#include <SoftwareSerial.h>

#define rxPin 5 // declarar el pin del RX
#define txPin 4 // declarar el pin del TX

// Set up a new SoftwareSerial object
SoftwareSerial mySerial =  SoftwareSerial(rxPin, txPin); // Config de los pines Rx y Tx como serie de software

// initialize digital pin LED.
int ledPin = 3; // LED digital conectado al pin 3 - Según pinout ATTiny 45

void setup()  {
    // Define pin modes for TX and RX
    pinMode(rxPin, INPUT);
    pinMode(txPin, OUTPUT);
    
    // Set the baud rate for the SoftwareSerial object
    mySerial.begin(9600);
}

void loop() {
    if (mySerial.available() > 0) {
        mySerial.read();
    }
    pinMode(ledPin, OUTPUT);      //Configures the LED pin as an output

  // fade in from min to max in increments of 5 points:

    for (int fadeValue = 0 ; fadeValue <= 255; fadeValue += 5) {

  // sets the value (range from 0 to 255):
  
    analogWrite(ledPin, fadeValue);

  // wait for 30 milliseconds to see the dimming effect
  
    delay(30);

    }
  // fade out from max to min in increments of 5 points:
  
  for (int fadeValue = 255 ; fadeValue >= 0; fadeValue -= 5) {
  
  // sets the value (range from 0 to 255):
    
    analogWrite(ledPin, fadeValue);

  // wait for 30 milliseconds to see the dimming effect

    delay(30);
  
    }
}