AN3375 datasheet(55/73 Pages) STMICROELECTRONICS

55 / 73 page

AN3375

M24LRXX-R Layer

Doc ID 018637 Rev 1

55/73

M24LRXX-R Layer

The M24LRXX-R layer is composed of:

●

the lib_M24LRXX.c source file

●

the lib_M24LRXX.h include file

4.1

Overview

The library includes all the commands defined in the M24LRXX-R datasheets. Since

M24LRXX-R devices are compliant with ISO15693 specifications, several functions of the

M24LRXX-R layer are identical to ISO15693 functions.

4.1.1

CRC management

The two-byte CRC can be either computed by the user or by the CR95HF device, depending

on the value of the AppendCRC input parameter.

●

If AppendCRC input parameter is set to ‘0’, the two-byte CRC is calculated by the user

application.

●

If AppendCRC input parameter is set to ‘1’, the two-byte CRC is calculated by the

CR95HF. This configuration is recommended to avoid calculation errors.

The CRC16 input parameter is appended to the ISO15693 command when the user has

chosen to manage the CRC.

4.1.2

Request flag management

The request flag byte is managed by the user application. Each bit or flag specifies the

actions to be performed by the contactless tag and whether the corresponding fields are

present or not. Bit 3 (Inventory_flag) of the request flag defines the contents of the 4 MSBs

(bits 5 to 8). When bit 3 is reset (0), bits 5 to 8 define the contactless tag selection criteria.

When bit 3 is set (1), bits 5 to 8 define the contactless tag Inventory parameters.

For more information, please refer to ISO15693 specification and to the M24LRXX-R

datasheets.

4.1.3

Request flags and CR95HF_ProtocolSelect functions

The CR95HF_ProtocolSelect function (defined into CR95HF layer) selects the RF protocol

and defines for CR95HF device, datarate and contactless tag response format (single or

double subcarrier). Once the protocol and the RF parameters are configured, the CR95HF

is able to decode only contactless tag responses with same format and datarate.

The datarate and contactless tag response format are also defined in the request flag byte

of each command. The user application must ensure that the datarate and subcarrier flags

match the CR95HF_ProtocolSelect function parameters. This check is performed by the

ISO15693 layer functions. If the parameters do not match, the functions are not executed

and the corresponding commands are not sent to the CR95HF.

AN3375 Datasheet(PDF) 55 Page - STMicroelectronics

AN3375 Datasheet(HTML) 55 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73

Datasheet Download

Link URL