CRX14 Datasheet, PDF (3/4 Pages) STMicroelectronics – Low Cost 13.56MHz / I²C Short Range Contactless Coupler Chip with anti-collision, CRC management and anti-clone function

CRX14
The CRX14 is organized in four blocks:
– The I²C bus controller handles the serial con-
nection with the application host. It is compliant
with the 400kHz I²C bus specification and it con-
trols the read/write access to all the CRX14 reg-
isters.
– The RAM buffer is bi-directional. It stores all the
request frame bytes to be transmitted to the tag
and all received bytes send by the tag on the an-
swer frame.
– The transmitter powers all the contactless tags,
within range, by generating a RF magnetic field
at 13.56MHz on an external antenna. The field
is 10% modulated using ASK (amplitude shift
keying) modulation for outgoing data.
– The receiver demodulates the signal generated
on the antenna by the load variation of the con-
tactless tag. The resulting signal is decoded by
a 847KHz BPSK (binary phase shift keying)
sub-carrier decoder.
The CRX14 is designed to be connected to a dig-
ital host (Microcontroller or ASIC) which has to
manage all the communication protocol in both
transmit and receive mode through the I²C serial
bus.
CRX14 DEVICE OPERATION
The CRX14 chip coupler provides four volatile reg-
isters. They control all the behaviour of the device
and are described in Table 2.
Table 2. CRX14 Control Registers
I2C Address
00h
Parameters register
01h
Input/Output frame register
02h
Authenticate register
03h
Slot Marker register
Access
Purpose
W Set parameter register
R Read parameter register
W
Store and send request frame to the tag.
Store tag answer frame
R Transfer register content to Host
W Start the Authenticate process
R Get the Authenticate status
W Launch the automated anti-collision process
R Not Applicable. Return data FFh.
PART NUMBERING
For a list of available options (speed, package,
etc.) or for further information on any aspect of this
device, please contact your nearest ST Sales Of-
fice.
Table 3. Ordering Information Scheme
Example:
CRX14
–
MQ / XX
Device Type
CRX14
Package
MQ = SO16 (150 mil width)
Customer Code
XX = Given by the issuer
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