Hub Datasheet

Intel

E7505 Chipset MCH Datasheet 149

System Address Map

4.1.2 PAM Memory Spaces

The address ranges in this space are:

• PAMC0 0_000C_0000 to 0_000C_3FFF

• PAMC4 0_000C_4000 to 0_000C_7FFF

• PAMC8 0_000C_8000 to 0_000C_BFFF

• PAMCC 0_000C_C000 to 0_000C_FFFF

• PAMD0 0_000D_0000 to 0_000D_3FFF

• PAMD4 0_000D_4000 to 0_000D_7FFF

• PAMD8 0_000D_8000 to 0_000D_BFFF

• PAMDC 0_000D_C000 to 0_000D_FFFF

• PAME0 0_000E_0000 to 0_000E_3FFF

• PAME4 0_000E_4000 to 0_000E_7FFF

• PAME8 0_000E_8000 to 0_000E_BFFF

• PAMEC 0_000E_C000 to 0_000E_FFFF

• PAMF0 0_000F_0000 to 0_000F_FFFF

The 256 KB PAM region is divided into three parts:

• ISA expansion region: 128 KB area between 0_000C_0000h and 0_000D_FFFFh

• Extended BIOS region: 64 KB area between 0_000E_0000h and 0_000E_FFFFh,

• System BIOS region: 64 KB area between 0_000F_0000h and 0_000F_FFFFh.

The ISA expansion region 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 subtractively decoded to ISA space.

The extended System BIOS region 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

HI_A. Typically, this area is used for RAM or ROM.

The system BIOS region is a single 64-KB segment. This segment can be assigned read and write

attributes. It is by default (after reset) read/write disabled and cycles are forwarded to HI_A. By

manipulating the read/write attributes, the MCH can shadow BIOS into the main memory.

Note that the PAM region can be accessed by HI_A or B. All reads or writes from any HI that hits

the PAM area is sent to DRAM. If the system is setup so that there are hub interface accesses to the

PAM regions, then the PAM region being accessed must be programmed to be both readable and

writable by the processor. If the accessed PAM region is programmed for either reads or writes to

be forwarded to HI_A and there are hub interface accesses to that PAM, the system may fault.