82801DB Datasheet, PDF (272/587 Pages) Intel Corporation – Intel 82801DB I/O Controller Hub 4 (ICH4)

LAN Controller Registers (B1:D8:F0)
7.2.11
7.2.12
General Control Register
Offset Address: 1Ch
Default Value: 00h
Attribute:
Size:
R/W
8 bits
Bit
Description
7:4 Reserved. These bits should be set to 0000b.
LAN Connect Software Reset — R/W.
3
0 = Cleared by software to begin normal LAN Connect operating mode. Software must not attempt
to access the LAN Connect interface for at least 1 ms after clearing this bit.
1 = Software can set this bit to force a reset condition on the LAN Connect interface.
2 Reserved. This bit should be set to 0.
Deep Power-Down on Link Down Enable — R/W.
0 = Disable
1
1 = The Intel^® ICH4’s internal LAN controller may enter a deep power-down state (sub-3 mA) in the
D2 and D3 power states while the link is down. In this state, the LAN controller does not keep
link integrity. This state is not supported for point-to-point connection of two end stations.
0 Reserved
General Status Register
Offset Address: 1Dh
Default Value: h
Attribute:
Size:
RO
8 bits
Bit
Description
7:3 Reserved
Duplex Mode — RO. This bit indicates the wire duplex mode.
2 0 = Half duplex
1 = Full duplex
Speed — RO. This bit indicates the wire speed.
1 0 = 10 Mbps
1 = 100 Mbps
Link Status Indication — RO. This bit indicates the status of the link.
0 0 = Invalid
1 = Valid
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Intel^® 82801DB ICH4 Datasheet