==== RFID RC522 ====
<wrap right>
{{:interfaces:rc522-2.jpg?200}}
</wrap>

This is a very inexpensive RFID module with an MFRC522 integrated circuit
and a PCB antenna.

Although the MFRC522 has I2C, serial and SPI interfaces, only SPI is
available on this module.

=== Pinout ===

<code>
+-------------------------------------+
|              ANTENNA                |
|                                     |
| XTAL         NXPRC522               |
|                                     |
+ *SDA SCK MOSI MISO IRQ GND RST 3V3  +

*SDA is the SPI NSS (slave select) input.
</code>

=== RPi ===

^Pin   ^ALT  ^RFID RC522 |
|GPIO8 |CE0  | SDA  |
|GPIO11|SCLK | SCK |
|GPIO10|MOSI | MOSI |
|GPIO9 |MISO | MISO |
|      |     | IRQ  |
|GND   |     | GND  |
|GPIO25|     | RST  |
|3V3   |     | 3V3  |

=== Resources ===
[[http://www.nxp.com/documents/data_sheet/MFRC522.pdf|Data-sheet]]