Introduction
This document describes the functionality and electrical specifications of the contactless reader/writer MFRC522.

General description
The MFRC522 is a highly integrated reader/writer IC for contactless communication at 13.56 MHz. The MFRC522 reader supports ISO/IEC 14443 A/MIFARE mode.
The MFRC522’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.
The MFRC522 supports MF1xxS20, MF1xxS70 and MF1xxS50 products. The MFRC522 supports contactless communication and uses MIFARE higher 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 dependant on pin voltage supply)
• I2C-bus interface

Features and benefits
■ Highly integrated analog circuitry to demodulate and decode responses
■ Buffered output drivers for connecting an antenna with the minimum number of
   external components
■ Supports ISO/IEC 14443 A/MIFARE
■ Typical operating distance in Read/Write mode up to 50 mm depending on the
   antenna size and tuning
■ Supports MF1xxS20, MF1xxS70 and MF1xxS50 encryption in Read/Write mode
■ Supports ISO/IEC 14443 A higher transfer speed communication up to 848 kBd
■ Supports MFIN/MFOUT
■ Additional internal power supply to the smart card IC connected via MFIN/MFOUT
■ Supported host interfaces
   ◆ SPI up to 10 Mbit/s
   ◆ I2C-bus interface up to 400 kBd in Fast mode, up to 3400 kBd in High-speed mode
   ◆ RS232 Serial UART up to 1228.8 kBd, with voltage levels dependant on pin
      voltage supply
■ FIFO buffer handles 64 byte send and receive
■ Flexible interrupt modes
■ Hard reset with low power function
■ Power-down by software mode
■ Programmable timer
■ Internal oscillator for connection to 27.12 MHz quartz crystal
■ 2.5 V to 3.3 V power supply
■ CRC coprocessor
■ Programmable I/O pins
■ Internal self-test