Read and Write access right byte (0x80) is ST proprietary?

[awong1900]

Posted on May 22, 2014 at 14:11

Hi ST guys,

On NDEF spec, the Read and Write access byte is 0x00 and 0xFF.

The 0x80 is ST proprietary ? any other company can use it ?

Thanks.

--

Ten 

#ndef

[Anais GALLIGANI]

Posted on May 22, 2014 at 18:40

Dear Ten,

In NFC Forum T4 Tag Operation specification, 0x80 value is specified as follows, for Read and Write access conditions:

• 80h to FEh indicate a limited read access granted; access is granted based on proprietary methods.
• 80h to FEh indicate a limited write access granted; access is granted based on proprietary methods.

This means that any chip manufacturer can use 80h to FEh values, if he wants to implement its own method for limiting Read/Write access.

There’s no additional specification, that will reserve specific values to specific manufacturer.

This means that any manufacturer can use 0x80 for its own method.

In other words, STMicroelectronics chose this value, but any other chip manufacturer may also use it.

If you face such value, you need to identify the chip manufacturer, to apply suitable proprietary method.

To discriminate STMicroelectronics chips, you can use the Manufacturer ID (0x02) of the tag UID (as returned at the end of anti-collision process).

Hope this clarifies this point for you.

Best regards,

[awong1900]

Posted on May 24, 2014 at 05:42

Thank you for your reply. Very useful.