ST25R95 datasheet(38/61 Pages) STMICROELECTRONICS

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How to modify analog register configuration register (ACC_A) values

•

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:

•

ST25R95 reply

>>>

0x02021208

<<<

0x0000

•

Read the analog register configuration register (ACC_A) value.

•

Write the ACC_A register index at 0x04:

•

ST25R95 reply:

>>>

>>>0x0903680004

<<<

0x0000

•

Read the ACC_A register value:

•

ST25R95 reply:

>>>

0x0803690100

<<<

0x000127

In this example, the ACC_A register value is

0x27, where “2” is the demodulator sensitivity and “7” is the load

modulation index.

•

Modify the load modulation index values with 0x25.

•

Write the ARC_A register index:

•

ST25R95 reply:

>>>

0x090468010425

<<<

0x0000

•

Read the analog configuration register (ACC_A) value.

•

Write the ACC_A register index at 0x04:

•

ST25R95 reply:

>>>

0x0903680004

<<<

0x0000

•

Read the ARC_A register value:

•

ST25R95 reply: <<<

>>>

0x0803690100

<<<

0x000125

Load modulation index and demodulator sensitivity values

Table 33. Possible load modulation index values

Code (bits [3:0] of ACC_A register)

...

Load modulation index

Min.

Default

Max.

Table 34. Possible demodulator sensitivity values

Code (bits [5:4] of ACC_A register)

0x1

0x2

Demodulator Sensitivity (1)

10%

100%

1. Characterized by design simulation.

Note:

Bits [7:6] of ACC_A register are RFU and must set to ‘0’.

ST25R95

Write Register (WrReg) command (0x09) description

DS12807 - Rev 4

page 38/61

ST25R95 Datasheet(PDF) 38 Page - STMicroelectronics

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