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Is there a problem on using watchdog timer against an CPU loop?

Latest Updated:12/01/2011

Question:

I use the watchdog timer as a countermeasure against an inadvertent CPU loop.
For program simplification purposes, I clear the watchdog timer within the periodically occurring timer interrupt servicing.
Is this a problem?

Answer:

Clearing the watchdog timer within timer interrupt servicing is not recommended.
With this method, if the timer interrupt is acknowledged, the watchdog timer is cleared.
In this case, even if the main routine falls into an inadvertent loop, the loop cannot be detected.
Suitable Products
RL78 Family
78K Family