13 power management, 1 acpi, Power management – chiliGREEN D945GBZ User Manual

Page 38: Acpi, Effects of pressing the power switch

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Intel Desktop Board D945GCZ Technical Product Specification

38

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 connectors
⎯ LAN wake capabilities
⎯ Instantly Available PC technology
⎯ Resume on Ring
⎯ Wake from USB
⎯ Wake from PS/2 devices
⎯ Power Management Event signal (PME#) wake-up support

1.13.1 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 9 on page 40)
• Support for a front panel power and sleep mode switch

Table 7 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 7.

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)

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