Register Description
R
62 Intel® 82845 MCH for SDR Datasheet

Extended System BIOS Area (E0000h–EFFFFh)

This 64 KB area is divided into four 16 KB segments that can be assigned with different attributes
via PAM control register as defined by the table above.

System BIOS Area (F0000h–FFFFFh)

This area is a single 64 KB segment, which can be assigned with different attributes via PAM
control register as defined by the table above.
3.5.22 FDHC—Fixed DRAM Hole Contr ol Regi ster (Device 0)
Address Offset: 97h
Default Value: 00h
Access: R/W
Size: 8 bits
This 8-bit register controls a fixed DRAM hole: 15–16 MB.
Bit Description
7 Hole Enable (HEN). This bit enables a memory hole in DRAM space. Host c ycles matching an
enabled hole are passed on to the ICH2 through the hub interface. The hub interface cycles
matching an enabled hole will be ignored by the MCH. Note that a selected hole is not re-
mapped.
0 = Disabled. No hole
1 = 15 MB–16 MB (1 MB hole)
6:0 Reserved.