AMD-761 Datasheet, PDF (236/264 Pages) Advanced Micro Devices – AMD-761-TM System Controller Software/BIOS Design Guide

Preliminary Information
AMD-761™ System Controller Software/BIOS Design Guide
24081D—February 2002
Registers
-----
Bits
0x0x0x84h
Description
PCI Arbitration Control
Initialized/
Required
Value
31:24 AGP VGA BIOS address decode
0Fh
23
Tgt_Latency
22:18
17
16
Reserved
AGP Chaining
PCI Chaining
15
MDA Support
14
PCI Write-Post retry
13
AGP Write Post retry
12
Dis Rd Data Err
0b
000_00b
1b
1b
0b
1b
1b
1b
Actual
Value
Key fcn()
Notes
System config dependent
Bit 31: 0D_C000 = 0D_FFFF
Bit 30: 0D_8000 = 0D_BFFF
A
…
Bit 24: 0C_0000 = 0C_3FFF
One or more of these bits
should be set if an AGP card
has a ROM BIOS.
0=AMD-751™ System
Controller-Compatible
B
0x0x0
x84[3]
1=PCI Maximum Target
Latency Rule. When =1,
0x0x0x84[3] must = 0.
r
B
Enabled = 1, when set CPU
writes to AGP are chained
B
Enabled = 1, when set CPU
writes to PCI are chained
Enabled = 1, allows
monochrome adapter for
AGP device driver debug.
A
Normally 0. See AMD-761™
System Controller Data
Sheet, order# 24088, for
information.
1 = Enables retry on PCI if
B
there are pending posted
writes
1 = Enables retry on AGP if
B
there are pending posted
writes
0 = Returns read data error
to processor on master
abort or target abort
B
1 = AMD-761™ system
controller returns all 1s on
data read error
KEY:
B= Mandatory BIOS function
A= AGP setup by BIOS
c = Calculated/set by AMD-761™ internal logic
P= Power management setup by BIOS o = Setup by OS or OS driver F = Performance enhancement set by BIOS
r = Hardcoded and reserved
u = PCI operational user interface E = Elective BIOS function
224
Recommended BIOS Settings
Chapter 7