B&B Electronics TPC-1261H user manual Table B.1 Watchdog Timer Registers

Table B.1: Watchdog Timer Registers

Address of	Attribute	Description
register (2E)
Read/Write	Value (2F)
	and
	description
87 (hex)	-----	Write this address to I/O address
		port 2E (hex) twice to unlock the
		W83627HF
07 (hex)	write	Write 08 (hex) to select register of
		watchdog timer.
30 (hex)	write	Write 01 (hex) to enable the function
		of the watchdog timer. Disabled is
		set as default.
F5 (hex)	write	Set seconds or minutes as units for
		the timer.

Write 0 to bit 3: set second as counting unit. [default]

Write 1 to bit 3: set minute as counting unit

F6 (hex)	write	0: stop timer [default]01~FF (hex):
		The amount of the count, in seconds
		or minutes, depends on the value
		set in register F5 (hex). This number
		decides how long the watchdog
		timer waits for strobe before gener-
		ating an interrupt or reset signal.
		Writing a new value to this register
		can reset the timer to count with the
		new value.
F7 (hex)	rd/wr	Bit 6: Write 1 to enable keyboard to
		reset the timer, 0 to disable.[default]
		Bit 5: Write 1 to generate a timeout
		signal immediately and automati-
		cally return to 0. [default=0] Bit 4:
		Read status of watchdog timer, 1
		means timer is "time out".
AA (hex)	-----	Write this address to I/O port 2E
		(hex) to lock the watchdog timer.2

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