How do you compare functional and test-mode readiness?
From PDVerse PnR Interview Handbook · pdVerse Mentor Guide
Short Answer
Compare clocks, constants, I/O constraints, exceptions, active checks, and expected sequential populations separately; neither mode substitutes for the other.
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: Functional mode is complete while scan/test clocks leave large no_clock groups. • Inspect: Keep at least two possible causes open, then use one named object and the active mode or scenario to separate them. • Correct: Return missing test intent to DFT/STA ownership or document why that mode is outside the current floorplanning gate.
Command Checks & Actions
• report_scenarios: shows the MCMM scenario matrix and analysis status
• report_clocks: shows clock definitions and relationships
• check_timing -include {no_clock unconstrained_endpoints}: finds missing or inconsistent timing setup
Run the commands in order. Each line answers a separate part of the check.Healthy, Suspicious & Hard-stop Results
• Expected: Compare clocks, constants, I/O constraints, exceptions, active checks, and expected sequential populations separately; neither mode substitutes for the other. • Investigate: Functional mode is complete while scan/test clocks leave large no_clock groups. • Stop before floorplanning when required logic or timing coverage is missing or unexplained. Return missing test intent to DFT/STA ownership or document why that mode is outside the current floorplanning gate.
Common Mistake
Do not assume the check passed just because ICC2 continued: Functional mode is complete while scan/test clocks leave large no_clock groups. 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: Functional mode is complete while scan/test clocks leave large no_clock groups.
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: Return missing test intent to DFT/STA ownership or document why that mode is outside the current floorplanning gate. Then I would reopen the clean checkpoint and rerun the same evidence.”
Practical Example
Symptom: Functional mode is complete while scan/test clocks leave large no_clock groups. Corrective path: Return missing test intent to DFT/STA ownership or document why that mode is outside the current floorplanning gate.
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