82801DB Datasheet, PDF (262/587 Pages) Intel Corporation – Intel 82801DB I/O Controller Hub 4 (ICH4)

LAN Controller Registers (B1:D8:F0)
7.2
LAN Control / Status Registers (CSR)
Table 7-4. Intel^® ICH4 Integrated LAN Controller CSR Space
Offset
01h–00h
03h–02h
07h–04h
0Bh–08h
0Dh–0Ch
0Eh
0Fh
13h–10h
17h–14h
18h
1A–19h
1Bh
1Ch
1Dh
1Eh–3Ch
Register Name
SCB Status Word
SCB Command Word
SCB General Pointer
PORT
Reserved
EEPROM Control Register
Reserved
MDI Control Register
Receive DMA Byte Count
Early Receive Interrupt
Flow Control Register
PMDR
General Control
General Status
Reserved
Default
0000h
0000h
0000 0000h
0000 0000h
—
00h
—
0000 0000h
0000 0000h
00h
0000h
00h
00
N/A
—
Type
R/WC
R/W
R/W
R/W-Special
—
R/W, RO, WO
—
R/W-Special
RO
R/W
R/W
R/WC
R/W
RO
—
7.2.1
System Control Block Status Word Register
Offset Address: 00–01h
Default Value: 0000h
Attribute:
Size:
R/WC, RO
16 bits
The ICH4’s integrated LAN controller places the status of its Command and Receive units and
interrupt indications in this register for the processor to read.
Bit
Description
Command Unit (CU) Executed (CX)— R/WC.
15 0 = Software acknowledges the interrupt and clears this bit by writing a 1 to the bit position.
1 = Interrupt signaled because the CU has completed executing a command with its interrupt bit set.
Frame Received (FR) — R/WC.
14 0 = Software acknowledges the interrupt and clears this bit by writing a 1 to the bit position.
1 = Interrupt signaled because the Receive Unit (RU) has finished receiving a frame.
CU Not Active (CNA) — R/WC.
0 = Software acknowledges the interrupt and clears this bit by writing a 1 to the bit position.
13 ^{1 = The Command Unit left the Active state or entered the Idle state. There are 2 distinct states of the}
CU. When configured to generate CNA interrupt, the interrupt will be activated when the CU
leaves the Active state and enters either the Idle or the Suspended state. When configured to
generate CI interrupt, an interrupt will be generated only when the CU enters the Idle state.
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Intel^® 82801DB ICH4 Datasheet