MFRC522 Datasheet, PDF (48/109 Pages) NXP Semiconductors – Contactless Reader IC

NXP Semiconductors
MFRC522
Contactless Reader IC
10.2.3 Write data
To write data to the MFRC522 using the SPI interface the following byte order has to be
used. It is possible to write out up to n-data bytes by only sending one’s address byte.
The first send byte defines both, the mode itself and the address byte.
Table 137: Byte Order for MOSI and MISO
byte 0
byte 1
byte 2
MOSI
adr 0
data 0
data 1
MISO
X
X
X
to
……..
……..
Remark: The most significant bit (MSB) has to be send first.
byte n
data n-1
X
byte n+1
data n
X
10.2.4 Address byte
The address byte has to fulfil the following format:
The MSB bit of the first byte defines the used mode. To read data from the MFRC522 the
MSB bit is set to logic 1. To write data to the MFRC522 the MSB bit has to be set to
logic 0. The bits 6 to 1 define the address and the LSB shall be set to logic 0.
Table 138. Address byte 0 register; address MOSI
7
6
5
4
3
2
1
0
1 (read)
0 (write)
address
RFU
MSB
LSB
10.3 UART Interface
10.3.1 Connection to a host
RX
TX
DTRQ
MX
RC522
RX
TX
DTRQ
MX
Fig 8. Connection to μ-Controllers with UART.
Remark: DTRQ and MX can be disabled by clearing the bit RS232LineEn in register
TestPinEnReg.
112132
Product data sheet
Rev. 3.2 — 22 May 2007
© NXP B.V. 2007. All rights reserved.
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