Aaeon PCM-4894 User Manual page 71

4. To refresh watchdog timer:
-- output the desired value to port 0x443. The timer will reset to
the new value and count down.
e.g. outportb(0x443,10);
...
outportb(0x443,20);
outportb(0x444, 0);
outportb(0x443, 10);
job1();
outputb(0x443,20);
job2();
outportb(0x443, 0);
...
// set time-out event to reset-system
// set time-out interval to 10 seconds
// execute your job here, be sure your job
will finished within 10 seconds
// set time-out interval to 20 seconds and
refresh watchdog timer, otherwise the
system will reset after time-out
// another job finished within 20 seconds
// disable watchdog timer
Appendix A Watchdog Timer Demo Program
// set time-out interval to
10 sec
// reset watchdog timer to
20 sec
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