User guide

Appendix A
Watchdog Timer
About Watchdog Timer
Software stability is major issue in most application. Some embedded systems are not
watched by human for 24 hours. It is usually too slow to wait for someone to reboot when
computer hangs. The systems need to be able to reset automatically when things go wrong.
The watchdog timer gives us solution.
The watchdog timer is a counter that triggers a system reset when it counts down to zero
from a preset value. The software starts counter with an initial value and must reset it
periodically. If the counter ever reaches zero which means the software has crashed, the
system will reboot.