/*
  Floppy Drive Music: Twinkle Twinkle Little Star
  Lapsus Antepedis
  Dec 25 2011
  Times are in microseconds
*/

// Constants
const int MAX_STEPS = 70;
int scale[20] = {7644,7214,6812,6428,6068,5728,5406,5102,4816,4546,4290,4048,3824,3608,3404,3214,3034,2864,2704,2550};

// Song, extra 0 at the start.
int note[]   = {0,0,0,7,7,9,9,7,5,5,4,4,2,2,0,7,7,5,5,4,4,2,7,7,5,5,4,4,2,0,0,7,7,9,9,7,5,5,4,4,2,2,0};
int length[] = {0,4,4,4,4,4,4,8,4,4,4,4,4,4,8,4,4,4,4,4,4,8,4,4,4,4,4,4,8,4,4,4,4,4,4,8,4,4,4,4,4,4,8};
int songlength = 43;
int tempo = 100000;

// Variables
int curnote = 0;
int stepcounter = 0;
int dir = 0;
unsigned long time = 0;
unsigned long next_step = 0;
unsigned long next_note = 0;
unsigned long delaycalc = 0;

// Pins
int DriveEnable = 2;
int Direction = 4;
int Step = 3;

void setup()
{
  pinMode(DriveEnable, OUTPUT);
  pinMode(Direction, OUTPUT);
  pinMode(Step, OUTPUT);

  digitalWrite(DriveEnable, LOW);
  digitalWrite(Direction, HIGH);
  digitalWrite(Step, LOW);

  // Zero the stepper
  for (int i = 0; i < 100; i++)
  {
    digitalWrite(Step, HIGH);
    delay(2);
    digitalWrite(Step, LOW);
    delay(2);
  }

  digitalWrite(Direction, dir);

  curnote = 0;
  next_step = micros() + 100000;
  next_note = next_step;

}

void loop()
{
  time = micros();

  // Step handling
  if (time >= next_step)
  {
    stepcounter++;
    if (stepcounter >= MAX_STEPS)
    {
      stepcounter = 0;
      dir = !dir;
      digitalWrite(Direction, dir);
    }
    digitalWrite(Step, HIGH);
    delayMicroseconds(1500);
    digitalWrite(Step, LOW);
    delaycalc = scale[note[curnote]];
    next_step = time + delaycalc;
  }

  // Note handling
  if (time >= next_note)
  {
    curnote++;
        if (curnote >= songlength)
        {
          curnote = 0;
          delay(10000);
        }
    delaycalc = length[curnote] * 100000;
    delay(50);
    next_note = micros() + delaycalc;
  }
}