The RC522 is a 13.56MHz RFID module that is based on the MFRC522 controller from NXP semiconductors. The module can supports I2C, SPI and UART and normally is shipped with a RFID card and key fob. It is commonly used in attendance systems and other person/object identification applications.
| Pin Number | Pin Name | Description |
|---|---|---|
| 1 | Vcc | Used to Power the module, typically 3.3V is used |
| 2 | RST | Reset pin – used to reset or power down the module |
| 3 | Ground | Connected to Ground of system |
| 4 | IRQ | Interrupt pin – used to wake up the module when a device comes into range |
| 5 | MISO/SCL/Tx | MISO pin when used for SPI communication, acts as SCL for I2c and Tx for UART. |
| 6 | MOSI | Master out slave in pin for SPI communication |
| 7 | SCK | Serial Clock pin – used to provide clock source |
| 8 | SS/SDA/Rx | Acts as Serial input (SS) for SPI communication, SDA for IIC and Rx during UART |