Timer output looped to counter input

[John Lowen]

Posted on August 02, 2017 at 20:01

I am using an STM32F746 for PWM generation and counting. When I loop the PWM output back to a counter, the amplitude of the PWM drops from 3.3v to about 2.0v. If I set the counter pin to input mode, the 3.3 v level is restored regardless of any pullup configuration. What is there about the counter input that will cause a timer output to drop when configured in counter mode?

[Tesla DeLorean]

Posted on August 02, 2017 at 20:49

Sounds like the pin/peripheral is misconfigured. A TIM input shouldn't drive the pin, yours looks to be.