Microsoft Bus Mouse Code

//interrupt number
#define int_quad1a 0 //pin 3
#define int_quad1b 1 //pin 2
#define int_quad2a 2 //pin 0
#define int_quad2b 3 //pin 1

//pin definitions
#define quad1a 3
#define quad1b 2
#define quad2a 0
#define quad2b 1
#define l_button 4
#define r_button 5

volatile byte x_diff = 0;
volatile byte y_diff = 0;
volatile boolean l_button_pressed = false;
volatile boolean r_button_pressed = false;
volatile boolean l_button_last = false;
volatile boolean r_button_last = false;
volatile boolean change = false;

void setup()
{
  pinMode(quad1a, INPUT);
  pinMode(quad1b, INPUT);
  pinMode(quad2a, INPUT);
  pinMode(quad2b, INPUT);
  pinMode(l_button, INPUT);
  pinMode(r_button, INPUT);
  digitalWrite(quad1a, HIGH);
  digitalWrite(quad1b, HIGH);
  digitalWrite(quad2a, HIGH);
  digitalWrite(quad2b, HIGH);
  digitalWrite(l_button, HIGH);
  digitalWrite(r_button, HIGH);
  Serial.begin(19200);
  //Mouse.begin();
  attachInterrupt(int_quad1a, quad1a_sub, CHANGE);
  attachInterrupt(int_quad1b, quad1b_sub, CHANGE);
  attachInterrupt(int_quad2a, quad2a_sub, CHANGE);
  attachInterrupt(int_quad2b, quad2b_sub, CHANGE);
}

void loop()
{
  /*if (change)
  {
    Serial.print("xdiff: ");
    Serial.print(x_diff);
    Serial.print(" ydiff: ");
    Serial.println(y_diff);
    Serial.print("l_button: ");
    Serial.print(l_button_pressed);
    Serial.print(" r_button: ");
    Serial.println(r_button_pressed);
    //delay(10);
    change = false;
  }*/
  if (digitalRead(l_button) == LOW && l_button_last == false)
  {
    change = true;
    //l_button_pressed = true;
    l_button_last = true;
    Mouse.press(MOUSE_LEFT);
  }
  else if (digitalRead(l_button) == HIGH && l_button_last == true)
  {
    change = true;
    //l_button_pressed = false;
    l_button_last = false;
    Mouse.release(MOUSE_LEFT);
  }
  if (digitalRead(r_button) == LOW && r_button_last == false)
  {
    change = true;
    //r_button_pressed = true;
    r_button_last = true;
    Mouse.press(MOUSE_RIGHT);
  }
  else if (digitalRead(r_button) == HIGH && r_button_last == true)
  {
    change = true;
    //r_button_pressed = false;
    r_button_last = false;
    Mouse.release(MOUSE_RIGHT);
  }
}

void quad1a_sub()
{
  change = true;
  if (digitalRead(quad1a) == digitalRead(quad1b))
  {
    //x_diff--;
    Mouse.move(-1,0,0);
  }
  else
  {
    //x_diff++;
    Mouse.move(1,0,0);
  }
}

void quad1b_sub()
{
  change = true;
  if (digitalRead(quad1a) != digitalRead(quad1b))
{
    //x_diff--;
    Mouse.move(-1,0,0);
  }
  else
  {
    //x_diff++;
    Mouse.move(1,0,0);
  }
}

void quad2a_sub()
{
  change = true;
  if (digitalRead(quad2a) == digitalRead(quad2b))
  {
    //y_diff++;
    Mouse.move(0,-1,0);
  }
  else
  {
    //y_diff--;
    Mouse.move(0,1,0);
  }
}

void quad2b_sub()
{
  change = true;
  if (digitalRead(quad2a) != digitalRead(quad2b))
  {
    //y_diff++;
    Mouse.move(0,-1,0);
  }
  else
  {
    //y_diff--;
    Mouse.move(0,1,0);
  }
}