Compaq 850 manual 3.2 LPC47B357 I/O Controller Miscellaneous Functions, System Status Power LED

Technical Reference Guide

4.8.3.2LPC47B357 I/O Controller Miscellaneous Functions

The desktop and minitower systems utilize the following specialized functions built into the LPC

47B357 I/O Controller:

♦Power/Hard drive LED control – The I/O controller provides color and blink control for the front panel LEDs used for indicating system events as listed below:

System Status	Power LED	HD LED
S0: System on (normal operation)	Steady green	Green w/HD activity
S1: Suspend	Blinks green @ 1 Hz	Off
S3: Suspend to RAM	Blinks green @ 1 Hz	Off
S4: Suspend to disk	Blinks green @ 0.5 Hz	Off
S5: Soft off	Off - clear	Off
Backplane board not seated	Steady red	Steady red
Processor not seated	Steady red	Off
CPU thermal shutdown	Blinks red @ 4 Hz	Off
ROM error	Blinks red @ 1 Hz	Off
Power supply crowbar activated	Blinks red @ 0.5 Hz	Off
System off	Off	Off

♦I/O security – The parallel, serial, and diskette interfaces may be disabled individually by software and the LPC47B357’s disabling register locked. If the disabling register is locked, a system reset through a cold boot is required to gain access to the disabling (Device Disable) register.

♦Processor present/speed detection – One of the battery-back general-purpose inputs (GPI26) of the LPC47B357 detects if the processor has been removed. The occurrence of this event is passed to the ICH that will, during the next boot sequence, initiate the speed selection routine for the processor. The speed selection function replaces the manual DIP switch configuration procedure required on previous systems.

♦Legacy/ACPI power button mode control – The LPC47B357 receives the pulse signal from the system’s power button and produces the PS On signal according to the mode (legacy or ACPI) selected. Refer to chapter 7 for more information regarding power management.

Compaq Deskpro EXS and Workstation 300 Personal Computers 4-39

Featuring the Intel Pentium 4 Processor

First Edition - December 2000