Datasheet

Product Description
31
1.12.1 ACPI
ACPI gives the operating system direct control over the power management and Plug and Play
functions of a computer. The use of ACPI with this 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 33)
• 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 state…
…and the power switch is
pressed for …the system enters this state
Off
(ACPI G2/G5 – Soft off)
Less than four seconds Power-on
(ACPI G0 – working state)
On
(ACPI G0 – working state)
Less than four seconds Soft-off/Standby
(ACPI G1 – sleeping state)
On
(ACPI G0 – working state)
More than four seconds Fail safe power-off
(ACPI G2/G5 – Soft off)
Sleep
(ACPI G1 – sleeping state)
Less than four seconds Wake-up
(ACPI G0 – working state)
Sleep
(ACPI G1 – sleeping state)
More than four seconds Power-off
(ACPI G2/G5 – Soft off)