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TIMx as a watchdog timer?

Question asked by s.gd on Feb 2, 2012
Latest reply on Jul 18, 2013 by Amol
I need a "watchdog timer" that automatically sets a port pin when it times out and not reset the processor. I don't think the IWDG or WWDG do this since they just reset the processor on time-out.
Therefore, I think the use of a timer such as TIM4 is needed to do this. I have TIM4_CH2 going to Pin PD13 (remapped). I want TIM4_CH2 to remain low as long as TIM4 remains not timed-out, which can be done by resetting the timer often enough during runtime using the "UG" bit. However, when it does time out, the output signal starts putting out repetitive pulses. Alternatively, I can set it to "one pulse" mode and it puts out a single pulse (low to high then back low), but this seems to require an additional reset step to re-enable the timer after setting the UG bit.
Is there a way to cause the time out condition to cause the output signal (TIM4_CH2) to just transition from low to high and just stay high?

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