Compaq W4000 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 DIMM configuration. The BIOS communicates with an EEPROM on each DIMM through the SMBus to obtain data on the following DIMM parameters:

♦Presence

♦Size

♦Type

♦Timing/CAS latency

♦PC133 capability

NOTE: Refer to Chapter 3, “Processor/Memory Subsystem” for the SPD format and DIMM 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 DIMM slots that are populated.

2.Determine the common CAS latency that can be supported by the DIMMs.

3.Determine the memory size for each DIMM and program the GMCH accordingly.

4.Enable refresh

5.Determine if the memory configuration will allow for 133MHz memory operation and program the memory clock and MCH (see note below)

NOTE: The presence of PC133-compliant DIMMS will be indicated by BIOS reading 75h from byte 9 and 64h or 85h from byte 126. For PC133 operation to occur the FSB of the processor must be running at 133 MHz and all installed DIMMs must be PC133-compliant and total no more than four “sides.” Refer to Chapter 3 for more details on PC133 operation.

7.3.4 BOOT 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 listed in the following table.

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 Evo and Workstation Personal Computers 7-5

Featuring the Intel Pentium 4 Processor

Second Edition - January 2003