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Handshake Protocols Across Domains: Step-by-Step Walkthrough

Step-by-Step Walkthrough for Handshake Protocols Across Domains.

Step-by-step analysis walkthrough

Use this sequence when owning Handshake Protocols Across Domains in a signoff review.

  1. Inspect warning class and severity.

  2. Trace crossing endpoints and domains.

  3. Check protocol/reset assumptions against spec.

  4. Review synchronizer or FIFO implementation detail.

  5. Run focused assertion or formal check.

  6. Draft fix options with risk and schedule impact.

  7. Execute regression and publish closure memo.

Artifacts to collect

  • handshake timing spec, assertion suite, latency histogram

  • crossing inventory

  • waiver board notes

  • regression report

Decision memo template

diagram
CDC/RDC DECISION MEMO — Handshake Protocols Across Domains
risk class:
mechanism:
evidence:
fix/waiver:
owners: RTL owner, verification owner, CDC owner

Reference visuals

Req/Ack flow

diagram
SRC: req -----> DEST
SRC: <----- ack  DEST

Rules:
1) req stable until ack observed
2) req/ack each cross through synchronizer
3) no combinational loop across domains

CDC/RDC deep dive

Protocol correctness is the bridge between structural clean and functional safe.

Concept diagram

diagram
PROTOCOL FLOW

intent -> transport protocol -> synchronization -> destination acceptance

Metric graph

diagram
PROTOCOL ISSUE BURNDOWN

open issues: 20 -> 11 -> 5 -> 0

Reports and artifacts

  • FIFO pointer proofs

  • req/ack liveness

  • pulse miss checks

  • protocol assertions

Mini case study

Async FIFO empty/full logic looked correct until gray decode mismatch appeared during reset overlap.

Debug branches

  • Pointer sync audit

  • formal liveness checks

  • reset interaction review

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.

Principal CDC/RDC review addendum

Two-way handshakes guarantee delivery across asynchronous clocks when both request and acknowledge paths are synchronized and protocol invariants are enforced.

Metric: req/ack completion reliability, deadlock risk, backpressure behavior

Practice this lesson