src/lib/BUTTON/button.h

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