src/lib/BUTTON/button.h

   1 #pragma once
   2
   3 class Button
   4 {
   5 private:
   6     // Constants
   7     static constexpr uint32_t MS_DEBOUNCE = 25;       // how long the switch must change state to be considered
   8     static constexpr uint32_t MS_LONG = 500;          // duration held to be considered a long press (repeats)
   9     static constexpr uint32_t MS_MULTI_TIMEOUT = 500; // duration without a press before the short count is reset
  10
  11     static constexpr unsigned STATE_IDLE = 0b111;
  12     static constexpr unsigned STATE_FALL = 0b100;
  13     static constexpr unsigned STATE_RISE = 0b011;
  14     static constexpr unsigned STATE_HELD = 0b000;
  15
  16     // State
  17     uint8_t _pin;
  18     bool _idlelow;
  19     uint32_t _lastCheck;  // millis of last pin read
  20     uint32_t _lastFallingEdge; // millis of last debounced falling edge
  21     uint8_t _state; // pin history
  22     bool _isLongPress; // true if last press was a long
  23     uint8_t _longCount; // number of times long press has repeated
  24     uint8_t _pressCount; // number of short presses before timeout
  25 public:
  26     // Callbacks
  27     void (*OnShortPress)();
  28     void (*OnLongPress)();
  29     // Properties
  30     uint8_t getCount() const { return _pressCount; }
  31     uint8_t getLongCount() const { return _longCount; }
  32
  33     Button() :
  34         _lastCheck(0), _lastFallingEdge(0), _state(STATE_IDLE),
  35         _isLongPress(false), _longCount(0), _pressCount(0)
  36     {
  37     }
  38
  39     void init(uint8_t pin, bool idlelow = false)
  40     {
  41         _pin = pin;
  42         _idlelow = idlelow,
  43         pinMode(_pin, _idlelow ? INPUT : INPUT_PULLUP);
  44     }
  45
  46     // Call this in loop()
  47     int update()
  48     {
  49         const uint32_t now = millis();
  50
  51         // Reset press count if it has been too long since last rising edge
  52         if (now - _lastFallingEdge > MS_MULTI_TIMEOUT)
  53             _pressCount = 0;
  54
  55         _state = (_state << 1) & 0b110;
  56         _state |= digitalRead(_pin) ^ _idlelow;
  57
  58         // If rising edge (release)
  59         if (_state == STATE_RISE)
  60         {
  61             if (!_isLongPress)
  62             {
  63                 DBGVLN("Button short");
  64                 ++_pressCount;
  65                 if (OnShortPress)
  66                     OnShortPress();
  67             }
  68             _isLongPress = false;
  69         }
  70         // Two low in a row
  71         else if (_state == STATE_FALL)
  72         {
  73             _lastFallingEdge = now;
  74             _longCount = 0;
  75         }
  76         // Three or more low in a row
  77         else if (_state == STATE_HELD)
  78         {
  79             if (now - _lastFallingEdge > MS_LONG)
  80             {
  81                 DBGVLN("Button long %d", _longCount);
  82                 _isLongPress = true;
  83                 if (OnLongPress)
  84                     OnLongPress();
  85                 // Reset time so long can fire again
  86                 _lastFallingEdge = now;
  87                 _longCount++;
  88             }
  89         }
  90         return MS_DEBOUNCE;
  91     }
  92 };