What commands would you use to generate a basic low-power implementation report (e.g. report_power_domains, report_mv_cells, report_pst)?
From PDVerse Low-Power Physical Design Mentor Guide, part of the pdVerse Mentor Guide
Short Answer
Start with what the tool resolved: report_power_domains (ICC2), report_supply_sets (ICC2) and report_pst (ICC2). Then check what it built with report_mv_cells (ICC2) and judge the result with check_mv_design (ICC2). Repeat the domain and supply reports in PrimeTime so signoff reads the same intent.
Technical Explanation
- Domains:
report_power_domains(ICC2) shows each domain with its elements and primary supply. - Supplies:
report_supply_sets(ICC2) shows which net sits behind each power and ground function. - States:
report_pst(ICC2) prints the power state table;-derivedshows the merged system-level states. - Cells:
report_mv_cells(ICC2) lists inserted MV cells;-retentionand-retention_clampnarrow it. - Library:
report_mv_lib_cells(ICC2) shows which library cells qualify as MV cells and their PG pins. - Verdict:
check_mv_design -all(ICC2) runs every multivoltage rule group, PG nets included; follow up a flagged cell withreport_mv_path(ICC2). report_pst -reconcile(ICC2) shows the voltage reconciliation settings between top and block levels, not a general PST check.
# [ICC2] icc2_shell
report_power_domains
report_supply_sets
report_pst -derived
report_mv_cells -retention
report_mv_lib_cells
check_mv_design -all
# [PrimeTime] pt_shell
report_power_domain
report_supply_netWhat To Check
- Domain elements and primaries match the intended architecture.
- Every supply set resolves to the nets you expect.
- The derived states include every mode firmware uses.
- Inserted MV cell counts match the number of crossings and retained registers.
Command Checks & Actions
report_power_domainsDomains, elements and primary supplies as resolved
report_pst -derivedMerged system-level power states
report_mv_cells -retentionRetention cells the strategies produced
check_mv_design -allPower intent and PG connectivity violations
report_mv_path -cell u_iso_0Why one flagged MV cell was inserted or not associated
report_power_domainDomains as PrimeTime reads them for signoff
report_supply_netSupply nets and voltages in PrimeTime
Healthy, Suspicious & Hard-stop Results
- Healthy (illustrative): All reports agree: four MYCHIP domains, 300 retention cells in PD_COP, and
check_mv_designwithout errors. - Suspicious (illustrative):
report_mv_cellsshows far more isolation cells than PD_COP outputs, which suggests redundant strategies. - Hard stop:
check_mv_designreports an isolation cell with no strategy (MV-071), or PrimeTime shows a different primary than ICC2.
Common Mistake
The Trap: Reading only report_power_domains and treating a tidy domain list as proof the implementation is correct.
- Missing cells, wrong supplies and state mismatches stay hidden until
check_mv_designor PrimeTime finds them much later.
What The Interviewer Is Testing
- Do you know which report answers which question?
- Do you end with a check, not only with reports?
Follow-up Question & Model Response
"check_mv_design reports an isolation cell not associated with any strategy. What next?"
Candidate Model Response: Run report_mv_path -cell on that cell. It shows the cell supply, drivers, sinks and the reason it was not associated with a strategy. Common causes are a strategy element list that no longer matches after a netlist change, or a cell inserted by hand. Fix the strategy or remove the cell, then rerun check_mv_design.
Practical Example
Design Scenario: (illustrative; u_iso_0 is an illustrative instance name) After create_mv_cells on MYCHIP, report_power_domains shows four domains and report_supply_sets shows SS_COP on VDD1p0_SW. report_mv_cells -retention lists 300 cells. check_mv_design flags one isolation cell with MV-071, and report_mv_path -cell u_iso_0 shows it came from an old hand edit. After removing it, check_mv_design is clean and PrimeTime reports the same domains.
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