CR14 STMicroelectronics, CR14 Datasheet - Page 13

• Manufacturer Part Number: CR14
• Description: Low Cost Iso14443 Type-b Contactless Coupler Chip With Anti-collision And Crc Management
• Manufacturer: STMicroelectronics

CR14
3.1
3.2
Parameter Register (00h)
The Parameter Register is an 8-bit volatile register used to configure the CR14, and thus, to
customize the circuit behavior. The Parameter Register is located at the I²C address 00h and it
is accessible in I²C Read and Write modes. Its default value, 00h, puts the CR14 in standard
ISO14443 type-B configuration.
Table 3.
1. RFU = Reserved for Future Use.
Input/Output Frame Register (01h)
The Input/Output Frame Register is a 36-Byte buffer that is accessed serially from Byte 0
through to Byte 35 (see
The Input/Output Frame Register is the buffer in which the CR14 stores the data Bytes of the
request frame to be sent to the PICC. It automatically stores the data Bytes of the answer frame
received from the PICC. The first Byte (Byte 0) of the Input/Output Frame Register is used to
store the frame length for both transmission and reception.
When accessed in I²C Write mode , the register stores the request frame Bytes that are to be
transmitted to the PICC. Byte 0 must be set with the request frame length (in Bytes) and the
frame is stored from Byte 1 onwards. At the end of the transmission, the 16-bit CRC is
automatically added. After the transmission, the CR14 wait for the PICC to send back an
answer frame. When correctly decoded, the PICC answer frame Bytes are stored in the Input/
Output Frame Register from Byte 1 onwards. Byte 0 stores the number of Bytes received from
the PICC.
When accessed in I²C Read mode, the Input/Output Register sends back the last PICC answer
frame Bytes, if any, with Byte 0 transmitted first. The 16-bit CRC is not stored, and it is not sent
back on the I²C bus.
b
b
b
b
b
b
b
b
Bit
0
1
2
3
4
5
6
7
Frame Standard
RFU
Answer Frame Format
ASK Modulation Depth
Carrier Frequency
t
Answer delay watchdog
RFU
WDG
Parameter Register Bits Description
Control
Table
0
1
0
0
1
0
1
0
1
b5=0, b6=0: Watchdog time-out = 500µs to be used for read
b5=0, b6=1: Watchdog time-out = 5ms to be used for read
b5=1, b6=0: Watchdog time-out = 10ms to be used for write
b5=1, b6=1: Watchdog time-out = 309ms to be used for MCU timings
0
4). It is located at the I²C address 01h.
Value
RFU
Not used
Answer PICC Frames are delimited by SOF and EOF
Answer PICC Frames do not provide SOF and EOF delimiters
10% ASK modulation depth mode
RFU
13.56MHz carrier on RF OUT is OFF
13.56MHz carrier on RF OUT is ON
Not used
ISO14443 type-B frame management
(1)
Description
3 CR14 registers
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