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TRF7960A: Writing continuous data

N.A
Intellectual 800 points
Part Number: TRF7960A
Other Parts Discussed in Thread: TRF7970A

Hi!  TI Support Team

We are trying to access Mifare DESFire EV3 with TRF7960A. The I/F between TRF and MCU is pararel.

Normal operations (reading the ID, AES authentication, & etc.) are fine. In writing more than 12 bytes of data, we have a problem.
Please advise us how to write 42 bytes data and the correct values of IRQ status.


In our procedure, the error is as follows.

TX 42 bytes data
First
  Send 12 bytes (because the FIFO size of TRF7960A is 12 bytes)
  Check the IRQ status register (0Ch) and receive 0xA0

Second
  Send 0x3F & 9 bytes
  Check the IRQ status register (0Ch) and receive 0xA0

3rd
  Send 0x3F & 9 bytes
  Check the IRQ status register (0Ch) and receive 0xA0

4th
  Send 0x3F & 9 bytes
  Check the IRQ status register (0Ch) and receive 0xA0

5th
  Send 0x3F & 3 bytes
  Check the IRQ status register (0Ch) and receive 0x83 *

* We think the correct response should be 0x80.

Please let me know what we investigate to get the correct response.

Best regards,

N.O

  • +1
    TI__Mastermind 18265 points

    Hi Naoki,

    you are right, the expected IRQ status would be 0x80 when the TX is ready. I do not know what data is transferred and if the tag has understood the transmitted data correct. The last IRQ status reported is a collision error and a timeout. This looks like the tag started to respond to early and the SOF from the tag was not seen by the TRF7970A. Please check if the transmitted command is correct and if the new TX data was provided fast enough so that the FIFO was never empty during the transmit.

    Best Regards,

    Helfried