7521Plus / N N/B MAINTENANCE
APM
Concept
This platform supports Advanced Power Management (APM1.2) developed by Microsoft and Intel. APM consists of one or more layers of software that support power management in computers with power manageable hardware.
Power State 1.Full Power
Default mode. System activity detected. This is the normal state of the system. If system power management is disabled, the system remains in this state until the power is turned off.
2. Idle
An APM driver will notify the APM BIOS about CPU usage but the APM BIOS determines the action to take. Idle is a state between full system power and standby. Enable/Disable by toggling the setting in Bios Setup Menu.
Idle Mode slows down the CPU during brief periods.
This state is attained by :
• The APM driver acknowledge APM BIOS that the system is idle. The APM BIOS issues “CPU HLT “ instruction. Events that can bring unit back to full power state :
•CPU idle until the next system event (typically an interrupt) occurs.
3.Standby
System may not be working and in a low power state with some power saving. Most devices are in a low power mode. The CPU clock is slowed. System returns quickly to full on state. Operational parameters are retained.
This state is attained by:
•Set “Standby Timeout “ in Bios Setup Menu.
•Triggered by the timeout timer of the standby timer.
Events that can bring unit back to full power state:
•Pressing any key on the keyboard.
•Wake on LAN.
• Modem answering call. | 26 |
