One required mode/corner combination is missing. Can floorplanning start?
From PDVerse PnR Interview Handbook · pdVerse Mentor Guide
Short Answer
If the missing scenario can change logical/timing readiness or design assumptions, it is a hard stop until the coverage matrix is restored.
Technical Explanation
Treat this as a readiness check. It should produce named objects and a result that another engineer can repeat from the same handoff.
What To Check
• Warning sign: Available scenarios are clean, but the required low-voltage or test combination is absent. • Inspect: Keep at least two possible causes open, then use one named object and the active mode or scenario to separate them. • Correct: Create/activate the approved scenario and apply its correct constraint classes; rerun the complete gate.
Command Checks & Actions
• report_scenarios: shows the MCMM scenario matrix and analysis status
Run the commands in order. Each line answers a separate part of the check.Healthy, Suspicious & Hard-stop Results
• Expected: If the missing scenario can change logical/timing readiness or design assumptions, it is a hard stop until the coverage matrix is restored. • Investigate: Available scenarios are clean, but the required low-voltage or test combination is absent. • Stop before floorplanning when required logic or timing coverage is missing or unexplained. Create/activate the approved scenario and apply its correct constraint classes; rerun the complete gate.
Common Mistake
Do not assume the check passed just because ICC2 continued: Available scenarios are clean, but the required low-voltage or test combination is absent. Fix or narrowly justify the named objects, then rerun the same command.
What The Interviewer Is Testing
Be ready to explain why this matters before floorplanning: Available scenarios are clean, but the required low-voltage or test combination is absent.
Follow-up Question & Model Response
Model response: “I would save the report, inspect one affected object in the correct block and scenario, and make or request this correction: Create/activate the approved scenario and apply its correct constraint classes; rerun the complete gate. Then I would reopen the clean checkpoint and rerun the same evidence.”
Practical Example
Symptom: Available scenarios are clean, but the required low-voltage or test combination is absent. Corrective path: Create/activate the approved scenario and apply its correct constraint classes; rerun the complete gate.
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