Chapter 7
Recommended BIOS Settings
249
24081D—February 2002
AMD-761™ System Controller Software/BIOS Design Guide
Preliminary Information
Registers
-----
Bits
Description
Initialized/
Required
Value
Actual
Value
Key
fcn( )
Notes
0x1x0x1Ch
PCI Command and Status
31
PERR_Rcv
0b
r
Not supported
30
SERR_Rcv
yb
u
R/W/1C from AMD-761™
system controller
29
Master ABRT
yb
u
R/W/1C from bus master
28
Target ABRT
yb
u
R/W/1c from bus master target
27
Target ABRTS Signaled
0b
r
Not supported
26:25
DEVSEL_Timing
01b
r
24
Data_PERR
0b
r
23
FastB2B
0b
r
22
UDF
0b
r
21
66M
1b
r
20
Cap_Lst
0b
r
19:16
Reserved
0h
r
15:12
IO_Lim[15:12]
xh
B
Upper 4 bits defining top
address that is used by the
bridge to forward I/O
transactions from one
interface to another.
11:8
IOLimit_R
1h
r
Lower 4 bits defining top
address that is used by the
bridge to forward I/O
transactions from one
interface to another. 0x1
indicates that 32 bit I/O
address decoding is available
7:4
IOBase [15:12]
xh
B
Writable 4 bits that defines
bottom address that is used
by the bridge to forward I/O
transactions from one
interface to another.
3:0
IOBase_R
1h
r
Lower 4 bits defining bottom
address that is used by the
bridge to forward I/O
transactions from one
interface to another. 0x1
indicates that 32 bit I/O
address decoding is available.
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