KSZ9021RL View Datasheet(PDF) - Micrel

Part Name

Description

Manufacturer

KSZ9021RL

Gigabit Ethernet Transceiver with RGMII Support

Micrel 

Micrel, Inc.

KSZ9021RL/RN

Strapping Options – KSZ9021RN

Pin Number Pin Name

Type(1) Pin Function

35

PHYAD2

I/O

The PHY Address, PHYAD[2:0], is latched at power-up/reset and is configurable to

15

PHYAD1

I/O

any value from 1 to 7. Each PHY address bit is configured as follows:

17

PHYAD0

I/O

Pull-up = 1

Pull-down = 0

PHY Address bits [4:3] are always set to ‘00’.

27

MODE3

I/O

The MODE[3:0] strap-in pins are latched at power-up/reset and are defined as

28

MODE2

I/O

follows:

31

MODE1

I/O

32

MODE0

I/O

MODE[3:0] Mode

0000

Reserved – not used

0001

Reserved – not used

0010

Reserved – not used

0011

Reserved – not used

0100

NAND Tree Mode

0101

Reserved – not used

0110

Reserved – not used

0111

Chip Power Down Mode

1000

Reserved – not used

1001

Reserved – not used

1010

Reserved – not used

1011

Reserved – not used

1100

RGMII Mode – advertise 1000Base-T full-duplex only

1101

RGMII Mode – advertise 1000Base-T full and half-duplex only

1110

RGMII Mode – advertise all capabilities (10/100/1000 speed

half/full duplex), except 1000Base-T half-duplex

1111

RGMII Mode – advertise all capabilities (10/100/1000 speed

half/full duplex)

33

CLK125_EN

I/O

CLK125_EN is latched at power-up/reset and is defined as follows:

Pull-up = Enable 125MHz Clock Output

Pull-down = Disable 125MHz Clock Output

Pin 41 (CLK125_NDO) provides the 125MHz reference clock output option for use by

the MAC.

41

LED_MODE

I/O

LED_MODE is latched at power-up/reset and is defined as follows:

Pull-up = Single LED Mode

Pull-down = Tri-color Dual LED Mode

Note:

1. I/O = Bi-directional.

Pin strap-ins are latched during power-up or reset. In some systems, the MAC receive input pins may be driven during

power-up or reset, and consequently cause the PHY strap-in pins on the RGMII signals to be latched to the incorrect

configuration. In this case, it is recommended to add external pull-ups/pull-downs on the PHY strap-in pins to ensure the

PHY is configured to the correct pin strap-in mode.

February 13, 2014

21

Revision 1.2

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