leeroy447 / rfid

Arduino RFID Library for MFRC522

MFRC522

Arduino library for MFRC522 and other RFID RC522 based modules.

Read and write different types of Radio-Frequency IDentification (RFID) cards on your Arduino using a RC522 based reader connected via the Serial Peripheral Interface (SPI) interface.

Pin Layout

The following table shows the typical pin layout used:

	PCD	Arduino
	MFRC522	Uno	Mega	Nano v3
Signal	Pin	Pin	Pin	Pin
RST/Reset	RST	9 [1]	5 [1]	D9
SPI SS	SDA [3]	10 [2]	53 [2]	D10
SPI MOSI	MOSI	11 / ICSP-4	52	D11
SPI MISO	MISO	12 / ICSP-1	51	D12
SPI SCK	SCK	13 / ICSP-3	50	D13

[1]	(1, 2) Configurable, typically defined as RST_PIN in sketch/program.

[2]	(1, 2) Configurable, typically defined as SS_PIN in sketch/program.

[3]	The SDA pin might be labeled SS on some/older MFRC522 boards.

Hardware

There are three hardware components involved:

1. Micro Controller:

• An Arduino or compatible executing the Sketch using this library.
• Prices vary from USD 7 for clones, to USD 75 for "starter kits" (which might be a good choice if this is your first exposure to Arduino; check if such kit already includes the Arduino, Reader, and some Tags).

2. Proximity Coupling Device (PCD):

• The PCD is the actual RFID Reader based on NXP MFRC522 Contactless Reader Integrated Circuit).
• Readers can be found on eBay for around USD 5: search for "rc522".
• You can also find them at several web stores, they are often included in "starter kits"; so check your favourite electronics provider as well.

3. Proximity Integrated Circuit Card (PICC):

• The PICC is the RFID Card or Tag using the ISO/IEC 14443A interface, for example Mifare or NTAG203.
• One or two might be included with the Reader or "starter kit" already.

Protocols

1. The micro controller and the reader use SPI for communication.

• The protocol is described in the NXP MFRC522 datasheet.
• See the Pin Layout section for details on connecting the pins.

2. The reader and the tags communicate using a 13.56 MHz electromagnetic field.

• The protocol is defined in ISO/IEC 14443-3:2011 Part 3.
  • Details are found in chapter 6 "Type A – Initialization and anticollision".
  • See http://wg8.de/wg8n1496_17n3613_Ballot_FCD14443-3.pdf for a free version of the final draft (which might be outdated in some areas).

History

The MFRC522 library was first created in Jan 2012 by Miguel Balboa (from http://circuitito.com) based on code by Dr. Leong (from http://B2CQSHOP.com) for "Arduino RFID module Kit 13.56 Mhz with Tags SPI W and R By COOQRobot".

It was translated into English and rewritten/refactored in the fall of 2013 by Søren Thing Andersen (from http://access.thing.dk).