
Micrel, Inc.
KSZ8851-16MLLJ
March 2010
71
M9999-030210-1.0
PHY 1 MII-Register Basic Control Register (0xE4 – 0xE5): P1MBCR
This register contains Media Independent Interface (MII) register for port 1 as defined in the IEEE 802.3 specification.
Bit
Default
R/W
Description
Bit is same as:
15
0
RO
Reserved
14
0
RW
Local (far-end) loopback (llb)
1 = perform local loopback at host
(host Tx -> PHY -> host Rx, see Figure 10)
0 = normal operation
13
1
RW
Force 100
1 = force 100Mbps if AN is disabled (bit 12)
0 = force 10Mbps if AN is disabled (bit 12)
Bit 6 in P1CR
12
1
RW
AN Enable
1 = auto-negotiation enabled.
0 = auto-negotiation disabled.
Bit 7 in P1CR
11-10
0
RW
Reserved
9
0
RW
Restart AN
1 = restart auto-negotiation.
0 = normal operation.
Bit 13 in P1CR
8
1
RW
Force Full Duplex
1 = force full duplex
0 = force half duplex.
if AN is disabled (bit 12) or AN is enabled but failed.
Bit 5 in P1CR
7-6
0
RO
Reserved
5
1
R/W
HP_mdix
1 = HP Auto MDI-X mode.
0 = Micrel Auto MDI-X mode.
Bit 15 in P1SR
4
0
RW
Force MDI-X
1 = force MDI-X.
0 = normal operation.
Bit 9 in P1CR
3
0
RW
Disable MDI-X
1 = disable auto MDI-X.
0 = normal operation.
Bit 10 in P1CR
2
0
RW
Reserved.
1
0
RW
Disable Transmit
1 = disable transmit.
0 = normal operation.
Bit 14 in P1CR
0
RW
Disable LED
1 = disable all LEDs.
0 = normal operation.
Bit 15 in P1CR