/* PWM Melody via DCB*/

//pin 10 pwm sound with pitch and volume control
#define piezoPin 10
#define minVol 1
#define maxVol 128

void setup(){
  pinMode(piezoPin,OUTPUT);
  pinMode(9,OUTPUT);
  TCCR1A = (1 << COM1A1) | (1 << COM1B1 | 1 << WGM10);// sets timer control bits to PWM Phase and Frequency Correct mode
  TCCR1B = 0x12; // sets timer control bits to Prescaler N = 8
  analogWrite(piezoPin, 127); //something less than full volume
}

int length = 15; // the number of notes
char notes[] = "ccggaagffeeddc "; // a space represents a rest
int beats[] = { 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 4 };
int tempo = 450;

void playNote(char note, int duration) {
  char names[] = { 'c', 'd', 'e', 'f', 'g', 'a', 'b', 'C', ' ' };
  int tones[] = { 1915, 1700, 1519, 1432, 1275, 1136, 1014, 958, 30 };
  int d = duration;
  // play the tone corresponding to the note name
  for (int i = 0; i < 9; i++) {
    if (names[i] == note) {
	OCR1A=tones[i];

	//attack
	for(int x = minVol; x < maxVol;x*=2){
	  analogWrite(piezoPin, note == ' '?minVol:x);
	  delay(10);
	  d-=10;
	}

	//decay
	int x = maxVol;
	while(d >= 2){
	  analogWrite(piezoPin, note == ' '?minVol:x);
	  x-=1;
	  if(x<minVol) x = minVol;
	  delay(5);
	  d-=5;
	}

	analogWrite(piezoPin, minVol);
	delay(2);
    }
  }
}


void loop() {
  for (int i = 0; i < length; i++) {
     playNote(notes[i], beats[i] * tempo);
  }
}