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Storing proprietary data in M24SR

AN4433

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Storing proprietary data in M24SR

3.1

Beyond NDEF message

As seen in Section 2, memory area beyond NDEF message can be used to store data, apart

from standard NDEF data.

A Proprietary application using ST Proprietary ExtendedReadMemory command, can

access this area (read and write) for its own purpose.

Warning:

–

A non-proprietary application will not be aware about the use of this area.

–

If it has write access rights to the NDEF file, an application may corrupt the

proprietary data when writing an NDEF message.

3.2

Proprietary NDEF record

When defining NDEF format, NFC Forum thought about providing a way to store proprietary

data in a specific record of an NDEF message.

This is possible by using a record with:

•

TNF = “NFC Forum external type” (0x04)

•

Type refers to a proprietary domain, and associated application

For more details about the way to construct such a record, see docs [2]. and [4].

A commonly used example of a proprietary NDEF record, is the Android Application Record

(AAR): this record is intended to Android system, and stores the name of the preferred

application to execute, when this tag is read by an Android device.

An AAR has:

•

TNF = 0x04 (“NFC Forum external type”)

•

Type = “android.com:pkg”

•

Payload = package name of the application

For more information on AAR, refer to Android documentation.

See Appendix B for an example of NDEF proprietary record, in an NFC Forum Type 4 Tag.

3.3

Proprietary file

With the help of ST proprietary UpdateFileType command, a M24SR memory administrator

can turn the M24SR file into a Proprietary one (see Section 2.3)

Advantages:

–

Tag can be fully dedicated to proprietary data with immediate access to the data,

from the beginning of the file

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