using pwm input to measure frequency

[Timothy]

I have an NRF9160 system running and I see mention of "The nRF9160 PWM peripheral can capture the period and pulse width of an external PWM signal" but  was a little confused as to how to implement it. I have used and I am using PWM as an output so that I understand. I have used a generic GPIO as input and used interrupts to start and stop a timer to measure time between edges. This uses two items a generic GPIO and a timer. as I understand the capture capability it just used a single PWM to do the measurement.

can you point me to any examples how to implement this if I am correct in assuming all I need is a single PWM pin.

[Susheel Nuguru]

Which Timer are you using? RTC? if so which instance? make sure that the instance you are using is not used by anything else in your system. Preferably use RTC1 or 2 if available.

[Timothy]

I have used a generic GPIO and timer on other examples in the past. I am not using it now for this application. I wanted to use the capture capability of the PWM. I see there is a ...\v3.02\zephyr\tests\drivers\pwm\pwm_loopback example. this looks like it uses a PWM output connected to a PWM input that does use capture capabilities. I tired to understand and build this but was unsuccessful. there is not an overlay for nRF9160 so I could not get it to compile. Is this what I need to understand to do PWM measure frequency and period. The example is not very clear is there some description of the PWM loopback example?

[Susheel Nuguru]

There are lots of efforts to implement a sample to count the incoming clock frequency through a GPIO. One of them is here with the implementation details. Please check if one of those can be used as template.

[Timothy]

the example you mentioned looks like it uses a timer and a generic GPIO pin. the pwm_loopback example uses the PWM capture capability but I could not get it to build. There is no overlay file for the nRF9160 I am using and the program uses the zephyr test features. Is there a nRF9160 example that uses the PWM capture?