Step-by-step analysis walkthrough

Use when you own Isolation Strategies in a low-power closure war room.

1. Open failing LP test and capture transition window.

2. Map source/destination domains and state at failure point.

3. Check isolation/retention/level-shifter policies on that crossing.

4. Verify PMU ordering against spec.

5. Check implementation reports for physical legality.

6. Run root-cause branch: intent vs sequence vs physical.

7. Patch minimal owner-controlled change.

8. Run focused test then full LP matrix.

9. Update signoff dashboard and closure note.

Artifacts to collect

• isolation strategy report, crossing matrix, and clamp-value audit

• UPF revision

• PMU sequence trace

• state coverage report

• waiver ledger

Decision memo template

LOW-POWER DECISION MEMO — Isolation Strategies
state transition:
observed metric:
root cause:
fix:
regression:
owners: UPF owner, RTL owner, verification owner

Reference visuals

Isolation clamp placement

ISOLATION STRATEGY

switchable_domain signal ---->[ISO CELL]----> always_on receiver
                               clamp=0/1
                               control=iso_en(aon)

Clamp value must match downstream protocol safe value.

Low-power deep dive

Isolation and retention are sequence-sensitive contracts, not static checkboxes.

Concept diagram

SEQUENCE

save -> isolate -> power-off -> power-on -> restore -> release

Metric graph

TRANSITION DEFECT MIX

polarity errors      ███████
late iso assertion   █████
restore ordering     ████

Reports and artifacts

• isolation crossing report

• retention list

• save/restore timing

• X-propagation log

Mini case study

A late isolation enable caused intermittent X leaks only on one PMU path.

Debug branches

• Validate control polarity

• Trace AON source

• Replay transition waveform

Senior review question

Ask: what transition evidence proves this topic is closed, and which owner signs it?

Key takeaways

• State transition context must accompany every low-power metric claim.

• Intent changes require simulation, formal, and implementation re-validation.

Common pitfalls

• Comparing results from mismatched UPF revisions.

• Assuming static checks replace transition validation.

• Shipping with aged waivers and unclear ownership.

Execution drill pack 1

Use this pack to rehearse low-power closure on low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

• State transition explicitly named with legal source/target states.

• Crossing and domain ownership are mapped and agreed.

• Policy controls are traced to always-on source logic.

• Waveform bookmarks align controls with state timestamps.

Review prompts

1. Which policy object is first to deviate from intent?

2. Which owner can apply the smallest reversible fix?

3. What regression matrix proves no collateral damage?

4. Which waiver conditions would still block release?

Evidence capsule

LP EVIDENCE CAPSULE 1

PATH: low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 2

Use this pack to rehearse low-power closure on low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

• State transition explicitly named with legal source/target states.

• Crossing and domain ownership are mapped and agreed.

• Policy controls are traced to always-on source logic.

• Waveform bookmarks align controls with state timestamps.

Review prompts

1. Which policy object is first to deviate from intent?

2. Which owner can apply the smallest reversible fix?

3. What regression matrix proves no collateral damage?

4. Which waiver conditions would still block release?

Evidence capsule

LP EVIDENCE CAPSULE 2

PATH: low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 3

Use this pack to rehearse low-power closure on low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

• State transition explicitly named with legal source/target states.

• Crossing and domain ownership are mapped and agreed.

• Policy controls are traced to always-on source logic.

• Waveform bookmarks align controls with state timestamps.

Review prompts

1. Which policy object is first to deviate from intent?

2. Which owner can apply the smallest reversible fix?

3. What regression matrix proves no collateral damage?

4. Which waiver conditions would still block release?

Evidence capsule

LP EVIDENCE CAPSULE 3

PATH: low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 4

Use this pack to rehearse low-power closure on low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

• State transition explicitly named with legal source/target states.

• Crossing and domain ownership are mapped and agreed.

• Policy controls are traced to always-on source logic.

• Waveform bookmarks align controls with state timestamps.

Review prompts

1. Which policy object is first to deviate from intent?

2. Which owner can apply the smallest reversible fix?

3. What regression matrix proves no collateral damage?

4. Which waiver conditions would still block release?

Evidence capsule

LP EVIDENCE CAPSULE 4

PATH: low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 5

Use this pack to rehearse low-power closure on low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

• State transition explicitly named with legal source/target states.

• Crossing and domain ownership are mapped and agreed.

• Policy controls are traced to always-on source logic.

• Waveform bookmarks align controls with state timestamps.

Review prompts

1. Which policy object is first to deviate from intent?

2. Which owner can apply the smallest reversible fix?

3. What regression matrix proves no collateral damage?

4. Which waiver conditions would still block release?

Evidence capsule

LP EVIDENCE CAPSULE 5

PATH: low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 6

Use this pack to rehearse low-power closure on low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

• State transition explicitly named with legal source/target states.

• Crossing and domain ownership are mapped and agreed.

• Policy controls are traced to always-on source logic.

• Waveform bookmarks align controls with state timestamps.

Review prompts

1. Which policy object is first to deviate from intent?

2. Which owner can apply the smallest reversible fix?

3. What regression matrix proves no collateral damage?

4. Which waiver conditions would still block release?

Evidence capsule

LP EVIDENCE CAPSULE 6

PATH: low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 7

Use this pack to rehearse low-power closure on low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

• State transition explicitly named with legal source/target states.

• Crossing and domain ownership are mapped and agreed.

• Policy controls are traced to always-on source logic.

• Waveform bookmarks align controls with state timestamps.

Review prompts

1. Which policy object is first to deviate from intent?

2. Which owner can apply the smallest reversible fix?

3. What regression matrix proves no collateral damage?

4. Which waiver conditions would still block release?

Evidence capsule

LP EVIDENCE CAPSULE 7

PATH: low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 8

Use this pack to rehearse low-power closure on low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

• State transition explicitly named with legal source/target states.

• Crossing and domain ownership are mapped and agreed.

• Policy controls are traced to always-on source logic.

• Waveform bookmarks align controls with state timestamps.

Review prompts

1. Which policy object is first to deviate from intent?

2. Which owner can apply the smallest reversible fix?

3. What regression matrix proves no collateral damage?

4. Which waiver conditions would still block release?

Evidence capsule

LP EVIDENCE CAPSULE 8

PATH: low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 9

Use this pack to rehearse low-power closure on low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

• State transition explicitly named with legal source/target states.

• Crossing and domain ownership are mapped and agreed.

• Policy controls are traced to always-on source logic.

• Waveform bookmarks align controls with state timestamps.

Review prompts

1. Which policy object is first to deviate from intent?

2. Which owner can apply the smallest reversible fix?

3. What regression matrix proves no collateral damage?

4. Which waiver conditions would still block release?

Evidence capsule

LP EVIDENCE CAPSULE 9

PATH: low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 10

Use this pack to rehearse low-power closure on low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

• State transition explicitly named with legal source/target states.

• Crossing and domain ownership are mapped and agreed.

• Policy controls are traced to always-on source logic.

• Waveform bookmarks align controls with state timestamps.

Review prompts

1. Which policy object is first to deviate from intent?

2. Which owner can apply the smallest reversible fix?

3. What regression matrix proves no collateral damage?

4. Which waiver conditions would still block release?

Evidence capsule

LP EVIDENCE CAPSULE 10

PATH: low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 11

Use this pack to rehearse low-power closure on low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

• State transition explicitly named with legal source/target states.

• Crossing and domain ownership are mapped and agreed.

• Policy controls are traced to always-on source logic.

• Waveform bookmarks align controls with state timestamps.

Review prompts

1. Which policy object is first to deviate from intent?

2. Which owner can apply the smallest reversible fix?

3. What regression matrix proves no collateral damage?

4. Which waiver conditions would still block release?

Evidence capsule

LP EVIDENCE CAPSULE 11

PATH: low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 12

Use this pack to rehearse low-power closure on low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

• State transition explicitly named with legal source/target states.

• Crossing and domain ownership are mapped and agreed.

• Policy controls are traced to always-on source logic.

• Waveform bookmarks align controls with state timestamps.

Review prompts

1. Which policy object is first to deviate from intent?

2. Which owner can apply the smallest reversible fix?

3. What regression matrix proves no collateral damage?

4. Which waiver conditions would still block release?

Evidence capsule

LP EVIDENCE CAPSULE 12

PATH: low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Execution drill pack 13

Use this pack to rehearse low-power closure on low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough: transition framing, policy ownership, implementation evidence, and release confidence.

Transition checklist

• State transition explicitly named with legal source/target states.

• Crossing and domain ownership are mapped and agreed.

• Policy controls are traced to always-on source logic.

• Waveform bookmarks align controls with state timestamps.

Review prompts

1. Which policy object is first to deviate from intent?

2. Which owner can apply the smallest reversible fix?

3. What regression matrix proves no collateral damage?

4. Which waiver conditions would still block release?

Evidence capsule

LP EVIDENCE CAPSULE 13

PATH: low-power/isolation-retention/isolation-strategies/step-by-step-walkthrough
STATE WINDOW: <from -> to>
POLICY OBJECT: <isolation / retention / shifter / switch>
OWNER: <name>
PRIMARY ARTIFACT: <report/waveform/formal result>
RELEASE DECISION: <close / bounded waiver / escalate>

Principal LP review addendum

Isolation cells clamp outputs from switchable domains before receivers in always-on or differently powered domains sample unknown values.

Metric: unisolated crossing count, isolation enable correctness, and X-propagation escapes