Chapter 2
AMD-761™ System Controller Programmer’s Interface
43
24081D—February 2002
AMD-761™ System Controller Software/BIOS Design Guide
Preliminary Information
Programming Notes
Bit Definitions
Extended BIU Control (Dev0:F0:0x44)
Bit
Name
Function
31–11
Reserved
Reserved
15–14
Reserved
Reserved
10–8
P0_WrDataDly
Write Data Delay
P0_WrDataDly is the time in SYSCLK periods from the launch of a SysDC WriteData
command until the launch of the first data object by the processor. This value is a
calculated part of the SIP stream. This value is not provided in the BIU SIP register and is
thus provided here.
7-4
Reserved
Reserved
3
P0_2BitPF
Two Bit Times Per Frame Enable
This bit enables the use of the two bit time commands on the AMD Athlon™ processor
system bus. This bit must be set when connected to an AMD Athlon processor and
disabled when connected to an Alpha processor. For proper operation, BIOS must not
clear this bit once it has been set.
0 = Two-bit time commands disabled
1 = Two-bit time commands enabled (AMD Athlon processor only)
2–0
Reserved
Reserved
These bits must be written with 0 (cleared) for normal operation.