What evidence makes an initial floorplan reviewable?
From PDVerse PnR Interview Handbook · pdVerse Mentor Guide
Short Answer
A reviewable floorplan has deliberate boundaries, utilisation, usable rows, justified macro locations, feasible channels, constrained pins, early congestion/timing evidence, PG reservation, voltage-area legality, classified findings, and reproducible write-out.
Technical Explanation
A screenshot shows appearance; reports and saved constraints show what the tool actually understands. Legality and quality are separate. A clean check can coexist with poor congestion, timing distance, or change risk.
Formula Or Decision Rule
Decision rule: proceed only when hard stops are closed and remaining risks have evidence, owners, and review dates.
What To Check
• Warning sign: The floorplan looks tidy but cannot be reproduced or has unexplained warnings. • Inspect: choose one affected region, macro, row, pin, path, or net and trace the physical cause. • Correct: Reopen the saved checkpoint, rerun the evidence package, and record the proceed/iterate decision.
Command Checks & Actions
• report_design -floorplan: reports the floorplan state understood by the tool
• check_design -checks {dp_pre_macro_placement dp_pre_power_insertion dp_pre_pin_placement dp_floorplan_rules}: runs named design-planning check groups
• write_floorplan -output <output_dir>: writes reproducible floorplan information to files
Run only the commands needed for this question. Save the report with the floorplan version and analysis context.Healthy, Suspicious & Hard-stop Results
• Healthy: A reviewable floorplan has deliberate boundaries, utilisation, usable rows, justified macro locations, feasible channels, constrained pins, early congestion/timing evidence, PG reservation, voltage-area legality, classified findings, and reproducible write-out. • Suspicious: The floorplan looks tidy but cannot be reproduced or has unexplained warnings. • Hard stop: required legality or physical feasibility is missing or unexplained. Reopen the saved checkpoint, rerun the evidence package, and record the proceed/iterate decision.
Common Mistake
Do not hide the symptom with an arbitrary utilisation, halo, channel, blockage, pin move, or die-size change. The floorplan looks tidy but cannot be reproduced or has unexplained warnings.
What The Interviewer Is Testing
The interviewer is testing whether you can connect “What evidence makes an initial floorplan reviewable?” to measurable physical evidence and an owned correction.
Practical Example
Symptom: The floorplan looks tidy but cannot be reproduced or has unexplained warnings. Corrective path: Reopen the saved checkpoint, rerun the evidence package, and record the proceed/iterate decision.
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