Appendix A. How To Use Watch-Dog Timer - Lanner electronics MB-X63 Series User Manual

APPENDIX A. How to use watch-dog timer

You can enable the watch-dog when your application software monitors an unexpected or not responding,
so then the timer generates a reset to reboot your system. During the period of enable to reset, you could
still cancel reset by disabling the watch-dog. Decide the way you want to set the period for reset by
selecting hardware or software watch-dog (if both of them are available). For hardware setting period,
select period by adjusting jumper. For software setting period, normally hardware watch-dog timer is set
to 16 sec. period.
Software watch-dog using example
EX.1: For DOS
Enable
C:\DOS> DEBUG
-o443 F
EX.2: For assemble Language
Enable
MOV
MOV
OUT DX, AL
Note : "F" is the period setting of software watch-dog timer (normally "F" indicated 0 sec.). 0 to
9 and A to F are used for represent different period. Normally, the step is 2 sec. That means "E"
is 2, "D" is 4, "2" is 26, "1" is 28 and "0" is 30 seconds.
:
DX, 443H
AL, 0FH
41
Disable
C:\DOS>DEBUG
-o441 F
Disable :
MOV DX, 441H
MOV AL, 0FH
OUT DX, AL