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2 Troubleshooting 2.4 System board Troubleshooting
2-22 [CONFIDENTIAL] TECRA M4 Maintenance Manual (960-521)
Table 2-3 Debug port (Boot mode) error status (1/10)
D port status Inspection items Details
Permission of A20 and Clear of
software reset bit
Prohibition of APIC
Initialization of MCHM, ICHM
Initialization of Super I/O
Initialization of debug port
Dummy read of 3
rd
Bus data
Setting of printer port (for models
supporting printer)
PIT CH0 initialization (for
HOLD_ON)
BIOS rewrite factor flag
initialization
Transition to protected mode
Boot block checksum (skipped when
returned to S3)
Halts when error occurs
F000h
CHECK SUM CHECK
Checksum other than boot block (skip
when returned to S3)
F001h
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
When a key is pressed, check if it is Tilde
key or Tab key.
F002h
Initialization of SC
Halts when error occurs. Dport=F1B3h or
B4h
F006h
BIOS rewrite request check
If Checksum check error occurred on
except Boot Block or rewrite is required by
user, go to “BIOS rewrite process”.
Transits to system BIOS IRT.
Initialization of ICHM. D31
DRAM configuration
Permission of cache (L1 cache only)
Memory clear
F007h
BIOS rewrite process
Transits to real mode and copies BIOS to
RAM.