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M24SR64 with NDEF File Length in 36 bytes

Question asked by lee.wen-kai on Jan 19, 2015
Latest reply on Mar 12, 2015 by alnstrom.nicklas
Dear Sirs:

We are using M24SR64.
Now we met a problem with NDEF File Length in 36 bytes.
Problem:
1. If the NDEF File Length is 36 bytes, it can not be a successful data in Android OS or NXP TagInfo app or NFC TagInfo app.
Only the app of ST "M24SR Demo" can show the payload we wrote.
2. If the NDEF File Length is 35 or 37 bytes, it is a successful Tag data.

At first, we used I2C to write the data and we met this strange behavior.
Then we used the M24SR Demo app to test it, it also fail in 36 bytes (35 or 37 are OK).

Here is a simple way to reproduce the stange behavior:
- Tested in Samsung S3 (Android 4.3, may PN544) and Nexus7 generation1 (Android 4.4.3, may 65N04)
- Use the app M24SR Demo (download from Google Play)
  -> Choose the NDEF editor and TEXT mode
  -> Key in the data (payload)
        1234567890
        1234567890
        12345678        (28 Bytes)
       or
        1234567890
        1234567890
        1234567890    (30 Bytes)
       => Above 2 are successful tag data (Record #1: TEXT record)
  -> Key in the data (payload)
        1234567890
        1234567890
        123456789       (29 Bytes)
       => The Android will not response the data is a Tag data
       => NXP TagInfo or NFC TagInfo app show "No NFC data set available"
       => Only M24SR Demo will show the payload we wrote.
  -> What I said 36 bytes is
      In NDEF file content
      00 24 (Total 36 bytes)
      D1 01 20 54 02 7A 68 (7 bytes)
      31 32 33 34 35 36 37 38 39 30
      31 32 33 34 35 36 37 38 39 30
      31 32 33 34 35 36 37 38 39       
     (29 bytes as 12345678901234567890123456789)

We do not know the reason in this length.
At first we thought we had a bug in our I2C code.
Then we double checked by app M24SR Demo, it has the same stange behavior.

Does anybody meet the similar problem before?
Or please inform or correct where is the bug we have.

Thanks for your help!
Thanks!


Wen-Kai

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