2.4 System Board Troubleshooting

2 Troubleshooting Procedures

Table 2-3 Printer port LED boot mode status (1/8)

LED Status

Test item

Contents

 

Start

Clear of software reset bit

 

 

Prohibition of APIC

 

 

 

Initialization of MCHM

 

 

 

Initialization of ICHM

 

 

 

Initialization of Super I/O

 

 

 

Initialization of debug port

 

 

Dummy read of 3rd Bus data

B0h

Flash ROM check

PIT CH0 initialization (for HOLD_ON)

 

 

BIOS rewrite factor flag initialization

 

 

CHECK SUM CHECK

 

 

 

Transition to protected mode

 

 

Boot block checksum (skip when returned to S3)

 

 

The program halts when checksum error occurred.

 

 

Checksum other than boot block (skip when

 

 

returned to S3)

 

B1h

KBC initialization

EC/KBC rewrite check

 

 

 

 

 

 

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

 

 

process”.

 

 

 

Transition of process to System BIOS IRT when

 

 

returned to S3)

 

 

 

Key input

 

 

 

 

 

 

 

Check of Tilde key (

key) and Tab key if a key

 

 

is pressed

 

 

 

 

B2h

BIOS rewrite request check

BIOS rewrite request check if Checksum check

 

 

error occurred on except Boot Block or rewrite is

 

 

required by user. “BIOS rewrite process”.

B3h

BIOS rewrite (1)

Transits to System BIOS IRT.

 

 

 

 

 

Initialization of ICHM. D31

 

 

 

 

 

 

DRAM configuration

 

 

 

 

 

 

Permission of cache (L1 cache only)

 

 

 

 

 

 

Memory clear

 

 

 

 

 

 

Transition to real mode and copy of BIOS to RAM

 

 

 

 

B5h

 

Saving of key scan code

 

 

 

 

 

 

Setting of TASK_1ms_TSC

 

 

 

 

B6h

BIOS rewrite

FAN control

 

 

 

 

 

 

Sound initialization (for BEEP sound)

 

 

 

 

 

System speaker enable

 

 

 

 

Satellite A10/TECRA A1/Satellite Pro A10 Maintenance Manual (960-445)

2-21

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Toshiba A10 manual Printer port LED boot mode status 1/8, LED Status Test item Contents