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Original question:

LAUNCHXL-F28379D: TIDM-1011

LAUNCHXL-F28379D: TIDM-1011

NICK LIN
Intellectual 270 points
Part Number: LAUNCHXL-F28379D

Hi experts, 

    I cannot get the correct abs-data from tamagawa-N8401. I captured the waveform below when I sent CF = DATA0. 

   my question is:

   1. The white square I marked, right or wrong?

   2. What is the read circles? Should they be there? Will they effect SPI to receive the correct data?

   3.  I print  tformatData.controlField and tformatData.statusField in Binary format after the code PM_tformat_receiveData(DATA0) . 

      controlFiled = 0010 0000b.  statusFiled = 0000 0010. But they should be 0100 0000 and 0000 0100. ( I have no battery, so SF has 1 bit error ea1=1.)

      It seems that an incorrect bit, insert to the data stream at the beginning.

Thanks for your reply.

Nick

  • 0
    TI__Guru* 89465 points

    Nick -

    For (1) and (3) - I agree the CF and SF look like they are off by a bit.   

    The red circled lines look like glitches - perhaps from noise - and yes, they could be the reason for the shift offset in the data stream.  

    Since the encoder is responding then the bit width (400ns duration) should be correct already. 

    I would suggest looking for noise issues. Making sure there is a common ground including the scope probes. 

    -Lori

  • 0 in reply to Lori Heustess
    Intellectual 270 points

    Hi Lori,

         The scope GND connect to the GND pin of launchpad. And these glitches are always there.  

         Would you please capture  a normal waveform of CMD_DATA0？

       Thanks for your help.

        Nick

  • 0 in reply to NICK LIN
    TI__Guru* 89465 points

    Hi Nick,

    I currently don't have working t-format hardware with me. (working from home due to the current state of things) 

    I will see about going into our lab next week to grab some waveforms.  

    Regards

    Lori

  • 0 in reply to Lori Heustess
    TI__Guru* 89465 points

    Nick,

    I regret to report I'm having some hardware difficulties and have not yet been able to get the waveform you requested.  I wanted to check if you have any update on your side?  

    Regards

    Lori