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TRF7970A： TRF7970A

user5769257
Intellectual 420 points
Part Number: TRF7970A

Dear team,

I transplanted the source code of TRF7970ABP_RFID_Reader_Demo to my TRF7970A NFC/RFID reader and found that there would be such a problem when there are multiple readers running close to each other: the value of each register of TRF7970A becomes 0xFF.Why?

Best regards,

Li

  • 0
    TI__Guru* 91206 points

    Dear Li - 

    from your description, there is a fatal bug (or possibly some hardware issue) in whatever you have done - I would recommend that you inspect the communications to understand if your firmware is doing what you think it is. If this only happens when there are other readers around, then you most likely did not allocate enough RAM in your MCU and the code is blowing the stack or possibly you did not implement the anti-collision or are not using external field detect feature/technique. 

    If you would like to provide more specifics on what exactly happens (on SPI, RF, power lines, etc) when failure occurs - we will be glad to look at it.   

  • 0
    TI__Guru*** 135355 points

    Hello Li,

    I agree with Josh, as the code you referenced has a check for external RF fields in the TRF79xxA_checkExternalRfField function. If an external field is detected, it should bail out from the reading of a tag.