Toshiba A200 manual Clears software rest bit

2 Troubleshooting Procedures 2.4 System Board Troubleshooting

Table 2-5 Debugging port status (1/7)

D port	Contents
Status
	Clears software rest bit.
	Permits A20 line.
	Initializes special register and Intel chipset.
F000h	Initializes PIT CH0 only (for HOLD_ON).
	Initializes flag of factor rewriting of BIOS.
	Checks CHECK SUM.
	Transition to protect mode.
	Calculates the checksum of Boot block? HLT at checksum error
	Calculates the checksum of block other than Boot block.
F001h	Checks rewriting EC/KBC? Goes to BIOS rewriting process at request for
	rewriting.
	Executes KBC initializing sequence.
	Transmits KBC enable command.
	Checks F12 key.
F002h	Checks for request of BIOS rewriting? Checksum error of blocks other than
	BootBlock, at the request of F12 rewriting request.
F003h	Transfers the process to the System BIOS IRT side.
	BIOS rewriting process
	Initializes peculiar HW to the model.
	Initializes GPIO I/O space.
	Permits BIOS writing.
	Controls serial interrupts.
	Releases the write-protect of BIOS.
	Permits the SMBus I/O space.
	Permits the access to SMBus.
	Configuration of DRAM
	Permits cache (only L1 Cache).
	Memory clear

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