The MFRC523 is a highly integrated reader/writer for contactless communication at 13.56 MHz. The MFRC523 reader supports ISO/IEC 14443 A/MIFARE mode. The MFRC523’s internal transmitter is able to drive a reader/writer antenna designed to communicate with ISO/IEC 14443 A/MIFARE cards and transponders without additional active circuitry. The receiver module provides a robust and efficient implementation for demodulating and decoding signals from ISO/IEC 14443 A/MIFARE compatible cards and transponders. The digital module manages the complete ISO/IEC 14443 A framing and error detection （parity and CRC） functionality. All protocol layers of the ISO/IEC 14443 A and ISO/IEC 14443 B communication standards are supported： ? additional components， such as the oscillator， power supply， coil etc are correctly applied ? standardized protocols， such as ISO/IEC 14443-4 and/or ISO/IEC 14443 B anticollision are correctly implemented The MFRC523 supports contactless communication using MIFARE higher baud rates （see Section 8.3.4.11 on page 22） at transfer speeds up to 848 kBd in both directions. The following host interfaces are provided： ? Serial Peripheral Interface （SPI） ? Serial UART （similar to RS232 with voltage levels dependent on pin voltage supply） ? I 2C-bus interface