//MIDI experiment
//takes midi input and converts to parallel nibble at pins 2-5

//remember to disconnect rx pin before uploading

//variables

int pin2=2;
int pin3=3;
int pin4=4;
int pin5=5;

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;
    } 
    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 (pin2,OUTPUT);
  digitalWrite (pin2,LOW);

  pinMode (pin3,OUTPUT);
  digitalWrite (pin3,LOW); 

  pinMode (pin4,OUTPUT);
  digitalWrite (pin4,LOW); 

  pinMode (pin5,OUTPUT);
  digitalWrite (pin5,LOW);   
}

void loop ()
{
  midiValue=checkMidi();

  if (midiValue!=-1)  //output note on four pins
  {
    if ((midiValue & 0x01)>0) digitalWrite(pin2,HIGH);  //lsb
    else digitalWrite(pin2,LOW);

    if ((midiValue & 0x02)>0) digitalWrite(pin3,HIGH);
    else digitalWrite(pin3,LOW);

    if ((midiValue & 0x04)>0) digitalWrite(pin4,HIGH);
    else digitalWrite(pin4,LOW);

    if ((midiValue & 0x08)>0) digitalWrite(pin5,HIGH);
    else digitalWrite(pin5,LOW);  
  }  
}