A macro remains a black box one day before floorplanning. Proceed or stop?
From PDVerse PnR Interview Handbook · pdVerse Mentor Guide
Short Answer
Stop unless the approved abstraction and next-stage interface requirements are complete and the project explicitly accepts that model state.
Technical Explanation
A black box hides internal logic on purpose. Its boundary still needs known pins, models, revision, and ownership; otherwise it is simply a missing part of the handoff.
What To Check
• Warning sign: A local stub makes linking pass but timing/interface evidence 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: Return the handoff to the IP/library owner, obtain matched views and revision, then rerun link, structure, and timing checks.
Command Checks & Actions
• report_unbound: lists objects that did not resolve
• report_ref_libs: shows the reference libraries used for linking
• check_netlist: reports structural connectivity problems
Run the commands in order. Each line answers a separate part of the check.Healthy, Suspicious & Hard-stop Results
• Expected: Stop unless the approved abstraction and next-stage interface requirements are complete and the project explicitly accepts that model state. • Investigate: A local stub makes linking pass but timing/interface evidence is absent. • Stop before floorplanning when required logic or timing coverage is missing or unexplained. Return the handoff to the IP/library owner, obtain matched views and revision, then rerun link, structure, and timing checks.
Common Mistake
Do not assume the check passed just because ICC2 continued: A local stub makes linking pass but timing/interface evidence 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: A local stub makes linking pass but timing/interface evidence 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: Return the handoff to the IP/library owner, obtain matched views and revision, then rerun link, structure, and timing checks. Then I would reopen the clean checkpoint and rerun the same evidence.”
Practical Example
Symptom: A local stub makes linking pass but timing/interface evidence is absent. Corrective path: Return the handoff to the IP/library owner, obtain matched views and revision, then rerun link, structure, and timing checks.
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