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Course contents

  • How to Use This Course
  • Low-Power Metrics Reference
  • Low-Power Glossary
  • Reading Path
  • Power Intent Fundamentals61
    • Supply Sets & Power States
    • Power Domain Basics
    • UPF Object Model
    • CPF vs UPF
      • CPF vs UPF: Mechanism
      • CPF vs UPF: Inputs & Outputs
      • CPF vs UPF: Reports & Metrics
      • CPF vs UPF: Debug Playbook
      • CPF vs UPF: Worked Example
      • CPF vs UPF: Pitfalls & Red Flags
      • CPF vs UPF: Interview Drills
      • CPF vs UPF: Review Checklist
      • CPF vs UPF: Theory Deep Dive
      • CPF vs UPF: Design Space
      • CPF vs UPF: Expanded Case Study
      • CPF vs UPF: Step-by-Step Walkthrough
      • CPF vs UPF: Comparison Matrix
      • CPF vs UPF: Software / Programmer View
      • CPF vs UPF: Silicon PPA Impact
    • Power Intent Fundamentals: Tricky Q&A
  • Isolation & Retention61
  • Level Shifters & Power Switches61
  • UPF Implementation Flow61
  • Low Power Verification61
  • PD & Power Grid Integration61
  • Low Power Interview Prep4
  • Low Power / UPF Cheatsheet
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‹CPF vs UPF
  1. Topics
  2. Low-Power Design
  3. Power Intent Fundamentals
  4. CPF vs UPF
  5. CPF vs UPF: Inputs & Outputs

Low Power / UPF · All levels

CPF vs UPF: Inputs & Outputs

Inputs & Outputs for CPF vs UPF.

On this page

    Inputs and outputs contract

    Inputs & Outputs for CPF vs UPF focuses on intent migration completeness, semantic mismatch count, and review waivers. The goal is to link observed behavior to power-intent mechanism, ownership, and release risk.

    Treat this as a signed interface between intent owners and implementers. Ambiguity here creates expensive late-stage debug loops.

    Diagram
    INPUTS
      - UPF policy file(s) and revision tags
      - RTL control interface and PMU sequencing assumptions
      - legal power-state table and crossing inventory
      - implementation constraints for LP cells and rails
    
    OUTPUTS
      - policy binding and insertion reports
      - transition coverage and assertion status
      - crossing risk list and ownership map
      - signoff decision memo

    Domain map

    Diagram
    POWER DOMAIN MAP — CPF vs UPF
    
      +------------------- always_on -------------------+
      | PMU / control / retention rail                  |
      +---------+----------------------------+----------+
                |                            |
       +--------v---------+         +--------v---------+
       | domain_A         |         | domain_B         |
       | switchable       |<------->| switchable       |
       | iso/ret controls | crossings require policy   |
       +------------------+         +------------------+
    
    Domain boundaries are policy boundaries, not drawing boundaries.

    State transitions

    Diagram
    STATE TRANSITIONS — CPF vs UPF
    
    ON  --save-->  RETENTION  --off-->  OFF
     ^               |                    |
     |               +----restore<--------+
     +--------------------power_up--------+
    
    Guard checks:
      - isolation asserted before OFF
      - restore before functional traffic
      - reset policy consistent with retained state

    Low-power deep dive

    Power intent must be explicit, reviewable, and tool-consistent from day one.

    Concept diagram

    Diagram
    POWER INTENT FLOW
    
    architecture -> UPF objects -> tool binding -> verification evidence

    Metric graph

    Diagram
    INTENT QUALITY
    
    bound policies      ████████████ high
    stale references    ███          medium risk
    missing states      ██           high risk

    Reports and artifacts

    • PST report

    • domain map

    • UPF lint

    • policy binding summary

    Mini case study

    One missing PST entry blocked legal retention mode and caused false debug loops.

    Debug branches

    • Check legal state table first

    • Audit policy binding IDs

    • Freeze UPF revision tags

    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/power-intent-fundamentals/cpf-vs-upf/inputs-outputs: 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

    Diagram
    LP EVIDENCE CAPSULE 1
    
    PATH: low-power/power-intent-fundamentals/cpf-vs-upf/inputs-outputs
    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/power-intent-fundamentals/cpf-vs-upf/inputs-outputs: 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

    Diagram
    LP EVIDENCE CAPSULE 2
    
    PATH: low-power/power-intent-fundamentals/cpf-vs-upf/inputs-outputs
    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/power-intent-fundamentals/cpf-vs-upf/inputs-outputs: 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

    Diagram
    LP EVIDENCE CAPSULE 3
    
    PATH: low-power/power-intent-fundamentals/cpf-vs-upf/inputs-outputs
    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/power-intent-fundamentals/cpf-vs-upf/inputs-outputs: 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

    Diagram
    LP EVIDENCE CAPSULE 4
    
    PATH: low-power/power-intent-fundamentals/cpf-vs-upf/inputs-outputs
    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/power-intent-fundamentals/cpf-vs-upf/inputs-outputs: 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

    Diagram
    LP EVIDENCE CAPSULE 5
    
    PATH: low-power/power-intent-fundamentals/cpf-vs-upf/inputs-outputs
    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/power-intent-fundamentals/cpf-vs-upf/inputs-outputs: 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

    Diagram
    LP EVIDENCE CAPSULE 6
    
    PATH: low-power/power-intent-fundamentals/cpf-vs-upf/inputs-outputs
    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/power-intent-fundamentals/cpf-vs-upf/inputs-outputs: 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

    Diagram
    LP EVIDENCE CAPSULE 7
    
    PATH: low-power/power-intent-fundamentals/cpf-vs-upf/inputs-outputs
    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/power-intent-fundamentals/cpf-vs-upf/inputs-outputs: 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

    Diagram
    LP EVIDENCE CAPSULE 8
    
    PATH: low-power/power-intent-fundamentals/cpf-vs-upf/inputs-outputs
    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/power-intent-fundamentals/cpf-vs-upf/inputs-outputs: 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

    Diagram
    LP EVIDENCE CAPSULE 9
    
    PATH: low-power/power-intent-fundamentals/cpf-vs-upf/inputs-outputs
    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/power-intent-fundamentals/cpf-vs-upf/inputs-outputs: 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

    Diagram
    LP EVIDENCE CAPSULE 10
    
    PATH: low-power/power-intent-fundamentals/cpf-vs-upf/inputs-outputs
    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/power-intent-fundamentals/cpf-vs-upf/inputs-outputs: 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

    Diagram
    LP EVIDENCE CAPSULE 11
    
    PATH: low-power/power-intent-fundamentals/cpf-vs-upf/inputs-outputs
    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/power-intent-fundamentals/cpf-vs-upf/inputs-outputs: 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

    Diagram
    LP EVIDENCE CAPSULE 12
    
    PATH: low-power/power-intent-fundamentals/cpf-vs-upf/inputs-outputs
    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/power-intent-fundamentals/cpf-vs-upf/inputs-outputs: 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

    Diagram
    LP EVIDENCE CAPSULE 13
    
    PATH: low-power/power-intent-fundamentals/cpf-vs-upf/inputs-outputs
    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

    CPF and UPF express similar low-power intent with different constructs; migration quality depends on preserving domain policy semantics, not syntax.

    Metric: intent migration completeness, semantic mismatch count, and review waivers

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    See also

    • CPF vs UPF: Debug Playbook
    • CPF vs UPF: Worked Example
    • CPF vs UPF: Pitfalls & Red Flags