micheleandCursor
45e820fabc
PS-SI-001 and decoupling skip without a numeric layout_rule. Tests use simple_project nets, not invented USBPHY boards. Co-authored-by: Cursor <cursoragent@cursor.com>
92 lines
2.8 KiB
Python
92 lines
2.8 KiB
Python
"""G1 SI: intra-pair skew only when the datasheet gives millimetres.
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Pair names (_DP/_DM, _P/_N) only identify which nets to compare. The
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limit is never 3W, USB spec folklore, or a default millimetre.
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"""
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from __future__ import annotations
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import math
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from backend.pinscopex.models import DesignGraph, Finding, LayoutGraph, LayoutSegment
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from backend.pinscopex.validate import _match_constraints
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_PAIR_SUFFIXES = (("_DP", "_DM"), ("_P", "_N"), ("+", "-"))
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def _seg_len(seg: LayoutSegment) -> float:
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return math.hypot(seg.end[0] - seg.start[0], seg.end[1] - seg.start[1])
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def net_length_mm(layout: LayoutGraph, net: str) -> float:
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return sum(_seg_len(s) for s in layout.segments if s.net == net)
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def partner_net(name: str) -> str | None:
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for a, b in _PAIR_SUFFIXES:
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if name.endswith(a):
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return name[: -len(a)] + b
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if name.endswith(b):
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return name[: -len(b)] + a
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return None
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def _length_match_limit_mm(constraints_map: dict, graph: DesignGraph) -> tuple[float, int | None] | None:
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for comp in graph.components.values():
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cons = _match_constraints(comp.mpn, constraints_map)
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if not cons:
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continue
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for rule in cons.layout_rules or []:
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if rule.get("kind") != "length_match":
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continue
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mm = rule.get("max_distance_mm")
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if mm is None:
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continue
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return float(mm), rule.get("source_page")
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return None
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def check_si(
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graph: DesignGraph,
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constraints_map: dict,
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layout: LayoutGraph | None,
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) -> list[Finding]:
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if layout is None or not layout.segments:
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return []
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limit = _length_match_limit_mm(constraints_map, graph)
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if limit is None:
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return []
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max_mm, page = limit
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seen: set[tuple[str, str]] = set()
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findings: list[Finding] = []
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names = {s.net for s in layout.segments if s.net}
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for net in names:
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partner = partner_net(net)
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if not partner or partner not in names:
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continue
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key = tuple(sorted((net, partner)))
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if key in seen:
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continue
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seen.add(key)
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skew = abs(net_length_mm(layout, net) - net_length_mm(layout, partner))
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if skew <= max_mm:
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continue
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findings.append(Finding(
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designator="layout",
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mpn="",
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aspect="si",
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finding=(
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f"Intra-pair skew {skew:.1f} mm on {key[0]}/{key[1]} "
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f"(datasheet max {max_mm:g} mm)."
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),
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why=f"length_match max_distance_mm={max_mm:g}.",
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status="ERROR",
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recommendation="Length-match the differential pair.",
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source="si_check",
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rule_id="PS-SI-001",
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net=net,
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pins=[],
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source_page=page,
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))
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return findings
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