RX95HF Datasheet, PDF (24/44 Pages) STMicroelectronics – Near field communication transceiver for tag emulation

Commands
RX95HF
Note:
How to modify Analog Register Configuration register (ACC_A) values
1. Use the PROTOCOLSELECT command (0x02) to select the correct communication
protocol.
For example, to select the ISO/IEC 14443-A card emulation protocol:
Send PROTOCOLSELECT command:
RX95HF reply:
>>>0x02021208
<<<0x0000
2. Read the Analog Register Configuration register (ACC_A) value.
a) Write the ACC_A register index at 0x04:
RX95HF reply:
>>>0x0903680004
<<<0x0000
b) Read the ACC_A register value:
RX95HF reply:
>>>0x0803690100
<<<0x0127
In this example, the ACC_A register value is 0x27, where “2” is the Demodulator
Sensitivity and “7” is the Load Modulation Index.
3. Modify the Load Modulation Index values with 0x25.
Write the ACC_A register index:
RX95HF reply:
>>>0x090468010425
<<<0x0000
4. Read the Analog Configuration register (ACC_A) value.
a) Write the ACC_A register index at 0x04:
RX95HF reply:
>>>0x0903680004
<<<0x0000
b) Read the ACC_A register value:
RX95HF reply:
>>>0x0803690100
<<<0x0125
Load Modulation Index and Demodulator Sensitivity values
.
Table 22. Possible Load Modulation Index values
Code (bits [3:0] of ACC_A register) 1
2
...
7
...
Load Modulation Index
Min.
Default
E
F
Max.
Table 23. Possible Demodulator Sensitivity values
Code (bits [5:4] of ACC_A register)
0x1
Demodulator Sensitivity ⁽¹⁾
10%
1. Characterized by design simulation.
Bits [7:6] of ACC_A register are RFU and must set to ‘0’.
0x2
100%
24/44
DocID023884 Rev 3