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fpgaSoft's avatar
fpgaSoft
Icon for New Contributor rankNew Contributor
2 years ago

DMA with NIOSII

Hi, I am using a Cyclone 10 FPGA with NIOS for a project and I am running into a few problems with the DMA IP block.

The DMA block in question is the Modular Scatter-gather DMA IP, in memory-mapped to stream mode.

I have the stream output going into signal tap to look at the data. Some of the time the data looks ok. i.e the data is available as soon as the source_valid goes high, the VALID is high for the 4x32 bit words I am sending.

However every now and then VALID is only high for one of the blocks of data, some are before it. I could be doing something wrong but according to the IP, VALID should be rasied when there is valid data & not after.

Is there something I am doing wrong? Or is this actually expected behaviour? If so how do I account for that, given I only the limited lines i have out of the block?

Best regards

Nios Cpu

6 Replies

  • KellyJialin_Goh's avatar
    KellyJialin_Goh
    Icon for Frequent Contributor rankFrequent Contributor
    2 years ago

    Hi,

    Any updates from your end whether the information provided was useful?


    Thank you.


    Regards,

    Kelly


  • KellyJialin_Goh's avatar
    KellyJialin_Goh
    Icon for Frequent Contributor rankFrequent Contributor
    2 years ago

    Hi,

    Any updates from your end whether the information provided was useful?


    Thank you.


    Regards,

    Kelly


    • fpgaSoft's avatar
      fpgaSoft
      Icon for New Contributor rankNew Contributor
      2 years ago

      Hi Kelly,

      sadly the information didnt help as to why the data is being sent out before the VALID line is asserted. I have ended up going back to using the memory-mapped to memory-mapped version of the DMA. However the streaming version does look more appropriate for my design so it would be good to know why it doesnt appear to be working properly

      Best regards

  • KellyJialin_Goh's avatar
    KellyJialin_Goh
    Icon for Frequent Contributor rankFrequent Contributor
    2 years ago

    Hi,

    Is there any further support needed from my end? Hope to hear on your feedback.


    Thanks.


    Regards,

    Kelly


  • EBERLAZARE_I_Intel's avatar
    EBERLAZARE_I_Intel
    Icon for Regular Contributor rankRegular Contributor
    2 years ago

    Hi,


    I now transition this thread to community support. If you have a new question, Please login to ‘https://supporttickets.intel.com’, view details of the desire request, and post a feed/response within the next 15 days to allow me to continue to support you. After 15 days, this thread will be transitioned to community support. The community users will be able to help you on your follow-up questions.



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