RFID & NFC Expansion Board Onion RFID and NFC Expansion Board is used to bring RFID and NFC functionality to the Omega2 module, and can plug directly into an Onion Expansion, Arduino or Power Dock. The board provides NFC and RFID communication, and makes use of the PN532 controller chip. This popular NFC chip is embedded in most smartphones and devices that support NFC. The chip reads and writes to tags and cards, communicates with phones (for example, payment processing), and acts like an NFC tag.