Datasheet

Datasheet 39
System Address Map
3.1.2 Expansion Area (C_0000h-D_FFFFh)
This 128 KB ISA Expansion region (000C_0000h – 000D_FFFFh) is divided into eight
16 KB segments. Each segment can be assigned one of four Read/Write states: read-
only, write-only, read/write, or disabled. Typically, these blocks are mapped through
MCH and are subtractive decoded to ISA space. Memory that is disabled is not
remapped.
Non-snooped accesses from PCI Express or DMI to this region are always sent to
DRAM.
3.1.3 Extended System BIOS Area (E_0000h–E_FFFFh)
This 64 KB area (000E_0000h – 000E_FFFFh) is divided into four 16 KB segments. Each
segment can be assigned independent read and write attributes so it can be mapped
either to main DRAM or to DMI Interface. Typically, this area is used for RAM or ROM.
Memory segments that are disabled are not remapped elsewhere.
Non-snooped accesses from PCI Express or DMI to this region are always sent to
DRAM.
Table 2. Expansion Area Memory Segments
Memory Segments Attributes Comments
0C0000h – 0C3FFFh WE RE Add-on BIOS
0C4000h – 0C7FFFh WE RE Add-on BIOS
0C8000h – 0CBFFFh WE RE Add-on BIOS
0CC000h – 0CFFFFh WE RE Add-on BIOS
0D0000h – 0D3FFFh WE RE Add-on BIOS
0D4000h – 0D7FFFh WE RE Add-on BIOS
0D8000h – 0DBFFFh WE RE Add-on BIOS
0DC000h – 0DFFFFh WE RE Add-on BIOS
Table 3. Extended System BIOS Area Memory Segments
Memory Segments Attributes Comments
0E0000h – 0E3FFFh WE RE BIOS Extension
0E4000h – 0E7FFFh WE RE BIOS Extension
0E8000h – 0EBFFFh WE RE BIOS Extension
0EC000h – 0EFFFFh WE RE BIOS Extension