Intel D15343-003 User Manual
Page 63
Register Description
D15343-003
63
Table 21.
PAM Registers and Associated System Memory Segments
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 system memory controlled by the GMCH, while the 128-kB
address range from 080000 to 09FFFFh can be mapped to PCI0 or to main DDR SDRAM. By
default this range is mapped to main system memory and can be declared as a main system
memory hole (accesses forwarded to PCI0) via GMCH's 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 PCI2 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 GMCH.
This area can be programmed as SMM area via the SMRAM register. When the GMCH is strapped
in other mode, or when used as an SMM space, this range can not be accessed from the Hub
interface.
Expansion Area (C0000h-DFFFFh)
This 128-kB area is divided into eight 16-kB segments that can be assigned with different attributes
via PAM Control register as defined in
.
PAM Reg
Attribute Bits
System Memory Segment
Comments
Offset
PAM0[3:0]
Reserved
59h
PAM0[7:4]
R
R
WE
RE
0F0000h–0FFFFFh
BIOS Area
59h
PAM1[3:0]
R
R
WE
RE
0C0000h–0C3FFFh
ISA Add-on BIOS
5Ah
PAM1[7:4]
R
R
WE
RE
0C4000h–0C7FFFh
ISA Add-on BIOS
5Ah
PAM2[3:0]
R
R
WE
RE
0C8000h–0CBFFFh
ISA Add-on BIOS
5Bh
PAM2[7:4]
R
R
WE
RE
0CC000h–0CFFFFh
ISA Add-on BIOS
5Bh
PAM3[3:0]
R
R
WE
RE
0D0000h–0D3FFFh
ISA Add-on BIOS
5Ch
PAM3[7:4]
R
R
WE
RE
0D4000h–0D7FFFh
ISA Add-on BIOS
5Ch
PAM4[3:0]
R
R
WE
RE
0D8000h–0DBFFFh
ISA Add-on BIOS
5Dh
PAM4[7:4]
R
R
WE
RE
0DC000h–0DFFFFh
ISA Add-on BIOS
5Dh
PAM5[3:0]
R
R
WE
RE
0E0000h–0E3FFFh
BIOS Extension
5Eh
PAM5[7:4]
R
R
WE
RE
0E4000h–0E7FFFh
BIOS Extension
5Eh
PAM6[3:0]
R
R
WE
RE
0E8000h–0EBFFFh
BIOS Extension
5Fh
PAM6[7:4]
R
R
WE
RE
0EC000h–0EFFFFh
BIOS Extension
5Fh