PrimeTime 2: Debugging Constraints


This workshop addresses the most time-consuming part of static timing analysis: debugging constraints. The workshop provides a method to identify potential timing problems, identify the cause, and determine the effects of these problems. Armed with this information, students will now be able to confirm that constraints are correct or, if incorrect, will have sufficient information to correct the problem.

Incorrect STA constraints must be identified because they obscure real timing violations and can cause two problems: either the real violations are missed and not reported or violations are reported that are not real, making it difficult to find the real violations hidden among them.


At the end of this workshop the student should be able to:

  • Pinpoint the cause and determine the effects of check_timing and report_analysis_coverage warnings
  • Execute seven PrimeTime commands and two custom procedures to trace from the warning to the cause and explore objects in that path
  • Systematically debug scripts to eliminate obvious problems using PrimeTime
  • Independently and fully utilize check_timing and report_analysis_coverage to flag remaining constraint problems
  • Identify key pieces of a timing report for debugging final constraint problems

Audience Profile

Design or Verification engineers who perform STA using PrimeTime


To benefit the most from the material presented in this workshop, students should have:

  • Have taken PrimeTime 1


Possess equivalent knowledge with PrimeTime including:

  • Script writing using Tcl
  • Reading and linking a design
  • Writing block constraints
  • Generating and interpreting timing reports using report_timing and report_constraint commands

Course Outline

Day 1

  • Finding Problems
  • Tools of the Trade
  • Applying Tools of the Trade to Common Scenarios
  • A Recommended Debugging Flow
  • Debugging Clocks
  • Conclusion

Synopsys Tools Used

  • PrimeTime 2011.06