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 72 of 95
NXP Semiconductors
MFRC522
Standard performance MIFARE and NTAG frontend
10.3.1.7 Receive
The MFRC522 activates the receiver path and waits for a data stream to be received. The
correct settings must be chosen before starting this command.
This command automatically terminates when the data stream ends. This is indicated
either by the end of frame pattern or by the length byte depending on the selected frame
type and speed.
Remark: If the RxModeReg register’s RxMultiple bit is set to logic 1, the Receive
command will not automatically terminate. It must be terminated by starting another
command in the CommandReg register.
10.3.1.8 Transceive
This command continuously repeats the transmission of data from the FIFO buffer and the
reception of data from the RF field. The first action is transmit and after transmission the
command is changed to receive a data stream.
Each transmit process must be started by setting the BitFramingReg register’s StartSend
bit to logic 1. This command must be cleared by writing any command to the
CommandReg register.
Remark: If the RxModeReg register’s RxMultiple bit is set to logic 1, the Transceive
command never leaves the receive state because this state cannot be cancelled
automatically.
10.3.1.9 MFAuthent
This command manages MIFARE authentication to enable a secure communication to
any MIFARE Mini, MIFARE 1K and MIFARE 4K card. The following data is written to the
FIFO buffer before the command can be activated:
• Authentication command code (60h, 61h)
• Block address
• Sector key byte 0
• Sector key byte 1
• Sector key byte 2
• Sector key byte 3
• Sector key byte 4
• Sector key byte 5
• Card serial number byte 0
• Card serial number byte 1
• Card serial number byte 2
• Card serial number byte 3
In total 12 bytes are written to the FIFO.
Remark: When the MFAuthent command is active all access to the FIFO buffer is
blocked. However, if there is access to the FIFO buffer, the ErrorReg register’s WrErr bit is
set.