void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  Serial2.begin(9600);
  //Serial2.begin(9600, SERIAL_8N1, 16, 17);

  int8_t _rxPin = uart_get_RxPin(2);
  int8_t _txPin = uart_get_TxPin(2);
  Serial.println(_rxPin);
  Serial.println(_txPin);

  Serial2.println("Hello Serial2");
  delay(20);
  while (Serial2.available()) {
    Serial.write(Serial2.read());
  }
  Serial.println("===END===");
}

void loop() {
  Serial2.println("loop");
  delay(1000); // this speeds up the simulation
  while (Serial2.available()) {
    Serial.write(Serial2.read());
  }
}