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AM4376: Specification of McSPI Data

shigehiro tsuda
Mastermind 9490 points
Part Number: AM4376


Hi,

There is a problem that the voltage of Data of McSPI decreases.
For details, please refer to the following.
Is there a specification that Data becomes Hiz when there is no change in CLK and it is not transmitting or receiving?

Best Regards,
Shigehiro Tsuda

  • 0
    TI__Genius 15940 points

    Hi, 

    What board is being used in this test? If this is a custom board, what are the SPI signals connected to?

    Is AM437x operating as Master or Slave? Is the data signal on this scope configured for MISO or MOSI?

    Regards,

    Melissa

  • 0 in reply to melissaw
    Mastermind 9490 points

    Hi Melissa,

    Thank you for quick reply.

    A custom board is used.
    AM437x is operating as Master and the data signal use MOSI.

    It is measured with the following.

    Best Reards,
    Shigehiro Tsuda

  • 0 in reply to shigehiro tsuda
    TI__Genius 15940 points
    Hi Shigehiro,

    From what I can tell, the Data becomes Hiz when the CLK is not toggling. To confirm this, you can connect a 10k through hole resistor to the Data signal & GND and rerun the test. The test could then be repeated with the 10k resistor connected to VDD, instead of GND.

    Is this behavior causing any issues? Or is your question more out of curiosity after observing the behavior?

    Regards,
    Melissa
  • 0 in reply to melissaw
    Mastermind 9490 points
    Hi Melissa,

    Thank you for quick reply.
    I understand that the Data becomes Hiz when the CLK is not toggling.
    We will check with your answer method.
    Our customer seemed to be not worried about data problems in particular, but just wondering why they got such results when they measured it.

    Best Regards,
    Shigehiro Tsuda