AN3955 datasheet(27/68 Pages) STMICROELECTRONICS

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AN3955

ISO/IEC 14443-3 layers

Doc ID 022017 Rev 1

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5.1.3

Parity bit management

The parity bit of a standard frame is managed by the CR95HF.

5.1.4

ISO/IEC 14443-3 Type A CRC16 management

The ISO/IEC 14443-3 Type A specification defines a two-byte CRC. It is appended to some

RF commands to check the data transmission between CR95HF and a contactless tag.

The 5th bit of the transmission flag of SendRecv command controls the CRC. When this bit

is set to 1, the CR95HF appends the CRC to RF commands.

Table 26 lists the ISO/IEC 14443-3 Type A commands and notifies if a CRC is required. The

functions of ISO/IEC 14443-3 Type A layer listed in Table 26 manage the transmission flag

and the CRC.

If the user application does not use the previous functions, it has to manage the CRC by

using bit 5 of the transmission flag.

Table 26.

ISO/IEC 14443-3 Type A commands

ISO/IEC 14443-3

Type A command

CRC

SendRecv

example

Comments

ISO/IEC 14443_A function

REQA

04 02 26 07

Command on 7

bits without

CRC

ISO14443A_REQA

WUPA

04 02 52 07

Command on 7

bits without

CRC

ISO14443A_WUPA

HLTA

Yes

04 03 50 00 28

The last byte

has 8 bits with

CRC

ISO14443A_HLTA

Anticollision

04 02 93 20 08

The last byte

has 8 bits

without CRC

ISO14443A_AntiCollisionLevelX

Select

Yes

04 02 93 70

88...28

The last byte

has 8 bits with

CRC

ISO14443A_SelectLevelX

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