Toshiba satellite A20 series Maintenance Manual page 73

2.12 Sound Troubleshooting
LED Status
FFh Start
B0h Flash ROM check
B1h EC/KBC rewrite check
B2h BIOS rewrite check
B3h System BIOS rewrite
transition to IRT
BIOS rewrite process
Satellite A20 Maintenance Manual (960-444)
Table 2-3 Printer port LED boot mode status (1/8)
Test item
2 Troubleshooting Procedures
Message
Register initialization for boot block
Clearing software reset bit
Permitting A20 line
Initialization of special register and Intel chip set
PIT CH0 initialization (for HOLD ON)
BIOS rewrite flag initialization
Checksum check
Transition to protected mode
Boot block checksum check (The system halts
when a checksum error is detected.)
Transition to BIOS rewriting when rewrite is
requested
Executing KBC initialization sequence
Enabling keyboard
[Tilde], [TAB] key check
BIOS rewrite request check when check sum error
except for Boot Block is detected, or rewrite is
requested by user
Transition to BIOS rewrite
System BIOS rewrite transition to IRT
Hardware initialization
Setting base for Power Management I/O Space
Enabling BIOS write
Special interrupt control
Disabling BIOS write protect
Enabling SMBus I/O space
Enable SMBus access
Opening work I/O for SDRAM initialization
Setting FDC prohibition
Hardware initialization for each model
PIT CH1 initialization (setting refresh interval to 30
m/s)
Initialization of PIT, DMAC, PIC
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