Chapter 3 Processor/Memory Subsystem
Compaq Deskpro Personal Computers
Third Edition - April 2001
3-8
3.4 SUBSYSTEM CONFIGURATION
The 82815 GMCH component provides the configuration function for the processor/memory
subsystem. Table 3-4 lists the configuration registers used for setting and checking such
parameters as memory control and PCI bus operation. These registers reside in the PCI
Configuration Space and accessed using the methods described in Chapter 4, section 4.2.
Table 3–4. Host/PCI Bridge Configuration Registers (GMCH, Function 0)
Table 3-4.
Host/PCI Bridge Configuration Registers (GMCH, Device 0)
 
PCI Config. 
Addr. 
 
Register 
Reset 
Value 
PCI Config. 
Addr. 
R 
egister 
Reset 
Value 
00, 01h  Vender ID  8086h  6A, 6Bh  DRAM Control Reg.  00h 
02, 03h  Device ID  1130h  6C..6Fh  Memory Buffer Strength  55h 
04, 05h  Command  0006h  70h  Multi-Transaction Timer  00h 
06, 07h  Status  [1]  71h  CPU Latency Timer  10h 
08h Revision ID  -- 72h SMRAM Control  02h 
0A..0Bh  Class Code  --  90h  Error Command  00h 
0Dh  Latency Timer  00h  91h  Error Status Register 0  00h 
0Eh  Header Type  00h  92h  Error Status Register 1  00h 
10..13h  Aperture Base Config.  [2]  93h  Reset Control  00h 
50, 51h  PAC Config. Reg.  00h  A0..A3h  AGP Capability Identifier  N/A 
53h  Data Buffer Control  83h  A4..A7h  AGP Status  N/A 
55..56h  DRAM Row Type  00h  A8..ABh  AGP Command  00h 
57h  DRAM Control  01h  B0..B3h  AGP Control  00h 
58h  DRAM Timing  00h  B4h  Aperture Size  0000h 
59..5Fh  PAM 0..6 Registers  00h  B8..BBh  Aperture Translation Table  0000h 
60..67h  DRAM Row Boundary  01h  BCh  Aperture I/F Timer  00h 
68h  Fixed DRAM Hole  00h  BDh  Low Priority Timer  00h 
 
NOTES:  
Refer to Intel Inc. documentation for detailed description of registers. 
Assume unmarked locations/gaps as reserved. 
[1] = 0090h for AGP (external graphics) implementation; = 0080h for GFX (internal i740) 
        implementation. 
[2] = 8 for AGP;  = 0 for GFX.