How to Connect a PN532 NFC Shield to a RaspberryPi via libnfc

2014-11-11

I’m working on an NFC project and to test things out I got a PN532 NFC shield working with a RaspberryPi via libnfc.

Adafruit has a good step-by-step tutorial, but it’s not up-to-date and it’s for the PN532 breakout board not the PN532 shield. They also have this one for Arduino – it’s not RaspberryPi, but still helpful for understanding the concepts.

Here’s how I got it going – hope this saves you some time.

1. Get Occidentalis v0.2

https://learn.adafruit.com/adafruit-raspberry-pi-educational-linux-distro/occidentalis-v0-dot-2

2. Make Occidentalis SD card

https://learn.adafruit.com/adafruit-raspberry-pi-lesson-1-preparing-and-sd-card-for-your-raspberry-pi/making-an-sd-card-using-a-windows-vista-slash-7

3. Run first time config

https://learn.adafruit.com/adafruits-raspberry-pi-lesson-2-first-time-configuration

4. Free UART on the Pi

https://learn.adafruit.com/adafruit-nfc-rfid-on-raspberry-pi/freeing-uart-on-the-pi

On step one remove any key-value pairs that reference ttyAMAO (i.e. console=ttyAMAO,115200) and keep everything else. http://www.raspberry-projects.com/pi/pi-operating-systems/raspbian/io-pins-raspbian/uart-pins

5. Get and Build libnfc

https://learn.adafruit.com/adafruit-nfc-rfid-on-raspberry-pi/building-libnfc

On step three you might get the following: “./configure command not found” if so then follow the instructions here: http://forums.adafruit.com/viewtopic.php?f=19&t=53935#p292489

6. Prepare the PN532

When I was going through this I was going under the assumption that libnfc only worked in UART mode (because that is what I found on from many sources), but I later found that it does support I2C and SPI. To get PN532 in UART mode you need to solder SEL0 on the board (make sure you are soldering SEL closest to MOSI on the board. In v.1 of PN532 SEL0 and SEL1 labels were reversed.