AMD-761 Datasheet, PDF (95/264 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
Bit Definitions
Bit Name
31–10 Reserved
9 SBA_En
8 AGP_En
7–6 Reserved
5 R4G_En
4 Fast_Writes
3 Reserved
2–0 Data_Transfer
_Mode
Programming Notes
AGP Command (Dev0:F0:0xA8)
Function
Reserved
Sideband Addressing Enable
When this bit is set, sideband addressing is enabled.
AGP Operations Enable
When this bit is set, the AMD-761™ system controller accepts AGP operations. When this
bit is clear, the AMD-761 system controller ignores AGP operations.
Reserved
4GB Address Indicator
This bit indicates that the AMD-761 system controller does not support addresses greater
than 4 Gbytes. The AMD-761 system controller supports only 32-bit addresses.
Fast Writes
0 = Fast writes disabled
1 = Fast writes enabled when the FW_Enable bit is also set in the AGP 4X Dynamic
Compensation register (Dev 0:F0:0xB4, bit 7)
Reserved
Data Transfer Mode
Only one bit must be set in this field to indicate the desired AGP data transfer rate.
001 = 1X AGP rate
010 = 2X AGP rate
100 = 4X AGP rate
Chapter 2
AMD-761™ System Controller Programmer’s Interface
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