#include <MD_Parola.h>

const byte cs = 10;
const byte max_dev = 4;
String data = "";
bool inv = true;

MD_Parola matrix = MD_Parola(MD_MAX72XX::PAROLA_HW, cs, max_dev);

void setup(){
  Serial.begin(9660);

  matrix.begin();
  matrix.displayClear();
  matrix.setTextAlignment(PA_CENTER);

  Serial.println("Enter text to display");
}

void loop(){
  if (Serial.available()) {
    data = Serial.readStringUntil('\n');
    Serial.println("Text: " + data);
  }
  else if (data != "") {
    inv = !inv;
    matrix.setInvert(inv);
    matrix.print(data);
    delay(1000);
  }
}