Input capture interrupt skip happens sometimes, even if input trigger is present. How could that be?
I use timer with input capture mode, to be able to measure time period of an optical encoder pulse. I experienced that measured value rarely is twice as the expected one. I tried with different timer prescaler values, but same problem remained. Suspected that interrupt service or input trigger signal is not proper, so I checked both of them (see measurement results below).
To check ISR, I put a gpio toggle function into the callback for a given pin I measured.
In ideal case, input signal should give a periodic pulse signal with a frequency value twice as the gpio signal made by the toggle pin function inside the callback.
It seems callback function is not called in every input. I did not experience if that skip should emerge in a periodical way. What could be the root-cause?
Evalboard: STM32F446RE (Nucleo Devboard)
My clock settings:
My TIMER_3 settings:
Measurement result (Input Capture input signal -- green; Capture Callback Function -- yellow)
Measurement result (zoomed)

