
E
7.1.18.
82371AB (PIIX4)
129
4/9/97 2:23 PM PIIX4aDS
INTEL CONFIDENTIAL
(until publication date)
PRELIMINARY
DEVRESB—DEVICE RESOURCE B (FUNCTION 3)
Address Offset:
Default Value:
Attribute:
60–63h
00h
Read/Write
Bit
Description
31
Game Port EIO Enable (GAME_EIO_EN)—R/W.
1=Enable PCI bus decode for accesses to the
Game Port enabled decode ranges to be claimed by PIIX4 and forwarded to the ISA/EIO bus.
0=Disable. The GAME_EN bit must be set to enable this range.
30
Keyboard EIO Enable (KBC_EIO_EN)—R/W.
1=Enable PCI access to the keyboard controller
enabled I/O ranges (60h and 64h) to be claimed by PIIX4 and forwarded to the ISA/EIO bus.
0=Disable. The KBC_EN_DEV11 bit must be set to enable the decode.
29
Device 5 EIO Enable (EIO_EN_DEV5)—R/W.
1=Enable PCI access to the floppy disk controller
enabled I/O ranges selected by FDC_DEC_SEL field to be claimed by PIIX4 and forwarded to the
ISA/EIO bus. 0=Disable. The FDC_MON_EN bit must be set to enable the decode.
28
Floppy Disk Controller Decode Select (FDC_DEC_SEL)—R/W.
1=Secondary FDC Address
(370h–375h, 377h). 0=Primary FDC Address (3F0h–3F5h, 3F7h). This field selects the floppy disk
controller I/O range enabled with bit 3.
27
Reserved.
26:25
LPT Controller Decode Select (LPT_DEC_SEL)—R/W.
Selects the parallel port (device 8) I/O
range enabled with the LPT_MON_EN bit. This field is decoded as follows:
Bits[26:25]
LPT Decode
00
3BCh–3BFh, 7BCh–7BEh
01
378h–37Fh, 778h–77Ah
10
278h–27Fh, 678h–67Ah
11
Reserved
24
Microsoft Sound System EIO Enable (MSS_EIO_EN)—R/W.
1=Enable PCI bus decode for
accesses to the Microsoft Sound System enabled decode ranges (DEVRESA: Bits[7:9]) to be
claimed by PIIX4 and forwarded to the ISA/EIO bus. 0=Disable. The MSS_EN bit must be set to
enable this range.
23
Device 9 Generic Decode Chip-select (CS_EN_DEV9)—R/W.
1=Enable assertion of the
chip-select signal PCS0# for all accesses within the device 9 I/O decode range. 0=Disable.
The EIO_EN_DEV9 bit must also be set to enable this function.
22
Device 9
EIO Enable (EIO_EN_DEV9)—R/W.
1=Enable PCI access to the device 9 enabled I/O
range or embedded controller IO range to be claimed by PIIX4 and forwarded to the ISA/EIO bus.
0=Disable. The GDEC_MON_DEV9 bit or EC_EN_DEV9 bit must be set to enable the decode.
21
Device 9 Generic Decode Monitor Enable (GDEC_MON_DEV9)—R/W.
1=Enable PCI bus
decode for accesses to the I/O address range selected by the BASE_DEV9 and MASK_DEV9
fields. 0=Disable. The EIO enable bit, idle enable bit, or trap enable bit for device 4 must also be set
in order to enable these respective functions.
20
Midi EIO Enable (MIDI_EIO_EN)—R/W.
1=Enable PCI bus decode for accesses to the Midi
enabled decode ranges (DEVRESA: Bits[0:2]) to be claimed by PIIX4 and forwarded to the ISA/EIO
bus. 0=Disable. The MIDI_EN bit must be set to enable this range.
19:16
Device 9 Generic Decode Mask (MASK_DEV9)—R/W.
Specifies the 4-bit I/O base address mask
used to determine the IO address range size for device 9 accesses. MASK_DEV9 (bits[19:16])
correspond to AD[3:0]. A ‘1’ in a bit position indicates that the corresponding address bit is masked
(i.e. ignored) when performing the decode. Note that programming these bits to certain patterns
(such as ‘1001’) results in a split address range.