// Gijs Gieskes juli 2009
// Sequencer for Synth Car V3
//
// credits: 
// http://mrbook.org/blog/2008/11/22/controlling-a-gakken-sx-150-synth-with-arduino/

#define DATAOUT 11//MOSI
#define DATAIN 12//MISO - not used, but part of builtin SPI
#define SPICLOCK  13//sck
#define SLAVESELECT 10//ss

volatile boolean goInt = false;

int incomingByte = 0;

//seq
unsigned long mtel = 0;

byte pentlader[] = {0, 4, 7, 11, 14, 17};

byte drPin[] = {5, 6, 7, 8};
byte effectPin = 9;

byte pent[] = {50, 20, 50,  15, 50, 29, 50, 30};
byte slide[] = { 1,   1,  1,  0,  0,  1,  1,  1};
byte effect[] = {0, 0, 0, 0, 0, 0, 0, 0};
byte drums[] = {0, 0, 0, 0, 0, 0, 0, 0};
byte length = 0;
byte out = 0;

byte reproCount = 0;
byte repeat = 8;
byte repeatB = 8;

byte octv = 24;

void setup()
{
  
  byte clr;
  pinMode(DATAOUT, OUTPUT);
  pinMode(DATAIN, INPUT);
  pinMode(SPICLOCK,OUTPUT);
  pinMode(SLAVESELECT,OUTPUT);
  digitalWrite(SLAVESELECT,HIGH); //disable device
  
  SPCR = (1<<SPE)|(1<<MSTR);
  clr=SPSR;
  clr=SPDR;
  delay(10);

  attachInterrupt(0, interCount, RISING);
  
  pinMode(drPin[0], OUTPUT);
  pinMode(drPin[1], OUTPUT);
  pinMode(drPin[2], OUTPUT);
  pinMode(drPin[3], OUTPUT);
  pinMode(effectPin, OUTPUT);
  pinMode(4, OUTPUT);
  Serial.begin(9600);
}

void write_value(uint16_t sample)
{
  uint8_t dacSPI0 = 0;
  uint8_t dacSPI1 = 0;
  dacSPI0 = (sample >> 8) & 0x00FF;
  dacSPI0 |= 0x10;
  dacSPI1 = sample & 0x00FF;
  digitalWrite(SLAVESELECT,LOW);
  SPDR = dacSPI0;                    // Start the transmission
  while (!(SPSR & (1<<SPIF)))     // Wait the end of the transmission
  {
  };
  
  SPDR = dacSPI1;
  while (!(SPSR & (1<<SPIF)))     // Wait the end of the transmission
  {
  };  
  digitalWrite(SLAVESELECT,HIGH);
  delay(5);
}

byte prevNote = 0;

void playNote(int incomingByte, boolean slideIn)
{
  noteOff();
  delayMicroseconds(100);
  
  if(slideIn){
    for(int i=incomingByte; i<prevNote; i++){
      int diff = 48 - i;
      diff *= 12;
      write_value (1125 - diff); 
    }
    for(int i=incomingByte; i>prevNote; i--){
      int diff = 48 - i;
      diff *= 12;
      write_value (1125 - diff); 
    }
  }else{
    int diff = 48 - incomingByte;
    diff *= 12;
    write_value (1125 - diff); 
  }
  
  // 1270 C4 60
  // 1125 C3 48
  // 980  C2 36    
  // 835  C1 24 
  // 690  C0 12      
}

void noteOff()
{
  write_value(0);
}

void loop()
{
  /*
  if(millis() - mtel > 100){
    mtel = millis();
    interCount();
  }
  */
    
  if(goInt){
    randomSeed(analogRead(0));
    
    mtel = millis();
    length++;
    length %= repeat;
       
    if(reproCount == 0){
      repro();
    }
    
    reproCount++;
    reproCount %= repeatB*2;
    
    playDrums(length);
    
    effectF();
  
    out = pent[length];
    if(slide[length] != 2){
      playNote(out, slide[length]);
    }
      
    prevNote = out;
    goInt = false;
  }
}

void effectF(){
  if(effect[length]){
    digitalWrite(effectPin, HIGH);  
  }else{
    digitalWrite(effectPin, LOW);  
  }
}

void playDrums(byte dsel){
  if(drums[dsel] < 4){
    for(byte i=0; i<8; i++){
      if(dsel == i){
        digitalWrite(drPin[i], HIGH);
      }else{
        digitalWrite(drPin[i], LOW);
      }
    }
  }
}

void interCount(){
  goInt = true;
}

void repro(){
  repeat = 8 >> random(3);
  repeatB = repeat*random(1,4);  
  for(byte i=0; i<8; i++){
    if(!random(5)){
      pent[i] = pentat();  
      slide[i] = random(3); 
      effect[i] = random(3);
    }
    if(!random(4)){
      drums[i] = random(6);  
    }
    octv = (12*random(1, 5))-1;
    Serial.println(map(analogRead(1), 0, 1023, 1, 9), DEC);
  }
}

int pentat(){
  int pt = pentlader[random(6)];
  pt += octv;
  return pt;
}