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Chapter 3

 

 

ACPI Function (Advanced Configuration and Power Interface):

ACPI gives the operating system direct control over the power management and Plug and Play functions of a computer. The ACPI functions are always “Enabled”. If you want ACPI functions to work normally, you should notice two things. One is your operating system must support ACPI, as of now only Microsoft® Windows® 98 and Windows® 2000 supports these functions. The second thing is that all devices and add-on cards in your system must fully support ACPI, both hardware and software (drivers). If you want to know if your devices or add-on cards support ACPI or not, please contact the device or add-on card manufacture for more information. If you want to know more about ACPI specifications, please go to the address below for more detailed information:

http://www.teleport.com/~acpi/acpihtml/home.htm

Note: If you enable the ACPI function in the BIOS setup, the SMI function will not work.

ACPI requires an ACPI-aware operating system. ACPI features include:

!Plug and Play (including bus and device enumeration) and APM functionality normally contained in the BIOS.

!Power management control of individual devices, add-in cards (some add-in cards may require an ACPI-aware driver), video displays, and hard disk drives.

!A Soft-off feature that enables the operating system to power off the computer.

!Support for multiple wake-up events (see Table 3-6-1).

!Support for a front panel power and sleep mode switch. Table 3-6-2 describes the system states based on how long the power switch is pressed, depending on how ACPI is configured with an ACPI-aware operating system.

Note

If you enable the ACPI function in the BIOS setup, the SMI switch function will not work.

System States and Power States

Under ACPI, the operating system directs all system and device power state transitions. The operating system puts devices in and out of low-power states based on user preferences and knowledge of how devices are being used by applications. Devices that are not being used can be turned off. The operating system uses information from applications and user settings to put the system as a whole into a low-power state.

The table below describes which devices or specific events can wake the computer from specific states.

Table 3-6-1: Wake Up Device and Events

 

 

These device/events can wake up the

 

computer……

……from this state

Power switch

Sleeping mode or power off mode

RTC alarm

Sleeping mode or power off mode

LAN

Sleeping mode or power off mode

Modem

Sleeping mode or power off mode

IR command

Sleeping mode

USB

Sleeping mode

PS/2 keyboard

Sleeping mode

PS/2 mouse

Sleeping mode

 

 

SD7-533 Motherboard