Toshiba A40 manual LED Status Test item Contents

2.4 System Board Troubleshooting 2 Troubleshooting Procedures

Table 2-5 Printer port LED status (1/8)

LED Status	Test item		Contents
	Start	Permission of A20 and 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 3rd Bus data
		Setting of printer port
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)
B1h	KBC initialization	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
		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”.
B3h	BIOS rewrite (1)	Transits to System BIOS IRT.
		Initialization of ICHM. D31
		DRAM configuration
		Permission of cache (L1 cache only)
		Memory clear
		Transition to real mode and copy of BIOS to RAM
B5h		Saving of key scan code
		Initialization of TASK_1ms_TSC setting screen
B6h	BIOS rewrite	FAN control
		Sound initialization (for BEEP sound)
		System speaker enable

Satellite A40 Maintenance Manual (960-458) 2-23