After the clock network report shows that all clock networks are constrained, you
can begin verifying the accuracy of the generated clocks. Because the Vivado tools automatically propagate clock constraints
through clock-modifying blocks, it is important to review the constraints that were
report_clocks to show which clocks were
created with a
create_clock constraint and which clocks
report_clocks results show that all clocks are propagated. The difference between the primary clocks (created with
create_clock) and the generated clocks is displayed in the attributes field:
- Clocks that are propagated (P) only are primary clocks.
- Clocks that are derived from other clocks are shown as both propagated (P) and generated (G).
- Clocks that are generated by a clock-modifying block are shown as auto-derived (A).
- Other attributes indicate that an auto-derived clock was renamed (R), a generated clock has an inverted waveform (I) relative to the incoming master clock, or a primary clock is virtual (V).
You can also create generated clocks using the
create_generated_clock constraint. For more information, see the
Vivado Design Suite User Guide: Using
no_clockcategory). The report is available from within the Report Timing Summary or by using the