82801DB Datasheet, PDF (266/587 Pages) Intel Corporation – Intel 82801DB I/O Controller Hub 4 (ICH4)

LAN Controller Registers (B1:D8:F0)
7.2.3
7.2.4
System Control Block General Pointer Register
Offset Address: 04–07h
Default Value: 0000 0000h
Attribute:
Size:
R/W
32 bits
Bit
Description
15:0
SCB General Pointer — R/W. The SCB General Pointer register is programmed by software to
point to various data structures in main memory depending on the current SCB Command word.
PORT Register
Offset Address: 08–0Bh
Default Value: 0000 0000h
Attribute:
Size:
R/W (special)
32 bits
The PORT interface allows the processor to reset the ICH4’s internal LAN controller, or perform
an internal self test. The PORT DWORD may be written as a 32-bit entity, two 16-bit entities, or
four 8-bit entities. The LAN controller will only accept the command after the high byte (offset
0Bh) is written; therefore, the high byte must be written last.
Bit
Description
Pointer Field — R/W (special). A 16-byte aligned address must be written to this field when issuing
31:4 a Self-Test command to the PORT interface.The results of the Self Test will be written to the
address specified by this field.
PORT Function Selection — R/W (special). Valid values are listed below. All other values are
Reserved.
0000 = PORT Software Reset: Completely resets the LAN controller (all CSR and PCI registers).
This command should not be used when the device is active. If a PORT Software Reset is
desired, software should do a Selective Reset (described below), wait for the PORT
register to be cleared (completion of the Selective Reset), and then issue the PORT
Software Reset command. Software should wait approximately 10 µs after issuing this
command before attempting to access the LAN controller’s registers again.
0001 = Self Test: The Self-Test begins by issuing an internal Selective Reset followed by a
3:0
general internal self-test of the LAN controller. The results of the self-test are written to
memory at the address specified in the Pointer field of this register. The format of the self-
test result is shown in Table 7-5. After completing the self-test and writing the results to
memory, the LAN controller will execute a full internal reset and will re-initialize to the
default configuration. Self-Test does not generate an interrupt of similar indicator to the
host processor upon completion.
0010 = Selective Reset: Sets the CU and RU to the Idle state, but otherwise maintains the current
configuration parameters (RU and CU Base, HDSSize, Error Counters, Configure
information and Individual/Multicast Addresses are preserved). Software should wait
approximately 10 µs after issuing this command before attempting to access the LAN
controller’s registers again.
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Intel^® 82801DB ICH4 Datasheet