Toshiba A1 Personal Computer User Manual


 
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 3
rd
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)
EC/KBC rewrite check B1h KBC initialization
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”.
Transits to System BIOS IRT.
Initialization of ICHM. D31
DRAM configuration
Permission of cache (L1 cache only)
Memory clear
B3h BIOS rewrite (1)
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