RTL / PMU / firmware view

Control sequencing and handshake timing shape safe bring-up.

What design teams feel

• PMU sequence flakiness

• unexpected X-propagation

• retention restore mismatch

Interface impact

• Control signal ownership

• reset vs restore ordering

• state machine observability

Tool interaction

• Synthesis LP insertion assumptions

• name stability for UPF bindings

Mitigations

• Assert transition order

• trace control ownership

• freeze interface contracts

RTL / PMU VIEW — Level Shifter Selection
// isolate before switch-off, restore before traffic release

Control ownership layers

LP OWNERSHIP LAYERS — Level Shifter Selection

layer                owns                          typical failure
------------------   ---------------------------   --------------------------
architecture         domain strategy               infeasible power states
UPF intent           policy objects + bindings     wrong/missing policy
implementation       LP cell insertion/routing     illegal physical behavior
verification         transition scenarios          uncovered LP bug
signoff governance   waiver + release decisions    late escape to silicon

Low-power deep dive

Voltage translation and switch topology must be co-optimized with transition reliability.

Concept diagram

CROSSING + GATING

domain crossing -> level shifter
domain enable   -> staged switches

Metric graph

INRUSH RISK

single-stage enable  █████████ high
staged enable        ███       lower

Reports and artifacts

• LS insertion summary

• switch enable schedule

• inrush profile

• AON control audit

Mini case study

Staged switch enable solved rail dip without violating wake latency budget.

Debug branches

• Check shifter direction map

• Audit switch staging

• Correlate with transient IR

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/level-shifters-switches/level-shifter-selection/software-programmer-view: 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/level-shifters-switches/level-shifter-selection/software-programmer-view
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/level-shifters-switches/level-shifter-selection/software-programmer-view: 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/level-shifters-switches/level-shifter-selection/software-programmer-view
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/level-shifters-switches/level-shifter-selection/software-programmer-view: 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/level-shifters-switches/level-shifter-selection/software-programmer-view
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/level-shifters-switches/level-shifter-selection/software-programmer-view: 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/level-shifters-switches/level-shifter-selection/software-programmer-view
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/level-shifters-switches/level-shifter-selection/software-programmer-view: 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/level-shifters-switches/level-shifter-selection/software-programmer-view
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/level-shifters-switches/level-shifter-selection/software-programmer-view: 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/level-shifters-switches/level-shifter-selection/software-programmer-view
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/level-shifters-switches/level-shifter-selection/software-programmer-view: 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/level-shifters-switches/level-shifter-selection/software-programmer-view
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/level-shifters-switches/level-shifter-selection/software-programmer-view: 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/level-shifters-switches/level-shifter-selection/software-programmer-view
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/level-shifters-switches/level-shifter-selection/software-programmer-view: 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/level-shifters-switches/level-shifter-selection/software-programmer-view
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/level-shifters-switches/level-shifter-selection/software-programmer-view: 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/level-shifters-switches/level-shifter-selection/software-programmer-view
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/level-shifters-switches/level-shifter-selection/software-programmer-view: 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/level-shifters-switches/level-shifter-selection/software-programmer-view
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/level-shifters-switches/level-shifter-selection/software-programmer-view: 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/level-shifters-switches/level-shifter-selection/software-programmer-view
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/level-shifters-switches/level-shifter-selection/software-programmer-view: 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/level-shifters-switches/level-shifter-selection/software-programmer-view
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

Signals crossing between voltage domains require up-shift or down-shift cells chosen by direction, threshold tolerance, and destination reliability constraints.

Metric: missing shifter count, wrong-direction insertion count, and shifted-path timing margin