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Chapter 8 BIOS ROM
Compaq iPAQ Family of Internet Devices
First Edition - March 2000
8-16
Three power states are defined under power management:
On
- The computer is running, all subsystems are on and drawing full power. Any activity in the
following subsystems will reset the activity timer, which has a default setting of 15 minutes
before Standby entered:
a. Keyboard (PS/2 only)
b. Mouse (PS/2 only)
c. Serial port
d. Hard drive
Standby
- The computer is in a low power state: video is off, some subsystems may be drawing
less power, and the microprocessor is halted except for servicing interrupts. Video graphics
controller is under driver control and/or VSYNC is off and the power supply fan is turned off.
Any of the following activities will generate a wake-up SMI and return the system to On:
a. Keyboard (PS/2 only)
b. Mouse (PS/2 only)
c. Serial port
d. Hard drive
e. RTC Alarm
f. Power Button
If no APM connection is present, the BIOS will set an APM timer to 45 minutes, at which time
the Suspend will be entered if no activity has occurred. This function can be defeated (so that
Suspend will
not
be achieved). If an APM connection is present, the BIOS APM timer is not used
and Suspend is entered only by user request either through an icon in Windows 95 or by pressing
and releasing the power button under 4 seconds.
Suspend
- The computer is in a low power state: video graphics controller is under driver control
and/or HSYNC and VSYNC are off, some subsystems may be drawing less power, and the
microprocessor is halted except for servicing interrupts. Any of the following activities will
generate a wake-up SMI and return the system to On:
a. Keyboard (PS/2 only)
b. Mouse (PS/2 only)
c. Serial port
d. Diskette drive
e. Hard drive
f. RTC Alarm
g. Network interface controller