#include <Mouse.h>

#define ENCA 2
#define ENCB 3

const uint8_t encodeA[] = {0b10, 0b00, 0b11, 0b01};
//const uint8_t encodeB[] = {0b01, 0b11, 0b00, 0b10};

volatile int counter;
volatile uint8_t preab;
int preCount;

void setup()
{
  pinMode(ENCA, INPUT_PULLUP);
  pinMode(ENCB, INPUT_PULLUP);
  
  //マウス初期化
  Mouse.begin();

  counter = 0;
  preCount = 0;
  preab = 0;
  
  attachInterrupt(digitalPinToInterrupt(ENCA), pulse, CHANGE);
  attachInterrupt(digitalPinToInterrupt(ENCB), pulse, CHANGE);
}

void pulse()
{
  uint8_t a, b, ab;

  a = digitalRead(ENCA);
  b = digitalRead(ENCB);

  ab = (a << 1) | b;
  if(preab != ab)
  {
    if(encodeA[preab] == ab)
      --counter;
    else //if(encodeB[preab] == ab)
      ++counter;
  
    preab = ab;
  }

  preab = ab;
}

void loop()
{
  int diff;

  diff = counter - preCount;

  if(diff != 0)
  {
    Mouse.move(diff << 3, 0, 0);
    preCount = counter;
  }
}