AN3955 datasheet(20/68 Pages) STMICROELECTRONICS

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CR95HF low level layer

AN3955

20/68

Doc ID 022017 Rev 1

CR95HF returns a specific correct code for ACK or NAK contactless response, coded on 4

bits, as described in Table 13.

Table 13.

Specific success code for ACK or NAK contactless response

Table 14 describes the CR95HF success response value for ISO/IEC 14443-3 Type B.

For more information, refer to CR95HF datasheet.

If CR95HF_SendRecv function fails, the CR95HF returns an error code in the pResponse

parameter (see Table 15). As an example, if no contactless tag is present in the RF field, the

CR95HF response is 0x8700.

For more information about CR95HF error code, refer to CR95HF datasheet.

Parameter name

Byte

Bit

Value

Comments

Result Code

7:0

0x90

Success code

Length

7:0

0x04

Number of valid bits: 4

Data

2:X

7:0

0x01: NAK

0x05: NAK

0x0A: ACK

Contactless tag response

Table 14.

CR95HF success response value for ISO/IEC 14443-3 Type B

Parameter

name

Byte

Bit

Value

Comments

Example

Result Code

7:0

0x80

Success code

0x800F50AA0B000500

000000B371716A2100

where:

80:

Success

0F:

Number of byte

50AA0B000500000000

B371716A21:

ATQB

00:

CRC Ok

Length

7:0

0xXX

Number of bytes of

Data + control bytes

Data

2:X

7:0

0xXX

Contactless tag

response

Control

bytes

X+1

7:2

0b0000

RFU

CRC error

no CRC error

CRC error or

contactless

response

-RFU

Table 15.

CR95HF error response value for ISO/IEC 14443-3 Type A and B

Parameter name

Byte

Bit

Value

Example

Result code

7:0

0x08

0x8700

: no contactless

tag in the field

Length

7:0

0x00

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