82801BA Datasheet, PDF (278/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

LPC Interface Bridge Registers (D31:F0)
9.1.28
FWH_DEC_EN1—FWH Decode Enable 1 Register
(LPC I/F—D31:F0)
Offset Address: E3h
Default Value: FFh
Attribute:
Size:
R/W
8 bits
This register determines which memory ranges will be decoded on the PCI bus and forwarded to
the FWH. The ICH2 will subtractively decode cycles on PCI unless POS_DEC_EN is set to 1.
Bit
Description
FWH Address Range Enable (FWH_F8_EN)—RO. Enables decoding two 512 KB FWH memory
ranges and one 128 KB memory range.
7
1 = Enable the following ranges for the FWH
FFF80000h–FFFFFFFFh
FFB80000h–FFBFFFFFh
000E0000h–000FFFFFh
FWH Address Range Enable (FWH_F0_EN)—R/W. Enables decoding two 512 KB FWH memory
ranges.
6
0 = Disable.
1 = Enable the following ranges for the FWH:
FFF00000h–FFF7FFFFh
FFB00000h–FFB7FFFFh
FWH Address Range Enable (FWH_E8_EN)—R/W. Enables decoding two 512 KB FWH memory
ranges.
5
0 = Disable.
1 = Enable the following ranges for the FWH:
FFE80000h–FFEFFFFh
FFA80000h–FFAFFFFFh
FWH Address Range Enable (FWH_E0_EN)—R/W. Enables decoding two 512 KB FWH memory
ranges.
4
0 = Disable.
1 = Enable the following ranges for the FWH:
FFE00000h–FFE7FFFFh
FFA00000h–FFA7FFFFh
FWH Address Range Enable (FWH_D8_EN)—R/W. Enables decoding two 512 KB FWH memory
ranges.
3
0 = Disable.
1 = Enable the following ranges for the FWH
FFD80000h–FFDFFFFFh
FF980000h–FF9FFFFFh
FWH Address Range Enable (FWH_D0_EN)—R/W. Enables decoding two 512 KB FWH memory
ranges.
2
0 = Disable.
1 = Enable the following ranges for the FWH
FFD00000h–FFD7FFFFh
FF900000h–FF97FFFFh
FWH Address Range Enable (FWH_C8_EN)—R/W. Enables decoding two 512 KB FWH memory
ranges.
1
0 = Disable.
1 = Enable the following ranges for the FWH
FFC80000h–FFCFFFFFh
FF880000h–FF8FFFFFh
FWH Address Range Enable (FWH_C0_EN)—R/W. Enables decoding two 512 KB FWH memory
ranges.
0
0 = Disable.
1 = Enable the following ranges for the FWH
FFC00000h–FFC7FFFFh
FF800000h–FF87FFFFh
9-16
82801BA ICH2 and 82801BAM ICH2-M Datasheet