mfrc522 NXP Semiconductors, mfrc522 Datasheet - Page 48

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

NXP Semiconductors
112132
Product data sheet
10.2.3 Write data
10.2.4 Address byte
10.3.1 Connection to a host
10.3 UART Interface
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
Remark: The most significant bit (MSB) has to be send first.
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
Remark: DTRQ and MX can be disabled by clearing the bit RS232LineEn in register
Fig 8. Connection to μ-Controllers with UART.
0 (write)
1 (read)
MSB
MOSI
MISO
7
TestPinEnReg.
byte 0
6
adr 0
X
DTRQ
Rev. 3.2 — 22 May 2007
RX
MX
TX
5
byte 1
data 0
X
4
address
byte 2
data 1
X
DTRQ
TX
RX
MX
3
RC522
……..
……..
to
2
Contactless Reader IC
data n-1
byte n
MFRC522
X
© NXP B.V. 2007. All rights reserved.
1
byte n+1
data n
RFU
48 of 109
LSB
X
0