/*

  Forum: https://forum.arduino.cc/t/pass-the-pulse-from-coin-acceptor-to-coffee-vending-machine-using-arduino-esp32/1178550
  Wokwi: https://wokwi.com/projects/379021820365072385

*/

#define WOKWI

#ifdef WOKWI
#include "MCAEmulation.h"
#endif

constexpr byte coinPin = 2;

volatile boolean       ISRFired = false;

volatile unsigned long changeTimeISR;
volatile byte          pinStateISR;
unsigned long          changeTime;
byte                   pinState;

unsigned long          previousChangeTime = 0;
unsigned long          countPulses = 0;


void IRAM_ATTR coinInterrupt() {
  changeTimeISR = millis();
  pinStateISR = digitalRead(coinPin);
  ISRFired = true;
}

void setup() {
  Serial.begin(115200);
  Serial.println("Start");
  pinMode(coinPin, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(coinPin), coinInterrupt, CHANGE);
}

void loop() {
#ifdef WOKWI
  // Only required for testing START
  MCAEmulation();
  // Only required for testing END
#endif

  if (newISRData()) {
    if (changeTime - previousChangeTime < 500) {
      if (pinState == LOW) {
        Serial.print("\tHIGH Time:\t");
      } else {
        Serial.print(++countPulses);
        Serial.print("\tLOW Time:\t");
      }
      Serial.println(changeTime - previousChangeTime);
    }
    previousChangeTime = changeTime;
  }
}


boolean newISRData() {
  boolean result = false;
  noInterrupts();
  if (ISRFired) {
    changeTime = changeTimeISR;
    pinState = pinStateISR;
    ISRFired = false;
    result = true;
  }  else {
    result = false;
  }
  interrupts();
  return result;
}