Appendix A Watchdog Timer; About Watchdog Timer - AXIOMTEK IFO2175-873 Series User Manual

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.
How to Use the Watchdog Timer
(Following is example to enable configuration by using debug tool)
Enable WDT
1.Enable SIO configuration
-O 2E 87
-O 2E 87
2. Select Logic device:
-O 2E 07
-O 2F 08
3. WDT Device Enable
-O 2E 30
-O 2F 01
5. Set timer unit
-O 2E F0
-O 2F 00  (00: Sec; 08: Minute)
4. Set base timer:
-O 2E F1
-O 2F 0A Set Reset Time (Ex.0A:10 Sec)
Disable WDT
1.Enable configuration
-O 2E 87
-O 2E 87
2. Select Logic device:
-O 2E 07
-O 2F 08
3. WDT Device Disable
-O 2E 30
-O 2F 00
Watchdog Timer
IFO2175-873 Series User's Manual
APPENDIX A
WATCHDOG TIMER
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