Datasheet
Functional Description
R
206 Datasheet
• C2 Stop Clock. Clock to CPU still running. Clock stopped to CPU core.
• C3 Deep Sleep. Clock to CPU stopped.
• C4 Deeper Sleep. Same as C3 with reduced voltage on the CPU.
System States:
• G0/S0 Full On
• G1/S1-M Power On Suspend (POS). System Context Preserved
• G1/S2 Not supported.
• G1/S3 Suspend to RAM (STR). Power and context lost to chipset.
• G1/S4 Suspend to Disk (STD). All power lost (except wakeup on ICH4-M)
• G2/S5 Soft off. Total reboot.
5.10 Enhanced Intel SpeedStep
®
Technology Overview
With Enhanced Intel SpeedStep technology the processor core voltage changes and allows true
CPU core frequency changes versus only clock throttling.
Table 47. Enhanced Intel SpeedStep
®
Technology Overview
CPU
Mobile Intel Pentium 4 processor, Mobile Intel
Pentium 4 processor supporting Hyper-Threading
Technology on 90-nm process technology
Benefit Over Non-power Managed CPU
Additional lower voltages and frequencies
Transition Prompt
OS based on CPU load demand, thermal control, or
user event based
CPU Availability
CPU unavailability can be restricted to ~10 µs (CPU
dependent) by s/w
5.11 External Thermal Sensor Input
An External Thermal sensor with a serial interface may be placed next to DDR SDRAM SO-
DIMM (or any other appropriate platform location), or a remote Thermal Diode may be placed
next to the SO-DIMM (or any other appropriate platform location) and connected to the External
Thermal sensor. Intel advises that the External Thermal sensor contains some form of hysteresis,
since none is provided by the GMCH/MCH hardware.
The external sensor can be connected to the ICH4-M via the SMBus interface to allow
programming and setup by BIOS software over the serial interface. The External sensor’s output
should include an Active-Low Open-Drain signal indicating an Over-Temp condition, which
remains asserted for as long as the Over-Temp Condition exists, and deasserts when temperature
has returned to within normal operating range. This External sensor output will be connected to
the GMCH/MCH input (EXTTS_0) and will trigger a Preset Interrupt and/or Read-Throttle on a
level-sensitive basis.