title: Programming a buffer using ATMEGA328
body: <p>Im just learning how to use the Arduino, so i bought a Arduino UNO that comes with the ATMega328. And just to start learning i was thinking to use the controller as a buffer:</p>
  
  <p><img src="https://i.stack.imgur.com/e7kNQ.gif" alt="Buffer"></p>
  
  <p>How would be the code for that? What pins can i use for a RS232 signal?
  Thanks a lot. </p>