mfrc522 NXP Semiconductors, mfrc522 Datasheet - Page 72

• Manufacturer Part Number: mfrc522
• Description: Contactless Reader Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
18. MFRC522 Command Set
112132
Product data sheet
18.1 General Description
18.2 General Behavior
18.3 MFRC522 Commands Overview
The behavior is determined by a state machine capable to perform a certain set of
commands. By writing the according command-code to register CommandReg the
command is executed.
Arguments and/or data necessary to process a command are exchanged via the FIFO
buffer.
Table 149: Command overview
Command
Idle
Mem
Generate
RandomID
CalcCRC
Transmit
NoCmd
Change
Receive
Transceive
-
MFAuthent
Soft Reset
•
•
•
•
Each command, that needs a data stream (or data byte stream) as input will
immediately process the data it finds in the FIFO buffer. An exception to this rule is the
Transceive command. Using this command the transmission is started with the
StartSend bit in the BitFramingReg register.
Each command that needs a certain number of arguments will start processing only
when it has received the correct number of arguments via the FIFO buffer.
The FIFO buffer is not cleared automatically at command start. Therefore, it is also
possible to write the command arguments and/or the data bytes into the FIFO buffer
and start the command afterwards.
Each command may be interrupted by the host by writing a new command code into
register CommandReg e.g.: the Idle-Command.
Command code Action
0000
0001
0010
0011
0100
0111
1000
1100
1101
1110
1111
Rev. 3.2 — 22 May 2007
No action; cancels current command execution.
Stores 25 byte into the internal buffer
Generates a 10 byte random ID number
Activates the CRC co-processor or performs a selftest.
Transmits data from the FIFO buffer.
No command change. This command can be used to modify
different bits in the command register without touching the
command. E.g. Power-down.
Activates the receiver circuitry.
Transmits data from FIFO buffer to the antenna and activates
automatically the receiver after transmission.
Reserved for further use
Performs the MIFARE
Resets the MFRC522
®
standard authentication as a reader
Contactless Reader IC
MFRC522
© NXP B.V. 2007. All rights reserved.
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