HP D315 System Timer, IDE Hard Drive Timer, Going to Sleep in Independent PM, System Standby

Technical Reference Guide

System Timer

In POST, the BIOS enables a timer in the south bridge component that generates an SMI once per minute. When the BIOS detects the SMI it checks status bits in the south bridge for device activity. If any of the device activity status bits are set at the time of the 1-minute SMI, BIOS resets the time-out minute countdown. The system timer can be configured through the Setup utility for counting down 0, 5, 10, 15, 20, 30, 40, 50, 60, 120, 180, or 240 minutes. The following devices are checked for activity:

♦Keyboard

♦Mouse

♦Serial port(s)

♦Parallel port

♦IDE primary controller

NOTE: The secondary controller is NOT included. This is done to support auto-sense of a CD-ROM insertion (auto-run) in case Windows or NT is running. ote also that SCSI drive management is the responsibility of the SCSI river. Any IDE hard drive access resets the hard drive timer.

IDE Hard Drive Timer

During POST, an inactivity timer each IDE hard drive is set to control hard drive spin down. Although this activity is independent of the system timer, the system will not go to sleep until the primary IDE controller has been inactive for the system time-out time. The hard drive timer can be configured through the Setup utility for being disabled or counting down 10, 15, 20, 30, 60, 120, 180, or 240 minutes, after which time the hard drive will spin down.

8.6.1.2 Going to Sleep in Independent PM

When a time-out timer expires, Standby for that timer occurs.

System Standby

When the system acquires the Standby mode the BIOS blanks the screen. Since the hard drive inactivity timer is in the drive and triggered by drive access, the system can be in Standby with the hard drives still spinning (awake).

NOTE: The BIOS does not turn the fan(s) off (as on previous products).

IDE Hard Drive Standby

During hard drive standby the platters stop spinning. Depending on drive type, some hard drives will also cut power to some of the drive electronics that are not needed. The drives can be in this state with the system still awake.

Compaq D315 and hp d325 Personal Computers8-15

Featuring the AMD Athlon XP Processor

Second Edition – April 2003