Advantech PCA-6187 user manual A.1.4 Example Program, Table A.1 Watchdog timer registers

F7 (hex)	read/write	Bit 6: Write 1 to enable key-
		board to reset the timer, 0
		to disable.[default]
		Bit 5: Write 1 to generate a
		timeout signal immediately
		and automatically return to
		0. [default=0]
		Bit 4: Read status of watch-
		dog timer, 1 means timer is
		""time out""."
AA (hex)	-----	Write this address to I/O
		port 2E (hex) to lock the
		watchdog timer.2

Table A.1: Watchdog timer registers

A.1.4 Example Program

1.Enable watchdog timer and set 10 sec. as timeout interval ;-----------------------------------------------------------

Mov dx,2eh		; Unlock W83627HF
Mov al,87h
Out dx,al
Out dx,al
;-----------------------------------------------------------
Mov al,07h		; Select registers of watchdog timer
Out	dx,al
Inc	dx
Mov	al,08h
Out	dx,al
;-----------------------------------------------------------
Dec dx		; Enable the function of watchdog timer
Mov	al,30h
Out	dx,al
Inc	dx
Mov	al,01h
Out	dx,al

93 AppendixA