const int LED_BuiltIn = 2;		// D2 встроенный светодиод
int my_pin = 4;
int my_serial;
bool b_my_pin; 
String my_string;

void setup() {
  Serial.begin(115200);
  pinMode (LED_BuiltIn, OUTPUT);
}

void loop() {
  if (Serial.available()) my_serial = Serial.parseInt();
  if (my_serial !=0) my_pin = my_serial;

  pinMode (my_pin, OUTPUT);

  digitalWrite(my_pin, 1); //записали 1
  delay(100);
  b_my_pin = digitalRead(my_pin); //прочитали
  digitalWrite(LED_BuiltIn, b_my_pin);
  Serial.println(b_my_pin);
  my_string = "";
  my_string += "Write-Read 1. Pin "; 
  my_string += my_pin; 
  Serial.println(my_string);

  delay(5000);

  digitalWrite(my_pin, 0); //записали 0
  delay(100);
  b_my_pin = digitalRead(my_pin); //прочитали
  digitalWrite(LED_BuiltIn, b_my_pin);
  Serial.println(b_my_pin); 
  my_string = "";
  my_string += "Write-Read 0. Pin "; 
  my_string += my_pin; 
  Serial.println(my_string);

  delay(5000);
  }