AMD-761 Datasheet, PDF (89/264 Pages) Advanced Micro Devices – AMD-761-TM System Controller Software/BIOS Design Guide

24081D—February 2002
Preliminary Information
AMD-761™ System Controller Software/BIOS Design Guide
PCI Top of Memory
Dev0:F0:0x9C
31
30
29
28
27
26
25
24
Bit
PCI_Mem_Top
Reset
1
0
0
0
0
0
0
0
R/W
R/W
23
22
21
20
19
18
17
16
Bit
Reserved
Reset
0
0
0
0
0
0
0
0
R/W
R
15
14
13
12
11
10
9
8
Bit
Reserved
Reset
0
0
0
0
0
0
0
0
R/W
R
7
6
5
4
3
2
1
0
Bit
Reserved
Reset
0
0
0
0
0
0
0
0
R/W
R
Register Description
This register is used to define the top of main system memory. It is used to compare the memory addresses of an external
PCI master to determine if it is in the range of the AMD-761™ system controller DRAM. If the address compares, then the
AMD-761 system controller responds to the bus master access with DEVSEL# assertion.
Chapter 2
AMD-761™ System Controller Programmer’s Interface
77