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Seadog's avatar
Seadog
Icon for Occasional Contributor rankOccasional Contributor
3 years ago

Ignored create_clock warning in C V design

I have a Cyclone V design with a DDR 3 controller. The reference clock for the DDR3 EMIF core is routed directly from a clock pin. The .sdc file for the project has a create_clock command for that reference clock; the .sdc file for the EMIF core also has a create_clock command for the same clock (referenced as pll_ref_clk per the port name on the EMIF top level).

Quartus is giving me the following warning:

Warning (332049): Ignored create_clock at ddr3_v20_p0.sdc(264): Incorrect assignment for clock. Source node: clkinbot_p already has a clock(s) assigned to it. Use the -add option to assign multiple clocks to this node. Clock was not created or updated.

Should I:

  • comment out the create_clock command in the project .sdc file
  • use the -add option (not sure why I would; the clock is routed to only one place)
  • ignore the warning

Thanks.

5 Replies

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

    You can either ignore the warning or remove your create_clock command since, as you say, the clock is not being used anywhere else in your design. Does the tool still show the design as fully constrained?

  • Seadog's avatar
    Seadog
    Icon for Occasional Contributor rankOccasional Contributor
    3 years ago

    The design is fully constrained, other than the parts I purposely did not constrain (it's on an eval board with a bunch of I/Os not really being used). And certainly the EMIF core is constrained.

  • AdzimZM_Altera's avatar
    AdzimZM_Altera
    Icon for Regular Contributor rankRegular Contributor
    3 years ago

    Hello,


    Sorry for the delay in this topic.

    You can either comment out the create_clock command in the project .sdc file or ignore the warning as has been mentioned by sstrell.

    Do you have any further question?


    Thanks.

    Adzim


  • AdzimZM_Altera's avatar
    AdzimZM_Altera
    Icon for Regular Contributor rankRegular Contributor
    3 years ago

    I’m glad that your question has been addressed, I now transition this thread to community support. If you have a new question, feel free to open a new thread to get the support from Intel experts. Otherwise, the community users will continue to help you on this thread. Thank you.