 
 // Interruption routine
 void ISR_rotate() {
+  #ifdef DEBUG
+    // Turns the LED on when entering the ISR
+    // Measures the duration of the interruption routine
+    digitalWrite (blinkLed, HIGH);
+  #endif
+
   uint16_t pos, sim_pos, tg;
   uint8_t dir;
-  
+
+/*  // Toggles LED status on each ISR callback
   #ifdef DEBUG
       bool status;
       status = digitalRead(blinkLed);

  pinMode(LASER_PIN, OUTPUT);
  #ifdef DEBUG
    pinMode (blinkLed, OUTPUT);
  #endif
  
  // Start the serial port

        digitalWrite(blinkLed, HIGH);
      }
  #endif
*/
  
  sei();  // Enable interrupts --> Serial, I2C (MotorShield)

