 
   if(refresh) untztrument.writeDisplay();
 
-  while(usbMIDI.read()); // Discard incoming MIDI messages
 }

#include <Wire.h>
#include <Adafruit_Trellis.h>
#include <Adafruit_UNTZtrument.h>

#define LED 13 // Pin for heartbeat LED (shows code is working)


    line(col, true);
    for(uint8_t row=0, mask=1; row<8; row++, mask <<= 1) {
      if(grid[col] & mask) {
          noteOn(pgm_read_byte(&channel[row]), pgm_read_byte(&note[row]), 127);
      }
    }
    prevBeatTime = t;
