Datasheet

Then upload the example to the Arduino and continue on. Note that you need to make a similar change to pick the

interface for any other NFC example from the library.

Testing MiFare

In the serial monitor, you should see that it found the PN532 chip. Then you can place your tag nearby and it will

display the 4 byte ID code (this one is 0xAE 0x4C 0xF0 0x6C) and then the integer version of all four bytes together.

You can use this number to identify each card. Recently NXP made so many cards that they actually ran through all 4

Bytes (2^32) so the number is not guaranteed to be absolutely unique. However, the chances are extremely slim you

will have two cards with the same ID so as long as you aren't using these cards for anything terribly important (like

money transfer) its fine to use the number as a unique identifier

// Uncomment just _one_ line below depending on how your breakout or shield

// is connected to the Arduino:

// Use this line for a breakout with a SPI connection:

//Adafruit_PN532 nfc(PN532_SCK, PN532_MISO, PN532_MOSI, PN532_SS);

// Use this line for a breakout with a hardware SPI connection. Note that

// the PN532 SCK, MOSI, and MISO pins need to be connected to the Arduino's

// hardware SPI SCK, MOSI, and MISO pins. On an Arduino Uno these are

// SCK = 13, MOSI = 11, MISO = 12. The SS line can be any digital IO pin.

//Adafruit_PN532 nfc(PN532_SS);

// Or use this line for a breakout or shield with an I2C connection:

Adafruit_PN532 nfc(PN532_IRQ, PN532_RESET);