CRX14_10 Datasheet, PDF (12/47 Pages) STMicroelectronics – ISO14443 type-B contactless coupler chip with anti-collision, CRC management and anti-clone function

CRX14 registers
3
CRX14 registers
CRX14
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 Table 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.
Table 2. CRX14 control registers
Address
Length Access
Purpose
00h
Parameter Register
W
1 Byte
R
Set parameter register
Read parameter register
W
01h
Input/output Frame Register 36 Bytes
R
Store and send request frame to the PICC.
Wait for PICC answer frame
Transfer PICC answered frame data to Host
02h
Authenticate Register
W
NA
R
Start the Authentication process
Get the Authentication status
03h
Slot Marker Register
W
1 Byte
R
Launch the automated anti-collision process
from Slot_0 to Slot_15
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
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 3. Parameter register bits description
Bit
Control
Value
Description
b₀ Frame Standard
0
ISO14443 type-B frame management
1
RFU⁽¹⁾
b₁ RFU
0
Not used
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Doc ID 8880 Rev 4