Description: Adafruit PN532 NFC controller/RFID 13.56 MHz - Shield for Arduino
Shield for Arduino, enabling the reading of data from the NFC devices and RFID at 13.56 MHz. The module is based on the popular PN532, has a built-in antenna, is powered by voltage from pins of the Arduino, by default, it communicates via two lines of the I2C interface, which can be changed to four pins of the SPI bus.
NFC (Near Field Communications) is the communication system between devices located very closely to each other (up to 20 cm). The interface does not require authorisation, it is an extension of RFID, focused primarily on data exchange in mobile phones, for example, to implement fast payment.
The module can read, so-called RFID tags, which are, for example, cards and keychains operating at a frequency of 13.56 MHz. Built-in antenna allows to communicate at a distance of up to 10 cm, even through non-metallic covers or housing.
Shield communicates via I2C or SPI bus. By default, the manufacturer has chosen I2C interface because it uses fewer pins: needed are only analog pins - 4 and 5. Connected is also digital pin 2, which handles an interrupt indicating about receive the data. Thanks to this solution, there's no need to constantly, in a loop to ask the boards if there appeared any RFID tags within range of the antenna.
In order to change to SPI communication, you should solder two jumpers located in the upper part of the board - a detailed description can be found in the user's guide.
Arduino Leonardo uses pin 2 for communication of the I2C bus so, to use Shield with this board, you need to make changes in the code and change the connection of interruption, for example, on pin 4 with jumper at the top part of the board - a detailed description can be found in the user guide.
Specification of Adafruit PN532 NFC controller/RFID 13.56 MHz
- I2C communication (by default or SPI)
- The I2C bus' address: 0x48
- Used Arduino pins: analog 4 and 5, digital 2
- Board sizes: 53,3 x 117,7 x 1.1 mm