Intel D945GCLF2 specifications Power Management, Acpi, Effects of Pressing the Power Switch

Product Description

1.13 Power Management

Power management is implemented at several levels, including:

•Software support through Advanced Configuration and Power Interface (ACPI)

•Hardware support:

⎯Power connector

⎯Fan headers

⎯LAN wake capabilities

⎯Instantly Available PC technology

⎯Wake from USB

⎯Wake from PS/2 devices

⎯Power Management Event signal (PME#) wake-up support

1.13.1ACPI

ACPI gives the operating system direct control over the power management and Plug and Play functions of a computer. The use of ACPI with the board requires an operating system that provides full ACPI support. ACPI features include:

•Plug and Play (including bus and device enumeration)

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

•Methods for achieving less than 15-watt system operation in the power-on/standby sleeping state

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

•Support for multiple wake-up events (see Table 8 on page 31)

•Support for a front panel power and sleep mode switch

Table 6 lists the system states based on how long the power switch is pressed, depending on how ACPI is configured with an ACPI-aware operating system.

Table 6. Effects of Pressing the Power Switch

If the system is in this	…and the power switch
state…	is pressed for	…the system enters this state
Off	Less than four seconds	Power-on
(ACPI G2/G5 – Soft off)		(ACPI G0 – working state)
On	Less than four seconds	Soft-off/Standby
(ACPI G0 – working state)		(ACPI G1 – sleeping state)
On	More than four seconds	Fail safe power-off
(ACPI G0 – working state)		(ACPI G2/G5 – Soft off)
Sleep	Less than four seconds	Wake-up
(ACPI G1 – sleeping state)		(ACPI G0 – working state)
Sleep	More than four seconds	Power-off
(ACPI G1 – sleeping state)		(ACPI G2/G5 – Soft off)

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