Power or pin checks report missing or wrong routing tracks. How do you proceed?
From PDVerse PnR Interview Handbook, part of the pdVerse Mentor Guide
Last updated:
Short Answer
Routing tracks are defined by real technology-layer rules — they're not decorative grid lines you can regenerate arbitrarily just to make a check pass. The right first move is confirming the technology-layer definitions themselves: preferred routing direction, pitch, offset, width, whether the track set covers the full core, any restricted regions, and — importantly — whether the tracks were deliberately regenerated at some point in the flow (which can be a legitimate reason for a mismatch).
Technical Explanation
- Pre-power-insertion and pre-pin-placement checks both depend on valid routing direction and track definitions being in place — if those checks are failing, the underlying track setup is the thing to verify, not just the specific pin or PG shape flagged.
- Compare whatever you find against the approved technology setup for the project — a locally "fixed" track definition that doesn't match the approved tech file is its own kind of defect, even if it silences the immediate warning.
- Never create arbitrary tracks just to make a missing/wrong-track check pass — that's treating the symptom while leaving the actual technology-file mismatch unresolved, and it can produce results the router can't actually honor.
Formula Or Decision Rule
Decision rule: required layers have approved track patterns crossing the intended regions.
What To Check
- Warning sign: A locally invented pattern fixes one pin but conflicts with spacing or the rest of the block.
- Inspect: choose one affected region, macro, row, pin, path, or net and trace the physical cause.
- Correct: Restore the approved track definition and rerun power, pin, and floorplan reports.
Command Checks & Actions
- create_track -layer <layer> -space <pitch> -coord <offset> -width <width> -dir <X_or_Y>: creates a routing-track pattern
check_design-checks {dp_pre_power_insertion dp_pre_pin_placement}: runs named design-planning check groups
Run only the commands needed for this question. Save the report with the floorplan version and analysis context.
Healthy, Suspicious & Hard-stop Results
- Healthy: Confirm technology-layer definitions, preferred directions, pitch, offset, width, core coverage, restrictions, and whether tracks were intentionally regenerated. Do not create arbitrary tracks to silence the check.
- Hard stop: required legality or physical feasibility is missing or unexplained.
Common Mistake
The Trap: Do not hide the symptom with an arbitrary utilisation, halo, channel, blockage, pin move, or die-size change.
What The Interviewer Is Testing
The interviewer is testing whether you can connect “Power or pin checks report missing or wrong routing tracks. ” to measurable physical evidence and an owned correction.
Follow-up Question & Model Response
"* Candidate Model Response: Model response: “I would change it if the same controlled rerun shows that a locally invented pattern fixes one pin but conflicts with spacing or the rest of the block. ”
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