Power Management - Contec SBC Series User Manual

Power Management

The PIIX4 power management function provides system designers with a range of
different functions and configuration options for implementing various power saving
modes.
PIIX4 performs the following four general types of power management.
- Clock control and processor complex management
- Peripheral device management
- System management (SMI generation, system management bus)
- System shutdown and restart
The following gives a brief explanation of the main power management functions.
Clock Control
The processor complex (processor, host bridge, DRAM, and L2 cache) does not need
to execute cycles when the operating system (OS), application program, and system
software are not performing any useful work. At times such as this, the system can
go into standby mode.
Peripheral Device Management
Peripheral resources are monitored to detect when particular devices are idle. The
system power management software can set the power management state (local
standby or power off, etc.) of individual devices.
the system power management software for monitoring.
System Shutdown
On determining that the system is completely idle or when a significant system event
has occurred, the system power management software can shutdown the system. This
provides a significant saving in power consumption. The software specifies
shutdown event, restart event and wakeup event settings to PIIX4 and PIIX4
automatically changes the system to the shutdown state in accordance with these
settings. Similarly, PIIX4 automatically restarts operation when a valid restart event
is detected.
PC-686BX(NLX)-LV, PC-686BX(NLX)-LVV
2. Specifications
PIIX4 notifies specific devices to
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