16
1.12
Power Management
Power management is implemented at several levels, including:
Software support through Advanced Configuration and Power Interface (ACPI)
Hardware support:
Power Input
Instantly Available PC technology
Wireless LAN wake capabilities
Wake from USB (When plugged into a compatible device)
Wake from S5
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 Compute Card 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
A Soft-off feature that enables the operating system to power-off the Compute Card
Support for multiple wake-up events (see Table 5 on page 18)
Table 3 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. Support is only available when the
Compute Card is plugged into a compatible device’s Compute Card slot.
Table 3. 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)
Note
On
(ACPI G0 – working state)
More than six 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 six seconds
Power-off
(ACPI G2/G5 – Soft off)
Note: Depending on power management settings in the operating system.
