#include <SoftwareSerial.h>

const int ledPin = PA7; // the pin that the LED is attached to
const int rx = PA0;
const int tx = PA1;

SoftwareSerial mySerial(rx, tx);

void setup() {
  // initialize serial communication:
  mySerial.begin(4800);
  // initialize the LED pin as an output:
  pinMode(ledPin, OUTPUT);
}

void loop() {
  if (mySerial.available() > 0) {
    mySerial.read ();
     digitalWrite (ledPin, HIGH);
     delay (1000);
     digitalWrite (ledPin, LOW);
     mySerial.write(1);


  }
}