Data Sheet

MFRC522 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2016. All rights reserved.
Product data sheet
COMPANY PUBLIC
Rev. 3.9 — 27 April 2016
112139 9 of 95
NXP Semiconductors
MFRC522
Standard performance MIFARE and NTAG frontend
The internal CRC coprocessor calculates the CRC value based on ISO/IEC 14443 A
part 3 and handles parity generation internally according to the transfer speed. Automatic
parity generation can be switched off using the MfRxReg register’s ParityDisable bit.
8.1 Digital interfaces
8.1.1 Automatic microcontroller interface detection
The MFRC522 supports direct interfacing of hosts using SPI, I
2
C-bus or serial UART
interfaces. The MFRC522 resets its interface and checks the current host interface type
automatically after performing a power-on or hard reset. The MFRC522 identifies the host
interface by sensing the logic levels on the control pins after the reset phase. This is done
using a combination of fixed pin connections. Table 5
shows the different connection
configurations.
Fig 6. Data coding and framing according to ISO/IEC 14443 A
001aak585
ISO/IEC 14443 A framing at 106 kBd
8-bit data 8-bit data 8-bit data
odd
parity
odd
parity
start
odd
parity
start bit is 1
ISO/IEC 14443 A framing at 212 kBd, 424 kBd and 848 kBd
8-bit data 8-bit data 8-bit data
odd
parity
odd
parity
start
even
parity
start bit is 0
burst of 32
subcarrier clocks
even parity at the
end of the frame
Table 5. Connection protocol for detecting different interface types
Pin Interface type
UART (input) SPI (output) I
2
C-bus (I/O)
SDA RX NSS SDA
I2C001
EA01EA
D7 TX MISO SCL
D6 MX MOSI ADR_0
D5 DTRQ SCK ADR_1
D4 - - ADR_2
D3 - - ADR_3
D2 - - ADR_4
D1 - - ADR_5