FabiaTech PC104, User Manual

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FabiaTech Corporation
Watchdog Timer Setting
The watchdog timer is a circuit that may be used from your program software to
detect system crashes or hang-ups. LED1 on this CPU board is the watchdog timer
indicator, which is located at the upper-right corner above the USB connector.
Whenever the watchdog timer is enabled, the LED will blink to indicate that the
timer is counting. The watchdog timer is automatically disabled after reset.
Once you have enabled the watchdog timer, your program must trigger the
watchdog timer every time before it times out. After you trigger the watchdog
timer, it will be set to non-zero value to watchdog counter and start to count down
again. If your program fails to trigger the watchdog timer before time-out, it will
generate a reset pulse to reset the system.
The factor of the watchdog timer time-out constant is approximately 1 seconds.
The period for the watchdog timer time-out is between 1 to FF timer factors.
If you want to reset your system when watchdog times out, the following table
listed the relation of timer factors between time-out periods.
Time-Out Period Time-Out Period
(Minutes)
Time Factor
(Seconds)
1 1 1
2 2 2
3 3 3
4 4 4
5 5 5
“ “ “
“ “ “
“ “ “
FF FF FF
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