Appendix A: Programming Watchdog Timer - Lanner NCA-4010 Series User Manual

Network Computing Platforms

Appendix A: Programming Watchdog Timer

A watchdog timer is a piece of hardware that can be used to automatically detect system
anomalies and reset the processor in case there are any problems. Generally speaking, a
watchdog timer is based on a counter that counts down from an initial value to zero. The
software selects the counter's initial value and periodically restarts it. Should the counter reach
zero before the software restarts it, the software is presumed to be malfunctioning
and the processor's reset signal is asserted. Thus, the processor will be restarted as if a
human operator had cycled the power.
For sample watchdog code, see folder under Driver and Utility on the