Interrupts and timers

Projects Programming
12

Finally found a solution that polls in the ISR of Timer2, wchich fires in a ~20ms rate. Seems to work fine and the loop stays free for other stuff.

volatile int pin_LED = 13;
volatile int pin_button = 2;

volatile boolean oldSwitchState = HIGH;
volatile boolean newSwitchState1 = HIGH;
volatile boolean newSwitchState2 = HIGH;
volatile boolean newSwitchState3 = HIGH;

volatile boolean LEDstatus = LOW;

void setup()
{
  //***Timer2***
  pinMode(13, OUTPUT);
  TCCR2A = 0;
  TCCR2B = 0;
  TCCR2A |= (1<<WGM21);                         //CTC Mode                                          (Timer zählt bis auf OCR2A und wird dann automatisch 0 gesetzt)
  TIMSK2 |= (1<<OCIE2A);                        //enable OCR1A Interrupt
  TCCR2B |= (1<<CS22) | (1<<CS21) | (1<<CS20);  //prescaler 1024                                    (Alle 1024 CPU Takte zählt der Timer einen Tick weiter)
  OCR2A = 200;                                  // OCR1A = f_clock / (prescaler * f_target) - 1     (Wert bis zu dem gezählt wird)
  
  //***LED***
  pinMode(pin_LED, OUTPUT);
  digitalWrite(pin_LED, LOW);

  //***Button***
  pinMode(pin_button, INPUT_PULLUP);
}

ISR(TIMER2_COMPA_vect)
{
  newSwitchState1 = digitalRead(pin_button);
  delay(1);
  newSwitchState2 = digitalRead(pin_button);
  delay(1);
  newSwitchState3 = digitalRead(pin_button);

  if (newSwitchState1 == newSwitchState2 && newSwitchState1 == newSwitchState3) {
    if ( newSwitchState1 != oldSwitchState ) { //hatt sich der zustand des schalter geändert?
      if ( newSwitchState1 == LOW ) {          //ist der schalter gedrückt (soll nur beim drücken nicht beim auslassen reagieren
        if ( LEDstatus == LOW ) {
          digitalWrite(pin_LED, HIGH);
          LEDstatus = HIGH;
        }
        else                    {
          digitalWrite(pin_LED, LOW);
          LEDstatus = LOW;
        }
      }
      oldSwitchState = newSwitchState1;
    }
  }
}

void loop()
{
}