Appendix C
Watchdog Timer Programming
©
National Instruments Corporation
C-7
PPC-2115/TPC-2515 User Manual
Example 4: Enable the Keyboard to Reset the Watchdog Timer
;-----------------------------------------------------------
Mov dx,2eh ; unlock W83627H
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
;-----------------------------------------------------------
Dec dx ; Enable watchdog timer to be strobed reset by keyboard
Mov al,0f7h
Out dx,al
Inc dx
In al,dx
Or al,40h
Out dx,al
;-----------------------------------------------------------
Dec dx ; lock W83627HF
Mov al,0aah
Out dx,al
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