priority 0 Ingress Limit Control 1
Register 247 (0xF7): Port 5 Priority 0 Ingress Limit Control 1
7 Reserved — RO 0
6-0 Port Based Ingress Data Rate Limit For Priority 0 Frames R/W 0000000
Priority 0 Ingress traffic from this port is shaped according to
Ingress Limit the Table 18 in “Rate Limiting Support” sub-section.
Register 184 (0xB8): Port 1 Priority 1 Ingress Limit Control 2
Register 200 (0xC8): Port 2 Priority 1 Ingress Limit Control 2
Register 216 (0xD8): Port 3 Priority 1 Ingress Limit Control 2
Register 232 (0xE8): Port 4 Priority 1 Ingress Limit Control 2
Register 248 (0xF8): Port 5 Priority 1 Ingress Limit Control 2
7 Reserved — RO 0
6-0 Port-Based Ingress Data Rate Limit For Priority 1 Frames R/W 0000000
Priority 1 Ingress traffic from this port is shaped according to
Ingress Limit the Table 18 in “Rate Limiting Support” sub-section.
Register 185 (0xB9): Port 1 Priority 2 Ingress Limit Control 3
Register 201 (0xC9): Port 2 Priority 2 Ingress Limit Control 3
Register 217 (0xD9): Port 3 Priority 2 Ingress Limit Control 3
Register 233 (0xE9): Port 4 Priority 2 Ingress Limit Control 3
Register 249 (0xF9): Port 5 Priority 2 Ingress Limit Control 3
7 Reserved — RO 0

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KSZ8795CLX
TABLE 4-13: ADDITIONAL ADVANCED CONTROL REGISTERS (Note 4-1) (CONTINUED)
Address Name Description Mode Default
6-0 Port-Based Ingress Data Rate Limit For Priority 2 Frames R/W 0000000
Priority 2 Ingress traffic from this port is shaped according to
Ingress Limit the Table 18 in “Rate Limiting Support” sub-section.
Register 186 (0xBA): Port 1 Priority 3 Ingress Limit Control 4
Register 202 (0xCA): Port 2 Priority 3 Ingress Limit Control 4
Register 218 (0xDA): Port 3 Priority 3 Ingress Limit Control 4
Register 234 (0xEA): Port 4 Priority 3 Ingress Limit Control 4
Register 250 (0xFA): Port 5 Priority 3 Ingress Limit Control 4
7 Port-Based Ingress Data Rate Limit For Priorities Setting Valid R/W 0
Ingress Rate Trigger port ingress rate limit engine to take effect
Limit Enable for all the priority queues according to priority
ingress limit control.

Note: Any write to this register will trigger port

ingress rate limit engine to take effect
for all the priority queues according to
priority ingress limit control. For the port
priority 0 - 3 ingress rate limit control to
take effect, Bit[7] of in Register 186,
202, 218, 234 and 250 for Ports 1, 2, 3,
4 and 5, respectively will need to set last
after configured Bits[6:0] of Port Ingress
Limit Control 1 - 4 registers.
6-0 Port-Based Ingress Data Rate Limit For Priority 3 Frames R/W 0000000
Priority 3 Ingress traffic from this port is shaped according to
Ingress Limit the Table 18 in “Rate Limiting Support” sub-section.
Register 187 (0xBB): Port 1 Queue 0 Egress Limit Control 1
Register 203 (0xCB): Port 2 Queue 0 Egress Limit Control 1
Register 219 (0xDB): Port 3 Queue 0 Egress Limit Control 1
Register 235 (0xEB): Port 4 Queue 0 Egress Limit Control 1
Register 251 (0xFB): Port 5 Queue 0 Egress Limit Control 1
7 Reserved — RO 0
6-0 Port Queue 0 Egress Data Rate Limit For Priority 0 Frames R/W 0000000
Egress Limit Egress traffic from this port is shaped according to
the Table 18 in “Rate Limiting Support” sub-section.
In four queues mode, it is lowest priority.
In two queues mode, it is low priority.
Register 188 (0xBC): Port 1 Queue 1 Egress Limit Control 2
Register 204 (0xCC): Port 2 Queue 1 Egress Limit Control 2
Register 220 (0xDC): Port 3 Queue 1 Egress Limit Control 2
Register 236 (0xEC): Port 4 Queue 1 Egress Limit Control 2
Register 252 (0xFC): Port 5 Queue 1 Egress Limit Control 2
7 Reserved — RO 0
6-0 Port Queue 1 Egress Data Rate Limit For Priority 1 Frames R/W 0000000
Egress Limit Egress traffic from this port is shaped according to
the Table 18 in “Rate Limiting Support” sub-section.
In four queues mode, it is low/high priority.
In two queues mode, it is high priority.
Register 189 (0xBD): Port 1 Queue 2 Egress Limit Control 3
Register 205 (0xCD): Port 2 Queue 2 Egress Limit Control 3
Register 221 (0xDD): Port 3 Queue 2 Egress Limit Control 3
Register 237 (0xED): Port 4 Queue 2 Egress Limit Control 3
Register 253 (0xFD): Port 5 Queue 2 Egress Limit Control 3

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 KSZ8795CLX
TABLE 4-13: ADDITIONAL ADVANCED CONTROL REGISTERS (Note 4-1) (CONTINUED)
Address Name Description Mode Default
7 Reserved — RO 0
6-0 Port Queue 2 Egress Data Rate Limit For Priority 2 Frames R/W 0000000
Egress Limit Egress traffic from this port is shaped according to
the Table 18 in “Rate Limiting Support” sub-section.
In four queues mode, it is high/low priority.
Register 190 (0xBE): Port 1 Queue 3 Egress Limit Control 4
Register 206 (0xCE): Port 2 Queue 3 Egress Limit Control 4
Register 222 (0xDE): Port 3 Queue 3 Egress Limit Control 4
Register 238 (0xEE): Port 4 Queue 3 Egress Limit Control 4
Register 254 (0xFE): Port 5 Queue 3 Egress Limit Control 4
7 Reserved — RO 0
6-0 Port Queue 3 Egress Data Rate Limit For Priority 3 Frames R/W 0000000
Egress Limit Egress traffic from this port is shaped according to
the Table 18 in “Rate Limiting Support” sub-section.
In four queues mode, it is highest priority.
Note 4-1 In the port priority 0 - 3 ingress rate limit mode, it is necessary to set all related egress ports to two
queues or four queues mode.
In the port queue 0 - 3 egress rate limit mode, the highest priority get exact rate limit based on the
rate select table, other priorities packets rate are based upon the ratio of the Port Control 14/15/16/
17 Registers when using more than one egress queue per port.

TABLE 4-14: ADVANCED CONTROL REGISTERS 191 - 255

Address Name Description Mode Default
Register 191 (0xBF): Testing Register
7-0 Reserved N/A Don’t Change. RO 0x80
Register 207 (0xCF): Reserved Control Register
7-0 Reserved N/A Don’t Change. RO 0x15
Register 223 (0xDF): Test Register 2
7-0 Reserved N/A Don’t Change. RO 0x0C
Register 239 (0xEF): Test Register 3
7-0 Reserved N/A Don’t Change. RO 0x32
Register 255 (0xFF): Testing Register 4
7-0 Reserved N/A Don’t Change. RO 0x00

TABLE 4-15: INDIRECT REGISTER DESCRIPTIONS

Control Indirect Address Contents
Direct Address 0x6E, 0x000 – 0x01F Static MAC address table entry 0 – 31
Function Select Bits[7-5] = 000,
Table_select Bits[3-2] = 00
Direct Address 0x6E, 0x000 – 0x1FF VLAN table bucket 0 – 1023 (4 entries
Function Select Bits[7-5] = 000, per bucket)
Table_select Bits[3-2] = 01
Direct Address 0x6E, 0x000 – 0x1FF Dynamic MAC address table entry 0 –
Function Select Bits[7-5] = 000, 1023
Table_select Bits[3-2] = 10

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KSZ8795CLX
TABLE 4-15: INDIRECT REGISTER DESCRIPTIONS (CONTINUED)
Control Indirect Address Contents
Direct Address 0x6E, 0x000 – 0x08F, 0x100 – 0x109 0x000 – 0x01F Port 1 MIB Counters
Function Select Bits[7-5] = 000, 0x020 – 0x03F Port 2 MIB Counters
Table_select Bits[3-2] = 11 0x040 – 0x05F Port 3 MIB Counters
0x060 – 0x07F Port 4 MIB Counters
0x080 – 0x09F Port 5 MIB Counters
0x100 – 0x113 Total Byte and
Dropped MIB Counter
Direct Address 0x6E, {0xn, 6h00} – {0xn, 6h05} Port-based 16-bit EEE Control
Function Select Bits[7-5] = 001, Registers 0 – 5
Bits[3-0] = Indirect Address n – Port number
Bits[11-8] = MSB Indirect Address = Use Indirect Byte Register (0xA0)
Port indirect register address 0xn
Direct Address 0x6E, {0xn, 6h00} – {0xn, 6h1F} ACL entry 0 – 15, 6h00 and 6h01 for
Function Select Bits[7-5] = 010, entry 0, etc.
Bits[3-0] = Indirect Address n = Port number
Bits[11-8] = MSB Indirect Address = Use Indirect Byte Register(0xA0)
Port indirect register address 0xn
Direct Address 0x6E, {0xn, 8h00} – {0xn, 8h4FF} Reserved for the factory.
Function Select Bits[7-5] = 011,
Bits[3-0] = Indirect Address
Bits [11-8] = MSB Indirect Address =
Port indirect register address 0xn
Direct Address 0x6E, {0xn, 8h00} – {0xn, 8h4FF} Configuration Registers, PME, etc.
Function Select Bits[7-5] = 100, n = 0 - Global
Bits[3-0] = Indirect Address n = 1 – 4 Port number
Bits[11-8] = MSB Indirect Address = Use Indirect Byte Register(0xA0)
Port indirect register address 0xn
Direct Address 0x6E, {0xn, 8h00} – {0xn, 8h4FF} Reserved for the factory.
Function Select Bits[7-5] = 101,
Bits[3-0] = Indirect Address
Bits [11-8] = MSB Indirect Address =
Port indirect register address 0xn

4.4 Static MAC Address Table

The KSZ8795CLX incorporates a static and a dynamic address table. When a DA look-up is requested, both tables will
be searched to make a packet forwarding decision. When an SA look-up is requested, only the dynamic table is
searched for aging, migration, and learning purposes. The static DA look-up result will have precedence over the
dynamic DA look-up result. If there are DA matches in both tables, the result from the static table will be used. The static
table can only be accessed and controlled by an external SPI master (usually a processor). The entries in the static table
will not be aged out by KSZ8795CLX. An external device does all addition, modification and deletion.
Note: Register bit assignments are different for static MAC table reads and static MAC table write, as shown in the
following table.

TABLE 4-16: STATIC MAC ADDRESS TABLE

Address Name Description Mode Default
Format of Static MAC Table for Reads (32 entries)
63 - 57 FID Filter VLAN ID, representing one of the 128 active RO 0000000
VLANs.
56 Use FID 1 = Use (FID+MAC) to look-up in static table. RO 0
0 = Use MAC only to look-up in static table.
55 Reserved — RO 0

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 KSZ8795CLX
TABLE 4-16: STATIC MAC ADDRESS TABLE (CONTINUED)
Address Name Description Mode Default
54 Override 1 = Override spanning tree “transmit enable = 0” or RO 0
“receive enable = 0* setting. This bit is used for
spanning tree implementation.
0 = No override.
53 Valid 1 = This entry is valid, the look-up result will be RO 0
used.
0 = This entry is not valid.
52 - 48 Forwarding These 5 bits control the forward ports. RO 00000
Ports For example:
00001 = Forward to Port 1
00010 = Forward to Port 2
00100 = Forward to Port 3
01000 = Forward to Port 4
10000 = Forward to Port 5
00110 = Forward to Port 2 and Port 3
11111 = Broadcasting (excluding the ingress port)
47 - 0 MAC 48-bit MAC address. RO 0x0
Address (DA)
Format of Static MAC Table for Writes (32 entries)
62 - 56 FID Filter VLAN ID, representing one of the 128 active W 0000000
VLANs.
55 Use FID 1 = Use (FID+MAC) to look-up in static table. W 0
0 = Use MAC only to look-up in static table.
54 Override 1 = Override spanning tree “transmit enable = 0” or W 0
“receive enable = 0” setting. This bit is used for
spanning tree implementation.
0 = No override.
53 Valid 1 = This entry is valid, the look-up result will be W 0
used.
0 = This entry is not valid.
52 - 48 Forwarding These 5 bits control the forward ports. W 00000
Ports For example,
00001 = Forward to Port 1
00010 = Forward to Port 2
00100 = Forward to Port 3
01000 = Forward to Port 4
10000 = Forward to Port 5
00110 = Forward to Port 2 and Port 3
11111 = Broadcasting (excluding the ingress port)
47 - 0 MAC 48-bit MAC address. W 0
Address (DA)
Examples:
1. Static Address Table Read (read the 2nd entry)
Write to Register 110 with 0x10 (read static table selected)
Write to Register 111 with 0x1 (trigger the read operation)
Then
Read Register 113 (63:56)
Read Register 114 (55:48)
Read Register 115 (47:40)
Read Register 116 (39:32)

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KSZ8795CLX
Read Register 117 (31:24)
Read Register 118 (23:16)
Read Register 119 (15:8)
Read Register 120 (7:0)
2. Static Address Table Write (write the 8th entry)
Write Register 113 (62:56)
Write Register 114 (55:48)
Write Register 115 (47:40)
Write Register 116 (39:32)
Write Register 117 (31:24)
Write Register 118 (23:16)
Write Register 119 (15:8)
Write Register 120 (7:0)
Write to Register 110 with 0x00 (write static table selected)
Write to Register 111 with 0x7 (trigger the write operation)

4.5 VLAN Table

The VLAN table is used for VLAN table look-up. If 802.1q VLAN mode is enabled (Register 5 Bit[7] = 1), this table is
used to retrieve VLAN information that is associated with the ingress packet. There are three fields for FID (filter ID),
Valid, and VLAN membership in the VLAN table. The three fields must be initialized before the table is used. There is
no VID field because 4096 VIDs are used as a dedicated memory address index into a 1024x52-bit memory space.
Each entry has four VLANs. Each VLAN has 13 bits. Four VLANs need 52 bits. There are a total of 1024 entries to sup-
port a total of 4096 VLAN IDs by using dedicated memory address and data bits. FID has 7 bits to support 128 active
VLANs.

TABLE 4-17: VLAN TABLE

Address Name Description Mode Initial Suggested Value
Format of Static VLAN Table (Support Max 4096 VLAN ID entries and 128 Active VLANs)
12 Valid 1 = The entry is valid. R/W 0
0 = Entry is invalid.
11 - 7 Membership Specifies which ports are members of the R/W 111111
VLAN.
If a DA look-up fails (no match in both
static and dynamic tables), the packet
associated with this VLAN will be for-
warded to ports specified in this field.
E.g., 11001 means Ports 5, 4, and 1 are in
this VLAN.
6-0 FID Filter ID. The KSZ8795CLX supports 128 R/w 0
active VLANs represented by these seven
bit fields. FID is the mapped ID. If 802.1q
VLAN is enabled, the look-up will be
based on FID+DA and FID+SA.
If 802.1q VLAN mode is enabled, the KSZ8795CLX assigns a VID to every ingress packet when the packet is untagged
or tagged with a null VID, the packet is assigned with the default Port VID of the ingress port. If the packet is tagged with
non-null VID, the VID in the tag is used. The look-up process starts from the VLAN table look-up based on VID number
with its dedicated memory address and data bits. If the entry is not valid in the VLAN table, the packet is dropped and
no address learning occurs. If the entry is valid, the FID is retrieved. The FID+DA and FID+SA lookups in MAC tables
are performed. The FID+DA look-up determines the forwarding ports. If FID+DA fails for look-up in the MAC table, the
packet is broadcast to all the members or specified members (excluding the ingress port) based on the VLAN table. If
FID+SA fails, the FID+SA is learned. To communicate between different active VLANs, set the same FID; otherwise set
a different FID.

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 KSZ8795CLX
The VLAN table configuration is organized as 1024 VLAN sets, each VLAN set consists of four VLAN entries, to support
up to 4096 VLAN entries. Each VLAN set has total 60 bits and three reversed bits are inserted between entries. Actually,
52 bits are used for the VLAN set which should be read or written at the same time specified by the indirect address.
The VLAN entries in the VLAN set are mapped to indirect data registers as follow:
• Entry0[12:0] maps to the VLAN set Bits[12:0] {Register 119[4:0], Register 120[7:0]}
• Entry1[12:0] maps to the VLAN set Bits[28:16] {Register 117[4:0], Register 118[7:0]}
• Entry2[12:0] maps to the VLAN set Bits[44:32] {Register 115[4:0], Register 116[7:0]}
• Entry3[12:0] maps to the VLAN set Bits[60:48] {Register 113[4:0], Register 114[7:0]}
In order to read one VLAN entry, the VLAN set is read first and the specific VLAN entry information can be extracted.
To update any VLAN entry, the VLAN set is read first then only the desired VLAN entry is updated and the whole VLAN
set is written back. The FID in the VLAN table is 7 bits, so the VLAN table supports unique 128 flow VLAN groups. Each
VLAN set address is 10 bits long (Maximum is 1024) in the Indirect Address Register 110 and 111, the Bits[9:8] of VLAN
set address is at Bits[1:0] of Register 110, and the Bits[7:0] of VLAN set address is at bits [7:0] of Register 111. Each
Write and Read can access up to four consecutive VLAN entries.
Examples:
1. VLAN Table Read (read the VID = 2 entry)
Write the indirect control and address registers first
Write to Register 110 (0x6E) with 0x14 (read VLAN table selected)
Write to Register 111 (0x6F) with 0x0 (trigger the read operation for VID = 0, 1, 2, 3 entries)
Then read the Indirect Data Registers Bits[38:26] for VID = 2 entry
Read Register 115 (0x73), (Register 115 [4:0] are Bits[12:8] of VLAN VID = 2 entry)
Read Register 116 (0x74), (Register 116 [7:0] are Bits[7:0] of VLAN VID = 2 entry)
2. VLAN Table Write (write the VID = 10 entry)
Read the VLAN set that contains VID = 8, 9, 10, 11.
Write to Register 110 (0x6E) with 0x14 (read VLAN table selected)
Write to Register 111 (0x6F) with 0x02 (trigger the read operation and VID = 8, 9, 10, 11 indirect address)
Read the VLAN set first by the Indirect Data Registers 113, 114, 115, 116, 117, 118, 119, 120.
Modify the Indirect Data Registers Bits[44:32] by the Register 115 Bit[4:0] and Register 116 Bits[7:0] as follows:
Write to Register 115 (0x73), (Register115 [4:0] are Bits[12:8} of VLAN VID = 10 entry)
Write to Register 116 (0x74), (Register116 [7:0] are Bits[7:0] of VLAN VID = 10 entry)
Then write the indirect control and address registers
Write to Register 110 (0x6E) with 0x04 (write VLAN table selected)
Write to Register 111 (0x6F) with 0x02 (trigger the write operation and VID = 8, 9, 10, 11 indirect address)
Table 4-18 shows the relationship of the indirect address/data registers and VLAN ID.

TABLE 4-18: VLAN ID AND INDIRECT REGISTERS

Indirect Address Indirect Data
VID Bit[12-2] in VID Bit[1-0] in
High/Low Bit[9-0] Registers Bits for VID Numbers
VLAN Tag VLAN Tag
for VLAN Sets Each VLAN Entry
0 Bits[12:0] 0 0 0
0 Bits[28:16] 1 0 1
0 Bits[44:32] 2 0 2
0 Bits[60:48] 3 0 3
1 Bits[12:0] 4 1 0
1 Bits[28:16] 5 1 1
1 Bits[44:32] 6 1 2
1 Bits[60:48] 7 1 3
2 Bits[12:0] 8 2 0

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TABLE 4-18: VLAN ID AND INDIRECT REGISTERS (CONTINUED)
Indirect Address Indirect Data
VID Bit[12-2] in VID Bit[1-0] in
High/Low Bit[9-0] Registers Bits for VID Numbers
VLAN Tag VLAN Tag
for VLAN Sets Each VLAN Entry
2 Bits[28:16] 9 2 1
2 Bits[44:32] 10 2 2
2 Bits[60:48] 11 2 3
: : : : :
: : : : :
: : : : :
1023 Bits[12:0] 4092 1023 0
1023 Bits[28:16] 4093 1023 1
1023 Bits[44:32] 4095 1023 2
1023 Bits[60:48] 4095 1023 3

4.6 Dynamic MAC Address Table

Table 4-19 is read-only.

TABLE 4-19: DYNAMIC MAC ADDRESS TABLE

Address Name Description Mode Default
Format of Dynamic MAC Address Table (1K entries)
71 MAC Empty 1 = There is no valid entry in the table. RO 1
0 = There are valid entries in the table.
70 - 61 No. of Valid Indicates how many valid entries in the table. RO 0
Entries 0x3ff means 1K entries
0x1 and Bit[71] = 0: means 2 entries
0x0 and Bit[71]= 0: means 1 entry
0x0 and Bit[71] = 1: means 0 entry
60 - 59 Time Stamp 2-bit counters for internal aging RO —
58 - 56 Source Port The source port where FID+MAC is learned. RO 0x0
000 = Port 1
001 = Port 2
010 = Port 3
011 = Port 4
100 = Port 5
55 Data Ready 1 = The entry is not ready, retry until RO —
this bit is set to 0.
0 = The entry is ready.
54 - 48 FID Filter ID RO 0x0
47 - 0 MAC 48-bit MAC address RO 0x0
Address
Examples:
1. Dynamic MAC Address Table Read (read the 1st entry), and retrieve the MAC table size
Write to Register 110 with 0x18 (read dynamic table selected)
Write to Register 111 with 0x0 (trigger the read operation) and then
Read Register 112 (71:64)
Read Register 113 (63:56); // the above two registers show # of entries
Read Register 114 (55:48) // if Bit[55] is 1, restart (reread) from this register

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 KSZ8795CLX
Read Register 115 (47:40)
Read Register 116 (39:32)
Read Register 117 (31:24)
Read Register 118 (23:16)
Read Register 119 (15:8)
Read Register 120 (7:0)
2. Dynamic MAC Address Table Read (read the 257th entry), without retrieving number of entries information
Write to Register 110 with 0x19 (read dynamic table selected)
Write to Register 111 with 0x1 (trigger the read operation) and then
Read Register 112 (71:64)
Read Register 113 (63:56)
Read Register 114 (55:48) // if Bit[55] is 1, restart (reread) from this register
Read Register 115 (47:40)
Read Register 116 (39:32)
Read Register 117 (31:24)
Read Register 118 (23:16)
Read Register 119 (15:8)
Read Register 120 (7:0)

4.7 PME Indirect Registers

The PME registers are provided on a global and per-port basis. These registers are read/write using indirect memory
access, as shown in Table 4-20.

TABLE 4-20: PME INDIRECT REGISTERS

Address Name Description Mode Default
Global PME Control Register
Reg. 110 (0x6E) Bits[7:5] =100 for PME, Reg.110 Bits[3:0] = 0x0 for the indirect global register,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x00 (Bits[31:24]), 0x01 (Bits[23:16]), 0x02 (Bit[15:8]), 0x03 (Bits[7:0]).
Location: (100 PME) -> {0x0, offset} -> 0xA0 holds the data.
31 - 2 Reserved — RO All ‘0’
1 PME Output 1= PME output pin is enabled. R/W 0
Enable 0= PME output pin is disabled.
0 PME Output 1= PME output pin is active-high. R/W 0
Polarity 0= PME output pin is active-low.
Port PME Control Status Register
Reg. 110 (0x6E) Bits[7:5] =100 for PME, Reg. 110 Bits[3:0] = 0xn for the Indirect Port Register (n = 1,2,3,4).
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x00 (Bits[31:24]), 0x01 (bits [23:16]), 0x02 (Bits[5:8]), 0x03 (Bits[7:0]).
Location: (100 PME) -> {0xn, offset} -> 0xA0 holds the data.
31 - 3 Reserved — RO All ‘0’
2 Magic Packet 1 = Magic packet is detected at any port (write 1 to R/W 0
Detect clear). W1C
0 = No magic packet is detected.
1 Link-Up 1 = Link up is detected at any port (write 1 to clear). R/W 0
Detect 0 = No link-up is detected. W1C
0 Energy 1 = Energy is detected at any port (write 1 to clear). R/W 0
Detect 0 = No energy is detected. W1C

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TABLE 4-20: PME INDIRECT REGISTERS (CONTINUED)
Address Name Description Mode Default
Port PME Control Mask Register
Reg. 110 (0x6E) Bits[7:5]=100 for PME, Reg. 110 Bits[3:0] = 0xn for port (n = 1, 2, 3, 4).
Reg. 111 (0x6F) Bits[7:0]= Offset to access the Indirect Byte Register 0xA0.
Offset: 0x04 (Bits[31:24]), 0x05 (Bits[23:16]), 0x06 (Bits[15:8]), 0x07 (Bits[7:0]).
Location: (100 PME) -> {0xn, offset} -> 0xA0 holds the data.
31 - 3 Reserved — RO All ‘0’
2 Magic Packet 1 = The PME pin will be asserted when a magic R/W 0
Detect packet is detected at host QMU.
Enable 0 = The PME pin will not be asserted by the magic
packet detection.
1 Link-Up 1 = The PME pin will be asserted when a link-up is R/W 0
Detect detected at any port.
Enable 0 = The PME pin will not be asserted by the link-up
detection.
0 Energy 1 = The PME pin will be asserted when energy on R/W 0
Detect line is detected at any port.
Enable 0 = The PME pin will not be asserted by the energy
detection.
Programming Examples
Read Operation
1. Use the Indirect Access Control Register to select register to be read, to read Global PME Control Register.
Write 0x90 to the Register 110 (0x6E) // PME selected and read operation, and 4 MSBs of port number (Register
110 Bits[3:0]) = 0 for the Global PME Register.
2. Write 0x03 to the Register 111 (0x6F) // trigger the read operation for bits [7:0] of the Global PME Control Register.
3. Read the Indirect Byte Register 160 (0xA0) // Get the value of the Global PME Control Register.
Write Operation
1. Write 0x80 to the Register 110 (0x6E) //PME selected and write operation, and 4 MSBs of Port number = 0 for
the Global PME Register.
2. Write 0x03 to the Register 111 (0x6F) // select write the bits [7:0] of the Global PME Control Address Register.
3. Write new value to the Indirect Byte Register 160 bits [7:0] (0xA0) //Write value to the Global PME Control Reg-
ister of the Indirect PME Data Register by the assigned the indirect data register address.

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4.8 ACL Rule Table and ACL Indirect Registers
4.8.1 ACL REGISTER AND PROGRAMMING MODEL
The ACL registers are accessible by the microcontroller through a serial interface. The per-port register set is accessed
through indirect addressing mechanism. The ACL entries are stored in the format shown in the following figure. Each
ACL rule list table can input up to 16 entries per port, with a total of five ACL rule list tables that can be set for five ports.

FIGURE 4-2: ACL TABLE ACCESS

To update any port-based ACL registers, it is suggested to execute a read modify write sequence for each 128-bit (112
are used) entry addressed by the Indirect Address Register to ensure the integrity of control content. Minimum two indi-
rect control writes and two indirect control reads are needed for each ACL entry read access (indirect data read shall
follow), and minimum one indirect control read and three indirect control writes are required for each ACL entry write
access. Each 112-bit port-based ACL word entry (ACL Word) is accomplished through a sequence of the Indirect
Access Control 0 Registers 110 (0x6E) accesses by specifying the Bits[3:0] 4-bit port number (Indirect address [11:8])
and 8-bit indirect register address (indirect address[7:0]) in the Indirect Access Control 1 Register 111 (0x6F). The
address numbers 0x00-0x0d are used to specify the byte location of each entry (see above figure), address 0x00 indi-
cates the byte 15 (MSB) of each 128-bit entry, address 0x01 indicates the byte 14 etc., bytes at address 0x0E and 0x0F
are reserved for the future. Address 0x10 and 0x11 hold bit-wise Byte Enable for each entry. Address 0x12 is used as
control and status register. The format of these registers is defined in the ACL Indirect Registers sub-section.

4.8.2 ACL INDIRECT REGISTERS

Table 4-21 is used to implement ACL mode selection and filtering on a per-port basis.

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KSZ8795CLX
TABLE 4-21: ACL INDIRECT REGISTERS FOR 14 BYTE ACL RULES
Address Name Description Mode Default
Port_ACL_0
ACL Port Register 0 (0x00)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x00 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Processing Field
7-4 Reserved — RO 0x0
3-0 FRN[3:0] First Rule Number R/W 0000
This is for the first rule number of the rule set.
There are total 16 entries per port in ACL rule table.
Each single rule can be set with other rule for a rule
set by the ACL port Register 12 (0x0c) and Regis-
ter 13 (0x0d).
Regardless single rule or rule set, have to assign
an entry for using which Action Field by FRN[3:0].
Port_ACL_1
ACL Port Register 1 (0x01)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x01 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields
7-6 Reserved — RO 00
5-4 MD[1:0] MODE R/W 00
00 = Disable the current rule list, no action taken
01 = Qualify rules for Layer 2 MAC header filtering
10 = Is used for Layer 3 IP address filtering
11 = Performs Layer 4 TCP port number/protocol
filtering

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 KSZ8795CLX
TABLE 4-21: ACL INDIRECT REGISTERS FOR 14 BYTE ACL RULES (CONTINUED)
Address Name Description Mode Default
3-2 ENB[1:0] ENABLE R/W 00
When MD=01:
00 = The 11 bits from PM, P, REP, MM in action
field specify a count value for packets matching
MAC Address and TYPE in matching field.
The count unit is defined in FORWARD field Bit[4];
Bit[4] = 0, µs will be used.
Bit[4] = 1, ms will apply.
The FORWARDED field Bit[3] determines the algo-
rithm used to generate interrupt when counter ter-
minated. Bit[3] = 0, an 11-bit counter will be loaded
with the count value from the list and start counting
down every unit time. An interrupt will be generated
when expires, i.e., next qualified packet has not
been received within the period specified by the
value.
Bit[3] = 1, the counter is incremented every
matched packet received and the interrupt is gen-
erated while terminal count reached, the count
resets thereafter.

01 = MAC address bit field is participating in test.

10 = MAC TYPE bit field is used for test.
11 = Both MAC address and TYPE are tested
against these bit fields in the list.

When MD=10:
00 = Reserved.
01 = IP address and mask or IP protocol is enabled
to be tested accordingly.
10 = SA and DA are compared; the drop/forward
decision is based on the E/Q bit setting.
11 = Reserved

When MD=11:
00 = Protocol comparison is enabled.
01 = TCP/UDP address comparison is selected.
10 = It is same with ‘01’
11 = The sequence number of TCP is compared.
1 S_D Source/Destination Address R/W 0
0 = DA is used to compare.
1 = SA is used to compare
0 EQ Compare Equal R/W 0
0 = Match if they are not equal.
1 = Match if they are equal.
Port_ACL_2
ACL Port Register 2 (0x02)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x02 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 2
7-0 MAC_ADDR MAC Address R/W 00000000
[47:40]

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KSZ8795CLX
TABLE 4-21: ACL INDIRECT REGISTERS FOR 14 BYTE ACL RULES (CONTINUED)
Address Name Description Mode Default
Port_ACL_3
ACL Port Register 3 (0x03)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x03 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 2
7-0 MAC_ADDR MAC Address R/W 00000000
[39:32]
Port_ACL_4
ACL Port Register 4 (0x04)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x04 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 2
7-0 MAC_ADDR MAC Address R/W 00000000
[31:24]
Port_ACL_5
ACL Port Register 5 (0x05)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x05 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 2
7-0 MAC_ADDR MAC Address R/W 00000000
[23:16]
Port_ACL_6
ACL Port Register 6 (0x06)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x06 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 2
7-0 MAC_ADDR MAC Address R/W 00000000
[15:8]
Port_ACL_7
ACL Port Register 7 (0x07)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x07 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 2
7-0 MAC_ADDR MAC Address R/W 00000000
[7:0]
Port_ACL_8
ACL Port Register 8 (0x08)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x08 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 2
7-0 TYPE[15:8] Ether Type R/W 00000000

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 KSZ8795CLX
TABLE 4-21: ACL INDIRECT REGISTERS FOR 14 BYTE ACL RULES (CONTINUED)
Address Name Description Mode Default
Port_ACL_9
ACL Port Register 9 (0x09)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x09 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 2
7-0 TYPE[7:0] Ether Type R/W 00000000
Note: Layer 2, Layer 3, and Layer 4 in matching field should be in different entries. Same layer should be in same
entry.
Port_ACL_2
ACL Port Register 2 (0x02)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x02 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 3
7-0 IP_ADDR IP Address R/W 00000000
[31:24]
Port_ACL_3
ACL Port Register 3 (0x03)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x03 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 3
7-0 IP_ADDR IP Address R/W 00000000
[23:16]
Port_ACL_4
ACL Port Register 4 (0x04)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x04 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 3 IP
7-0 IP_ADDR IP Address R/W 00000000
[15:8]
Port_ACL_5
ACL Port Register 5 (0x05)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x05 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 3
7-0 IP_ADDR IP Address R/W 00000000
[7:0]
Port_ACL_6
ACL Port Register 6 (0x06)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x06 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 3
7-0 IP_Mask IP Mask R/W 00000000
[31:24]

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KSZ8795CLX
TABLE 4-21: ACL INDIRECT REGISTERS FOR 14 BYTE ACL RULES (CONTINUED)
Address Name Description Mode Default
Port_ACL_7
ACL Port Register 7 (0x07)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x07 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 3
7-0 IP_Mask IP Mask R/W 00000000
[23:16]
Port_ACL_8
ACL Port Register 8 (0x08)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x08 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 3
7-0 IP_Mask IP Mask R/W 00000000
[15:8]
Port_ACL_9
ACL Port Register 9 (0x09)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x09 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 3
7-0 IP_Mask IP Mask R/W 00000000
[7:0]
Note: Layer 2, Layer 3, and Layer 4 in matching field should be in different entries. Same layer should be in same
entry.
Port_ACL_2
ACL Port Register 2 (0x02)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x02 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 4
7-0 MAX Port For range of TCP port number or sequence num- R/W 00000000
[15:8] ber matching
Port_ACL_3
ACL Port Register 3 (0x03)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x03 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 4
7-0 MIN Port For range of TCP port number or sequence num- R/W 00000000
[7:0] ber matching
Port_ACL_4
ACL Port Register 4 (0x04)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x04 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 4
7-3 Reserved — RO 00000

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 KSZ8795CLX
TABLE 4-21: ACL INDIRECT REGISTERS FOR 14 BYTE ACL RULES (CONTINUED)
Address Name Description Mode Default
2-1 PC[1:0] 00 = The port comparison is disabled. R/W 00
01 = Matching either one of MAX or MIN.
10 = Match if the port number is in the range of
MAX and MIN.
11 = Match if the port number is out of the range
0 PRO[7] IP Protocol — 0
For the IP protocol to be matched
Port_ACL_5
ACL Port Register 5 (0x05)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x05 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 4
7-1 PRO[6:0] IP Protocol R/W 0000000
For the IP protocol to be matched
0 FME Flag Match Enable R/W 0
0 = Disable TCP FLAG matching
1 = Enable TCP FLAG matching
Port_ACL_6
ACL Port Register 6 (0x06)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x06 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 4
7-0 FMSK[7:0] TCP FLAG Mask R/W 00000000
Port_ACL_7
ACL Port Register 7 (0x07)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x07 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Matching Fields for Layer 4
7-0 FLAG[7:0] TCP FLAG R/W 00000000
Port_ACL_8
ACL Port Register 8 (0x08)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x08 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
7-0 Reserved — RO 00000000
Port_ACL_9
ACL Port Register 9 (0x09)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x09 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
7-0 Reserved — RO 00000000
Note: Layer 2, Layer 3, and Layer 4 in matching field should be in different entries. Same layer should be in same
entry.

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KSZ8795CLX
TABLE 4-21: ACL INDIRECT REGISTERS FOR 14 BYTE ACL RULES (CONTINUED)
Address Name Description Mode Default
Port_ACL_A
ACL Port Register 10 (0x0A)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x0A to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Action Field
7-6 PM[1:0] Priority Mode R/W 00
00 = No priority is selected; the priority determined
by QoS/Classification is used in the tagged
packets.
01 = Priority in P [2:0] bits field is used if it is
greater than QoS result in the 3-bit priority field of
the tagged packets received.
10 = Priority in P [2:0] bits field is used if it is
smaller than QoS result in the 3-bit priority field of
the tagged packets received.
11 = P [2:0] bits field will replace the 3-bit priority
field of the tagged packets received.
5-3 P[2:0] Priority R/W 000
Note: The 3-bit priority value to be used
depends on PM [1:0] setting in Bits[7:6].
2 RPE Remark Priority Enable R/W 0
0 = No remarking is necessary.
1 = VLAN priority bits in the packets are replaced
by RP[2:1] bits field below in the list.
1-0 RP[2:1] Remark Priority R/W 00
00 = Priority 0
01 = Priority 1
10 = Priority 2
11 = Priority 3
Port_ACL_B
ACL Port Register 11 (0x0B)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x0B to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Action Field
7 RP[0] Remark Priority R/W 0
6-5 MM[1:0] Map Mode R/W 00
00 = No forwarding remapping is necessary. Don’t
use the forwarding map in FORWARD field; use
the forwarding map from the look-up table only.
01 = The forwarding map in FORWARD field is
OR’ed with the forwarding map from the look-up
table.
10 = The forwarding map in FORWARD field is
AND’ed with the forwarding map from the look-up
table.
11 = The forwarding map in FORWARD field
replaces the forwarding map from the look-up
table.

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 KSZ8795CLX
TABLE 4-21: ACL INDIRECT REGISTERS FOR 14 BYTE ACL RULES (CONTINUED)
Address Name Description Mode Default
4-0 FORWARD Port Map R/W —
[4:0] Each bit indicates forwarding decision of one port.
Bit[0] = Port 1
Bit[1] = Port 2
Bit[2] = Port 3
Bit[3] = Port 4
Bit[4] = Port 5

When MD = 01 and ENB = 00,

Bit[4] is used as count unit:
0 = µs
1 = ms
Bit[3] is used to select count modes:
0 = count down in the 11-bit counter from an
assigned value in the Action field PM, P, RPE, RP,
and MM, an interrupt will be generated when
expired.
1 = count up in the 11-bit counter for every matched
packet received up to reach an assigned value in
the Action field PM, P, RPE, RP and MM, and then
an interrupt will be generated.

Note: See ENB field description for detail.

Port_ACL_C
ACL Port Register 12 (0x0C)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x0C to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Processing Field
7-0 RULESET Rule Set R/W 00000000
[15:8] Each bit indicates this entry in bits 0 to 16, total 16
entries of the rule list can be assigned for the rule
set to be used in the rules cascade per port.
Port_ACL_D
ACL Port Register 13 (0x0D)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x0D to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
Processing Field
7-0 RULESET Rule Set R/W 00000000
[7:0] Each bit indicates this entry in bits 0 to 16, total 16
entries of the rule list can be assigned for the rule
set to be used in the rules cascade per port.

TABLE 4-22: TEMPORAL STORAGE FOR 14 BYTES ACL RULES

Address Name Description Mode Default
Port_ACL_BYTE_ENB_MSB
ACL Port Register 14 (0x10)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, and 4.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x10 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
7-6 Reserved — RO 00

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KSZ8795CLX
TABLE 4-22: TEMPORAL STORAGE FOR 14 BYTES ACL RULES (CONTINUED)
Address Name Description Mode Default
5-0 BYTE_ENB Byte Enable in ACL table; 14-Byte per entry R/W 0
[13:8]
1 = Byte is selected for read/write
0 = Byte is not selected

Bit[0] of BYTE_ENB[13:0] is for byte address 0x0D

in ACL table entry,
Bit[1] of BYTE_ENB[13:0] is for byte address 0x0C
in ACL table entry, etc.
Bit[13] of BYTE_ENB[13:0] is for byte address
0x00 in ACL table entry.
Port_ACL_ BYTE_ENB_LSB
ACL Port Register 15 (0x11)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x11 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
7-0 BYTE_ENB Byte Enable in ACL table; 14-Byte per entry R/W 0x00
[7:0]
1 = Byte is selected for read/write
0 = Byte is not selected

Bit[0] of BYTE_ENB[13:0] is for byte address 0x0D

in ACL table entry,
Bit[1] of BYTE_ENB[13:0] is for byte address 0x0C
in ACL table entry, etc.
Bit[13] of BYTE_ENB[13:0] is for byte address
0x00 in ACL table entry.

TABLE 4-23: ACL READ/WRITE CONTROL

Address Name Description Mode Default
Port_ACL_ACCESS_CONTROL1
ACL Port Register 16 (0x12)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x12 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
7 Reserved — RO 0
6 WRITE_ Write Operation Status RO 1
STATUS
1 = Write completed
0 = Write is in progress
5 READ_ Read Operation Status RO 1
STATUS
1 = Read completed
0 = Read is in progress
4 WRITE_ Request Type R/W 0
READ
1 = Write
0 = Read

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 KSZ8795CLX
TABLE 4-23: ACL READ/WRITE CONTROL (CONTINUED)
Address Name Description Mode Default
3-0 ACL_ENTRY ACL Entry Address R/W 0000
_ADDRESS 0000 = Entry 0.
0001 = Entry 1.
…..
1111 = Entry 15.
Port_ACL_ ACCESS_CONTROL2
ACL Port Register 17 (0x13)
Reg. 110 (0x6E) Bits[7:5] = 010 for ACL, Reg. 110 Bits[3:0] = 0xn for Ports 1, 2, 3, 4, and 5.
Reg. 111 (0x6F) Bits[7:0] = Offset 0x13 to access the Indirect Byte Register 0xA0.
Location: (010 ACL) -> {0xn, offset} -> 0xA0 holds the data.
7-1 Reserved — RO 0000000
0 Force DLR 1 = DLR filtering uses single ACL entry. DLR R/W 0
Miss packet matching the ACL entry will be considered
as MISS
0 = DLR filtering uses multiple ACL entries. DLR
packet matching the rule set for DLR packet will be
considered as HIT.
Note: DLR is defined as Device Level Redun-
dancy.
The ACL registers can be programmed using the read/write examples following:
Examples:
Read Operation
1. Steps to set Byte Enable Register to select all bytes in ACL word from 0x00-0x0d in ACL table entry:
Use the Indirect Access Control Register to select register to be read. To read Entry0 that is 1st entry of Port 1:
Write 0x41 to Register 110 (0x6E) // select ACL and write to Port 1 (Port 2, 3, 4, and 5 are 0x42, 0x43, 0x44, and
0x45)
Write 0x10 to Register 111 (0x6F) // trigger the write operation for Port 1 in the ACL Port Register 14 (Byte Enable
MSB register) address.
Write 0x3F into the Indirect Byte Register 160 (0xA0) for MSB of Byte Enable word.
Write 0x41 to Register 110 (0x6E) // select write to Port 1.
Write 0x11 to Register 111 (0x6F) // trigger the write operation for Port 1 in the ACL Port Register 15 (Byte Enable
LSB Register) address. (The above 2 may be part of burst).
Write 0xFF into the Indirect Byte Register 160 (0xA0) for LSB of Byte Enable word.
Write 0x41 to Register 110 (0x6E) // select ACL and write operations to Port 1.
Write 0x12 to Register 111 (0x6F) // Write ACL read/write control register address 0x12 to the indirect address in
Register 111 to trigger the read operation for Port 1 in the ACL Port Register 16 (ACL Access Control Register) to read
entry 0.
Write 0x00 into the Indirect Byte Register 160 (0xA0)//ACL Port Register 16 (0x12) Bit[4] = 0 to read ACL and
Bits[3:0] = 0x0 for entry 0.
2. Steps set ACL control register to read ACL entry word 0).
Write 0x51 to Register 110 (0x6E) //select ACL and read to Port 1 (Port 2, 3, 4, and 5 are 0x52, 0x53, 0x54 and
0x55).
Write 0x12 to Register 111 (0x6F) //trigger the read operation for Port 1 in the ACL Port Register 16 (ACL Access
Control 1).
Read the Indirect Byte Register 160 (0xA0) to get data (if bit[5] is set, the read completes in the ACL port Register
16 [0x12] and goes to next step. Otherwise, repeat the above polling step).
Write 0x51 to Register 110 (0x6E) // select read to Port 1.

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KSZ8795CLX
Write 0x00 to Register 111 (0x6F) // trigger the read/burst read operation(s) based on the Byte Enable Register set-
ting by the Port 1 ACL access Register 0 (0x00). Read/Burst read the Indirect Byte Register 160 (0xA0) // to get data of
ACL entry word 0, write 0x00 to 0x0D indirect address and read Register 160 (0xA0) after each byte address write to
Register 111 (0x6F).
Write Operation
1. Steps set Byte Enable register to select odd address bytes in ACL word:
Use the Indirect Access Control Register to select register to be written. To write even byte number of 15th entry of Port
5:
Write 0x55 to Register 110 (0x6E) // select ACL and read to Port 5.
Write 0x12 to Register 111 (0x6F) // trigger the read operation for Port 5 ACL Access Control Register read.
Read the Indirect Byte Register 160 (0xA0) to get data (If Bit[6] is set, the previous write completes and go to next
step. Otherwise, repeat the above polling step).
Write 0x45 to Register 110 (0x6E) // select ACL and write to Port 5.
Write 0x00 to Register 111 (0x6F) //set offset address for Port 5 ACL Port Register 0.
Write/Burst write the Indirect Byte Register 160 (0xA0) for ACL Port Register 0, 1, 2, …,13 from 0x00 to 0x0D)
(Write or Burst write even bytes of Port 5 ACL access Registers 0, 1, …, 13 to holding buffer).
Write 0x45 to Register 110 (0x6E) // select ACL and write to Port 5.
Write 0x10 to Register 111 (0x6F) // trigger the write operation for Port 5 in the ACL Port Register 14 (Byte Enable
MSB register).
Write 0x15 into the Indirect Byte Register 160 (0xA0) for MSB of Byte Enable word to enable odd bytes address
0x01, 0x03 and 0x05.
2. Steps set ACL Control Register to write ACL entry word 15 from holding buffer:
Write 0x45 to Register 110 (0x6E) // select write to Port 5.
Write 0x11 to Register 111 (0x6F) // trigger the write operation for Port 5 in the ACL Port Register 15 (Byte Enable
LSB register).
Write 0x55 into the Indirect Byte Register 160 (0xA0) for LSB of Byte Enable word to enable odd bytes address
0x07, 0x09, 0x0B and 0x0D.
Write 0x45 to Register 110 (0x6E) // select write to Port 5.
Write 0x12 to Register 111 (0x6F) // write the port ACL access control register address (0x12) to the Indirect
Address Register 111 for setting the write operation to Port 5 in the ACL Port Register 16 to write entry 15 bytes 1, 3,
5…,13.
Write 0x1F into the Indirect Byte Register 160 (0xA0) // for the write operation to 15th entry in the ACL Port Register
16 (0x12) bit4=1 to write ACL, Bits[3:0] = 0xF to write entry 15.
The bit arrangement of the example above assumes Layer 2 rule of MODE = 01 in ACL Port Register 1 (0x01), refer to
ACL format for MODE = 10 and 11.

4.9 EEE Indirect Registers

The EEE function is for all copper ports only. The EEE registers are provided on global and per-port basis. These reg-
isters are read/write using indirect memory access as below: LPI means low power idle.

TABLE 4-24: EEE GLOBAL REGISTERS

Address Name Description Mode Default
EEE Global Register 0
Global EEE QM Buffer Control Register
Reg. 110 (0x6E) Bits[7:5] = 001 for EEE, Reg. 110 Bits[3:0] = 0x0 for the indirect global register,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x30 (Bits[15:8]), 0x31 (Bits[7:0])
Location: (001 EEE) -> {0x0, offset} -> 0xA0 holds the data.
15 - 8 Reserved — RO 0x40

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 KSZ8795CLX
TABLE 4-24: EEE GLOBAL REGISTERS (CONTINUED)
Address Name Description Mode Default
7 LPI 1 = LPI request will be stopped if input traffic is R/W 0
Terminated detected.
By Input Traf- 0 = LPI request won’t be stopped by input traffic.
fic Enable
6-0 Reserved — RO 0x10
EEE Global Register 1
Global Empty TXQ to LPI Wait Time Control Register
Reg. 110 (0x6E) Bits[7:5] = 001 for EEE, Reg. 110 Bits[3:0] = 0x0 for the indirect global register,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x32 (Bits[15:8]), 0x33 (Bits[7:0])
Location: (001 EEE) -> {0x0, offset} -> 0xA0 holds the data.
15 - 0 Empty TXQ This register specifies the time that the LPI request R/W 0x10
to LPI Wait will be generated after a TXQ has been empty
Time exceeds this configured time. This is only valid
when EEE 100BT is enabled. This setting will apply
to all the ports. The unit is 1.3 ms. The default
value is 1.3s (range from 1.3 ms to 86 seconds)
EEE Global Register 2
Global EEE PCS DIAGNOSTIC Register
Reg. 110 (0x6E) Bits[7:5] = 001 for EEE, Reg. 110 Bits[3:0] = 0x0 for the indirect global register,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x34(Bits[15:8]), 0x35 (Bits[7:0])
Location: (001 EEE) -> {0x0, offset} -> 0xA0 holds the data.
15 - 12 Reserved — RO 0x6
11 - 8 Reserved — RO 0x8
7-4 Reserved — RO 0x0
3 Port 4 Next 1 = Enable next page exchange during Auto-Nego- R/W 1
Page Enable tiation.
0 = Skip next page exchange during Auto-Negotia-
tion.
2 Port 3 Next 1 = Enable next page exchange during Auto-Nego- R/W 1
Page Enable tiation.
0 = Skip next page exchange during Auto-Negotia-
tion.
1 Port 2 Next 1 = Enable next page exchange during Auto-Nego- R/W 1
Page Enable tiation.
0 = Skip next page exchange during Auto-Negotia-
tion.
0 Port 1 Next 1 = Enable next page exchange during Auto-Nego- R/W 1
Page Enable tiation.
0 = Skip next page exchange during Auto-Negotia-
tion.
EEE Global Register 3
Global EEE Minimum LPI cycles before back to Idle Control Register
Reg. 110 (0x6E) Bits[7:5] = 001 for EEE, Reg. 110 Bits[3:0] = 0x0 for the indirect global register,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x36 (Bits[15:8], 0x37 (Bits[7:0])
Location: (001 EEE) -> {0x0, offset} -> 0xA0 holds the data.
15 - 0 Reserved — RO 0x0000

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KSZ8795CLX
TABLE 4-24: EEE GLOBAL REGISTERS (CONTINUED)
Address Name Description Mode Default
EEE Global Register 4
Global EEE Wakeup Error Threshold Control Register
Reg. 110 (0x6E) Bits[7:5] = 001 for EEE, Reg. 110 Bits[3:0] = 0x0 for the indirect global register,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x38 (Bits[15:8]), 0x39 (Bits[7:0])
Location: (001 EEE) -> {0x0, offset} -> 0xA0 holds the data.
15 - 0 EEE Wakeup This value specifies the maximum time allowed for RO 0x0201
Threshold PHY to wake up.
If wakeup time is longer than this, EEE wakeup
error count will be incremented.
Note: This is EEE standard, don’t change.
EEE Global Register 5
Global EEE PCS Diagnostic Control Register
Reg. 110 (0x6E) Bits[7:5] = 001 for EEE, Reg. 110 Bits[3:0] = 0x0 for the indirect global register,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x3A (Bits[15:8]), 0x3B (Bits[7:0])
Location: (001 EEE) -> {0x0, offset} -> 0xA0 holds the data.
15 - 0 Reserved — RO 0x0001

TABLE 4-25: EEE PORT REGISTERS

Address Name Description Mode Default
EEE Port Register 0
Port Auto-Negotiation Expansion Status Register
Reg. 110 (0x6E) Bits[7:5] = 001 for EEE, Reg. 110 Bits[3:0] = 0xn, n = 1-4 for the Indirect Port Register,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x0C (Bits[15:8]), 0x0D (Bits[7:0])
Location: (001 EEE) -> {0xn, offset} -> 0xA0 holds the data.
15 - 7 Reserved — RO 9h000
6 Receive Next 1 = Received Next Page storage location is speci- RO 1
Page Loca- fied by bits[6:5]
tion Able 0 = Received Next Page storage location is not
specified by bits[6:5]
5 Received 1 = Link Partner Next Pages are stored in MIIM RO 1
Next Page Register 8h (Additional next page)
Storage 0 = Link Partner Next Pages are stored in MIIM
Location Register 5h
4 Parallel 1 = A fault has been detected via the Parallel R/LH 0
Detection Detection function.
Fault 0 = A fault has not been detected via the Parallel
Detection function.

This bit is cleared after reading.

3 Link Partner 1 = Link Partner is Next Page abled RO 0
Next Page 0 = Link Partner is not Next Page abled
Able
2 Next Page 1 = Local Device is Next Page abled RO 1
Able 0 = Local Device is not Next Page abled
1 Page 1 = A New Page has been received R/LH 0
Received 0 = A New Page has not been received

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 KSZ8795CLX
TABLE 4-25: EEE PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
0 Link Partner 1 = Link Partner is Auto-Negotiation abled RO 0
Auto-Negoti- 0 = Link Partner is not Auto-Negotiation abled
ation Able
EEE Port Register 1
Port Auto-Negotiation Next Page Transmit Register
Reg. 110 (0x6E) Bits[7:5] = 001 for EEE, Reg. 110 Bits[3:0] = 0xn, n = 1-4 for the Indirect Port Register ,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x0E (Bits[15:8]), 0x0F (Bits[7:0])
Location: (001 EEE) -> {0xn, offset} -> 0xA0 holds the data.
This register doesn’t need to be set if EEE Port Register 5 Bit[7] = 1 default for Automatically perform EEE
capability
15 Next Page Next Page (NP) is used by the Next Page function R/W 0
to indicate whether or not this is the last Next Page
to be transmitted. NP shall be set as follows:

1 = Additional Next Page(s) will follow.

0 = Last page.
14 Reserved — RO 0
13 Message Message Page (MP) is used by the Next Page R/W 1
Page function to differentiate a Message Page from an
Unformatted Page. MP shall be set as follows:

1 = Message Page
0 = Unformatted Page
12 Acknowledge Acknowledge 2 (Ack2) is used by the Next Page R/W 0
2 function to indicate that a device has the ability to
comply with the message. Ack2 shall be set as fol-
lows:

1 = Will comply with message.

0 = Cannot comply with message.
11 Toggle Toggle (T) is used by the Arbitration function to RO 0
ensure synchronization with the Link Partner during
Next
Page exchange. This bit shall always take the
opposite value of the Toggle bit in the previously
exchanged
Link Codeword. The initial value of the Toggle bit in
the first Next Page transmitted is the inverse of
Bit[11]
in the base Link Codeword and, therefore, may
assume a value of logic one or zero. The Toggle bit
shall be set as follows:

1 = Previous value of the transmitted Link Code-

word equal to logic zero.
0 = Previous value of the transmitted Link Code-
word equal to logic one.
10 - 0 Message/ Message/Unformatted Code field Bits[10:0] R/W 1
Unformatted
Code Field

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KSZ8795CLX
TABLE 4-25: EEE PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
EEE Port Register 2
Port Auto-Negotiation Link Partner Next Page Receive Register
Reg. 110 (0x6E) Bits[7:5] = 001 for EEE, Reg. 110 Bits[3:0] = 0xn, n = 1-4 for the Indirect Port Register,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x10 (Bits[15:8]), 0x11 (Bits[7:0])
Location: (001 EEE) -> {0xn, offset} -> 0xA0 holds the data.
15 Next Page Next Page (NP) is used by the Next Page function RO 0
to indicate whether or not this is the last Next Page
to be transmitted. NP shall be set as follows:

1 = Additional Next Page(s) will follow.

0 = Last page.
14 Acknowledge Acknowledge (Ack) is used by the Auto-Negotiation RO 0
function to indicate that a device has successfully
received its Link Partner’s Link Codeword. The
Acknowledge Bit is encoded in Bit D14 regardless
of the value of the Selector Field or Link Codeword
encoding. If no Next Page information is to be sent,
this bit shall be set to logic one in the Link Code-
word after the reception of at least three consecu-
tive and consistent FLP Bursts (ignoring the
Acknowledge bit value).
13 Message Message Page (MP) is used by the Next Page RO 0
Page function to differentiate a Message Page from an
Unformatted
Page. MP shall be set as follows:

1 = Message Page
0 = Unformatted Page
12 Acknowledge Acknowledge 2 (Ack2) is used by the Next Page RO 0
2 function to indicate that a device has the ability to
comply with the message. Ack2 shall be set as fol-
lows:

1 = Will comply with message.

0 = Cannot comply with message.
11 Toggle Toggle (T) is used by the Arbitration function to RO 0
ensure synchronization with the Link Partner during
Next Page exchange. This bit shall always take the
opposite value of the Toggle bit in the previously
exchanged Link Codeword. The initial value of the
Toggle bit in the first Next Page transmitted is the
inverse of Bit[11] in the base Link Codeword and,
therefore, may assume a value of logic one or zero.
The Toggle bit shall be set as follows:

1 = Previous value of the transmitted Link Code-

word equal to logic zero.
0 = Previous value of the transmitted Link Code-
word equal to logic one.
10 - 0 Message/ Message/Unformatted Code field bits [10:0] RO 0
Unformatted
Code Field

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 KSZ8795CLX
TABLE 4-25: EEE PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
EEE Port Register 3
Link Partner EEE Capability Status and Local Device EEE Capability Advisement Register
Reg. 110 (0x6E) Bits[7:5] = 001 for EEE, Reg. 110 Bits[3:0] = 0xn, n = 1-4 for the Indirect Port Register,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x28 (Bits[15:8]), 0x29 (Bits[7:0])
Location: (001 EEE) -> {0xn, offset} -> 0xA0 holds the data.
15 Reserved — RO 0
14 LP 1 = EEE is supported for 10GBASE-KR RO 0
10GBASE- 0 = EEE is not supported for 10GBASE-KR
KR EEE
Note: LP = Link Partner
13 LP 1 = EEE is supported for 10GBASE-KX4 RO 0
10GBASE- 0 = EEE is not supported for 10GBASE-KX4
KX4 EEE
12 LP 1 = EEE is supported for 1000BASE-KX RO 0
1000BASE- 0 = EEE is not supported for 1000BASE-KX
KX EEE
11 LP 1 = EEE is supported for 10GBASE-T RO 0
10GBASE-T 0 = EEE is not supported for 10GBASE-T
EEE
10 LP 1 = EEE is supported for 1000BASE-T RO 0
1000BASE-T 0 = EEE is not supported for 1000BASE-T
EEE
9 LP 1 = EEE is supported for 100BASE-TX RO 0
100BASE-TX 0 = EEE is not supported for 100BASE-TX
EEE
8-2 Reserved — RO 7h’0
1 Local 1 = EEE is supported for 100BASE-TX R/W 1
100BASE-TX 0 = EEE is not supported for 100BASE-TX
EEE
Note: This is for local port to support EEE
capability
0 Reserved — RO 0
EEE Port Register 4
Port EEE Wake Up Error Count Register
Reg. 110 (0x6E) Bits[7:5] = 001 for EEE, Reg. 110 Bits[3:0] = 0xn, n = 1-4 for the Indirect Port Register,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x2A (Bits[15:8]), 0x2B (Bits[7:0])
Location: (001 EEE) -> {0xn, offset} -> 0xA0 holds the data.
15 - 0 EEE Wakeup This count is incremented by one whenever a RO 0x0000
Error wakeup from LPI to Idle state is longer than the
Counter Wake-Up error threshold time specified in EEE
Global Register 4. The default of Wake-Up error
threshold time is 20.5 µs. This register is read-
cleared.

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KSZ8795CLX
TABLE 4-25: EEE PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
EEE Port Register 5
Port EEE Control Register
Reg. 110 (0x6E) Bits[7:5] = 001 for EEE, Reg. 110 Bits[3:0] = 0xn, n = 1-4 for the Indirect Port Register,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x2C (Bits[15:8]), 0x2D (bits[7:0])
Location: (001 EEE) -> {0xn, offset} -> 0xA0 holds the data.
15 10BT EEE 1 = 10BT EEE mode is disabled R/W 1
Disable 0 = 10BT EEE mode is enabled
Note: 10BT EEE mode save power by reduc-
ing signal amplitude only.
14 - 8 Reserved — RO 7h’0
7 H/W Based 1 = H/W will automatically perform EEE capability R/W 1
EEE NP exchange with Link Partner through next page
Auto-Negoti- exchange. EEE 100BT enable (Bit[0] of this regis-
ation Enable ter). Will be set by H/W if EEE capability is
matched.
0 = H/W-based EEE capability exchange is off.
EEE capability exchange is done by software.
6 H/W 100BT 1 = 100BT EEE is enabled by H/W-based np R 0
EEE Enable exchange
Status 0 = 100BT EEE is disabled
5 TX LPI 1 = Indicates that the transmit PCS has received R/RC 0
Received low power idle signaling one or more times since
the register was last read.
0 = Indicates that the PCS has not received low
power idle signaling.
This bit is cleared after reading.
4 TX LPI 1 = Indicates that the transmit PCS is currently R 0
Indication receiving low power idle signals.
0 = Indicates that the PCS is not currently receiving
low power idle signals.
3 RX LPI 1 = Indicates that the receive PCS has received R/RC 0
Received low power idle signaling one or more times since
the register was last read.
0 = Indicates that the PCS has not received low
power idle signaling.

This bit is cleared after reading.

2 RX LPI 1 = Indicates that the receive PCS is currently R 0
Indication receiving low power idle signals.
0 = Indicates that the PCS is not currently receiving
low power idle signals.
1 EEE SW 1 = EEE is enabled through S/W setting Bit[0] of R/W 0
Mode Enable this register.
0 = EEE is enabled through H/W Auto-Negotiation
0 EEE SW 1 = EEE 100BT is enabled R/W 0
100BT 0 = EEE 100BT is disabled
Enable
Note: This bit could be set by S/W or H/W if H/
W-based EEE Next Page Auto-Negotia-
tion enable is on.

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 KSZ8795CLX
TABLE 4-25: EEE PORT REGISTERS (CONTINUED)
Address Name Description Mode Default
EEE Port Register 6
Port EEE LPI Recovery Time Register
Reg. 110 (0x6E) Bits[7:5] = 001 for EEE, Reg. 110 Bits[3:0] = 0xn, n = 1-4 for the Indirect Port Register,
Reg. 111 (0x6F) Bits[7:0] = Offset to access the Indirect Byte Register 0xA0.
Offset: 0x2E (Bits[15:8]), 0x2F (Bits[7:0])
Location: (001 EEE) -> {0xn, offset} -> 0xA0 holds the data.
15 - 8 Reserved — RO 1
7-0 LPI Recovery This register specifies the time that the MAC device R/W 0x27
Counter has to wait before it can start to send out packets.
This value should be the maximum of the LPI
recovery time between local device and remote
device. The unit is 640 ns.
The default is about 25 µs = 39 (0x27) × 640 ns
Note: This value can be adjusted if PHY
recovery time is less than the standard
20.5 µs for the packets to be sent out
quickly from EEE LPI mode.
Programming Examples:
Read Operation
1. Use the Indirect Access Control Register to select register to be read, to read the EEE Global Register 0 (Global
EEE QM Buffer Control Register).
2. Write 0x30 to the Register 110 (0x6E) // EEE selected and read operation, and 4 MSBs of port number = 0 for
the global register.
3. Write 0x30 to the Indirect Register 111 (0x6F) // trigger the read operation and ready to read the EEE Global Reg-
ister 0 Bits[15:8].
4. Read the Indirect Byte Register 160 (0xA0) // Get the Bits[15:8] value of the EEE Global Register 0.
Write Operation
1. Write 0x20 to Register 110 (0x6E) // EEE selected and write operation, 4 MSBs of port number = 0 is for global
register.
2. Write 0x31 to Register 111 (0x6F) // select the offset address, ready to write the EEE Global Register 0 Bits[7:0].
3. Write new value to the Indirect Byte Register 160 (0xA0) Bits[7:0].

4.10 Management Information Base (MIB) Counters

The MIB counters are provided on per port basis. These counters are read using indirect memory access as in Table 4-
26.

TABLE 4-26: PORT MIB COUNTER INDIRECT MEMORY OFFSETS

Offset Counter Name Description
0x0 RxHiPriorityByte Rx hi-priority octet count including bad packets.
0x1 RxUndersizePkt Rx undersize packets w/good CRC.
0x2 RxFragments Rx fragment packets w/bad CRC, symbol errors or alignment errors.
0x3 RxOversize Rx oversize packets w/good CRC (maximum: 1536 or 1522 bytes).
0x4 RxJabbers Rx packets longer than 1522 bytes w/either CRC errors, alignment
errors, or symbol errors (depends on max packet size setting) or Rx
packets longer than 1916 bytes only.
0x5 RxSymbolError Rx packets w/ invalid data symbol and legal preamble, packet size.
0x6 RxCRCerror Rx packets within (64,1522) bytes w/an integral number of bytes and a
bad CRC (upper limit depends on max packet size setting).

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KSZ8795CLX
TABLE 4-26: PORT MIB COUNTER INDIRECT MEMORY OFFSETS (CONTINUED)
Offset Counter Name Description
0x7 RxAlignmentError Rx packets within (64,1522) bytes w/a non-integral number of bytes
and a bad CRC (upper limit depends on max packet size setting).
0x8 RxControl8808Pkts The number of MAC control frames received by a port with 88-08h in
EtherType field.
0x9 RxPausePkts The number of PAUSE frames received by a port. PAUSE frame is
qualified with EtherType (88-08h), DA, control opcode (00-01), data
length (64 byte min), and a valid CRC.
0xA RxBroadcast Rx good broadcast packets (not including errored broadcast packets or
valid multicast packets).
0xB RxMulticast Rx good multicast packets (not including MAC control frames, errored
multicast packets or valid broadcast packets).
0xC RxUnicast Rx good unicast packets.
0xD Rx64Octets Total Rx packets (bad packets included) that were 64 octets in length.
0xE Rx65to127Octets Total Rx packets (bad packets included) that are between 65 and 127
octets in length.
0xF Rx128to255Octets Total Rx packets (bad packets included) that are between 128 and 255
octets in length.
0x10 Rx256to511Octets Total Rx packets (bad packets included) that are between 256 and 511
octets in length.
0x11 Rx512to1023Octets Total Rx packets (bad packets included) that are between 512 and
1023 octets in length.
0x12 Rx1024to1522Octets Total Rx packets (bad packets included) that are between 1024 and
1522 octets in length.
0x13 Rx1523to2000Octets Total Rx packets (bad packets included) that are between 1523 and
2000 octets in length.
0x14 Rx2001toMax-1Octets Total Rx packets (bad packets included) that are between 2001 and
Max-1 octets in length (upper limit depends on max packet size ?1).
0x15 TxHiPriorityByte Tx hi-priority good octet count, including PAUSE packets.
0x16 TxLateCollision The number of times a collision is detected later than 512 bit-times into
the Tx of a packet.
0x17 TxPausePkts The number of PAUSE frames transmitted by a port.
0x18 TxBroadcastPkts Tx good broadcast packets (not including errored broadcast or valid
multicast packets).
0x19 TxMulticastPkts Tx good multicast packets (not including errored multicast packets or
valid broadcast packets).
0x1A TxUnicastPkts Tx good unicast packets.
0x1B TxDeferred Tx packets by a port for which the 1st Tx attempt is delayed due to the
busy medium.
0x1C TxTotalCollision Tx total collision, half-duplex only.
0x1D TxExcessiveCollision A count of frames for which Tx fails due to excessive collisions.
0x1E TxSingleCollision Successful Tx frames on a port for which Tx is inhibited by exactly one
collision.
0x1F TxMultipleCollision Successful Tx frames on a port for which Tx is inhibited by more than
one collision.

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 KSZ8795CLX
TABLE 4-27: FORMAT OF PER-PORT MIB COUNTER
Address Name Description Mode Default
For Port 2, the base is 0x20, same offset definition (0x20-0x3f)
For Port 3, the base is 0x40, same offset definition (0x40-0x5f)
For Port 4, the base is 0x60, same offset definition (0x60-0x7f)
For Port 5, the base is 0x80, same offset definition (0x80-0x9f)
38 Overflow 1 = Counter overflow. RO 0
0 = No Counter overflow.
37 Count Valid 1 = Counter value is valid. RO 0
0 = Counter value is not valid.
36 - 30 Reserved — RO All ‘0’
29 - 0 Counter Counter Value RO 0
Values

TABLE 4-28: ALL PORT DROPPED PACKET MIB COUNTERS

Offset Counter Name Description
0x100 Port 1 Rx Total Bytes Port 1 Rx total octet count, including bad packets.
0x101 Port 1 Tx Total Bytes Port 1 Tx total good octet count, including PAUSE packets.
0x102 Port 1 Rx Drop Packets Port 1 Rx packets dropped due to lack of resources.
0x103 Port 1 Tx Drop Packets Port 1 Tx packets dropped due to lack of resources.
0x104 Port 2 Rx Total Bytes Port 2 Rx total octet count, including bad packets.
0x105 Port 2 Tx Total Bytes Port 2 Tx total good octet count, including PAUSE packets.
0x106 Port 2 Rx Drop Packets Port 2 Rx packets dropped due to lack of resources.
0x107 Port 2 Tx Drop Packets Port 2 Tx packets dropped due to lack of resources.
0x108 Port 3 Rx Total Bytes Port 3 Rx total octet count, including bad packets.
0x109 Port 3 Tx Total Bytes Port 3 Tx total good octet count, including PAUSE packets.
0x10A Port 3 Rx Drop Packets Port 3 Rx packets dropped due to lack of resources.
0x10B Port 3 Tx Drop Packets Port 3 Tx packets dropped due to lack of resources.
0x10C Port 4 Rx Total Bytes Port 4 Rx total octet count, including bad packets.
0x10D Port 4 Tx Total Bytes Port 4 Tx total good octet count, including PAUSE packets.
0x10E Port 4 Rx Drop Packets Port 4 Rx packets dropped due to lack of resources.
0x10F Port 4 Tx Drop Packets Port 4 Tx packets dropped due to lack of resources.
0x110 Port 5 Rx Total Bytes Port 5 Rx total octet count, including bad packets.
0x111 Port 5 Tx Total Bytes Port 5 Tx total good octet count, including PAUSE packets.
0x112 Port 5 Rx Drop Packets Port 5 Rx packets dropped due to lack of resources.
0x113 Port 5 Tx Drop Packets Port 5 Tx packets dropped due to lack of resources.

TABLE 4-29: FORMAT OF PER-PORT RX/TX TOTAL BYTES MIB COUNTER (IN TABLE 4-28)
Address Name Description Mode Default
38 Overflow 1 = Counter overflow. RO 0
0 = No Counter overflow.
37 Count Valid 1 = Counter value is valid. RO 0
0 = Counter value is not valid.
36 Reserved — RO 0
35 - 0 Counter Counter value RO 0
Values

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KSZ8795CLX
TABLE 4-30: FORMAT OF ALL DROPPED PACKET MIB COUNTER (IN TABLE 4-28)
Address Name Description Mode Default
38 Overflow 1 = Counter overflow. RO 0
0 = No Counter overflow.
37 Count Valid 1 = Counter value is valid. RO 0
0 = Counter value is not valid.
36 - 16 Reserved — RO All ‘0’
15 - 0 Counter Counter value RO 0
Values
Please note that all per-port MIB counters are Read-Clear.
KSZ8795CLX also offers the statistic control capability by the Global Register 8 to control MIB to flush counter or freeze
counter per port.
The KSZ8795CLX provides a total of 36 MIB counters per port. These counters are used to monitor the port activity for
network management and maintenance. These MIB counters are read using indirect memory access, per the following
examples.
1. MIB counter read (read Port 1 Rx64Octets counter)
Write to Register 110 with 0x1c (read MIB counters selected)
Write to Register 111 with 0xd (trigger the read operation)
Then:
Read Register 116 (counter value [39:32])
// If Bit [38] = 1, there was a counter overflow
Read Register 117 (counter value [31:24])
Read Register 118 (counter value [23:16])
Read Register 119 (counter value [15:8])
Read Register 120 (counter value [7:0])
2. MIB counter read (read Port 2 Rx64Octets counter)
Write to Register 110 with 0x1c (read MIB counter selected)
Write to Register 111 with 0x2d (trigger the read operation)
Then:
Read Register 116 (counter value [39:32])
// If Bit[38] = 1, there was a counter overflow
Read Register 117 (counter value [31:24])
Read Register 118 (counter value [23:16])
Read Register 119 (counter value [15:8])
Read Register 120 (counter value [7:0])
3. MIB counter read (read Port 1 TX drop packets)
Write to Register 110 with 0x1d
Write to Register 111 with 0x03
Then:
Read Register 116 (counter value [39:32])
// If Bit[38] = 1, there was a counter overflow
Read Register 119 (counter value [15:8])
Read Register 120 (counter value [7:0])

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 KSZ8795CLX
To read out all the counters, the best performance over the SPI bus is (160+3) × 8 × 20 = 26 µs, where there are 160
registers, 3 overhead, 8 clocks per access, at 50 MHz. In the heaviest condition, the byte counter will overflow in 2 min-
utes. It is recommended that the software read all the counters at least every 30 seconds. All port MIB counters are
designed as “read clear.”

4.11 MIIM Registers

All the registers defined in this section can be also accessed via the SPI interface.
Note that different mapping mechanisms are used for MIIM and SPI. The “PHYAD” defined in IEEE is assigned as “0x1”
for Port 1, “0x2” for Port 2, “0x3” for Port 3 and “0x4” for Port 4. The “REGAD” supported are 0x0-0x5 (0h-5h), 0x1D
(1dh) and 0x1F (1fh).

TABLE 4-31: MIIM REGISTERS

Address Name Description Mode Default
Register 0h: Basic Control
15 Soft Reset 1 = PHY soft reset. R/W 0
0 = Normal operation. (SC)
14 Loopback 1 = Perform MAC loopback, loopback path as fol- R/W 0
lows:
Assume the loopback is at Port 1 MAC, Port 2 is
the monitor port.
Port 1 MAC Loopback (Port 1 Reg. 0,
Bit[14] = ‘1’
Start: RXP2/RXM2 (Port 2). Can also start from
Port 3, 4, 5
Loopback: MAC/PHY interface of Port 1’s MAC
End: TXP2/TXM2 (Port 2). Can also end at Ports 3,
4, 5 respectively

Setting address 0x3, 4, 5 Reg. 0, Bit[14] = ‘1’ will

perform MAC loopback on Ports 3, 4, 5, respec-
tively.
0 = Normal Operation.
13 Force 100 1 = 100 Mbps. R/W 1
0 = 10 Mbps.
12 AN Enable 1 = Auto-Negotiation enabled. R/W 1
0 = Auto-Negotiation disabled.
11 Power Down 1 = Power down. R/W 0
0 = Normal operation.
10 PHY Isolate 1 = Electrical PHY isolation of PHY from Tx+/Tx-. R/W 0
0 = Normal operation.
9 Restart AN 1 = Restart Auto-Negotiation. R/W 0
0 = Normal operation.
8 Force Full 1 = Full duplex. R/W 1
Duplex 0 = Half duplex.
7 Reserved — RO 0
6 Reserved — RO 0
5 Hp_mdix 1 = HP Auto-MDI/MDIX mode R/W 1
0 = Microchip Auto-MDI/MDIX mode
4 Force MDI 1 = MDI mode when disable Auto-MDI/MDIX. R/W 0
0 = MDIX mode when disable Auto-MDI/MDIX.
3 Disable Auto 1 = Disable Auto-MDI/MDIX. R/W 0
MDI/MDI-X 0 = Enable Auto-MDI/MDIX.
2 Disable Far 1 = Disable far end fault detection. R/W 0
End Fault 0 = Normal operation.

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KSZ8795CLX
TABLE 4-31: MIIM REGISTERS (CONTINUED)
Address Name Description Mode Default
1 Disable 1 = Disable transmit. R/W 0
Transmit 0 = Normal operation.
0 Disable LED 1 = Disable LED. R/W 0
0 = Normal operation.
Register 1h: Basic Status
15 T4 Capable 0 = Not 100 BASET4 capable. RO 0
14 100 Full 1 = 100BASE-TX full-duplex capable. RO 1
Capable 0 = Not capable of 100BASE-TX full-duplex.
13 100 Half 1 = 100BASE-TX half-duplex capable. RO 1
Capable 0 = Not 100BASE-TX half-duplex capable.
12 10 Full 1 = 10BASE-T full-duplex capable. RO 1
Capable 0 = Not 10BASE-T full-duplex capable.
11 10 Half 1 = 10BASE-T half-duplex capable. RO 1
Capable 0 = 10BASE-T half-duplex capable.
10 - 7 Reserved — RO 0
6 Reserved — RO 0
5 AN Complete 1 = Auto-Negotiation complete. RO 0
0 = Auto-Negotiation not completed.
4 Far End Fault 1 = Far end fault detected. RO 0
0 = No far end fault detected.
3 AN Capable 1 = Auto-Negotiation capable. RO 1
0 = Not Auto-Negotiation capable.
2 Link Status 1 = Link is up. RO 0
0 = Link is down.
1 Reserved — RO 0
0 Extended 0 = Not extended register capable. RO 0
Capable
Register 2h: PHYID HIGH
15 - 0 Phyid High High order PHYID bits. RO 0x0022
Register 3h: PHYID LOW
15 - 0 Phyid Low Low order PHYID bits. RO 0x1550
Register 4h: Advertisement Ability
15 Reserved — RO 0
14 Reserved — RO 0
13 Reserved — RO 0
12 - 11 Reserved — RO 01
10 Pause 1 = Advertise pause ability. R/W 1
0 = Do not advertise pause ability.
9 Reserved — R/W 0
8 Adv 100 Full 1 = Advertise 100 full-duplex ability. R/W 1
0 = Do not advertise 100 full-duplex ability.
7 Adv 100 Half 1 = Advertise 100 half-duplex ability. R/W 1
0 = Do not advertise 100 half-duplex ability.
6 Adv 10 Full 1 = Advertise 10 full-duplex ability. R/W 1
0 = Do not advertise 10 full-duplex ability.
5 Adv 10 Half 1 = Advertise 10 half-duplex ability. R/W 1
0 = Do not advertise 10 half-duplex ability.

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 KSZ8795CLX
TABLE 4-31: MIIM REGISTERS (CONTINUED)
Address Name Description Mode Default
4-0 Selector [00001] = IEEE 802.3 RO 00001
Field
Register 5h: Link Partner Ability
15 Reserved — RO 0
14 Reserved — RO 0
13 Reserved — RO 0
12 - 11 Reserved — RO 0
10 Pause 1 = Link partner flow control capable. RO 0
0 = Link partner not flow control capable.
9 Reserved — RO 0
8 Adv 100 Full 1 = Link partner 100BT full-duplex capable. RO 0
0 = Link partner not 100BT full-duplex capable.
7 Adv 100 Half 1 = Link partner 100BT half-duplex capable. RO 0
0 = Link partner not 100BT half-duplex capable.
6 Adv 10 Full 1 = Link partner 10BT full-duplex capable. RO 0
0 = Link partner not 10BT full-duplex capable.
5 Adv 10 Half 1 = Link partner 10BT half-duplex capable. RO 0
0 = Link partner not 10BT half-duplex capable.
4-0 Reserved — RO 00001
Register 1dh: LinkMD Control/Status
15 CDT_Enable 1 = Enable cable diagnostic. After CDT test has R/W 0
completed, this bit will be self-cleared. (SC)
0 = Indicates cable diagnostic test (if enabled) has
completed and the status information is valid for
reading.
14 - 13 CDT_Result 00 = Normal condition RO 00
01 = Open condition detected in cable
10 = Short condition detected in cable
11 = Cable diagnostic test has failed
12 CDT 10M 1 = Less than 10 meter short RO 0
Short
11 - 9 Reserved — RO 0
8-0 CDT_- Distance to the fault, approximately 0.4m × CDT_- RO 000000000
Fault_Count Fault_Count[8:0]
Register 1fh: PHY Special Control/Status
15 - 11 Reserved — RO 0000000000
10 - 8 Port Indicate the current state of port operation mode: RO 001
Operation 000 = Reserved
Mode 001 = still in auto-negotiation
Indication 010 = 10BASE-T half duplex
011 = 100BASE-TX half duplex
100 = Reserved
101 = 10BASE-T full duplex
110 = 100BASE-TX full duplex
111 = PHY/MII isolate
7-6 Reserved — RO 00
5 Polrvs 1 = Polarity is reversed RO 0
0 = Polarity is not reversed
4 MDI-X Status 1 = MDI RO 0
0 = MDI-X

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KSZ8795CLX
TABLE 4-31: MIIM REGISTERS (CONTINUED)
Address Name Description Mode Default
3 Force_lnk 1 = Force link pass R/W 0
0 = Normal operation
2 Pwrsave 1 = Enable power save R/W 0
0 = Disable power save
1 Remote 1 = Perform Remote loopback, loop back path as R/W 0
Loopback follows:
Port 1 (PHY ID address 0x1 Reg. 1fh,
Bit[1] = ‘1’
Start: RXP1/RXM1 (Port 1)
Loopback: PMD/PMA of Port 1’s PHY
End: TXP1/TXM1 (Port 1)
Setting PHY ID address 0x2, 3, 4, 5 Reg. 1fh, Bit[1]
= ‘1’, will perform remote loopback on Ports 2, 3, 4,
5.
0 = Normal Operation.
0 Reserved — RO 0

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 KSZ8795CLX
5.0 OPERATIONAL CHARACTERISTICS

5.1 Absolute Maximum Ratings*

Supply Voltage
(VDD12A, VDD12D) ...................................................................................................................................... –0.5V to +1.8V
(VDDAT, VDDIO) .......................................................................................................................................... –0.5V to +4.0V
Input Voltage ............................................................................................................................................. –0.5V to +4.0V
Output Voltage .......................................................................................................................................... –0.5V to +4.0V
Lead Temperature (soldering, 10s) ....................................................................................................................... +260°C
Storage Temperature (TS)...................................................................................................................... –55°C to +150°C
Maximum Junction Temperature ........................................................................................................................... +125°C
ESD Rating ................................................................................................................................................................ 5 kV
*Exceeding the absolute maximum rating may damage the device. Stresses greater than the absolute maximum rating
may cause permanent damage to the device. Operation of the device at these or any other conditions above those spec-
ified in the operating sections of this specification is not implied. Maximum conditions for extended periods may affect
reliability.

5.2 Operating Ratings**

Supply Voltage
(VDD12A, VDD12D) .............................................................................................................................. +1.140V to +1.260V
(VDDAT @ 3.3V)................................................................................................................................. +3.135V to +3.465V
(VDDAT @ 2.5V)................................................................................................................................. +2.375V to +2.625V
(VDDIO @ 3.3V) ................................................................................................................................. +3.135V to +3.465V
(VDDIO @ 2.5V) ................................................................................................................................. +2.375V to +2.625V
(VDDIO @ 1.8V) ................................................................................................................................. +1.710V to +1.890V
Ambient Temperature (TA)
Commercial .................................................................................................................................................. 0°C to +70°C
Industrial .................................................................................................................................................. –40°C to +85°C
Package Thermal Resistance (ΘJA, Note 5-1)...............................................................................................+55.05°C/W
Package Thermal Resistance (ΘJC, Note 5-1)+25.06°C/W**The device is not guaranteed to function outside its operat-
ing ratings. Unused inputs must always be tied to an appropriate logic voltage level (GND or VDD).
Note 5-1 No heat spreader in package. The thermal junction-to-ambient (ΘJA) and the thermal junction-to-case
(ΘJC) are under air velocity 0m/s.

Note: Do not drive input signals without power supplied to the device.

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KSZ8795CLX
6.0 ELECTRICAL CHARACTERISTICS
VIN = 1.2V/3.3V (typical); TA = +25°C. Specification is for packaged product only. There is no additional transformer con-
sumption due to use on chip termination technology with internal biasing for 10BASE-T and 100BASE-TX. The test con-
dition is in Port 5 RGMII mode (default). Measurements were taken with operating ratings.

TABLE 6-1: ELECTRICAL CHARACTERISTICS

Parameters Symbol Min. Typ. Max. Units Note
100BASE-TX Operation - All Ports 100% Utilization
100BASE-TX (Transmitter)
IDX — 142 — VDDAT
3.3V Analog
100BASE-TX 1.2V ID12 — 35 — mA VDD12A + VDD12D
100BASE-TX (Digital IO)
IDDIO — 15 — VDDIO
3.3V Digital
10BASE-T Operation - All Ports 100% Utilization
10BASE-T (Transmitter)
IDX — 135 — VDDAT
3.3V Analog
10BASE-T 1.2V ID12 — 30 — mA VDD12A + VDD12D
10BASE-T (Digital IO) 3.3V
IDDIO — 14 — VDDIO
Digital
Auto-Negotiation Mode
3.3V Analog IDX — 66 — VDDAT
1.2V Analog/Digital ID12 — 35 — mA VDD12A + VDD12D
3.3V Digital I/O IDDIO — 14 — VDDIO
Power Management Mode
Soft Power-Down Mode
ISPDM1 — 0.07 — VDDAT + VDDIO
3.3V
Soft Power-Down Mode
ISPDM2 — 0.2 — VDD12A + VDD12D
1.2V
Energy Detect Mode
IEDM1 — 21 — VDDAT + VDDIO
(EDPD) 3.3V
mA
Energy Detect Mode
IEDM2 — 26.5 — VDD12A + VDD12D
(EDPD) 1.2V
100BT EEE Mode at Idle
IEEE1 — 22.5 — VDDAT + VDDIO
3.3V
100BT EEE Mode at Idle
IEEE2 — 27 — VDD12A + VDD12D
1.2V
CMOS Input
2.0 — — VDDIO = 3.3V
Input High Voltage VIH 1.8 — — V VDDIO = 2.5V
1.3 — — VDDIO = 1.8V
— — 0.8 VDDIO = 3.3V
Input Low Voltage VIL — — 0.7 V VDDIO = 2.5V
— — 0.5 VDDIO = 1.8V
Input Current (Excluding
IIN — — 10 µA VIN = GND ~ VDDIO
Pull-Up/Pull-Down)
CMOS Outputs
2.4 — — VDDIO = 3.3V
Output High Voltage VOH 2.0 — — V VDDIO = 2.5V
1.5 — — VDDIO = 1.8V

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 KSZ8795CLX
TABLE 6-1: ELECTRICAL CHARACTERISTICS (CONTINUED)
Parameters Symbol Min. Typ. Max. Units Note
— — 0.4 VDDIO = 3.3V
Output Low Voltage VOL — — 0.4 V VDDIO = 2.5V
— — 0.3 VDDIO = 1.8V
Output Tri-State Leakage IOZ — — 10 µA VIN = GND ~ VDDIO
100BASE-TX Transmit (measured differentially after 1:1 transformer)
Peak Differential Output 100Ω termination on the differential
VO 0.95 — 1.05 V
Voltage output
100Ω termination on the differential
Output Voltage Imbalance VIMB — — 2 %
output
Rise/Fall Time 3 — 5 —
tr/tf ns
Rise/Fall Time Imbalance 0 — 0.5 —
Duty Cycle Distortion — — — ±0.5 ns —
Overshoot — — — 5 % —
Output Jitters — 0 0.75 1.4 ns Peak-to-Peak
10BASE-T Receive
Squelch Threshold VSQ 300 400 585 mV 5 MHz square wave
10BASE-T Transmit (measured differentially after 1:1 transformer) VDDAT = 3.3V
Peak Differential Output 100Ω termination on the differential
VP 2.2 2.5 2.8 V
Voltage output
Output Jitters — — 1.4 3.5 ns Peak-to-Peak
Rise/Fall Times — — 28 30 ns —
I/O Pin Internal Pull-Up and Pull-Down Resistance
I/O Pin Effective Pull-Up
R1.8PU 75 95 135 VDDIO = 1.8V
Resistance
I/O Pin Effective Pull-Down
R1.8PD 53 68 120 VDDIO = 1.8V
Resistance
I/O Pin Effective Pull-Up
R2.5PU 46 60 93 VDDIO = 2.5V
Resistance
kΩ
I/O Pin Effective Pull-Down
R2.5PD 46 59 103 VDDIO = 2.5V
Resistance
I/O Pin Effective Pull-Up
R3.3PU 35 45 65 VDDIO = 3.3V
Resistance
I/O Pin Effective Pull-Down
R3.3PD 37 46 74 VDDIO = 3.3V
Resistance

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KSZ8795CLX
7.0 TIMING DIAGRAMS

FIGURE 7-1: GMII SIGNALS TIMING DIAGRAM

TABLE 7-1: GMII TIMING PARAMETERS

Symbol Parameter Min. Typ. Max. Units
— Clock Cycle — 8 —
tIS Set-Up Time 1.2 — —
ns
tIH Hold Time 1.2 — —
tOD Output Delay Respect to Clock Falling Edge — — 1

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 KSZ8795CLX
FIGURE 7-2: RGMII V2.0 SPECIFICATION

TXC (SOURCE OF DATA) TXC (WITH INTERNAL

DELAY ADDED)

TXD[8:5][3:0] TXD[8:5]
TXD[3:0] TsetupT
TXD[7:4]
TXD[7:4][3:0]
TholdT
TXD[4] TXD[9
TX_CTL TXEN TXERR

TXC (AT RECEIVER) TholdR

TsetupR

RXC (SOURCE OF DATA) RXC (WITH INTERNAL

DELAY ADDED)

RXD[8:5][3:0]
RXD[3:0] RXD[8:5] TsetupT
RXD[7:4][3:0] RXD[7:4]
TholdT
RXD[4] RXD[9
RX_CTL RXDV RXERR

RXC (AT RECEIVER) TholdR

TsetupR

TABLE 7-2: RGMII TIMING PARAMETERS

Symbol Parameter Min. Typ. Max. Units
TskewT Data to clock output skew (at transmitter) (Note 7-1) –500 0 500 ps
TskewR Data to clock input skew (at receiver) (Note 7-1) 1 — 2.6
TsetupT Data to clock output setup (at transmitter – integrated delay) 1.0 2.0 —
TholdT Clock to data output hold (at transmitter – integrated delay) 1.0 2.0 —
ns
TsetupR Data to clock input setup (at receiver – integrated delay) 0.8 2.0 —
TholdR Clock to data input hold (at receiver – integrated delay) 0.8 2.0 —
Tcyc Clock Cycle Duration (Note 7-2) 7.2 8.0 8.8
Duty_G Duty Cycle for Gigabit 45 50 55
%
Duty_T Duty Cycle for 10/100T 40 50 60
tr/tf Rise/Fall Time (20-80%) — — 0.75 ns
Note 7-1 RGMII v2.0 add Internal Delay (RGMII-ID) option to match the data to clock output/input skew for
RGMII transmit and receiving, see the register 86 bits[4:3] for detail.
Note 7-2 For 10 Mbps and 100 Mbps. Tcyc will scale to 400 ns ±40 ns and 40 ns ±4 ns.

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KSZ8795CLX
FIGURE 7-3: MAC MODE MII TIMING - DATA RECEIVED FROM MII
RECEIVE TIMING

FIGURE 7-4: MAC MODE MII TIMING - DATA TRANSMITTED FROM MII

TRANSMIT TIMING

TABLE 7-3: MAC MODE MII TIMING PARAMETERS

10BASE-T/100BASE-TX
Symbol Parameter
Min. Typ. Max. Units
tcyc3 Clock Cycle — 400/ —
40
ts3 Set-Up Time 2 — — ns
th3 Hold Time 2 — —
tov3 Output Valid 3 8 10

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 KSZ8795CLX
FIGURE 7-5: PHY MODE MII TIMING - DATA RECEIVED FROM MII
RECEIVE TIMING

FIGURE 7-6: PHY MODE MII TIMING - DATA TRANSMITTED FROM MII

TRANSMIT TIMING

TABLE 7-4: PHY MODE MII TIMING PARAMETERS

10BASET/100BASET
Symbol Parameter
Min. Typ. Max. Units
tcyc4 Clock Cycle — 400/40 —
ts4 Set-Up Time 10 — —
ns
th4 Hold Time 0 — —
tov4 Output Valid 16 20 25

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KSZ8795CLX

FIGURE 7-7: RMII TIMING - DATA RECEIVED FROM RMII

TRANSMIT TIMING tCYC

REFCLK

t1

t2

TX_EN
TXD[1:0]

FIGURE 7-8: RMII TIMING - DATA TRANSMITTED FROM RMII

RECEIVE TIMING

tCYC

REFCLK

CRSDV
RXD[1:0]

tOD

TABLE 7-5: RMII TIMING PARAMETERS

Symbol Parameter Min. Typ. Max. Units
tcyc Clock Cycle — 20 —
t1 Set-Up Time 4 — —
ns
t2 Hold Time 2 — —
tod Output Delay 3 — 10

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 KSZ8795CLX

FIGURE 7-9: SPI INPUT TIMING

tSHSL

SPIS_N
tCHSL tSLCH tCHSH tSHCH

SPIC

tDVCH tCHDL

tCHDX tCLCH

SPID MSB LSB

tDLDH
tDHDL

HIGH IMPEDANCE
SPIQ

TABLE 7-6: SPI INPUT TIMING PARAMETERS

Symbol Parameter Min. Typ. Max. Units
fC Clock Frequency — — 50 MHz
tCHSL SPIS_N Inactive Hold Time 2 — —
tSLCH SPIS_N Active Set-Up Time 4 — —
tCHSH SPIS_N Active Hold Time 2 — —
tSHCH SPIS_N Inactive Set-Up Time 4 — — ns
tSHSL SPIS_N Deselect Time 10 — —
tDVCH Data Input Set-Up Time 4 — —
tCHDX Data Input Hold Time 2 — —
tCLCH Clock Rise Time — — 1
tCHCL Clock Fall Time — — 1
µs
tDLDH Data Input Rise Time — — 1
tDHDL Data Input Fall Time — — 1

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KSZ8795CLX

FIGURE 7-10: SPI OUTPUT TIMING

SPIS_N
tCH

SPIC

tCLQV tCL tSHQZ

tCLQX

SPIQ
tQLQH
tQHQL

SPID

TABLE 7-7: SPI OUTPUT TIMING PARAMETERS

Symbol Parameter Min. Typ. Max. Units
fC Clock Frequency — — 50 MHz
tCLQX SPIQ Hold Time 0 — 0
tCLQV Clock to Low SPIQ Valid — — 60
tCH Clock High Time 9 — —
tCL Clock Low Time 9 — — ns
tQLQH SPIQ Rise Time — — 50
tQHQL SPIQ Fall Time — — 50
tSHQZ SPIQ Disable Time — — 15

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 KSZ8795CLX

FIGURE 7-11: AUTO-NEGOTIATION TIMING

FLP FLP
BURST BURST

TX+/TX–
tFLPW

tBTB

CLOCK DATA CLOCK DATA

PULSE PULSE PULSE PULSE
TX+/TX–
tPW tPW

tCTD

tCTC

TABLE 7-8: AUTO-NEGOTIATION TIMING PARAMETERS

Symbol Parameter Min. Typ. Max. Units
tBTB FLP Burst to FLP Burst 8 16 24
ms
tFLPW FLP Burst Width — 2 —
tPW Clock/Data Pulse Width — 100 — ns
tCTD Clock Pulse to Data Pulse 55.5 64 69.5
µs
tCTC Clock Pulse to Clock Pulse 111 128 139
— Number of Clock/Data Pulses per Burst 17 — 33 —

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KSZ8795CLX

FIGURE 7-12: MDC/MDIO TIMING

tP

MDC

tMD1 tMD2

MDIO VALID VALID

(PHY INPUT) DATA DATA

tMD3

MDIO VALID
(PHY OUTPUT) DATA

TABLE 7-9: MDC/MDIO TYPICAL TIMING PARAMETERS

Symbol Parameter Min. Typ. Max. Units
fC Clock Frequency — 2.5 25 MHz
tP MDC Period — 400 —
tMD1 MDIO (PHY Input) Set-Up to Rising Edge of MDC 10 — —
ns
tMD2 MDIO (PHY Input) Hold from Rising Edge of MDC 4 — —
tMD3 MDIO (PHY Output) Delay from Rising Edge of MDC 5 222 —

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 KSZ8795CLX

FIGURE 7-13: POWER-DOWN/POWER-UP AND RESET TIMING

SUPPLY VOLTAGE
tVR tSR

RST#
tCS tCH

STRAP-IN VALUE
tRC

STRAP-IN/OUTPUT PIN

TABLE 7-10: RESET TIMING PARAMETERS

Symbol Parameter Min. Typ. Max. Units
tSR Stable Supply Voltages to Reset High 10 — — ms
tCS Configuration Set-Up Time 5 — —
tCH Configuration Hold Time 5 — — ns
tRC Reset to Strap-In Pin Output 6 — —
tVR 3.3V Rise Time 200 — — µs

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KSZ8795CLX
8.0 RESET CIRCUIT
The following discrete reset circuit, shown in Figure 8-1, is recommended when powering up the KSZ8795 device. For
an application where the reset circuit signal comes from another device (e.g., CPU, FPGA, etc.), the reset circuit as
shown in Figure 8-2 is recommended.

FIGURE 8-1: RECOMMENDED RESET CIRCUIT

VDDIO

D1: 1N4148

D1 R
10k
KS8795
RST

C
10µF

FIGURE 8-2: RECOMMENDED CIRCUIT FOR INTERFACING WITH CPU/FPGA RESET

VDDIO

D1 R
KS8795 10k CPU/FPGA
RST RST_OUT_n

C D2
10µF

D1, D2: 1N4148

Figure 8-2 shows a reset circuit recommended for applications where reset is driven by another device (for example,
the CPU or an FPGA). The reset out RST_OUT_n from CPU/FPGA provides the warm reset after power up reset. D2
is required if using different VDDIO voltage between switch and CPU/FPGA. Diode D2 should be selected to provide
maximum 0.3V VF (Forward Voltage), for example, VISHAY BAT54, MSS1P2L. Alternatively, a level shifter device can
also be used. D2 is not required if switch and CPU/FPGA use same VDDIO voltage.

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 KSZ8795CLX
9.0 SELECTION OF ISOLATION TRANSFORMER
One simple 1:1 isolation transformer is needed at the line interface. An isolation transformer with integrated common-
mode choke is recommended for exceeding FCC requirements at line side. Request to separate the center taps of RX/
TX at chip side. The IEEE 802.3u standard for 100BASE-TX assumes a transformer loss of 0.5 dB. For the transmit line
transformer, insertion loss of up to 1.3 dB can be compensated by increasing the line drive current by means of reducing
the ISET resistor value. Table 9-1 gives recommended transformer characteristics.

TABLE 9-1: 25 MHZ CRYSTAL/REFERENCE CLOCK SELECTION CRITERIA

Characteristics Value Test Condition
Turns Ratio 1 CT : 1 CT —
Open-Circuit Inductance (min.) 350 µH 100 mV, 100 kHz, 8 mA
Insertion Loss (max.) 1.1 dB 0.1 MHz to 100 MHz
HIPOT (min.) 1500 VRMS —

Table 9-2 lists the transformer vendors that provide compatible magnetic parts for this device.

TABLE 9-2: QUALIFIED MAGNETIC VENDORS

Number Number
Vendors and Parts Auto MDIX Vendors and Parts Auto MDIX
of Ports of Ports
Pulse H1164NL Yes 4 Pulse H1102 Yes 1
YCL PH406082 Yes 4 Bel Fuse S558-5999- Yes 1
U7
TDK TLA-6T718A Yes 1 YCL PT163020 Yes 1
LanKom LF-H41S Yes 1 Transpower HB726 Yes 1
Datatronic NT79075 Yes 1 Delta LF8505 Yes 1

10.0 SELECTION OF REFERENCE CRYSTAL

Table 10-1 lists the typical reference crystal characteristics for this device.

TABLE 10-1: TYPICAL REFERENCE CRYSTAL CHARACTERISTICS

Characteristics Value
Frequency 25.00000 MHz
Frequency Tolerance (max.) ≤ ±50 ppm
Load Capacitance (max.) (Note 10-1) 27 pF
Series Resistance (max. ESR) 40Ω
Note 10-1 Typical value varies per specific crystal specs.

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KSZ8795CLX
11.0 PACKAGE OUTLINES

Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging

FIGURE 11-1: 80-LEAD 10 MM X 10 MM LQFP

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 KSZ8795CLX
APPENDIX A: DATA SHEET REVISION HISTORY

TABLE A-1: REVISION HISTORY

Revision Section/Figure/Entry Correction

DS00002112B (01-05-17) All Sales listing and cover pages updated. Minor text
changes throughout.

Table 3-8, “Port 5 SW5-MII Updated right-most column header to be “MAC-to-

Connection,” on page 31 PHY Connection KSZ8795CLX SW5-MII MAC
Mode.”

Table 3-9, “Port 5 SW5-GMII Updated incorrect External GMAC column values.
Connection,” on page 31

Table 4-6, “Advanced control Updated the register 110 (0x6E) bits [7:5] to 101 =
Registers 110 - 111,” on Reserved.
page 64

DS00002112A (03-28-16) — Converted Micrel data sheet KSZ8795CLX to

Microchip DS00002112A. Minor text changes
throughout.

Section 4.0, "Device Regis- Updated various port register descriptions.

ters," on page 47

GMII and RGMII Diagrams Updated images and associated table parameters.

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KSZ8795CLX
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
contains 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
seminars 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
document.
Technical support is available through the web site at: http://microchip.com/support

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 KSZ8795CLX
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.

PART NO. X X X X X Examples:

a) KSZ8795CLXCC
Device Interface Package Special Temperature Bond Wire Configurable Interface
Attribute 80-pin LQFP
Commercial Temperature
Copper Wire Bonding
Device: KSZ8795 - Integrated 5-Port, 10/100 Managed Ethernet b) KSZ8795CLXIC
Switch with Gigabit GMII/RGMII and MII/RMII Interfaces Configurable Interface
80-pin LQFP
Industrial Temperature
Interface: C = Configurable Copper Wire Bonding

Package: L = 80-pin LQFP

Special Attribute: X = None

Temperature: C = 0C to +70C (Commercial)

I = –40C to +85C (Industrial)

Bond Wire: C = Copper

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KSZ8795CLX
NOTES:

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 KSZ8795CLX

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 Micro-
chip 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, implicitly or
otherwise, under any Microchip intellectual property rights unless otherwise stated.

Trademarks
The Microchip name and logo, the Microchip logo, AnyRate, AVR, AVR logo, AVR Freaks, BeaconThings, BitCloud, CryptoMemory, CryptoRF,
dsPIC, FlashFlex, flexPWR, Heldo, JukeBlox, KEELOQ, KEELOQ logo, Kleer, LANCheck, LINK MD, maXStylus, maXTouch, MediaLB, megaAVR,
MOST, MOST logo, MPLAB, OptoLyzer, PIC, picoPower, PICSTART, PIC32 logo, Prochip Designer, QTouch, RightTouch, SAM-BA, SpyNIC,
SST, SST Logo, SuperFlash, tinyAVR, UNI/O, and XMEGA are registered trademarks of Microchip Technology Incorporated in the U.S.A. and
other countries.
ClockWorks, The Embedded Control Solutions Company, EtherSynch, Hyper Speed Control, HyperLight Load, IntelliMOS, mTouch, Precision
Edge, and Quiet-Wire are registered trademarks of Microchip Technology Incorporated in the U.S.A.
Adjacent Key Suppression, AKS, Analog-for-the-Digital Age, Any Capacitor, AnyIn, AnyOut, BodyCom, chipKIT, chipKIT logo, CodeGuard,
CryptoAuthentication, CryptoCompanion, CryptoController, dsPICDEM, dsPICDEM.net, Dynamic Average Matching, DAM, ECAN,
EtherGREEN, In-Circuit Serial Programming, ICSP, Inter-Chip Connectivity, JitterBlocker, KleerNet, KleerNet logo, Mindi, MiWi, motorBench,
MPASM, MPF, MPLAB Certified logo, MPLIB, MPLINK, MultiTRAK, NetDetach, Omniscient Code Generation, PICDEM, PICDEM.net, PICkit,
PICtail, PureSilicon, QMatrix, RightTouch logo, REAL ICE, Ripple Blocker, SAM-ICE, Serial Quad I/O, SMART-I.S., SQI, SuperSwitcher,
SuperSwitcher II, Total Endurance, TSHARC, USBCheck, VariSense, ViewSpan, WiperLock, Wireless DNA, and ZENA 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.
Silicon Storage Technology is a registered trademark of Microchip Technology Inc. in other countries.
GestIC is a registered trademark of Microchip Technology Germany II GmbH & Co. KG, a subsidiary of Microchip Technology Inc., in other
countries.
All other trademarks mentioned herein are property of their respective companies.
© 2016-2017, Microchip Technology Incorporated, All Rights Reserved.
ISBN: 978-1-5224-1262-5

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.

 2016-2017 Microchip Technology Inc. DS00002112B-page 133

 Worldwide Sales and Service
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Fax: 44-118-921-5820

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