CRX14 registers CRX14
12/47 Doc ID 8880 Rev 4
3 CRX14 registers
The CRX14 chip coupler contains six volatile registers. It is entirely controlled, at both digital
and analog level, using the four registers listed below and shown in Ta ble 2:
● Parameter Register
● Input/Output Frame Register
● Authentication Register
● Slot Marker Register
The other 3 registers are located at addresses 02h, 04h and 05h. They are “ST Reserved”,
and must not be used in end-user applications.
In the I²C protocol, all data Bytes are transmitted Most Significant Byte first, with each Byte
transmitted Most significant bit first.
3.1 Parameter register (00h)
The Parameter Register is an 8-bit volatile register used to configure the CRX14, 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 CRX14 in
standard ISO14443 type-B configuration.
Table 2. CRX14 control registers
Address Length Access Purpose
00h Parameter Register 1 Byte
W Set parameter register
R Read parameter register
01h Input/output Frame Register 36 Bytes
W
Store and send request frame to the PICC.
Wait for PICC answer frame
R Transfer PICC answered frame data to Host
02h Authenticate Register NA
W Start the Authentication process
R Get the Authentication status
03h Slot Marker Register 1 Byte
W
Launch the automated anti-collision process
from Slot_0 to Slot_15
R Return data FFh
04h ST Reserved NA R and W ST Reserved. Must not be used
05h ST Reserved NA R and W ST Reserved. Must not be used
Table 3. Parameter register bits description
Bit Control Value Description
b
0
Frame Standard
0 ISO14443 type-B frame management
1
RFU
(1)
b
1
RFU 0 Not used
