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AMD-761™ System Controller Programmer’s Interface
Chapter 2
AMD-761™ System Controller Software/BIOS Design Guide
24081D—February 2002
Preliminary Information
2.2.1
Special Cycles
Special cycles generated by the AMD Athlon processor are
forwarded down to the PCI bus with specific values in the
address and data fields of the PCI special cycle command.
Table 4 defines these values. The AMD Athlon processor
g e n e ra t e s A M D A t h l o n p ro c e s s o r s y s t e m b u s W r LW s
commands to a single address (1 F8000 0000) with the data
field specifying the desired special cycle. The AMD-761 system
controller maps the AMD Athlon processor system bus data
value onto the PCI for both address and data phases of the
Special Cycle Transaction.
.
Table 4.
AMD Athlon™ Processor Special Cycle Encodings
Special Cycle
PCI Address and
Data Field
Contents
Processor Description
Northbridge and Southbridge
Description
SHUTDOWN
0000 0000
The AMD Athlon™ processor gener-
ates in response to a shutdown condi-
tion. AMD Athlon processor system
bus WrLWs command: SysAddOut:
MSB=0 & [33:0] = 1 F8000 0000
SysDatOut: [31:0] = 0000 0000
The AMD-761™ system controller
forwards onto the PCI bus the PCI
special cycle command: AD[31:0] =
0000 0000 (address and data).
AMD-766™ peripheral bus controllers
asserts INIT to processor.
HALT
0000 0001
The AMD Athlon processor generates
in response to executing a HALT
instruction: WrLWs command:
SysAddOut: MSB=0 & [33:0] = 1
F8000 0000
SysDatOut: [31:0] = 0000 0001
The AMD-761 system controller waits
for all queues to memory to be empty
(assumes the PCI grant enable register
is clear, “Dev0:F0:0x84” on page 70).
AMD-761 system controller optionally
(via “Dev0:F0:0x60” on page 61)
initiates an AMD Athlon system bus
disconnect to this specific CPU. The
AMD-761 system controller forwards
onto the PCI bus (after the optional
AMD Athlon system bus disconnect).
PCI special cycle command: AD[31:0] =
0000 0001 (address and data)
AMD-766 peripheral bus controllers
ignores.
WB
INVALIDATE
0001 0002
The AMD Athlon processor generates
in response to executing a WBINV
instruction WrLWs command:
SysAddOut: MSB=0 & [33:0] = 1
F8000 0000
SysDatOut: [31:0] = 0001 0002
The AMD-761 system controller
forwards onto the PCI bus, PCI special
cycle command: AD[31:0] = 0001 0002
(address and data).
AMD-766 peripheral bus controllers
ignores.