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.
|Used to Power the module, typically 3.3V is used
|Reset pin – used to reset or power down the module
|Connected to Ground of system
|Interrupt pin – used to wake up the module when a device comes into range
|MISO pin when used for SPI communication, acts as SCL for I2c and Tx for UART.
|Master out slave in pin for SPI communication
|Serial Clock pin – used to provide clock source
|Acts as Serial input (SS) for SPI communication, SDA for IIC and Rx during UART