mfrc531 NXP Semiconductors, mfrc531 Datasheet - Page 73

• Manufacturer Part Number: mfrc531
• Description: Iso/iec 14443 Reader Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
11. MFRC531 command set
Table 129. MFRC531 commands overview
MFRC531_34
Product data sheet
PUBLIC
Command
StartUp
Idle
Transmit
Receive
10.5.8.7 Reserved registers 3Eh, 3Fh
3Fh
00h
1Ah
16h
Value Action
11.1 MFRC531 command overview
runs the reset and initialization phase. See
Section 11.1.2 on page
Remark: This command can only be activated by
Power-On or Hard resets.
no action; cancels execution of the current command.
See
transmits data from the FIFO buffer to the card. See
Section 11.2.1 on page 76
activates receiver circuitry. Before the receiver starts,
the state machine waits until the time defined in the
RxWait register has elapsed. See
page
Remark: This command may be used for test
purposes only, since there is no timing relationship to
the Transmit command.
Table 128. Reserved register (address: 3Eh, 3Fh) reset value: xxxx xxxxb, xxh bit allocation
Remark: This register is reserved for future use.
MFRC531 operation is determined by an internal state machine capable of performing a
command set. The commands can be started by writing the command code to the
Command register. Arguments and/or data necessary to process a command are mainly
exchanged using the FIFO buffer.
Bit
Symbol
Access
•
•
•
•
Section 11.1.3 on page 75
79.
Each command needing a data stream (or data byte stream) as an input immediately
processes the data in the FIFO buffer
Each command that requires arguments only starts processing when it has received
the correct number of arguments from the FIFO buffer
The FIFO buffer is not automatically cleared at the start of a command. It is, therefore,
possible to write command arguments and/or the data bytes into the FIFO buffer
before starting a command.
Each command (except the StartUp command) can be interrupted by the
microprocessor writing a new command code to the Command register e.g. the Idle
command.
W
7
x
75.
Rev. 3.4 — 26 January 2010
W
6
x
Section 11.2.2 on
056634
W
5
x
W
4
x
FIFO communication
Arguments and data
sent
-
-
data stream
-
W
3
x
W
ISO/IEC 14443 reader IC
2
x
MFRC531
© NXP B.V. 2010. All rights reserved.
Data received
-
-
-
data stream
W
1
x
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W
0
x