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TRF7960A output Continuous IRQ

Other Parts Discussed in Thread: TRF7960A, TRF7970A

Hi,

Currently our customer is doing an electrical test(noise test) on the TRF7960A custom board
and there is problem that the TRF7960A outputs IRQ signal continously without stopping.

When a noise(150KHz, 10V) is applied to the on the RFID cable, there is a continous IRQ signal (ON/OFF).
Even if the IRQ state is changed to OFF state from the MCU, IRQ signal starts again after 20 to 50us.

Please let us know if there is any know issue or pointers on this problem.

Regards
Prad

  • Hi Prad

    If your interrupt is ACTIVE HIGH add a pull down resistor in your interrupt line or if your interrupt is ACTIVE LOW add a pull up.It may help. Keep your interrupt edge triggered. I was having the same issue with TRF7970A when i was interfacing with the a non TI processor.

  • Hi deep,

    Thank you.
    We shall try with the resistor with the next revision of the board.

    Meanwhile we are trying to understand, what could be reason for the
    continous IRQ signal(it continues even after the noise is removed).
    And also we are doing the continuous read & "dummy read" as per the SPI errata.

    Please let us know if this kind of "continous IRQ" issue is something related
    to SPI errata(SLOA140)?

    Best Regards
    Prad

  • Prad - 

    if you are feeding noise onto the line, the RX'er most likely is trying to deal with that. Another approach might be to have some logic to read the IRQ status register - you should get some error condition since you are inducing it - then turn off the RX'ers using direct command 0x96.