Using Arduino Uno or Nano as UART Adapters


I have both, an arduino uno r3 and an arduino nano and would like to use the nano as an UART adapter for my PN532 Breakout Shield. My current setup is:

  • Connect RST to GND on the Nano
  • TX to TX
  • RX to RX
  • 5V to 5V
  • GND to GND

However when I am trying to connect with libnfc (lib-poll) it doesn't work. The chip on the arduino is C340G and the current drivers are installed.

The shield works as well, because when I use CP2102 it connects just fine.

What could the problem be? I have the same problem with the uno.

TX and RX may need to be swapped, if one set of markings isn't already swapped.

Why are you not just using a standalone serial adapter if you want to talk to it over serial? They're under $5 shipped...

Isn't the reset on that part active low? (so by pulling it to ground, you're keeping the board in perpetual reset?) Check the datasheet.