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TPS65381A-Q1: Read the status data twice, different data output

Shinichi Inoue
Guru 22301 points

Part Number: TPS65381A-Q1
Other Parts Discussed in Thread: TMS570LS3137,

Dear Specialists,

My customer is evaluating TPS65381A-Q1 and TMS570LS3137, and has a question.

I would be grateful if you could advise.

---

I confirmed TPS65381A-Q1 and TMS570LS3137.

When I read the same adress twice, different data output.

Could you please see attached file and  let me know why this occur?

 ---

I appreciate your great help in advance.

Best regards,

Shinichi

question about TPS65381-Q1 20190222.xlsx

  • 0
    TI__Genius 10885 points
    Hi Shinichi,

    I am looping in the product expert to comment on this SPI communication behavior.

    Best Regards,
    Rick S.
  • 0 in reply to Richard Solarski
    Guru 22301 points
    Hi Rick,

    Thank you for your reply.

    I'm looking forward to hearing from you.

    Best regards,
    Shinichi
  • 0 in reply to Shinichi Inoue
    TI__Mastermind 20600 points
    Hi Shinichi-san,

    The responses are different because at least in the first SPI frame in each example the TPS65381A-Q1 is interpreting the SPI frame in error. This is seen by the first byte on SOMI on the 2nd SPI frame. In the Device Status Flag Byte Response (first byte of data sent during SPI) the output is 1010 (fixed pattern) for STAT[7] to STAT[4] and then STAT[3:0] provide status info. In both examples STAT[0] is set on the second SPI frame indicating a SPI error with the previous frame.

    It is difficult to tell what is going wrong without being able to zoom in on the scope plot and measure actual times vs the set up and hold timing for the SPI of the device.

    I would recommend the customer zoom in and double check actual timing, MCU set up for the SPI and the requirements of the TPS65381A-Q1 to make sure there isn't something in the SPI setup a little bit off.

    Also, they can check the next SPI frame to see if STAT[0] is also set indicating a problem with the second SPI frame in the plots provided.
  • 0 in reply to Scott Monroe
    Guru 22301 points
    Hi Scott,

    Thank you for your reply.

    I understand there is a problem with SPI timing.

    I'll share this information with the customer.

    If he has an additional question, I consult you again.

    I appreciate your great help.

    Best regards,
    Shinichi
  • 0 in reply to Shinichi Inoue
    TI__Mastermind 20600 points
    Hello Shinichi-san,

    Since I haven't seen any other update for a week on this topic I'm moving it to closed. If there is another question please re-open it or add a new thread.
  • 0 in reply to Scott Monroe
    Guru 22301 points

    Hi Scott,

    Thank you for your reply.

    I sent your suggestion to the customer and he is confirming.

    I'm waiting for his response.

    So I'll confirm current situation, could you please wait for a couple of days.

    I appreciate your great help.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    Guru 22301 points

    Hi Scott,

    I confirmed the customer.

    He hasn't confirmed yet because he needed to respond to other rash jobs.

    I'll send the information when I could get it, but it may take some time.

    If you'd like to close this thread, I consult a related question.

    I appreciate your great help.

    Best regards,

    Shinichi