/* 8 note MIDI sequencer */
      /* Version 1.6 Sam Harmon 2008 */
      /* http://www.glacialcommunications.com */

      /* contains parts of... */
      /*
       * codeexample for useing a 4051 * analog multiplexer / demultiplexer
       * by david c. and tomek n.* for k3 / malmš hšgskola
       *
       */  
       
      int r0 = 0;      //value select pin at the 4051 (s0)
      int r1 = 0;      //value select pin at the 4051 (s1)
      int r2 = 0;      //value select pin at the 4051 (s2)
      int row = 0;     // storeing the bin code
      int count = 0;    // just a count
      int clockCount = 0;
      int  bin [] = {000, 1, 10, 11, 100, 101, 110, 111};//bin = binŠr, some times it is so easy
      int tempoPin = 1;  //pin for tempo read
      int tempoDelay = 0; //current amount to delay (aka tempo)
      int notePin = 0; //pin for reading current MIDI note
      int noteRead = 0; //
      int noteValue = 65; //MIDI note number
      //int noteDuration = 100; //length of note (for now)
      int velocity = 127; //MIDI velocity (default, for now)
      int fracDelay = 0; 
      int analogOut = 0; //value to send to CV out
       
      void setup(){
       
        pinMode(6, OUTPUT); //s0
        pinMode(7, OUTPUT);    // s1
        pinMode(8, OUTPUT);    // s2 
        pinMode(9, OUTPUT);    // PWM "CV"
        pinMode(5, OUTPUT);    // "GATE"
        pinMode(4, INPUT);    //on/off switch  - not implemented yet
                // MIDI/CV switch
       //initialize CV/Gate
        analogWrite(9, 0);
        digitalWrite(5, LOW);
       // beginSerial(9600); //debug
        Serial.begin(31250);
      }
       
      void loop () {
       
        for (count=0; count<=7; count++) {
          tempoDelay = 1024-analogRead(tempoPin)+6; //in case sensor is zero, we want 1 ms delays
          noteRead = (analogRead(notePin));
          //MIDI limited to 0-127
          noteValue = noteRead/8;
          //PWM limited to 0-255
          analogOut = noteRead/4;
          row = bin[count];      
          r0 = row & 0x01;
          r1 = (row>>1) & 0x01;
          r2 = (row>>2) & 0x01;

          digitalWrite(6, r0);
          digitalWrite(7, r1);
          digitalWrite(8, r2);
          delay(10);
          if (noteValue > 0){
            noteOn(0x90, noteValue, velocity);
            digitalWrite(5, HIGH);
            analogWrite(9, analogOut);
          }          
          fracDelay = tempoDelay / 6;
          for (clockCount = 0; clockCount <=5;clockCount++){
            syncSignal(0xF8);
            delay (fracDelay);
          } 
          if (noteValue > 0){ 
            noteOn(0x90,noteValue, 0x00);
            digitalWrite(5, LOW);
            analogWrite(9, 0);
          }
        }  
      }

void syncSignal(char cmd){
  Serial.print(cmd, BYTE);
}  
void noteOn(char cmd, char data1, char data2) {
  Serial.print(cmd, BYTE);
  Serial.print(data1, BYTE);
  Serial.print(data2, BYTE);
}