AC82GL40-SLB95 Datasheet, PDF (11/98 Pages) Intel Corporation – Intel® Celeron® Mobile Processor Dual-Core on 45-nm Process

Low Power Features
2 Low Power Features
2.1
Table 1.
Figure 1.
Clock Control and Low Power States
The processor supports the C1/AutoHALT, C1/MWAIT, C2, C3 and some support the C4
core low-power states, along with their corresponding package-level states for power
management. See Chapter 3 to see if C4 is supported. These package states include
Normal, Stop Grant, Stop Grant Snoop, Sleep, and Deep Sleep. The processor’s central
power management logic enters a package low-power state by initiating a P_LVLx
(P_LVL2, P_LVL3, P_LVL4) I/O read to the (G)MCH. Figure 1 shows the package-level
low-power states and Figure 2 shows the core low-power states. Refer to Table 1 for a
mapping of core low-power states to package low-power states.
The processor implements two software interfaces for requesting low-power states:
MWAIT instruction extensions with sub-state hints and P_LVLx reads to the ACPI P_BLK
register block mapped in the processor’s I/O address space. The P_LVLx I/O reads are
converted to equivalent MWAIT C-state requests inside the processor and do not
directly result in I/O reads on the processor FSB. The monitor address does not need to
be setup before using the P_LVLx I/O read interface. The sub-state hints used for each
P_LVLx read can be configured through the IA32_MISC_ENABLES Model Specific
Register (MSR).
If the processor encounters a chipset break event while STPCLK# is asserted, it asserts
the PBE# output signal. Assertion of PBE# when STPCLK# is asserted indicates to
system logic that the processor should return to the Normal state.
Coordination of Core-Level Low-Power States at the Package Level
Core States Package States
C0
C1⁽¹⁾
C2
C3
C4
Normal
Normal
Stop Grant
Deep Sleep
Deeper Sleep
NOTE: AutoHALT or MWAIT/C1
Package-Level Low-Power States
Normal
STPCLK# asserted
STPCLK# deasserted
Stop
Grant
SLP# asserted
SLP# deasserted
Sleep
DPSLP# asserted
DPRSTP# asserted
Deep
Sleep
Deeper
Sleep^†
DPSLP# deasserted
DPRSTP# deasserted
Snoop Snoop
serviced occurs
Stop Grant
Snoop
† — Deeper Sleep includes the Deeper Sleep state and Deep C4 sub-state
Datasheet
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