82845MP Datasheet, PDF (67/157 Pages) Intel Corporation – Intel 845 Family Chipset-Mobile 82845MP/82845MZ Chipset Memory Controller Hub Mobile (MCH-M)

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Intel^® 82845MP/82845MZ Chipset-Mobile (MCH-M)
Table 23. PAM Register Details
PAM Reg
Attribute Bits
PAM0[3:0]
Reserved
PAM0[7:4]
PAM1[3:0]
PAM1[7:4]
PAM2[3:0]
PAM2[7:4]
PAM3[3:0]
PAM3[7:4]
PAM4[3:0]
PAM4[7:4]
PAM5[3:0]
PAM5[7:4]
PAM6[3:0]
PAM6[7:4]
R
R
WE
R
R
WE
R
R
WE
R
R
WE
R
R
WE
R
R
WE
R
R
WE
R
R
R
R
WE
R
R
WE
R
R
WE
R
R
WE
R
R
WE
Memory Segment
Comments
90h 0F0000h - 0FFFFFh BIOS Area
91h 0C0000h - 0C3FFFh ISA Add-on BIOS
91h 0C4000h - 0C7FFFh ISA Add-on BIOS
92h 0C8000h - 0CBFFFh ISA Add-on BIOS
92h 0CC000h- 0CFFFFh ISA Add-on BIOS
93h 0D0000h- 0D3FFFh ISA Add-on BIOS
93h 0D4000h- 0D7FFFh ISA Add-on BIOS
94h 0D8000h- 0DBFFFh ISA Add-on BIOS
94h 0DC000h- 0DFFFFh ISA Add-on BIOS
95h 0E0000h- 0E3FFFh BIOS Extension
95h 0E4000h- 0E7FFFh BIOS Extension
96h 0E8000h- 0EBFFFh BIOS Extension
96h 0EC000h- 0EFFFFh BIOS Extension
Offset
90h
90h
91h
91h
92h
92h
93h
93h
94h
94h
95h
95h
96h
96h
For details on overall system address mapping scheme see the Address Decoding Section of this
document.
DOS Application Area (00000h-9FFFh)
The DOS area is 640 KB in size and it is further divided into two parts. The 512-KB area at 0 to 7FFFFh
is always mapped to the main memory controlled by the MCH-M, while the 128-KB address range from
080000 to 09FFFFh can be mapped to PCI0 or to main DRAM. By default this range is mapped to main
memory and can be declared as a main memory hole (accesses forwarded to PCI0) via MCH-M FDHC
configuration register.
Video Buffer Area (A0000h-BFFFFh)
Attribute bits do not control this 128-KB area. The host -initiated cycles in this region are always
forwarded to either PCI0 or AGP unless this range is accessed in SMM mode. Routing of accesses is
controlled by the Legacy VGA control mechanism of the “virtual” PCI-PCI bridge device
embedded within the MCH-M.
This area can be programmed as SMM area via a special configuration register. When used as SMM
space this range cannot be accessed from the hub interface or AGP.
Expansion Area (C0000h-DFFFFh)
This 128-KB area is divided into eight 16-KB segments, which can be assigned with different attributes
via PAM control register as defined by above.
250687-002
Datasheet
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