ST25DV64K NDEF Message

[emil28]

Hello,

I made my own board with a ST25DV64K and a microcontroleur STM32L031K6. I would like to put in the NFC tag a NDEF message (URL/text...). For the moment, I don't use the microcontroleur. I use the Android App ST25, built by ST, to put the NDEF message into the tag. The communication between my smartphone and the tag is OK, I can read the UID, the memory, and verify that the NDEF message is written in the eeprom memory. Then, when I put my tag on my smartphone, it says that the tag is empty.

I have an eval-board CLOUD-ST25TA and on this tag, everything works. I can put an URL into the memory via the ST25 Android App, and when I put the tag on the smartphone, an internet Browser opens with the URL.

I think I am missing a configuration into the ST25DC64, but I don't find which one.

[emil28]

*ST25DV64K

I tried with another smartphone, and it works ! It looks like NDEF message doesn't work on my honor 9 and ST25DV chip... Any idea how to fix this problem ?

[Berenice BENVEGUDA]

​Hello,

First of all thanks for your interest in ST25DV64K product !

Could you, please, indicate us what is the NDEF message length you write into the tag and what is the Android OS version on both smartphones you used ( on honor 9 and the other one). Some earlier version of Android can have troubles with large NDEF messages.

Best Regards,

BB

[emil28]

Hello,

Thank you for your answer !

The NDEF message written into the ST25DV64K memory is just a text message: "Test".

The smartphone which can read the NDEF message is a Samsung Galaxy J3 (SM-J330FN) with Android 9. The other smartphone which can't read the NDEF message is a Honor 9 with Android 7.

I am surprised, because the Honor 9 can read NDEF messages written into the Evaluation Board "CLOUD-ST25TA".

Regards,

Emilien

[JL. Lebon · Accepted solution]

​Hello Emil28,

ST26DV64K is a T5T tag (type 5 tag in NFC Forum standard). Prior to Android 9, support for T5T tags in android was faulty, and did not support correctly T5T tags with large memory (memory>8Kbits). This has been fixed in Android 9.

With an android < 9, you will be able to write the NDEF message using the ST application, has this application correctly support large memory T5T tags. But when trying to "natively" read the NDEF message with android (out of a dedicated application), it will not work.

(the exact reason behind this is that when trying to read an NDEF message, android will send a "Get System Info" command to the tag (when it should not according to NFC specifications) to retrieve tag's memory size. Unfortunately, this command doesn't return memory size for large memory tags (The Extended Get system Info should be used in place), so android throw an error and stops reading the NDEF message. Starting from android 9, this bug is fixed) 

CLOUD-ST25TA embed a T4T tag (type 4 tag). T4T tags are quiet different from T5T tags in term of technology: T4T is based on ISO14333, when T5T is based on ISO15693. Both have different implementation in android stacks, which explains the different behavior.

Hope this is clear.

To go more in deep in NDEF messages for T5T tags, you can read the following application note: (AN4911) https://www.st.com/content/ccc/resource/technical/document/application_note/group0/21/49/e4/1a/37/dc/4f/e4/DM00328901/files/DM00328901.pdf/jcr:content/translations/en.DM00328901.pdf

Best regards.