Low Power Features; Clock Control And Low Power States; Normal State; Autohalt Power-Down State - Intel RH80536GC0332M - Pentium M 1.8 GHz Processor Datasheet

2

Low Power Features

2.1

Clock Control and Low Power States

The Pentium M processor supports the AutoHALT Power-Down, Stop Grant, Sleep, Deep Sleep,
and Deeper Sleep states for optimal power management. See
of the processor low-power states.
Figure 2-1. Clock Control States
Normal
halt
break
instruction
Auto Halt
2.1.1

Normal State

This is the normal operating state for the processor.
2.1.2

AutoHALT Power-Down State

AutoHALT Power-Down is a low-power state entered when the processor executes the HALT
instruction. The processor will transition to the Normal state upon the occurrence of SMI#, INIT#,
LINT[1:0] (NMI, INTR), or FSB interrupt message. RESET# will cause the processor to
immediately initialize itself.
A system management interrupt (SMI) handler will return execution to either Normal state or the
AutoHALT Power-Down state. See the IA-32 Intel
Volume 3: System Programmer's Guide for more information.
Datasheet
STPCLK# asserted
STPCLK# deasserted
STPCLK#
asserted
snoop
HLT
serviced
STPCLK#
deasserted
snoop
occurs
snoop
serviced
Halt break - A20M#, INIT#, INTR, NMI, PREQ#, RESET#, SMI#, or APIC interrupt
Figure 2-1
SLP# asserted
Stop
Grant
SLP# deasserted
snoop
occurs
core voltage raised
HALT/
Deeper
Grant
Sleep
Snoop
core voltage lowered
V0001-04
®
Architecture Software Developer's Manual,
Low Power Features
for a visual representation
Sleep
DPSLP#
DPSLP#
de-asserted
asserted
Deep
Sleep
11