82551IT Datasheet, PDF (68/102 Pages) Intel Corporation – Fast Ethernet PCI Controller

82551IT — Networking Silicon
Table 24. Register 0: Control
Bit(s)
Name
11
Power-Down
10
Reserved
9
Restart Auto-
Negotiation
8
Duplex Mode
7
Collision Test
6:0
Reserved
Description
Default R/W
This bit sets the PHY unit into a low power mode. In low
power mode, the PHY unit consumes no more than 30
mA.
1 = Power-Down enabled
0 = Power-Down disabled (Normal operation)
0
RW
This bit is reserved and should be set to 0b.
0
RW
This bit restarts the Auto-Negotiation process and is self-
clearing.
1 = Restart Auto-Negotiation process
0
RW
SC
This bit controls the duplex mode when Auto-Negotiation
is disabled. If the PHY reports that it is only able to
operate in one duplex mode, the value of this bit shall
correspond to the mode which the PHY can operate.
When the PHY is placed in Loopback mode, the behavior
of the PHY shall not be affected by the status of this bit,
bit 8.
1 = Full Duplex
0 = Half Duplex
0
RW
This bit will force a collision in response to the assertion
of the transmit enable signal.
1 = Force COL
0 = Do not force COL
0
RW
These bits are reserved and should be set to 0b.
0
RW
9.1.2
Register 1: Status Register
Table 25. Register 1: Status
Bit(s)
Name
15
Reserved
Description
This bit is reserved and should be set to 0b.
14
100BASE-TX Full 1 = PHY able to perform full duplex 100BASE-TX
Duplex
13
100 Mbps Half 1 = PHY able to perform half duplex 100BASE-TX
Duplex
12
10 Mbps Full
1 = PHY able to operate at 10Mbps in full duplex
Duplex
mode
11
10 Mbps Half
1 = PHY able to operate at 10 Mbps in half duplex
Duplex
mode
10:7 Reserved
These bits are reserved and should be set to 0b.
6
Management
0 = PHY will not accept management frames with
Frames Preamble preamble suppressed
Suppression
5
Auto-Negotiation 1 = Auto-Negotiation process completed
Complete
0 = Auto-Negotiation process has not completed
4
Remote Fault
0 = No remote fault condition detected
Default
0
1
R/W
RO
E
RO
1
RO
1
RO
1
RO
0
RO
0
RO
0
RO
0
RO
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Datasheet