Datasheet

KSZ9031RNX
DS00002117F-page 12  2016-2017 Microchip Technology Inc.
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 an incorrect
configuration. In this case, external pull-up or pull-down resistors should be added on the PHY strap-in pins to ensure
the PHY is configured to the correct pin strap-in mode.
Note 2-2 I/O = Bi-directional.
TABLE 2-2: STRAP-IN OPTIONS - KSZ9031RNX
Pin Number Pin Name
Type
Note 2-2
Description
35
15
17
PHYAD2
PHYAD1
PHYAD0
I/O
I/O
I/O
The PHY address, PHYAD[2:0], is sampled and latched at power-up/
reset and is configurable to any value from 0 to 7. Each PHY address
bit is configured as follows:
Pull-up = 1
Pull-down = 0
PHY Address Bits [4:3] are always set to ‘00’.
27
28
31
32
MODE3
MODE2
MODE1
MODE0
I/O
I/O
I/O
I/O
The MODE[3:0] strap-in pins are sampled and latched at power-up/
reset and are defined as follows:
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 sampled and latched at power-up/reset and is
defined as follows:
Pull-up (1) = Enable 125 MHz clock output
Pull-down (0) = Disable 125 MHz clock output
Pin 41 (CLK125_NDO) provides the 125 MHz reference clock output
option for use by the MAC.
41 LED_MODE I/O
LED_MODE is sampled and latched at power-up/reset and is
defined as follows:
Pull-up (1) = Single-LED mode
Pull-down (0) = Tri-color dual-LED mode