Chapter 2
AMD-761™ System Controller Programmer’s Interface
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24081D—February 2002
AMD-761™ System Controller Software/BIOS Design Guide
Preliminary Information
Bit Definitions
AGP/PCI Command and Status (Dev1:0x04)
Bit
Name
Function
31
PERR_Rcv
Detected Parity Error
This bit is always Low because the AMD-761™ system controller does not support
parity checking.
30
SERR_Rcv
Signaled System Error
This bit is set whenever the AMD-761 system controller received AGP SERR# and
subsequently asserted PCI SERR#. This bit is cleared by writing a 1. Refer to Table 7 on
page 34 for details about SERR# assertion and status.
29
Mas_ABRT
Received Master Abort
This bit is always 0.
28
Trgt_ABRT
Receive Target Abort
This bit is always 0.
27
Trgt_ABRTS
_Signaled
Signaled Target Abort
This bit is always 0.
26–25
DEVSEL_Timing
DEVSEL# Timing
This field is always 0b01, indicating that the AMD-761 system controller supports medium
DEVSEL# timing.
24
Data_PERR
Data PERR#
This bit is always 0 because the AMD-761 system controller does not report data
parity errors.
23
Fast_B2B
Fast Back-to-Back Capable
This bit is always 0, indicating that the AMD-761 system controller as a target is not
capable of accepting fast back-to-back transactions when the transactions are not to the
same agent.
22
UDF
User-Definable Features
This bit is always 0, indicating that UDF is not supported on the AMD-761 system
controller.
21
66M
66-MHz Capable
This bit is always 1, indicating that the AMD-761 system controller supports 66 MHz on
device 1.
20
Cap_Lst
Capabilities List
This bit is always 0, indicating that the configuration space of this device does not support
a capabilities list.
19–10
Reserved
Reserved
9
FBACK
Fast Back-to-Back to Different Devices Enable
This bit is always 0, because the AMD-761 system controller does not allow generation of
fast back-to-back transactions to different agents.