// Teensyduino MIDI Beat Clock 
// LSDJ and Nanoloop Sync
// by Sebastian Tomczak
// 30 August 2011

// At the time of writing, requires edited Teensyduino usb_midi/usb_api.cpp and usb_midi/usb_api.h
// See here: http://little-scale.blogspot.com/2011/08/how-to-deal-with-real-time-midi-beat.html

byte counter; 
byte CLOCK = 248; 
byte START = 250; 
byte CONTINUE = 251; 
byte STOP = 252; 

void setup() {
  pinMode(11, OUTPUT); 
  pinMode(0, OUTPUT); 
  pinMode(1, OUTPUT); 
  digitalWrite(11, HIGH); 
  usbMIDI.setHandleRealTimeSystem(RealTimeSystem);
}

void loop() {
  usbMIDI.read(); 

}

void RealTimeSystem(byte realtimebyte) {
  if(realtimebyte == 248) {
    lsdjSync(); 
    nanoSync(); 

    counter++; 
    if(counter == 24) {
      counter = 0; 
      digitalWrite(11, HIGH); 
    }

    if(counter == 12) {
      digitalWrite(11, LOW); 
    }
  }

  if(realtimebyte == START || realtimebyte == CONTINUE) {
    counter = 0; 
    digitalWrite(11, HIGH); 
  }

  if(realtimebyte == STOP) {
    digitalWrite(11, LOW); 
  }

}

void lsdjSync() {
  for(int i = 0; i < 8; i ++) {
    digitalWrite(0, LOW); 
    digitalWrite(0, HIGH); 
  }
}


void nanoSync() {
  digitalWrite(1, counter % 12); 
}