Troubleshooting Procedures - Toshiba Portege M200 Maintenance Manual

2 Troubleshooting Procedures

D port
status
F000h Clearing software reset bit
Enabling address line A20
Initializing special registers and M1535
Initializing the CH0 of a PIT (for HOLD_ON)
Initializing flag for BIOS rewriting factor
CHECK SUM CHECK (FEFC0000h to FEFF7FFFh)
Shifting to protected mode
Examining the checksum of Boot Block
Examining the checksum of data except Boot Block
F001h Checking if EC/KBC firmware is to be rewritten
Executing KBC initializing sequence
Sending KBC enable command
Checking F12 key-in
F002h Initializing security controller
F003h to Checking whether BIOS rewrite is requested
F005h
F006H Checking BIOS signature
F007h Shifting process to System BIOS IRT side
BIOS rewriting process
Initializing unique HW for this model
Initializing GPIO I/O space
Enabling BIOS writing
Serial interrupt control
Canceling BIOS write protection
Enabling SMBus I/O space
Enabling SMBus access
Configuring DRAM
Enabling L1 cache memory
Clearing memory
F008h Changing ROM BIOS to RAM BIOS
F009h Storing key scan codes
Setting up TASK_1ms_TSC
Displaying message on navipanel (EC/KBC UPDATE,
BIOS UPDATE/DAMAGED)
2-22
Table 2-3 D port status (1/7)
Details
2.4 System Board Troubleshooting
Remarks
HALT when checksum is not correct.
Shifting to BIOS rewriting process if
BIOS rewriting request exists
Checksum error except Boot Block or
rewriting request by F12key-in
For BIOS rewriting process
Portege M200 Maintenance Manual (960-457)