//MIDI experiment
//takes midi input and converts to analog voltage to communicate with tuning module
//cycles through each channel repeatedly to prevent last channel from dominating

//remember to disconnect rx pin before uploading (unplug sheild) cause it is used for midi and downloading

//variables


int chan0=5;
int chan1=6;

int channelNumber;
int midiNote=0;
int remappedNote=0;
int midiVolume=0;
byte incomingByte=0;
int midiValue=0;
int statevariable=0;




//functions			//pin 10 display note is sharp

int checkMidi () 
{  
  remappedNote=-1;

  if (Serial.available() > 0) 
  {
    // read the incoming byte:
    incomingByte = Serial.read();
    if ((incomingByte & 0xF0) == 0x90)  // note on message  starting  
    { 
      statevariable=1;
      channelNumber=incomingByte & 0x0F;
    } 
    else if (statevariable==1) //"note on", could be real "note on" or effective "note off"
    {
      if  (incomingByte!=0) //real "note on"
      {
        midiNote=incomingByte;
        remappedNote= (midiNote+8) % 12;  //+8 maps c=0 to e=0
        midiNote=0;  //reset for next new event
        statevariable=3;  //a velocity will follow
      }
      else statevariable=0;  //effective note off, done   
    } 
    else if (statevariable==3)  //get velocity, done
    {
      midiVolume=incomingByte;
      statevariable=0; 
    }
    else if (statevariable==3) //real note off, done
    {
      statevariable=0;
      midiNote=0;
    }  
  }
  return remappedNote;
}


void setup ()
{
  //start serial with Midi baudrate 31250 or 38400 for debugging
  Serial.begin(31250);


  pinMode (chan0,OUTPUT);
  //digitalWrite (chan0,LOW);  

  pinMode (chan1,OUTPUT);
  //digitalWrite (chan1,LOW); 


}

void loop ()
{
  midiValue=checkMidi();

  if (midiValue!=-1)  //store pending midi values
  {
    if (channelNumber==0) analogWrite(chan0, midiValue*23);  //map 0-11 to 0-253
    if (channelNumber==1) analogWrite(chan1, midiValue*23);
  } 
}