Appendix A Watchdog Timer; About Watchdog Timer; Sample Program - AXIOMTEK MANO521 Series User Manual

A.1

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.
A.2

Sample Program

1. Enter ADU, and press <F4> to select the superior ITE
2. PORT setting 002E, 002F
3. Address 07h setting 07 GPIO
4. Address 72h to set the countdown, for example Sec: C0, Min: 40
5. Address 73h set the countdown time, for example 10sec: 0A
Watchdog Timer
MANO521 Mini ITX Motherboard
Appendix A
Watchdog Timer
57