/*
This is a demo of the FreqMeasure library 

On an Uno, jumpering pin 3 to pin 8 reports the PWM frequency of 490.20Hz

490.20
490.20
490.20
490.20
490.20
...

With the pin floating with a loose jumper it reports 60Hz hum.  
It does not report with pin 8 grounded.

On Wokwi this doesn't appear to work.  
I reported this as https://github.com/wokwi/wokwi-features/issues/352 and it is being 
tracked in https://github.com/wokwi/avr8js/issues/125

Code: https://wokwi.com/projects/330562550517203540

This is a modificaton of the https://www.pjrc.com/teensy/td_libs_FreqMeasure.html demo code
to add a PWM output on pin 3.

It adds some code to track pin 8;

With the jumper to pin 13 and the switch, you can see the pwm output on the built-in LED and toggle 
the connection.


*/
#include <FreqMeasure.h> // https://www.pjrc.com/teensy/td_libs_FreqMeasure.html

void setup() {
  Serial.begin(115200);
  FreqMeasure.begin();
  pinMode(3,OUTPUT); analogWrite(3,127);  // 50% duty cycle on pin 3
}

double sum=0;
int count=0;
static uint32_t count8=0;

void loop() {
  if (FreqMeasure.available()) {
    // average several reading together
    sum = sum + FreqMeasure.read();
    count = count + 1;
    if (count > 30) {
      float frequency = FreqMeasure.countToFrequency(sum / count);
      Serial.println(frequency);
      sum = 0;
      count = 0;
    }
  }
  count8 += digitalRead(8)==LOW;
  report();
}

void report(){
  static uint32_t last = -1000;
  if(millis() - last >= 1000){
    last+=1000;
    Serial.print("count8: ");
    Serial.println(count8); 
  }
}