Compaq 850 manual Memory Detection and Configuration, Boot Error Codes, Visual Audible Meaning

Technical Reference Guide

7.3.3 MEMORY DETECTION AND CONFIGURATION

This system uses the Serial Presence Detect (SPD) method of determining the installed RIMM configuration. The BIOS communicates with an EEPROM on each RIMM through the SMBus to obtain data on the following RIMM parameters:

♦Presence

♦Size

♦Type

♦PC800 capability

NOTE: Refer to Chapter 3, “Processor/Memory Subsystem” for the SPD format and RIMM data specific to this system.

The BIOS performs memory detection and configuration with the following steps:

1.Program the buffer strength control registers based on SPD data and the RIMM slots that are populated.

2.Determine the memory size for each RIMM and program the MCH accordingly.

3.Enable refresh.

7.3.4BOOT ERROR CODES

The BIOS provides visual and audible indications of a failed system boot by using the keyboard LEDs and the system speaker. The error conditions are as follows:

Table 7-2.Boot Error Codes

Visual [1]	Audible	Meaning
Num Lock LED blinks	1 short, 2 long beeps	System memory not present or incompatible.
Scroll Lock LED blinks	2 long, 1 short beeps	Hardware failure before graphics initialization.
Caps Lock LED blinks	1 long, 2 short beeps	Graphics controller not present or failed to
		initialize.
Num, Caps, Scroll Lock LEDs	1 long, 3 short beeps	ROM failure.
blink
Num, Caps, Scroll Lock LEDs	none	Network service mode
blink in sequence

NOTE:

[1] Provided with PS/2 keyboard only.

Compaq Deskpro EXS and Workstation 300 Personal Computers 7-5

Featuring the Intel Pentium 4 Processor

First Edition - December 2000