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efe373's avatar
efe373
Icon for New Contributor rankNew Contributor
3 years ago
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DCFIFO Mixed Width Recovery Removal Timing

Hi,

It is described here that for older versions of Quartus, DCFIFO with mixed width which read width is smaller than the write width contains an connection error in design which causes Recovery faults. However, there is not any solution mentioned. I am also facing this issue in a design which I have a DCFIFO fits the properties above and has a aclr signal externally synchronized to the write clock. What should be done if someone is obligated to use older versions of Quartus and facing this problem?

Thanks,

Efe

  • RichardT_altera's avatar
    RichardT_altera
    3 years ago

    Which device and Quartus version do you plan to use? I always recommend users to use the latest Quartus version as usually a lot of bug has been fix with latest version.


    The post do mentioned that:

    This is a bug in the DCFIFO generation for mixed widths when the read side is smaller than the write side, for instance the write side it 256 bits wide and the read side is 16 bits wide. In cases where you are seeing the above, make sure the asychronous reset into the DCFIFO is synchronized to the write side, then change the external reset to be synchronized to the read side clock domain. You will see two recovery violations to the write side aclr synchronization registers and it is OK to false path them.


    Isn't the sentence in bold, the workaround provided?

    You may checkout this user guide as well:

    https://www.intel.com/content/www/us/en/docs/programmable/683522/18-0/recovery-and-removal-timing-violation.html


    Best Regards,

    Richard Tan


3 Replies

  • RichardT_altera's avatar
    RichardT_altera
    Icon for Super Contributor rankSuper Contributor
    3 years ago

    Which device and Quartus version do you plan to use? I always recommend users to use the latest Quartus version as usually a lot of bug has been fix with latest version.


    The post do mentioned that:

    This is a bug in the DCFIFO generation for mixed widths when the read side is smaller than the write side, for instance the write side it 256 bits wide and the read side is 16 bits wide. In cases where you are seeing the above, make sure the asychronous reset into the DCFIFO is synchronized to the write side, then change the external reset to be synchronized to the read side clock domain. You will see two recovery violations to the write side aclr synchronization registers and it is OK to false path them.


    Isn't the sentence in bold, the workaround provided?

    You may checkout this user guide as well:

    https://www.intel.com/content/www/us/en/docs/programmable/683522/18-0/recovery-and-removal-timing-violation.html


    Best Regards,

    Richard Tan


  • RichardT_altera's avatar
    RichardT_altera
    Icon for Super Contributor rankSuper Contributor
    3 years ago

    Thank you for acknowledge the solution provided.

    I’m glad that your question has been addressed, 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.

    Thank you.

    Best Regards,

    Richard Tan

    p/s: If any answer from the community or Intel Support are helpful, please feel free to give best answer or rate 4/5 survey.


  • RichardT_altera's avatar
    RichardT_altera
    Icon for Super Contributor rankSuper Contributor
    3 years ago

    Thank you for acknowledge the solution provided.

    I’m glad that your question has been addressed, 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.

    Thank you.

    Best Regards,

    Richard Tan

    p/s: If any answer from the community or Intel Support are helpful, please feel free to give best answer or rate 4/5 survey.