CDC/RDC Whiteboard Framework

What this topic teaches

CDC/RDC Whiteboard Framework focuses on closing CDC/RDC risk with mechanism-level reasoning. Strong interview answers trace crossing intent, failure mechanism, containment strategy, and signoff evidence in a deterministic sequence. Senior signoff depends on proving behavior with targeted evidence, not just clearing tool warnings.

The senior-engineer question

When problem decomposition quality, mechanism-first answer quality regresses, can you classify the hazard, identify accountable owners, and choose the smallest fix or waiver backed by evidence?

CDC/RDC SIGNOFF FLOW — CDC/RDC Whiteboard Framework

crossing inventory + reset map
          |
          v
crossing classification (level/pulse/bus/reset)
          |
          v
structure + protocol + reset checks
          |
          v
critical issues + waiver review
          |
          v
fix / validate / regress / signoff

Picture the crossing behavior

Draw the behavior before touching tools. These visuals are the expected whiteboard baseline for reviews and interviews.

Interview whiteboard shape

intent -> crossing type -> failure mode
      -> evidence -> fix -> regression -> signoff

Crossing sequence

CROSSING FLOW — CDC/RDC Whiteboard Framework

source clock domain -> launch signal -> crossing structure -> destination sample
      |                    |                 |                    |
   source FF           protocol           sync / fifo         destination FF

Key metric: problem decomposition quality, mechanism-first answer quality

Ownership layers

CDC/RDC OWNERSHIP LAYERS — CDC/RDC Whiteboard Framework

layer                 owns                            common failure
------------------    -----------------------------   -----------------------------
design intent         crossing architecture           wrong topology selected
protocol semantics    req/ack, fifo, ordering        liveness/deadlock bugs
reset behavior        assert/deassert sequencing      boot instability
analysis setup        tool rules + waivers            false confidence
signoff governance    risk acceptance + dashboard     stale critical waivers

Evidence to collect

• Primary metric: problem decomposition quality, mechanism-first answer quality.

• Primary artifact: whiteboard template, interview rubric, sample answers.

• Owners to involve: candidate, interviewer, hiring panel.

• At least one reproducer tied to mode/reset/traffic context.

• Decision record: fix, waive, or escalate with rationale.

Ownership map

OWNERSHIP MAP — CDC/RDC Whiteboard Framework

artifact                  owner
----------------------    -------------------------
design intent           candidate
verification evidence   interviewer
signoff decision        hiring panel

Every open CDC/RDC issue needs one accountable owner before waiver or fix.

Subpages in this topic

Each topic includes mechanism, I/O contract, metrics, debug, worked example, pitfalls, interview drills, checklist, theory, design tradeoffs, expanded case study, walkthrough, comparison matrix, software view, and silicon impact.

Key takeaways

• Classify crossing/reset hazards before proposing fixes.

• Pair structural results with protocol/reset behavioral proof.

• Treat waivers as bounded risk contracts, not cleanup shortcuts.

Common pitfalls

• Mass-waiving warnings near tapeout.

• Assuming local IP cleanliness guarantees SoC behavior.

• Skipping reconvergence and reset stress after CDC fixes.

CDC/RDC deep dive

Interview performance reflects production signoff thinking quality.

Concept diagram

INTERVIEW FLOW

classify -> explain mechanism -> propose fix -> state regression

Metric graph

PRACTICE SCORE

session1 62%
session2 78%
session3 89%

Reports and artifacts

• scenario completion

• answer rubric scores

• trap recovery quality

Mini case study

Candidate gave command-heavy answer but missed risk framing and waiver governance.

Debug branches

• Use mechanism-first structure

• name ownership and evidence

• close with signoff decision

Senior review question

Ask: what evidence proves this risk is closed for silicon, not just tool-clean?

Key takeaways

• State crossing class, assumptions, and owner with every issue.

• Run structural and dynamic regressions after each fix.

Common pitfalls

• Treating all warnings as equivalent risk.

• Waiving issues without containment evidence.

• Skipping reset and reconvergence stress after CDC fixes.