void setup() {
  // put your setup code here, to run once:
Serial.begin(115200);
Serial1.begin(115200);
pinMode(2, OUTPUT);
   digitalWrite(2,LOW);
   delay(1000);
   digitalWrite(2,HIGH);
   delay(1000);
   digitalWrite(2,LOW);
}

void loop() {
  // put your main code here, to run repeatedly:

char Char_In;

  while (Serial1.available())
  { 
      Char_In = Serial1.read();
      Serial.write(Char_In);
      Serial.println();
      if(Char_In == 'A')   digitalWrite(2,HIGH);
      if(Char_In == 'a') digitalWrite(2,LOW);
      delay(1000);
    }

}