Preliminary Information
AMD Athlon™ XP Processor Model 10 Data Sheet | 26237C— May 2003 |
Figure 4 shows STPCLK# assertion resulting in the processor in the Stop Grant state and the AMD Athlon system bus disconnected.
STPCLK#
AMD Athlon™
System Bus 
Stop Grant 
CONNECT
PROCRDY
CLKFWDRST
PCI Bus 
Stop Grant
Figure 4. AMD Athlon™ System Bus Disconnect Sequence in the Stop Grant State
An example of the AMD Athlon system bus disconnect sequence is as follows:
1.The peripheral controller (Southbridge) asserts STPCLK# to place the processor in the Stop Grant state.
2.When the processor recognizes STPCLK# asserted, it enters the Stop Grant state and then issues a Stop Grant special cycle.
3.When the special cycle is received by the Northbridge, it deasserts CONNECT, assuming no probes are pending, initiating a bus disconnect to the processor.
4.The processor responds to the Northbridge by deasserting
PROCRDY.
5.The Northbridge asserts CLKFWDRST to complete the bus disconnect sequence.
6.After the processor is disconnected from the bus, the processor enters a
14 | Power Management | Chapter 4 |
