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TRF7970A IRQ under card emulation mode

Seishin
Genius 4135 points
Other Parts Discussed in Thread: TRF7970A

Hi,

TRF7970A doesn't work properly in our customers' production process.(Frequency of occurrence = 1 per 500)


When the TRF7970A in power down mode (EN = 0, EN2 = 0) under card emulation mode,without touching the IC

card to the reader, IRQ is asserted.There is no RF field.


IRQ is not output when I separate connection between MISO/EN/EN2 pins and MCU physically.It operates correctly

when the TRF7970A replaced with another TRF7970A device.


Is there something that is considered to be the cause of that?

How can the customer work around this issue?


Best regards,
Seishin

  • 0
    TI__Guru*** 135355 points

    Hello Seishin,

    I am not sure what the root cause of this issue would be based on the description alone. Can you please provide as much information as possible for the following questions so we can try and determine the root cause for this issue?

    • Can you provide a schematic of at least the TRF7970A connections so we can verify the hardware connections?
      • Also knowing which MCU is being used would be helpful as well.
    • Is this project using any of our software examples? If so, which one?
    • What are the register configuration settings for the part prior to powering it down?
    • Can you describe the firmware flow which is occurring before the error appears?
    • Would it be possible to get Logic State Analyzer shots when the issue occurs with all SPI lines (MOSI, MISO, SS, CLK), plus the Enables (EN and EN2), plus IRQ? This would be very helpful if it is possible to get.

  • 0 in reply to Ralph Jacobi
    Genius 4135 points

    Hello Ralph,

    Thank you for your quick response.

    I'm sorry for not getting back to you sooner.

    I want to send detailed information from the customer, but that file is our customer NDA.

    How can I contact you in this case?

    Regards,
    Seishin
    (My real name is Shinichi Morita of KTL Corporation,Japan)

  • 0 in reply to Seishin
    TI__Guru*** 135355 points
    Hi Seishin,

    I'll send you an E2E friend request so we can take this conversation off of the public forums.