Compliance Hooks: Templates, Presets & Evidence Packs
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Compliance Hooks turn measurements and bring-up into repeatable proof: standardized templates, presets, and evidence packs that any lab or vendor can reproduce and compare.
The goal is to eliminate “looks better” artifacts and shorten blame cycles by locking settings, capturing the right logs, and enforcing data-based pass criteria across builds, fixtures, and sites.
Definition & Scope: What “Compliance Hooks” Means
Compliance hooks are reusable templates, presets, and logs that convert “it seems to work” into provable, repeatable results across labs, vendors, and production.
Definition (engineering-grade)
- A hook is not a theory note; it is an executable and versioned artifact.
- A pass/fail decision is considered handoff-ready only if it is backed by an Evidence Pack.
- Hooks must enable single-variable comparisons (change one knob, explain one delta).
Scope Guard (to prevent content overlap)
This page covers
- SSC / jitter reporting templates (fields, capture checklist, export rules).
- CTLE/DFE preset packs (structure, scan discipline, snapshot requirements).
- EDID / HDCP / PCI-style artifacts (minimal evidence sets & timelines).
- Evidence Pack organization (naming, indexing, diff-ready comparisons).
This page does NOT cover
- SSC theory / loop-BW derivations (link to the dedicated SSC page).
- CTLE/DFE algorithm design or circuit implementation (link to EQ/Retimer pages).
- Protocol-spec encyclopedias (HDMI/DP/PCIe) beyond what is needed to produce artifacts.
Rule: without a versioned Evidence Pack, a “pass” cannot be trusted, compared, or transferred to another station.
What you’ll get (three deliverable packs)
Template Pack
Instrument capture settings (BW/trigger/sampling/averaging), export formats, and “minimal capture” checklists that prevent settings artifacts.
Preset Pack
CTLE/DFE preset maps plus a snapshot contract (firmware build ID + register dump checksum + link conditions) for diff-ready comparisons and rollbacks.
Evidence Pack
A handoff-ready bundle (plots/screenshots/logs/condition matrix/deviations) that makes results reproducible across labs, vendors, and production.
Reader paths (pick one)
- Need standardized SSC/jitter reporting → follow the Template Pack chapters.
- Need safe EQ/retimer presets with traceability → follow the Preset Pack chapters.
- Need interoperability/compliance handoff to a vendor/customer → follow the Evidence Pack chapters.
Artifact Taxonomy: Templates / Presets / Evidence Pack
This taxonomy turns compliance work into managed assets. Every future chapter must produce artifacts that land in one of these three buckets—otherwise results cannot be compared, audited, or reproduced.
Minimal Evidence Principle
- Evidence is not “more screenshots”; it is the smallest set that enables independent reproduction.
- Every Evidence Pack must include context (inputs + versions) and outputs (plots/logs/counters).
Single-Variable Rule (diff-ready comparisons)
- Change one variable per run (one preset knob, one fixture, one setting), then label the delta in the filename and run log.
- If multiple variables change, the run becomes non-attributable and should not be used for pass/fail correlation.
Taxonomy table (what each artifact must contain)
| Category | Primary purpose | Must-capture fields (minimum) | Typical files |
|---|---|---|---|
| Templates | Prevent settings artifacts and enable station-to-station reproducibility. | BW / filter, trigger, sampling window, averaging, de-embed profile ID & version, export format. | instrument_setup.yml, capture_checklist.md, report_template.md |
| Presets | Make tuning traceable, diff-ready, and rollback-safe across teams and vendors. | preset ID, firmware build ID, register snapshot checksum, link rate/topology/temp, lane map. | preset_map.csv, regdump_lane0.bin, fw_build.txt |
| Evidence Pack | Provide handoff-ready proof (what ran, how, under which conditions, and what happened). | CaseID, setup/topology, versions, run log, outputs (plots/logs/counters), deviations, attachment index. | case_012_eye.png, case_012_log.txt, matrix_conditions.csv |
Note: the table is intentionally “minimum fields”. The goal is reproducibility, not paperwork.
Naming convention (diff-ready by design)
Use a filename key that makes context discoverable without opening the file: [Protocol]_[Rate]_[Topology]_[Temp]_[Rev]_[Date] (optional: _ToolVer, _PresetID).
PCIe_Gen5_Backplane_25C_RevB_2026-01-13_Tool1.4_PresetL2
HDMI_6G_Coax_70C_RevA_2026-01-13_Tool2.1_PresetSafe
Measurement Hygiene: Prevent “Settings Artifacts”
Measurement results can look “better” without any real improvement. The most common causes are changes in RBW/VBW, trigger conditions, probing/fixtures, averaging, or de-embedding profiles. This section standardizes the minimum capture contract so results remain comparable across stations.
Minimum capture contract (must be recorded)
If any item below is missing, the plot/screenshot is not diff-ready and should not be used for pass/fail handoff.
Instrument settings (Template Pack)
- BW / RBW / VBW: [X]
- Filter type / detector: [X]
- Timebase / sample length: [X]
- Trigger mode / source: [X]
- Averaging mode / count: [X]
- Export format + scaling: [X]
Measurement chain (Evidence Pack context)
- Probe / fixture type + bandwidth class: [X]
- Fixture/cable/adapter revision: [X]
- De-embed profile ID + version: [X]
- Calibration state/date (if applicable): [X]
Operational rule: treat every plot as invalid until the capture contract is satisfied.
Golden setup (station-to-station correlation)
Correlation requires a shared reference set. Use a Golden DUT, a Golden run script, and a Golden settings template. Differences should be captured as template version deltas, not personal judgement.
- Run the Golden DUT at Station A and export a complete Evidence Pack.
- Run the same Golden template at Station B and export a complete Evidence Pack.
- Allow only necessary adapters; record any change in the deviation note.
- Compare deltas (Δ metrics) using identical settings and de-embed version.
- If deltas exceed [X threshold], classify root cause as settings / fixture / de-embed / trigger.
- Freeze the corrected station template as Template vX.Y and reuse it.
Single-variable A/B discipline (diff-ready by design)
Allowed (change one per run)
- One instrument variable: RBW/VBW, averaging, trigger, filter.
- One physical variable: cable length/topology, fixture revision.
- One configuration variable: de-embed profile version, preset ID.
Not allowed (non-attributable)
- Changing multiple variables in a single run.
- Switching probes/fixtures without logging the change.
- Using a “better-looking” curve without the capture contract.
[CaseID]_[Metric]_[Date]_delta-RBW_[X]
[CaseID]_[Metric]_[Date]_delta-Preset_[ID]
[CaseID]_[Metric]_[Date]_delta-DeEmbed_[Ver]
Do / Don’t (quick sanity guide)
Do
- Freeze templates and version them (Template vX.Y).
- Use Golden DUT correlation before debating results.
- Run single-variable A/B comparisons only.
- Attach the capture contract to every plot.
Don’t
- Compare plots with different RBW/VBW or averaging.
- Switch probes/fixtures without logging revisions.
- Change de-embed profiles without version control.
- Treat “better-looking” curves as proof by default.
SSC Templates: What to Capture and How to Report
This section standardizes the minimum SSC evidence set for compliance and interoperability reporting. It focuses on capture and handoff artifacts, not SSC mechanism theory.
SSC Evidence Checklist (minimum set)
A) Config snapshot (Preset/Config artifact)
- Mod depth: [X%]
- Mod rate: [X kHz]
- Mode: Down-spread / Center
- Enable state: On / Off
- Reference clock (if relevant): [X MHz]
B) Frequency-domain evidence (Template + Evidence)
- Spectrum screenshot with recorded RBW/VBW/span.
- Marker/peak list export (CSV or equivalent).
- Instrument template version: [vX.Y]
C) Time-domain / statistics (Evidence)
- Jitter statistics (fields as placeholders): RJ rms [X ps], TJ@BER [X ps].
- Sampling window + averaging mode must match the template.
D) Behavior evidence (Logs)
- Error counters (BER/CRC): [X]
- Lock/unlock or drop events (timestamped): [X]
- Retrain count (if applicable): [X]
Handoff rule: if any category (A–D) is missing, the SSC report is not transferable and should not be used for compatibility claims.
Compatibility validation matrix (Evidence Pack indexing)
Validate SSC behavior across peers, cables, and temperature. Each matrix point should map to a distinct CaseID folder.
| Dimension | Values (examples) | Must capture | Pass criteria (placeholders) |
|---|---|---|---|
| Peer / Partner | Vendor A (FW [X]), Vendor B (FW [X]), Platform Rev [X] | Config snapshot + event logs | drop count < [X], BER < [X] |
| Cable / Topology | short / long, direct / with extender (type [X]) | Spectrum + jitter stats + counters | TJ@BER < [X ps], CRC < [X] |
| Temperature | cold / room / hot (°C [X]) | Same template settings + same profile version | lock events = [0], retrain < [X] |
Keep the matrix compact: each row is a CaseID folder with a complete SSC Evidence Pack.
Jitter Reporting Templates: RJ/DJ/TJ + Eye/Bathtub Snapshots
A jitter report is only comparable when fields, units, BER points, and capture context are aligned. This section standardizes a report schema that enables reproducible and diff-ready comparisons across labs and production.
Field dictionary (schema contract)
A) Core jitter metrics (comparable by definition)
- RJ rms: [X ps]
- DJ pp: [X ps]
- TJ@BER: [X ps] @ BER=[1e-12 / 1e-15]
TJ is only comparable when the BER point is identical.
B) Eye + bathtub snapshots (evidence, not claims)
- Eye height: [X mV]
- Eye width: [X ps]
- Bathtub snapshot: BER=[1e-12 / 1e-15]
Snapshots must reference the same capture window and template settings.
C) Capture context (Template Pack)
- Template version: [vX.Y]
- Timebase / window / acquisition length: [X]
- Trigger mode / source: [X]
- Averaging mode / count (if used): [X]
- De-embed profile ID + version: [ID / vX.Y]
D) Environment + setup (required metadata)
- Temperature: [X °C] (soak [X min])
- Power ripple (point + bandwidth): [X mVpp @ X MHz]
- Cable/topology: [length / type]
- Probe/fixture class + revision: [X]
- Preset ID + FW build (snapshot checksum): [ID / X]
Comparability rule: missing context → results are non-transferable and should not be used for cross-station claims.
Report example (diff-ready, one-page)
CaseID: [Protocol]_[Rate]_[Topology]_[Temp]_[Rev]_[Date]
Template: vX.Y De-embed: [ProfileID] vX.Y Units: ps / mV
Preset: [PresetID] FW build: [X] Snapshot checksum: [X]
Core metrics:
RJ rms = [X ps]
DJ pp = [X ps]
TJ @ BER = [X ps] (BER=[1e-12/1e-15])
Eye snapshots:
Eye height = [X mV]
Eye width = [X ps]
Bathtub = snapshot attached (BER=[1e-12/1e-15])
Environment:
Temperature = [X °C] (soak [X min])
Power ripple = [X mVpp @ X MHz] (probe point [X])
Cable/topology= [X]
Probe/fixture = [class] (rev [X])
Behavior evidence:
BER/CRC count = [X]
Drop/lock evt = [X] (timestamps attached)
Retrain count = [X]
Deviations from golden:
- [none / list one change per line]
Keep the schema stable across teams so a report can be compared by field-level diffs instead of screenshots.
Quick rules (to prevent “mismatched” jitter claims)
- Compare TJ only at the same BER point.
- Compare RJ only with the same capture window, trigger, and template version.
- Compare eye width/height only with the same de-embed profile version.
- Attribute improvement to EQ/preset only if preset ID and snapshot checksum match.
CTLE/DFE Preset Strategy: Build a Safe Preset Pack
A safe preset pack is a versioned, recoverable set of EQ snapshots with explicit use-cases and risk labels. This section describes how to structure a preset pack and how to scan it reliably without diving into circuit implementation.
Preset map (use-case + risk + evidence)
Baseline (reference + recovery)
- Use-case: short/clean links, correlation runs.
- Risk: may leave residual ISI on long links.
- Evidence: eye + counters as reference baseline.
Aggressive (reach-first)
- Use-case: long/losy links needing fast convergence.
- Risk: noise amplification and “edge-lock” behavior.
- Evidence: bathtub tail + drop/retrain counters.
Noise-safe (stability-first)
- Use-case: noisy rails, EMI-heavy systems, temperature stress.
- Risk: reduced reach if ISI dominates.
- Evidence: stable counters across temperature sweeps.
Long-cable (targeted reach)
- Use-case: defined cable class/length families.
- Risk: topology-specific; may fail on different fixtures.
- Evidence: case-matched eye + BER with CaseID indexing.
PresetID: [Pack]_[Rate]_[Topo]_[CTLE]_[DFE]_[Rev]
Snapshot: FW build [X] + regdump checksum [X] + template vX.Y
Scan strategy (coarse → fine, single-variable)
Step 1 — Coarse scan
- Sweep a small CTLE grid (gain/peaking) first.
- Hold DFE in a safe state (fixed or off).
- Goal: identify a stable region boundary quickly.
Step 2 — Fine scan
- Refine near the stable region (one dimension at a time).
- Adjust DFE taps only after CTLE is stable.
- Freeze every candidate as a versioned preset snapshot.
Stop rules (prevent “trial-and-error drift”)
- If drop/retrain spikes → rollback and mark as non-convergent.
- If eye improves but counters worsen → mark as noise-amplifying.
- If pass criteria met → promote to pack and lock the snapshot.
Failure mode mapping (symptom → label)
Over-EQ noise amplification
- Symptom: bathtub tail worsens; intermittent errors appear.
- Quick check: error counters worsen under temperature stress.
- Action: step back to Noise-safe presets; reduce peaking.
Residual ISI (under-equalized)
- Symptom: eye width limited; pattern sensitivity remains.
- Quick check: improvements correlate with controlled CTLE changes.
- Action: increase CTLE gradually; add limited DFE taps.
CDR edge-lock (looks locked, behaves marginal)
- Symptom: lock is reported but CRC/frame errors persist.
- Quick check: retrain/lock events accumulate over time.
- Action: rollback from Aggressive; target stable region presets.
Pass criteria (placeholders)
- BER < [X] over a defined run window.
- Eye margin > [X] (height/width as applicable).
- Drop events = [0] (or < [X]).
- Retrain count < [X].
Training & Margin Hooks: Capture the “why” behind a pass/fail
Training success is not a guarantee of system stability. This section turns “passes training but drops in system” into a traceable evidence chain by standardizing logs, timestamps, and margin scans that explain what happened and why it happened.
Minimal training evidence set (required)
A) State + timeline (what happened, when)
- Phase ID: [P0…Pn] (abstract IDs, not spec names)
- Start/End timestamps: [ms] (per phase)
- Result code: [OK/Fail + subcode]
- Retry/fallback count: [X]
- Total training time: [X ms]
B) Convergence counters (how it converged)
- Convergence iterations: [X] (per phase)
- Settling time: [X ms] (per phase)
- Update count (equalization/adaptation): [X]
- “Last stable” snapshot ID: [ID]
C) Behavior events (what the system did later)
- Retrain count (run window): [X]
- Drop/unlock events: [X] (with timestamps)
- Error counters: [CRC/BER/FEC… placeholders]
- Event timeline file: events.log
D) Context contract (required metadata)
- Template version: vX.Y
- Preset ID + FW build + snapshot checksum: [X]
- Cable/topology revision: [X]
- Temperature + slope: [X °C] @ [X °C/min]
- Power ripple (point + BW): [X mVpp @ X MHz]
Rule: missing A–D fields → training results are not transferable across stations/vendors.
Margin hooks (templates, protocol-agnostic)
Voltage margin scan template
- Axis: swing/offset [units placeholder]
- Step: ΔV [X] ; dwell per point: [X s]
- Per-point record: error counters + retrain/drop events
- Output: margin map (grid) + event timeline correlation
Time/phase margin scan template
- Axis: sampling phase/UI offset [units placeholder]
- Step: Δφ [X] ; dwell per point: [X s]
- Per-point record: counters + events + stable time
- Output: pass-band width [X] + “edge sensitivity” flags
Discipline: only one variable changes per scan; every scan binds to a preset snapshot ID and a context contract.
Reproduction discipline (make “intermittent” repeatable)
Fixed seed
- Pattern/traffic seed: [X]
- Goal: prevent “different randomness, different outcome”.
Fixed traffic
- Rate/load profile: [X]
- Goal: make noise/thermal coupling reproducible.
Fixed temperature slope
- Ramp: [X °C/min] ; soak: [X min]
- Goal: separate drift-sensitive issues from random ones.
Aligned run window
- Window: [X min] or [X Gbits]
- Goal: statistics remain comparable across stations.
Hook → Symptom → What it proves
Training timeline (per phase)
Symptom: certain phases stretch or repeat before “OK”.
Proves: training is marginal; correlation must include convergence counters and stop rules.
Convergence iterations
Symptom: iterations increase and fluctuate across temperature.
Proves: the link needs more adaptation effort; candidate presets should be labeled “reach-first” vs “stability-first”.
Retrain + drop events
Symptom: “locked” link still accumulates CRC/errors and retrains.
Proves: behavior is marginal and time-dependent; margin scans must be tied to event timestamps.
Margin scan outputs
Symptom: tiny voltage/phase shifts trigger sharp error cliffs.
Proves: “pass” is near the edge; stable presets should prioritize wider pass bands, not just peak eye shape.
EDID/HDCP Artifacts: Minimal Evidence Set for Interoperability
Display interoperability issues are rarely solved by a single screenshot. This section defines a minimal evidence set that captures EDID, HDCP handshake outcomes, and hot-plug timing as reviewable artifacts (logs, dumps, and timelines) without re-teaching protocol internals.
Interoperability Evidence Pack (Display) — checklist
EDID (dump + summary + validation)
- Raw EDID dump: edid_raw.bin / edid_raw.txt
- Read method (abstract): [I²C/bridge/OS API]
- Parsed summary: version + extension count [X]
- Checksum result (per block): [pass/fail]
- Change detection: hash/CRC vs last known-good [X]
HDCP (timeline + failure class + retries)
- Handshake stage timeline (abstract stage IDs): hdcp_timeline.csv
- Failure class: [Timeout/AuthFail/CapabilityMismatch/RepeaterIssue]
- Retry policy: count + interval [X]
- Outcome snapshot: success/fail + code [X]
HPD / hot-plug (event timing, ms-level)
- HPD rising/falling timestamps: [ms]
- EDID read start/end: [ms]
- HDCP start/auth/end: [ms]
- Video stable timestamp: [ms]
- Any resets/re-enumeration markers: [X]
Goal: the evidence set should answer: “what was read”, “where it failed”, and “what sequence happened” without protocol debate.
Evidence-first failure taxonomy (for fast triage)
EDID class
- Checksum fail, extension count changes, or summary hash mismatch.
- Minimum proof: raw dump + checksum + summary hash.
HDCP class
- Timeout, capability mismatch, auth fail, or retry-dependent “success”.
- Minimum proof: stage timeline + failure class + retry record.
HPD/timing class
- HPD chatter, abnormal sequence, or window too short (ms-level).
- Minimum proof: HPD timeline aligned to EDID and HDCP timestamps.
Delivery structure (artifact folder layout)
/Display_EvidencePack/[CaseID]/
edid_raw.bin
edid_raw.txt
edid_summary.json
hdcp_timeline.csv
hdcp_failclass.txt
hpd_timeline.csv
context.yaml (temp / cable / topology / fw build / bridge rev)
screenshots/ (only if necessary)
Keep artifact names stable so interoperability issues can be escalated with a complete, reviewable pack.
PCI-SIG / Industry Compliance Artifacts: What to keep, how to compare
Compliance outcomes must be reviewable and comparable across runs. This section standardizes artifact packaging and a diff-friendly record for the same testcase when retimers, presets, or board revisions change.
Checklist (minimal compliance artifact set)
A) Testcase identity
- Testcase ID: [X]
- Suite / profile version: [X]
- Run mode (rate/topology variant): [X]
B) Setup contract
- Topology ID (sketch reference): [X]
- Board revision: [X]
- Retimer/redriver + FW build: [X]
- Preset pack ID: [X]
- Cable/fixture revision: [X]
- Measurement template version: vX.Y
C) Result evidence
- Pass/fail + numeric margins: [X]
- Raw exports preferred: CSV/JSON
- Waveforms/screenshots named by testcase ID
- Error/event counters (same window): [X]
D) Deviation note
- Deviation type: [Setting/Fixture/Env/Interop/Unknown]
- Observed delta: [Δmargin / Δevents]
- Root category: [Noise/ISI/Clock/Power]
- Repro contract: seed + traffic + temp slope
E) Attachments
- Run/command snapshot (parameters only)
- Config snapshot checksum/ID: [X]
- Environment snapshot: [X °C] + [X mVpp@BW]
- Fixture baseline reference: [X]
Hard rule: missing setup contract → no cross-run conclusions; missing deviation note → no actionable escalation.
Checklist + Diff report template (copy-ready)
Diff discipline: same testcase ID • change only one variable (retimer OR preset OR board rev) • bind the same template ID • compare the same export type.
Diff report header
- Testcase ID: [X] ; profile: [X]
- CaseIDs: [CaseA] vs [CaseB]
- One variable changed: [retimer/preset/rev]
Constant contract (must match)
- Topology ID + cable/fixture rev: [X]
- Template ID (RBW/VBW/trigger/de-embed): vX.Y
- Temperature contract: [X °C @ X °C/min]
- Traffic/seed/run window: [X]
Delta summary (numeric first)
- Margin delta: Δ[X]
- Event delta (retrain/drop/errors): Δ[X]
- Outcome: [pass/pass, pass/fail, fail/fail]
Deviation note + next check
- Deviation class: [Setting/Fixture/Env/Interop]
- Single next check: [one action]
- Pass criteria placeholder: [threshold X + uncertainty U]
Vendor alignment (10 fields): testcase ID • profile version • board rev • retimer+FW • preset ID • topology ID • cable/fixture rev • instrument+template ID • temp+slope • ripple point+B W.
Evidence Pack folder layout (stable)
/Compliance_EvidencePack/[CaseID]/
00_README_summary.md
10_Setup/
setup.yaml
topology_id.txt
20_Results/
result.csv
logs/
screenshots/
30_Deviation/
deviation.md
40_Attachments/
command_snapshot.txt
config_checksum.txt
context.yaml
90_DiffReports/
diff_[TestcaseID]_[CaseA]_vs_[CaseB].md
Cross-Lab Correlation: Align instruments, fixtures, and pass criteria
Cross-lab disagreement is usually caused by mismatched templates, fixtures, or field definitions. This section provides a closed-loop correlation plan using a Golden DUT and a Golden script to make results transferable.
Three alignment pillars (with acceptance points)
1) Instrument alignment
- Shared template ID: vX.Y (BW/trigger/avg/de-embed)
- Golden setup check: same DUT/cable, compare deltas [ΔX]
- Record calibration status + model/SW build: [X]
2) Fixture alignment
- Fixture baseline: IL/RL/XTALK snapshot ID [X]
- Wear tracking: insertions [X] + cleaning rule [X]
- Reference plane definition: [X] (consistent)
3) Field alignment
- Same field dictionary: DUT ID / setup ID / template ID / preset ID
- Same run contract: window [X] + temp slope [X]
- Script-friendly exports: CSV/JSON (diff-ready)
Gate: if any pillar is not aligned, cross-site pass/fail comparisons are not valid.
Correlation workflow (1 → 6)
Step 1 — Define the contract
Input: field dictionary + template ID + pass criteria placeholders. Output: 1-page correlation plan.
Step 2 — Golden DUT readiness
Input: Golden DUT ID + history. Output: Golden DUT passport (baseline evidence pack).
Step 3 — Golden script / runbook
Input: fixed seed + traffic + temp slope + run window. Output: golden_runbook + command snapshot.
Step 4 — Round-robin execution
Lab A → Lab B → Factory using the same contract. Output: one Evidence Pack per site.
Step 5 — Delta attribution
Attribute deltas to settings, fixture, or environment using template/fixture/context fields.
Step 6 — Freeze pass criteria
Output: threshold [X] + uncertainty [U] + guard band [G] with a clear decision rule.
Attribution order + pass criteria writing template
Attribution order (evidence-first)
- Settings mismatch (template ID / BW / trigger / de-embed)
- Fixture mismatch (baseline / wear / reference plane)
- Environment mismatch (temp slope / ripple / grounding)
- DUT drift (history / aging / thermal memory)
Pass criteria template (placeholders)
- Threshold: Metric ≥/≤ [X]
- Uncertainty budget: ±[U] (instrument + fixture + de-embed)
- Guard band: [G]
- Decision rule: pass when metric meets threshold under uncertainty and guard band.
Engineering Checklist (design → bring-up → production)
Compliance hooks become reliable only when transformed into repeatable SOP: design-time provisions → bring-up template runs → production gates with attribution fields. Every checklist item below maps to an auditable artifact in the Evidence Pack.
Design: reserve hooks that make evidence reproducible
1) Loopback / BIST / PRBS entry points (fixed seed + fixed window)
Artifact: bist_mode, prbs_seed=[X], ber_window=[X]. Pass criteria: BER < [X].
2) Register/config snapshots with checksum (detect “looks same” drift)
Artifact: regdump.bin, config_checksum=[X], fw_build=[X]. Pass criteria: checksum stable across runs under same contract.
3) Exportable counters (errors / retrain / drop) with defined clear/read contract
Artifact: counters.csv (fixed field dictionary). Pass criteria: counter deltas consistent for the same window length [X].
4) Reference plane + topology contract (probe points are part of evidence)
Artifact: topology_id, ref_plane=[X], cable_fixture_rev=[X]. Pass criteria: same topology ID required for A/B diff reports.
5) Power noise evidence points (ripple measurement must be attachable)
Artifact: ripple_mVpp=[X] @BW=[X] @point=[X]. Pass criteria: ripple stays within guard band [X].
Design-enabler BOM (examples; verify interfaces/grades)
- I²C mux for isolating debug domains: TI TCA9548A
- GPIO expander for strap/status capture: NXP PCA9539
- I²C EEPROM for config/version tags: Microchip 24AA02 / 24LC02
- SPI flash for evidence/config blobs: Winbond W25Q64JV
- Jitter-cleaner reference option (platform-level): Silicon Labs Si5341
Artifact rule: every “enabler” must contribute a stable identifier to version_manifest.
Bring-up: run Template Pack once → generate Evidence Pack
1) Bind measurement hygiene template (settings become part of evidence)
Artifact: template_id=vX.Y, BW/trigger/avg/de-embed profile ID. Pass criteria: cross-bench delta within [X].
2) Preset scanning discipline (coarse → fine; change one axis only)
Artifact: preset_id=[X], scan_axis=[CTLE/DFE], convergence counts. Pass criteria: BER < [X] + stable retrain count [X].
3) Training + margin hooks captured as “why” behind pass/fail
Artifact: training states, retrain counters, margin sweep summaries (voltage/time). Pass criteria: margin > [X] with fixed run contract.
4) Jitter/Eye report fields always complete (diff-friendly)
Artifact: RJ rms [X ps], DJ pp [X ps], TJ@BER [X ps], Eye height/width [X]. Pass criteria: TJ@BER ≤ [X].
5) A/B diff report: same testcase, one variable changed
Artifact: diff_[Testcase]_[CaseA]_vs_[CaseB].md + raw exports. Pass criteria: delta attribution completed (Setting/Fixture/Env/Interop).
Production: gates + attribution fields (prevent “mystery yield”)
1) Golden DUT + Golden script as station reference
Artifact: golden passport + golden run contract. Gate: station results must correlate within [X].
2) Sampling fields aligned with vendor intake (10-field minimum)
Artifact: testcase ID, profile version, board rev, FW build, preset ID, topology ID, cable/fixture rev, template ID, temp+slope, ripple point+BW.
3) “Monday effect” diagnostic fields (environment/log completeness)
Artifact: humidity/temp, AC state, ripple, fixture insertion count, calibration status, missing-field flags. Gate: missing logs → result marked non-actionable.
Pass criteria writing template (placeholders)
- Threshold: metric ≥/≤ [X]
- Uncertainty: ±[U] (instrument + fixture + de-embed)
- Guard band: [G]
- Decision: pass only when threshold holds under uncertainty + guard band.
Applications & IC Selection Notes (before FAQ)
Applications below are framed as “scenario → failure signature → hook needed”. Selection focuses on capability checklists and concrete reference material numbers (examples only; verify data rate, package, suffix, grade, and availability).
High-value scenarios for Compliance Hooks
Long cable / extension links
Signature: intermittent errors or drop under temperature/cable swaps. Hook needed: preset pack + training logs + margin sweep + diff report.
Backplane / multi-connector paths
Signature: lab passes, system fails at full load. Hook needed: RJ/DJ/TJ fields + topology contract + correlation workflow + golden assets.
Hot-plug / HPD-like event paths
Signature: “works after reboot” or flaky re-auth/training. Hook needed: event timeline (ms) + retry counters + version manifest + evidence checklist.
Multi-vendor interoperability
Signature: one partner fails while others pass. Hook needed: minimal evidence sets, structured deviation notes, and A/B deltas with constant contracts.
Mass production consistency
Signature: yield collapse with weak attribution. Hook needed: sampling fields + golden DUT/script + Monday-effect diagnostics + pass criteria with uncertainty.
Capability checklist (no product list) + evidence fields
Must-have
- Exportable config snapshot + checksum (field: config_checksum=[X])
- Programmable preset bank (field: preset_id=[X])
- BIST/PRBS/loopback (fields: seed=[X], window=[X])
- Training status + retrain counters (field: retrain_count=[X])
- Margin hooks (field: margin_summary=[X])
- Script-friendly exports (preferred: CSV/JSON)
- Counter contract (clear/read) (field: counter_window=[X])
- Version manifest (fields: fw_build/tool_id/template_id)
Nice-to-have
- Event timeline with ms tags (field: event_timeline.csv)
- One-click Evidence Pack generation (field: case_index.json)
- Fine-grained margin sweep automation (field: sweep_grid=[X])
- Supply noise monitor hooks (field: ripple_mVpp=[X])
- Interop summary exports (field: interop_summary.json)
- Correlation-ready tags (field: station_id/template_id)
Power note (placeholder): ripple ≤ [X] mVpp @BW=[X] measured at point [X] must be attached to every evidence pack.
Reference material numbers (examples only; map to hook capabilities)
Debug/export enablers (snapshots, scripting, config tags)
- USB-to-multi-protocol bridge (for scripted register snapshots): FTDI FT2232H
- USB-to-UART bridge (console + timestamped logs): FTDI FT232R
- I²C mux (segment domains for reproducible A/B): TI TCA9548A
- GPIO expander (strap/status capture): NXP PCA9539
- I²C EEPROM (version tags / small evidence blobs): Microchip 24AA02 / 24LC02
- SPI flash (evidence/config blobs): Winbond W25Q64JV
Equalization / retiming examples (preset packs, margin studies)
- High-speed retimer class (preset banks + eye/BER tooling): TI DS280DF810
- PCIe redriver class (preset-based EQ tuning): TI DS80PCI402
- USB3 redriver class (EQ + debug-friendly behavior): TI TUSB1046
- DisplayPort redriver class (link/preset-related hooks): TI TDP158
Note: these are reference examples to illustrate “preset/export hooks”; selection must match protocol generation, rate, and board topology.
Timing/clock evidence enablers (correlation stability)
- Jitter attenuator / cleaner example: Silicon Labs Si5341
- Clock fanout example (distribution for repeatable measurements): TI LMK00304
- Glitch-free mux class (hitless switchover hooks): TI LMK1C1104
Protection parts (keep evidence stable after ESD/plug events)
- Low-cap ESD array (USB/HS lines example): TI TPD4E05U06
- Low-cap ESD array (general HS example): Nexperia PESD5V0S1UL
Evidence rule: every selected part must have a captured identifier (part number + package + suffix + FW/build when applicable) in version_manifest.json.
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FAQs (Compliance Hooks)
Purpose: close long-tail troubleshooting without expanding the main body. Each answer is a fixed 4-line, data-structured playbook that produces auditable Evidence Pack artifacts.
Same DUT, two labs report very different TJ@BER — which “settings field” to check first?
Likely cause: measurement template mismatch (RBW/VBW/averaging/trigger/timebase/de-embed profile) or different BER extrapolation setup.
Quick check: compare template_id and the template hash fields: RBW=[X], VBW=[X], avg=[X], timebase=[X], trigger=[X], deembed_profile_id=[X], BER_method=[X].
Fix: enforce a single Template Pack (same template_id) and rerun one identical window length; attach both raw exports + template manifest into the same CaseID Evidence Pack.
Pass criteria: |TJ@BER(1e-[X])_LabA − TJ@BER(1e-[X])_LabB| ≤ [X] ps AND |RJ_rms delta| ≤ [X] ps under the same template_id.
After changing RBW/VBW, jitter “looks better” — how to tell a settings artifact from real improvement?
Likely cause: the metric is bandwidth-limited by instrument filters/averaging, not improved link physics.
Quick check: do a strict A/B: keep all constant and sweep only RBW or only VBW (one variable); record {RBW, VBW, avg, filter} + the same acquisition length [X].
Fix: lock RBW/VBW/avg/filter into Template Pack; report jitter with the template fields and provide raw exports so the same settings can be replayed.
Pass criteria: metric stability under approved RBW/VBW range: max(TJ@BER) − min(TJ@BER) ≤ [X]% (or ≤ [X] ps) for RBW∈[X..X], VBW∈[X..X].
After swapping a fixture, margin drops — how to run golden correlation correctly?
Likely cause: reference plane moved (connector/TP), de-embed profile mismatch, or fixture loss/return path changed.
Quick check: run Golden DUT through both fixtures using identical template_id; capture fixture_id, ref_plane=[X], deembed_profile_id=[X], and the same testcase window [X].
Fix: normalize to the same reference plane (documented) and update/lock the correct de-embed profile; store both baselines as fixture_baseline_id_A/B inside Evidence Pack.
Pass criteria: Golden correlation delta within limits: |EyeWidth_A − EyeWidth_B| ≤ [X] ps AND |EyeHeight_A − EyeHeight_B| ≤ [X] mV (or BER delta ≤ [X]) at the same ref_plane.
Stronger CTLE makes the eye larger but BER worse — how to quickly confirm “noise amplification”?
Likely cause: CTLE boosts high-frequency noise and jitter while improving apparent eye opening; BER degrades due to SNR collapse or CDR stress.
Quick check: sweep CTLE gain in steps [X] with fixed DFE; log {BER, RJ_rms, TJ@BER, error_event_rate} per step and compare “eye-only” vs “BER”.
Fix: switch to a Noise-safe preset (lower peaking) and re-balance with minimal DFE; keep one-variable discipline and document preset_id per run.
Pass criteria: BER improves with CTLE change (not just eye): BER ≤ [X] AND (TJ@BER ≤ [X] ps OR RJ_rms ≤ [X] ps) at the selected preset_id.
Larger DFE tap leads to occasional burst errors — what logs prove “edge convergence”?
Likely cause: marginal DFE convergence (tap limits/overflow, adaptation oscillation) causing intermittent wrong decisions and clustered errors.
Quick check: capture convergence counters and burst histogram: {dfe_tap=[X], adapt_iter=[X], converge_fail=[X], retrain_count=[X], burst_len_p95=[X]} over a fixed time window [X].
Fix: cap the problematic tap range, revert one step toward stability, and retune CTLE/FFE conservatively; store a “Long-cable stable” preset_id and prevent auto-escalation beyond [X].
Pass criteria: burst error rate ≤ [X] per [X] s AND retrain_count ≤ [X] per [X] s under the same run_contract.
Training passes but drops under stress traffic — what is the minimal evidence chain of counters?
Likely cause: marginal link stability revealed by payload pattern/thermal drift/supply ripple; training-only evidence is insufficient.
Quick check: log a fixed set during stress run: {retrain_count, link_drop_count, error_counter_total, burst_error_count, margin_min=[X], temp=[X], ripple_mVpp=[X]} over duration [X].
Fix: lock run_contract (seed/traffic profile/temp slope), switch to a stability-focused preset_id, and re-run with one-variable discipline to attribute the drop to {preset / environment / fixture}.
Pass criteria: during stress duration [X], link_drop_count = 0 AND error_counter_total ≤ [X] AND retrain_count ≤ [X] with margin_min ≥ [X].
EDID is occasionally misread causing black screen — which timestamps and retry paths must be recorded?
Likely cause: transient bus/HPD timing window, retries not logged, or corrupted read without checksum/summary evidence.
Quick check: capture event timeline (ms): t0=HPD↑, t1=EDID_read_start, t2=EDID_read_end, retry_count=[X], parse_summary=[X], block_crc_ok=[true/false].
Fix: standardize the EDID Evidence Pack: raw capture + parsed summary + CRC results + retry strategy fields; compare good vs bad by diff template under the same topology_id.
Pass criteria: EDID read success rate ≥ [X]% over [N] plug cycles AND max(EDID_read_latency) ≤ [X] ms with retry_count ≤ [X].
HDCP fails only after hot-plug — which event timeline should be captured first?
Likely cause: hot-plug state transition leaves the system in a partial handshake/retry loop; missing ms-level ordering hides the failure stage.
Quick check: record timeline: HPD↑ → EDID_ok → Auth_start → Auth_done/fail_code → Video_stable; include {auth_fail_code=[X], retry_count=[X], stage_timeout_ms=[X]}.
Fix: normalize retry strategy and timeouts into a preset/log template; attach both good and failing event traces and compare stage deltas under identical run_contract.
Pass criteria: Auth success rate ≥ [X]% over [N] hot-plug cycles AND auth_total_time ≤ [X] ms with retry_count ≤ [X].
Vendor A blames the board, Vendor B blames the peer — how to align quickly using Evidence Pack?
Likely cause: mismatched testcase IDs, missing setup fields, or non-diffable attachments; both sides argue from incomplete context.
Quick check: require the same Evidence Pack schema: CaseID → Setup → Result → Deviation note → Attachments; Setup must include {template_id, preset_id, topology_id, ref_plane, deembed_profile_id, temp, ripple_mVpp, version_manifest_hash}.
Fix: exchange one Golden DUT run or a mirrored run_contract; generate a diff report that changes only one variable (peer / cable / preset) to isolate blame with evidence.
Pass criteria: both parties reproduce within agreed deltas: |TJ@BER delta| ≤ [X] ps AND |EyeWidth delta| ≤ [X] ps (or BER delta ≤ [X]) using the same CaseID schema.
Factory passes but field fails — what are the minimum 5 fields to collect on-site?
Likely cause: the field environment violates unlogged assumptions (topology/cable/temp/ripple) or the actual preset/config differs from factory.
Quick check: collect these 5 first: (1) version_manifest_hash=[X], (2) preset_id=[X], (3) topology_id + cable_length=[X], (4) template_id=[X], (5) temp=[X] (optional add: ripple_mVpp=[X]).
Fix: re-run one short on-site stress window using the same run_contract; produce a field Evidence Pack and diff against factory CaseID with one-variable attribution.
Pass criteria: mismatch is explained by fields OR the field run meets limits: BER ≤ [X] over [X] s AND no drop events (drop_count=0) at recorded temp/ripple.
This page turns the electrical layer into a deliverable: a measurable link budget from swing/common-mode and termination to FFE and Rx eye/jitter margin, with clear pass/fail thresholds at a declared reference plane.
The goal is not “a pretty eye,” but a repeatable workflow that maps channel inputs (IL/RL/XT) to a safe preset window and verified BER-time stability across cables, ports, and temperature.
Likely cause: “version string” is equal but runtime configuration differs (straps, NVM defaults, hidden registers, calibration tables).
Quick check: compare config_checksum and a deterministic regdump diff; include {fw_build_id=[X], board_rev=[X], preset_id=[X], nvm_profile_id=[X]}.
Fix: lock configuration via a versioned Preset Pack, disable “auto” defaults beyond policy, and store the final applied config snapshot in every CaseID.
Pass criteria: config一致: config_checksum matches AND regdump diff count = 0; config不一致 must be attributable with ≤ [X] critical fields changing (documented in deviation note).
You have screenshots but cannot reproduce — what’s the most-missed “script/condition matrix” item?
Likely cause: missing run_contract (seed/traffic/duration/temp slope) and missing condition matrix (peer/cable/topology/power) make screenshots non-replayable.
Quick check: verify the Evidence Pack contains: run_contract.yaml (seed=[X], traffic_profile=[X], duration=[X], temp_slope=[X]) AND conditions.csv (peer_id=[X], cable=[X], topology_id=[X], ripple_mVpp=[X], template_id=[X], preset_id=[X]).
Fix: generate the missing run_contract and conditions matrix, then rerun the same CaseID using “one variable per change”; screenshots become attachments, not the primary evidence.
Pass criteria: replay success: ≥ [X]% of reruns reproduce the same outcome AND key metrics remain within delta bounds (e.g., |TJ@BER delta| ≤ [X] ps or BER delta ≤ [X]) under identical run_contract.
