Intel 4 3.20 GHz BX80532PG3200F User Manual

Product codes

BX80532PG3200F

Intel

Pentium

4 Processor on 0.13 Micron Process Datasheet

Features

6.2.2

AutoHALT Powerdown State—State 2

AutoHALT 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#, BINIT#, INIT#, or
LINT[1:0] (NMI, INTR). RESET# will cause the processor to immediately initialize itself.

The return from a System Management Interrupt (SMI) handler can be to either Normal Mode or
the AutoHALT Power Down state. See the Intel

Architecture Software Developer's Manual,

Volume III: System Programmer's Guide for more information.

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.

While in AutoHALT Power Down state, the processor will process bus snoops and interrupts.

Figure 6-1. Stop Clock State Machine

2. Auto HALT Power Down State

BCLK running.
Snoops and interrupts allowed.

4. HALT/Grant Snoop State

BCLK running.
Service snoops to caches.

Snoop
Event
Occurs

Snoop
Event
Serviced

HALT Instruction and
HALT Bus Cycle generated

INIT#, BINIT#, INTR, NMI,
SMI#, RESET#

Snoop event occurs

Snoop event serviced

1. Normal State

Normal execution.

3. Stop Grant State

BCLK running.
Snoops and interrupts allowed.

STPCLK#
Asserted

STPCLK#
De-asserted

5. Sleep State

BCLK running.
No snoops and interrupts allowed.

SLP#
Asserted

SLP# De-asserted

STPCLK# Asserted

STPCLK# De-asserted