AN3375 datasheet(22/73 Pages) STMICROELECTRONICS

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ISO15693 library (intermediate layer)

AN3375

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Doc ID 018637 Rev 1

3.1.3

Request flag management

The request flags 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 contain 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 or to the M24LRXX-R

datasheets.

Request flags and CR95HF_ProtocolSelect functions

The CR95HF_ProtocolSelect function (see Section 2.3.3) selects the RF protocol and

defines the CR95HF datarate and contactless tag response format (single or double

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

decode only contactless tag responses of same format and datarate.

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

of each ISO15693 command. The user application must ensure that the datarate and

subcarrier flags match the CR95HF_ProtocolSelect function parameters. This check is

performed by the functions of the ISO15693 layer. If the parameters do not match, the

functions are not executed and the corresponding commands are not sent to the CR95HF.

3.1.4

Command code and data management

The command code is given by the function while data are managed by the user application.

3.2

ISO15693 functions

The CR95HF library includes all the commands defined in ISO/IEC FCD 15693-3

specifications. For more information, refer to the ISO15693 specifications.

The table below lists all the functions of the ISO15693 layer.

Table 21.

ISO15693 functions

Function name

Brief description

CRC management functions

ISO15693_CRC16

Compute CRC according to ISO15693

specification

ISO15693_IsCorrectCRC16Residue

Checks CRC residue according to ISO15693

specification

ISO15693 command functions

ISO15693_CreateRequestFlag

Create a request flags

ISO15693_Inventory

Sends an inventory command

ISO15693_InventoryOneSlot

Sends an inventory command 1 slot command

ISO15693_Inventory16Slots

Send an inventory command 16 slots command

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