2 Troubleshooting Procedures

2.4 System Board Troubleshooting

Table 2-4 Printer port LED boot mode status (1/9)

LED Status

Test item

Contents

 

Permission of A20 and clear of software

 

 

reset bit

 

 

Prohibition of APIC

 

 

 

 

 

Initialization of MCH, ICH

 

 

 

 

 

Initialization of Super I/O

 

 

 

 

 

Initialization of debug port (For models

 

 

supporting debug port)

 

 

Dummy read of 3rd Bus data

 

 

Setting of printer port (For models

 

 

supporting printer port)

 

B0h

PIT CH0 initialization (for HOLD_ON)

 

 

 

 

 

BIOS rewrite factor flag initialization

 

 

 

 

 

CHECK SUM CHECK

Transition to protected mode

 

 

Boot block checksum (skipped when

 

 

returned from S3)

 

 

Halts when error occurs

 

 

Checksum other than boot block (skipped

 

 

when returned from S3)

 

 

 

B1h

EC/KBC rewrite check

If “rewrite” is requested, go to “BIOS rewrite

 

 

process”.

 

 

 

B2h

Initialization of SC

HLT at LED=B3H or B4, when error occurs

 

 

 

 

Key input (skipped when returned from

When a key is pressed, check if it is Tilde

 

S3)

key or Tab key. (skipped when returned from

 

 

S3)

 

 

 

B5h

Enables CPU cache

 

 

 

 

B6h

Security check

 

 

 

 

 

BIOS rewrite request check

If Checksum check error occurred on except

 

 

Boot Block or rewrite is required by user, go

 

 

to “BIOS rewrite process”.

 

 

 

B7h

Transits to System BIOS IRT

 

 

 

 

 

BIOS rewrite process

 

 

 

 

 

Initialization of ICH. D31

 

 

 

 

 

DRAM configuration

 

 

 

 

 

Permission of cache (L1 cache only)

 

 

 

 

 

Memory clear

 

 

 

 

 

Transition to real mode and copy of BIOS

 

 

to RAM

 

 

 

 

2-20

[CONFIDENTIAL]

TECRA S3 Maintenance Manual (960-532)

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Toshiba S4 manual LED Status Test item Contents