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OrF's avatar
OrF
Icon for Occasional Contributor rankOccasional Contributor
2 years ago

CLK-30028 - Invalid Generated Clock

Hi I'm trying to define generated clock out of the pll. and I get the following violation notification "CLK-30028: Invalid Generated Clock" https://www.intel.la/content/www/xl/es/programmable/quar...
Timing
sstrell's avatar
sstrell
Icon for Super Contributor rankSuper Contributor
2 years ago

derive_pll_clocks is supported with the newer devices, you just don't need to explicitly put it in your .sdc file anymore. The generated clock constraints are automatically created.

roeekalinsky's avatar
roeekalinsky
Icon for Contributor rankContributor
2 years ago

@sstrell, that doesn't appear to be the case. Have you tried it? I just tried it again to confirm. Quartus is definitely not automatically creating generated clock constraints for PLL clocks from a hand-instantiated IOPLL atom in Stratix 10 or Agilex. Without user-added create_generated_clock constraints, the PLL clocks remain unconstrained.

This can be confirmed in multiple places:

  • During the flow, Quartus rightly issues "Warning (332060): .... <name> was determined to be a clock but was found without an associated clock assignment" for each used PLL clock.
  • During the flow, the PLL clocks don't show up in the "Info (332111)" tables that list the constrained clocks found in the design and their periods.
  • In the STA report, in the "Clocks" table, the PLL clocks don't show up.
  • In the STA report, in the "Unconstrained Paths Summary" table, you can see them counted in the "Unconstrained Clocks" count.
  • In the STA report, in the "Clock Status Summary" table, they explicitly show up with Status "Unconstrained" .
  • In the STA report, paths in these clock domains aren't analyzed.
  • Etc.
  • sstrell's avatar
    sstrell
    Icon for Super Contributor rankSuper Contributor
    2 years ago

    I've never not used the IP Parameter Editor for a PLL, so I don't doubt you.

    • roeekalinsky's avatar
      roeekalinsky
      Icon for Contributor rankContributor
      2 years ago

      If you're curious: With the IP Parameter Editor, have a look at the SDC file and related TCL scripts that it generates. That's where your create_generated_clocks constraints are coming from.