We've tested sending data. It's time to test receiving it. Except that there's no other device that can send us some data ... or is there?
You can send data to yourself! Not very useful in production but very useful for debugging.
TXO and the
RXI pins of the serial module together using a male to male jumper wire
as shown above.
Now enter some text into minicom/PuTTY and observe. What happens?
You should see three things:
- As before, the TX (red) LED blinks on each key press.
- But now the RX (green) LED blinks on each key press as well! This indicates that the serial module is receiving some data; the one it just sent.
- Finally, on the minicom/PuTTY console, you should see that what you type echoes back to the console.
Now that you are familiar with sending and receiving data over serial port using minicom/PuTTY, let's make your microcontroller and your laptop talk!