243658-020 Datasheet, PDF (16/128 Pages) Intel Corporation – Intel Celeron Processor up to 1.10 GHz

Intel^® Celeron^® Processor up to 1.10 GHz
2.2.1
Normal State—State 1
This is the normal operating state for the processor.
2.2.2
AutoHALT Power Down 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 (Order Number 243192) for more information.
FLUSH# will be serviced during the AutoHALT state, and the processor will return to the
AutoHALT state.
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.
Figure 1. Clock Control State Machine
2. Auto HALT Power Down State
BCLK running.
Snoops and interrupts allowed.
HALT Instruction and
HALT Bus Cycle generated
INIT#, BINIT#, INTR, SMI#,
RESET#
1. Normal State
Normal execution.
Snoop
Event
Occurs
Snoop
Event
Serviced
4. Auto HALT Power Down State
BCLK running.
Snoops and interrupts allowed.
STPCLK# Deasserted
and Stop Grant entered
from Auto HALT.
Snoop event occurs
Snoop event serviced
STPCLK#
asserted
STPCLK#
deasserted
3. Stop Grant State
BCLK running.
Snoops and interrupts allowed.
SLP#
asserted
SLP#
deasserted
5. Sleep State
BCLK running.
Snoops and interrupts allowed.
BCLK
input
stopped
BCLK
input
restarted
6. Deep Sleep State
BCLK stopped.
No Snoops and interrupts allowed.
16
Datasheet