One required mode/corner combination is missing. Can floorplanning start?

Short Answer

" If yes, that missing coverage is a hard stop, full stop, regardless of how much other work seems ready to start. This is fundamentally a readiness check on the coverage matrix (modes x corners x scenarios), not a floorplan-specific problem — floorplanning just happens to be the stage where the gap becomes consequential.

Technical Explanation

• A missing scenario can hide real risk: a corner that would reveal a different critical path, or a mode that changes which logic is even active, can silently invalidate assumptions the floorplan is being built on.
• The output of this check needs to be concrete and reproducible — name the exact missing mode/corner combination and the specific objects/paths affected, so whoever restores coverage knows precisely what to add back.
• Starting floorplanning "provisionally" while coverage is incomplete is a real option in some projects, but only if it's an explicit, documented risk decision with an owner — not a silent default because nobody flagged the gap.

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.

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.
• Stop before floorplanning when required logic or timing coverage is missing or unexplained.

What The Interviewer Is Testing

Be ready to explain why this matters before floorplanning.

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. ”