82801BA Datasheet, PDF (147/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

Functional Description
5.12.8.4
Processor-Initiated Passive Cooling (Via Programmed Duty Cycle on
STPCLK#)
Using the THTL_EN and THTL_DTY bits, the ICH2 can force a programmed duty cycle on the
STPCLK# signal. This reduces the effective instruction rate of the processor and cut its power
consumption and heat generation.
5.12.8.5
Active Cooling
Active cooling involves fans. The GPIO signals from the ICH2 can be used to turn on/off a fan.
5.12.9 Intel^® SpeedStep^™ Technology Protocol
(82801BAM ICH2-M only)
The Intel^® SpeedStep^™ technology feature enables a mobile system to operate in multiple
processor performance/thermal states and to transition smoothly between them. The internal
processor clock setting and processor supply voltage setting determines these states. The ICH2-M
supports one Low Power mode and one High Performance mode.
Figure 5-14. Intel^® SpeedStep^™ Block Diagram (82801BAM ICH2-M only)
SpeedStep™
Enabled Mobile
Intel^® Processors
CPUPERF#
CPUPW RGD
STPCLK#
VddCore
Processor's
Voltage Regulator
Module (VRM)
VGATE
PW ROK
GMUXSEL
ICH2-M
From Main
Power Supply
VRCODE[4:0]
5
5
High Voltage
5
Low Voltage
82801BA ICH2 and 82801BAM ICH2-M Datasheet
5-85