82845MP Datasheet, PDF (124/157 Pages) Intel Corporation – Intel 845 Family Chipset-Mobile 82845MP/82845MZ Chipset Memory Controller Hub Mobile (MCH-M)

Intel^®82845MP/82845MZ Chipset-Mobile (MCH-M)
R
5.4.3.
General Description of ACPI System States
• S0 (Awake): In this state all power planes are active.
• S1-M (Powered on Suspend for Mobile Systems): Power is maintained to the CPU and all system
components, but most clocks are stopped by the clock synthesizer.
• S2: ACPI S2 state is not supported in the Intel 845MP/845MZ Chipset platform.
• S3 (Suspend To RAM): The next level of power reduction occurs when the clock synthesizer and
core well power planes for the processor and chipset are shut down, but the main memory power
plane and the ICH3-M resume well remain active. This is the Suspend To RAM (STR) state. All
clocks from synthesizers are shut down during the S3 state.
• S4 (Suspend to Disk) and S5 (Soft Off): In these states the main memory power plane is shut
down in addition to the clock synthesizer and core well power planes for the processor and chipset.
The ICH3-M resume well is still powered.
• G3 (Mechanical Off): In this state only the RTC (Real Time Clock) well is powered. The system
can only be reactivated via the power switch.
5.4.4. Power Transitions
Table 33. Intel 845MP/845MZ Power Transitions
ACPI
CO
C1
State/Feature
DDR
RAC
DRCG
Active/Standby
& Nap
Active
Running
Active/Standby
& Nap
Active
Running
C2/S1D
Nap, Active, &
Standby
Active
Running
Clock Gating
GTL Control
Buffer Sense
Amp Disable
Hublink Interface
Yes (during
writes)
No
Active
Yes (during
writes)
No
Yes (enabled
during snoops)
No
Active
Active
CPU PLL
AGP/Hublink
PLL
Intel SpeedStep
Technology
Transition
Dynamic RAC
Power
Reduction
Running
Running
No
Enabled
Running
Running
No
Enabled
Running
Running
No
Enabled
C3/C4
Power-down
Power-down
Clock Stop
Mode
Yes
Yes
Active
Running
Running
No
Enabled
S1M
Power-down
Power-down
Power-down
Yes
Yes
Power-down
REQ1
Running
Running
No
Enabled
124
Datasheet
250687-002