Raspberry Pi Interface with PN532 NFC Module

Demonstration

Physical connections

Notes

1. The PN532 module has connections for UART, SPI, I²C, selectable by jumper. So far I have only tried the SPI interface
   (The jumpers are upper left on the picture. The UART connection are on the same pins as I²C; the labels are on the other side of the board.)
2. SPI connections:
   • SCK, MISO, MOSI, GND as expected
   • SS to either CE0 or CE1; I think libnfc can handle either, but the example uses CE0.
     See libnfc configuration information for setup
   • V_CC can be 3.3V, so no level shifting is needed for the Raspberry Pi.
   • No connections to IRQ or RSTO

Python code

import subprocess
import time

def nfc_raw():
	lines=subprocess.check_output("/usr/bin/nfc-poll", stderr=open('/dev/null','w'))
	return lines

def read_nfc():
	lines=nfc_raw()
	return lines

try:
	while True:
		myLines=read_nfc()
		buffer=[]
		for line in myLines.splitlines():
			line_content=line.split()
			if(not line_content[0] =='UID'):
				pass
			else:
				buffer.append(line_content)
		str=buffer[0]
		id_str=str[2]+str[3]+str[4]+str[5]
		print (id_str)


except KeyboardInterrupt:
        pass
    

Notes

1. It might make sense to put more of the decoding into read_nfc(), which basically does nothing at present.