michele
1b3529501f
Package/pinout/ratings mismatches, SPOF as REVIEW, EMI only with a datasheet quote, and Tj from copper+vias+θJA when every parameter exists. Re-extract SI layout_rules from 1.12.0; ImpedenceFinder license stays UNKNOWN.
135 lines
4.7 KiB
Python
135 lines
4.7 KiB
Python
"""Single-point-of-failure on power rails — REVIEW, never RULE ERROR.
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FACT: how many regulators drive a rail and how many ICs sit on it.
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REQUIREMENT: redundancy is not a datasheet shall unless stated.
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INFERENCE: this rail is a SPOF — review, do not invent IEC SIL.
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"""
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from __future__ import annotations
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from collections import defaultdict
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from backend.periscopex.models import (
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ComponentConstraints,
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ComponentType,
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DesignGraph,
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Finding,
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NetType,
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)
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from backend.periscopex.pcb_net_match import normalize_kicad_hierarchy_net
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from backend.periscopex.power_margin_check import _regulators
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_SKIP_RAIL = frozenset({"GND", "AGND", "DGND", "PGND", "VSS"})
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def check_spof(
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graph: DesignGraph,
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constraints_map: dict[str, ComponentConstraints] | None = None,
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) -> list[Finding]:
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cmap = constraints_map or {}
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producers: dict[str, list[str]] = defaultdict(list)
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for ref, _comp, _cons, _vin, vout in _regulators(graph, cmap):
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key = normalize_kicad_hierarchy_net(vout)
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if key.upper() in _SKIP_RAIL:
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continue
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producers[key].append(ref)
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out: list[Finding] = []
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seen: set[str] = set()
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for net_name, net in sorted(graph.nets.items()):
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key = normalize_kicad_hierarchy_net(net_name)
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if key in seen or key.upper() in _SKIP_RAIL:
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continue
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if net.net_type != NetType.POWER and not producers.get(key):
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continue
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regs = producers.get(key) or []
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if len(regs) != 1:
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continue
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ics = [
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r for r in graph.components_on_net(net_name)
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if r in graph.components
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and graph.components[r].component_type == ComponentType.IC
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and r not in regs
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]
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if len(ics) < 1:
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continue
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seen.add(key)
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reg = regs[0]
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rcomp = graph.components[reg]
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rec = (
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f"Review whether '{net_name}' needs a second source; {reg} is the "
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f"only regulator feeding {len(ics)} IC(s). This is not a design-rule ERROR."
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)
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out.append(Finding(
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designator=reg,
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mpn=rcomp.mpn or "",
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aspect="spof",
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finding=(
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f"Rail '{net_name}' has a single regulator ({reg}) and "
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f"{len(ics)} downstream IC(s) ({', '.join(ics[:8])}"
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f"{'…' if len(ics) > 8 else ''})."
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),
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facts=(
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f"producers={regs}; downstream_ics={ics}; "
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f"net_type={net.net_type.value}."
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),
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requirement=(
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"Redundancy / dual-supply is REVIEW unless a datasheet shall "
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"names a second source (none assumed)."
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),
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inference="Single point of failure on this rail — engineering review.",
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why="SPOF is not a measured RULE; no IEC SIL invented.",
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status="INFO",
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recommendation=rec,
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action=rec,
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source="spof_check",
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rule_id="PE-SPOF-001",
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evidence_status="SUFFICIENT",
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net=net_name,
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pins=[],
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))
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# Crystal / clock: one XTAL feeding one MCU is normal — only flag when
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# several ICs share one crystal net with no second oscillator FACT.
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for ref, comp in sorted(graph.components.items()):
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if comp.component_type != ComponentType.CRYSTAL:
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continue
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nets = [n for n in set(comp.pins.values()) if n]
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ics: list[str] = []
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for n in nets:
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for r in graph.components_on_net(n):
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c = graph.components.get(r)
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if c and c.component_type == ComponentType.IC and r not in ics:
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ics.append(r)
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xtals = [
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r for r, c in graph.components.items()
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if c.component_type == ComponentType.CRYSTAL
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]
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if len(ics) < 2 or len(xtals) > 1:
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continue
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rec = (
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f"Review clock redundancy: {ref} is the only crystal and feeds "
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f"{len(ics)} ICs. Not a RULE."
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)
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out.append(Finding(
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designator=ref,
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mpn=comp.mpn or "",
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aspect="spof",
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finding=(
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f"{ref} is the only crystal and clocks {len(ics)} ICs "
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f"({', '.join(ics)})."
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),
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facts=f"xtals={xtals}; ics_on_crystal_nets={ics}.",
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requirement="A second oscillator is not assumed from IEC or folklore.",
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inference="Clock SPOF — REVIEW.",
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why="Counted crystals and IC pins on those nets.",
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status="INFO",
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recommendation=rec,
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action=rec,
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source="spof_check",
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rule_id="PE-SPOF-001",
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evidence_status="SUFFICIENT",
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pins=[],
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))
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return out
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