RotaryEncoder.h

// -----
// RotaryEncoder.h - Library for using rotary encoders.
// This class is implemented for use with the Arduino environment.
// Copyright (c) by Matthias Hertel, http://www.mathertel.de
// This work is licensed under a BSD style license. See http://www.mathertel.de/License.aspx
// More information on: http://www.mathertel.de/Arduino
// -----
// 18.01.2014 created by Matthias Hertel
// 16.06.2019 pin initialization using INPUT_PULLUP
// -----

#pragma once

#include "Arduino.h"

#define LATCHSTATE 3
#define NO_MILLIS_BETWEEN_ROTATIONS	// disabled use of getMillisBetweenRotations() function that use millis(); saves space in case you do not use it

class RotaryEncoder {
public:
  enum class Direction : int8_t { FAST_CCW = -2, COUNTERCLOCKWISE = -1, NOROTATION = 0, CLOCKWISE = 1, FAST_CW = 2 };

  // ----- Constructor -----
  RotaryEncoder(int8_t pin1, int8_t pin2);		// ShaggyDog - changed type from int to int8_t
  
  // retrieve the current position
  inline long getPosition() const { return _positionExt; }
  
  // simple retrieve of the direction the knob was rotated at. 0 = No rotation, 1 = Clockwise, -1 = Counter Clockwise
  Direction getDirection();

  // adjust the current position
  void setPosition(long newPosition);

  // call this function every some milliseconds or by using an interrupt for handling state changes of the rotary encoder.
  void tick(void);

  // Returns the time in milliseconds between the current observed 
#ifndef NO_MILLIS_BETWEEN_ROTATIONS
  inline unsigned long getMillisBetweenRotations() const {
    return _positionExtTime - _positionExtTimePrev; 
  }
#endif

private:
  int8_t _pin1, _pin2; // Arduino pins used for the encoder. // ShaggyDog - changed type from int to int8_t
  
  volatile int8_t _oldState;
  
  volatile long _position;         // Internal position (4 times _positionExt)
  volatile long _positionExt;      // External position
  volatile long _positionExtPrev;  // External position (used only for direction checking)
#ifndef NO_MILLIS_BETWEEN_ROTATIONS
  unsigned long _positionExtTime;     // The time the last position change was detected.
  unsigned long _positionExtTimePrev; // The time the previous position change was detected.
#endif
};
// End