Intel Pentium 4 672 HH80547PG1122MH User Manual
Product codes
HH80547PG1122MH
Intel
®
Pentium
®
4 Processor in the 423-pin Package
76
The system can generate a STPCLK# while the processor is in the AutoHALT Power Down state.
When the system deasserts the STPCLK# interrupt, the processor will return execution to the
HALT state.
When the system deasserts the STPCLK# interrupt, the processor will return execution to the
HALT state.
While in AutoHALT Power Down state, the processor will process bus snoops.
7.2.3
Stop-Grant State—State 3
When the STPCLK# pin is asserted, the Stop-Grant state of the processor is entered 20 bus clocks
after the response phase of the processor-issued Stop Grant Acknowledge special bus cycle. Once
the STPCLK# pin has been asserted, it may only be deasserted once the processor is in the Stop
Grant state.
after the response phase of the processor-issued Stop Grant Acknowledge special bus cycle. Once
the STPCLK# pin has been asserted, it may only be deasserted once the processor is in the Stop
Grant state.
Since the AGTL+ signal pins receive power from the system bus, these pins should not be driven
(allowing the level to return to V
(allowing the level to return to V
CC
) for minimum power drawn by the termination resistors in this
state. In addition, all other input pins on the system bus should be driven to the inactive state.
BINIT# will not be serviced while the processor is in Stop-Grant state. The event will be latched
and can be serviced by software upon exit from the Stop Grant state.
and can be serviced by software upon exit from the Stop Grant state.
Figure 27. Stop Clock State Machine
2. Auto HALT Power Down State
BCLK running.
Snoops and interrupts allowed.
Snoops and interrupts allowed.
HALT Instruction and
HALT Bus Cycle Generated
HALT Bus Cycle Generated
INIT#, BINIT#, INTR, NMI,
SMI#, RESET#
SMI#, RESET#
1. Normal State
Normal execution.
STPCLK#
Asserted
Asserted
STPCLK#
De-asserted
De-asserted
3. Stop Grant State
BCLK running.
Snoops and interrupts allowed.
Snoops and interrupts allowed.
SLP#
Asserted
Asserted
SLP#
De-asserted
De-asserted
5. Sleep State
BCLK running.
No snoops or interrupts allowed.
No snoops or interrupts allowed.
BCLK
Input
Stopped
Input
Stopped
BCLK
Input
Restarted
Input
Restarted
6. Deep Sleep State
BCLK stopped.
No snoops or interrupts allowed.
No snoops or interrupts allowed.
4. HALT/Grant Snoop State
BCLK running.
Service snoops to caches.
Service snoops to caches.
Snoop Event Occurs
Snoop Event Serviced
Snoop
Event
Occurs
Event
Occurs
Snoop
Event
Serviced
Event
Serviced
STPC
LK# A
sserte
d
STPC
LK# D
e-asse
rted