Datasheet
KSZ9031RNX
DS00002117F-page 44 2016-2017 Microchip Technology Inc.
TABLE 4-6: MMD REGISTER DESCRIPTIONS
Address Name Description
Mode
Note 4-1
Default
MMD Address 0h, Register 3h – AN FLP Burst Transmit – LO
0.3.15:0 AN FLP
Burst Trans-
mit – LO
This register and the following register set the
Auto-Negotiation FLP burst transmit timing. The
same timing must be set for both registers.
0x4000 = Select 8 ms interval timing (default)
0x1A80 = Select 16 ms interval timing
All other values are reserved.
RW 0x4000
MMD Address 0h, Register 4h – AN FLP Burst Transmit – HI
0.4.15:0 AN FLP
Burst Trans-
mit – HI
This register and the previous register set the Auto-
Negotiation FLP burst transmit timing. The same
timing must be set for both registers.
0x0003 = Select 8 ms interval timing (default)
0x0006 = Select 16 ms interval timing
All other values are reserved.
RW 0x0003
MMD Address 1h, Register 5Ah – 1000BASE-T Link-Up Time Control
1.5A.8:4 Reserved Reserved RW 1_0000
1.5A.3:1 1000BASE-T
Link-Up Time
When the link partner is another KSZ9031 device,
the 1000BASE-T link-up time can be long. These
three bits provide an optional setting to reduce the
1000BASE-T link-up time.
100 = Default power-up setting
011 = Optional setting to reduce link-up time when
the link partner is a KSZ9031 device.
All other settings are reserved and should not be
used.
The optional setting is safe to use with any link
partner.
Note: Read/Write access to this register bit is avail-
able only when Reg. 0h is set to 0x2100 to disable
auto-negotiation and force 100BASE-TX mode.
RW 100
1.5A.0 Reserved Reserved RW 0
MMD Address 2h, Register 0h – Common Control
2.0.15:5 Reserved Reserved RW 0000_0000_000
2.0.4 LED Mode
Override
Override strap-in for LED_MODE
1 = Single-LED mode
0 = Tri-color dual-LED mode
This bit is write-only and always reads back a value
of ‘0’. The updated value is reflected in Bit [3] of
this register.
WO 0
2.0.3 LED Mode LED_MODE Status
1 = Single-LED mode
0 = Tri-color dual-LED mode
RO Set by LED_MODE
strapping pin.
See the Strap-In
Options -
KSZ9031RNX
section for details.
Can be updated by
Bit [4] of this register
after reset.
2.0.2 Reserved Reserved RW 0