USB_IN_OUT_MIDI_LOOPER.ino

/*
 * A piezo transducer is wired to pins 19 and 18 to trigger 
 * cycling through the Record/Play/Stop modes.  The code can 
 * be altered to also work with a simple push button.
 */

#include <usbh_midi.h>
#include <usbhub.h>
#ifdef dobogusinclude
#include <spi4teensy3.h>
#include <SPI.h>
#endif

USB  Usb;
USBH_MIDI  Midi(&Usb);

IntervalTimer tmrMIDI;
volatile byte midiFlag = 0;

//MIDI VARIABLES
byte recButtonID = 19;

byte recButton = 0;
byte recButtonState = 0;
unsigned long recStartTime = 0;
int recPointer = 0;

byte red = 5;
byte green = 6;
byte blue = 20;

byte rec[3000+1];
unsigned long recTime[3000+1];

long recButtonTimer = 0;
byte thresh = 200;

byte recFlag = 0;
 
void setup() {
  Serial.begin(38400);

  //Workaround for non UHS2.0 Shield 
  pinMode(7,OUTPUT);
  digitalWrite(7,HIGH);

  if (Usb.Init() == -1) {
    while(1); //halt
  }//if (Usb.Init() == -1...
  delay( 200 );

  pinMode(recButtonID,INPUT);
  pinMode(recButtonID - 1,INPUT_PULLUP);
  pinMode(red,OUTPUT);
  pinMode(green,OUTPUT);
  pinMode(blue,OUTPUT);
  digitalWrite(red,LOW);
  digitalWrite(green,LOW);
  digitalWrite(blue,HIGH);

  tmrMIDI.begin(procMIDI, 1000);
}

void loop() {

  uint8_t msg[4];
  uint8_t outBuf[3];
  uint8_t msgSize;

  Usb.Task();

  /* Process midi data according to timer event for 
   * more accurate timing on playback. 
   */
  if (midiFlag == 1){

    if (recButtonState == 1){

      /* If max record length is reached, automatically 
       * start playing. 
       */  
      if (recPointer>=2999){
        recButtonState = 2;
        recFlag = 1;
        digitalWrite(red,LOW);
        digitalWrite(green,HIGH);
        digitalWrite(blue,LOW);
      }
      else{  
        if( Usb.getUsbTaskState() == USB_STATE_RUNNING ){
          int x = micros() - recStartTime;
          msgSize=Midi.RecvData(outBuf);
          if( (msgSize) > 0 ){
            if (outBuf[0] < 240){
              Serial.print(recButtonState);
              Serial.print(" ");
              Serial.print(outBuf[0]);
              Serial.print(" ");
              Serial.print(outBuf[1]);
              Serial.print(" ");
              Serial.println(outBuf[2]);
              recTime[recPointer] = x;
              rec[recPointer] = outBuf[0];
              recPointer++;
              recTime[recPointer] = x;
              rec[recPointer] = outBuf[1];
              recPointer++;
              recTime[recPointer] = x;
              rec[recPointer] = outBuf[2];
              recPointer++;
            }
          } 
        }
      }
    }
    if (recButtonState == 2){
      if (recFlag == 1){
        rec[recPointer] = 255;
        recTime[recPointer] = micros() - recStartTime;
        recStartTime = micros();
        recPointer = 0;
        recFlag = 0;
        digitalWrite(red,LOW);
        digitalWrite(green,HIGH);
        digitalWrite(blue,LOW);
      }
      byte f = 0;  
//      while ((micros() - recStartTime > recTime[recPointer]) && (f == 0)){
      while (f == 0){
        if (rec[recPointer] == 255){
          recStartTime = micros();
          recPointer = 0;
          f = 1;
        }
        else{
          msg[0] = rec[recPointer];
          recPointer++;
          msg[1] = rec[recPointer];
          recPointer++;
          msg[2] = rec[recPointer];
          recPointer++;
          Midi.SendData(msg, 0);
          Serial.print(recButtonState);
          Serial.print(" ");
          Serial.print(msg[0]);
          Serial.print(" ");
          Serial.print(msg[1]);
          Serial.print(" ");
          Serial.println(msg[2]);
        }
      }
    }
    noInterrupts();
    midiFlag = 0;
    interrupts();
  }

  /* Process Button Push
   *  
   */
  int b1 = analogRead(recButtonID-1) - analogRead(recButtonID);
  if (b1<0)  b1 = -b1;
  if (micros() - recButtonTimer > 50000){
    if (b1 > thresh){
      recButtonTimer = micros();
      recButtonState++;
      if (recButtonState > 2){
        recButtonState = 0;
      }
      if (recButtonState == 2){
        recFlag = 1;
        digitalWrite(red,LOW);
        digitalWrite(green,HIGH);
        digitalWrite(blue,LOW);
     }
      else if (recButtonState == 0){
        digitalWrite(red,LOW);
        digitalWrite(green,LOW);
        digitalWrite(blue,HIGH);
      }  
      else{
        digitalWrite(red,HIGH);
        digitalWrite(green,LOW);
        digitalWrite(blue,LOW);
        recStartTime = micros();
        recPointer = 0;
      }              
      Serial.println(recButtonState);
    }
  }
}

void procMIDI(void){
  midiFlag = 1;
}