What I need is simple; but after spending a week on this it is time to find some help, because my head is starting to spin.
XIAO sending the square wave:
- Generate (on pin D10) a square wave that is running independently of the loop() call
- Modify the frequency of the square wave within the loop() call
XIAO reading the square wave:
- Read on pin D10 (independently of the loop() call) the duration (period) of the square wave
- Assign the read value to a variable
I asked the same question in more detail here.