Simple Serial TxRx

import processing.serial.*;
float data = 0;
Serial myPort;

void setup() {
  size(160, 128);
  println(Serial.list());
  myPort = new Serial(this, Serial.list()[3], 9600);
  myPort.bufferUntil('\n');
}

void draw() {
}

void serialEvent(Serial myPort) {
  String inString = myPort.readStringUntil('\n');
  if (inString != null) {
    inString = trim(inString);
    float[] coordinates = float(split(inString, ","));
    if (coordinates.length >=1) {
      data = coordinates[0];
      println(data);
     // y = coordinates[1];
     // z = coordinates[2];
    }
  }
}