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TRF7963A: UID mismatch

na na78
Guru 16770 points
Part Number: TRF7963A

Hi

Our customer uses TRF7963A, a tag is NTAG213 which complies to ISO14443A

In operation, our customer faced mismatch of UID.
NTAG213 has 7Byte UID, for example, 04 0C AC 12 ED 4C 81.

I describe example of UID mismatch.

UID : 04 0C AC 12 ED 4C 81
Reading UID : 88 04 0C 12 FF FF FF

The value of "88" in reading UID seeems to have meaning because
it is CT (Cascade TAG) which is defined in NTAG213 datasheet.
Regarding to appearing "FF FF FF" and "AC" is disappeared, I have no idea.

Questions.
1.
When TRF7963A read tag, is it normal operation that CT is included in UID?

2.
Is there possibility that the anticollision process would affect to read tag?
In customer system, a single tag should be read. So we don't need to acitvate anticollision.

Could you please give us your feedback?

BestRegards

  • 0
    TI__Guru*** 135355 points

    Hello na na78,

    Even without anticollision, ISO14443A won't send the whole UID in a single transaction unless it is a 4 byte UID. For anything larger than 4 bytes, you need to send multiple commands to get the UID. That is just how ISO14443A operates.

    Since the tag is a 7 byte UID tag, it will always send the "88" to request a Cascade 2 Select Command to receive the rest of the UID.

    The whole process to handle this is done in our SLOA297 example code under the ISO14443A_selectTag API in iso14443a.c

  • 0 in reply to Ralph Jacobi
    Guru 16770 points
    Hi Ralph

    Thank you for your reply.

    I will ask to check the sample again.

    BestRegards