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Identifies differential pairs on a KiCad PCB by pin function via datasheet lookup, catching pairs whose net names don't follow P/N conventions. Recommends per-interface routing parameters (differential impedance, gap, intra-pair matching) and outputs ready-to-use route_diff.py commands.
默认使用会先检查来源的 Prompt；你也可以切换为直接命令，或下载本地副本。
决定是否安装前，请先阅读 SKILL.md，以及 SkillsMP 当前展示的配套文件。
用 Codex 或 Claude 帮你安装 复制这段 Prompt，粘贴到 Codex、Claude 或其他助手里，让它检查 Skill 页面并帮你完成安装。
直接命令不会经过审查 Prompt；运行前请先检查来源。
npx skills add https://github.com/drandyhaas/KiCadRoutingTools --skill identify-diff-pairs命令会保持在同一行。复制前请横向滚动并检查完整内容。
想先保存到本地？可下载 SkillsMP 当前能够提供的文件。
Analyses a KiCad PCB's PLACEMENT and produces a placement plan. Measures whether the board should be placed or re-placed at all and decides from that measurement, detects an unplaced board, separates the parts whose position is a mechanical fact from the ones a search may move, reconstructs a damaged placement (pattern fit, rigid vectors, exact assignment, minimal-move legalize), repairs local violations, offers a slate of arrangements, and grades the result against a declared floorplan intent. Never changes the board outline, and never routes.
Plans a KiCad PCB end to end when ONE run must both place and route it. Sequences the placement skill and the routing skill, and owns the rules that exist only when the two meet: that placement invalidates every downstream routed board, that a routing failure must be classified before it is retried, and that a placement-shaped failure re-enters placement rather than burning retries in the router. Use when the board needs both; use the individual skills when it needs one.
Analyzes a KiCad PCB file and creates a comprehensive routing plan. Examines components for fanout needs (BGA/QFN/QFP/PGA), identifies differential pairs, categorizes power/ground nets, and presents a step-by-step routing workflow with explanations.
基于 SOC 职业分类
正在显示 SKILL.md
| name | identify-diff-pairs |
| description | Identifies differential pairs on a KiCad PCB by pin function via datasheet lookup, catching pairs whose net names don't follow P/N conventions. Recommends per-interface routing parameters (differential impedance, gap, intra-pair matching) and outputs ready-to-use route_diff.py commands. |
When this skill is invoked with a KiCad PCB file, find all differential pairs — including ones name-based detection misses — and recommend routing parameters per interface.
python3 py_router/list_nets.py path/to/file.kicad_pcb --diff-pairs
This catches pairs following P/N naming conventions. Record the result as the baseline.
For each IC likely to have differential interfaces (footprint/value keywords: FPGA, PHY, SERDES, USB, ETH, HDMI, LVDS, MIPI, SATA, PCIE, DDR, transceiver, redriver):
from kicad_parser import parse_kicad_pcb
pcb = parse_kicad_pcb('path/to/file.kicad_pcb')
fp = pcb.footprints['U3']
for pad in fp.pads:
print(pad.pad_number, pad.pinfunction, pad.net_name)
Differential pin functions usually pair as ..._P/..._N, TX+/TX-, D+/D-.
Where pinfunction is missing or generic, WebSearch the part's datasheet pinout and map differential pin pairs to pad numbers, then to nets via the pads.
Trace through series passives: if a differential pin connects to a 2-pad R/C/L, follow to the net on the component's other pad — the pair often gets its "real" net name on the far side of AC coupling caps or series resistors.
A pair is confirmed when both nets trace back to a documented differential pin pair. Nets that look paired only by name or topology are suspected — list them separately for the user to confirm.
| Interface | Differential impedance | Notes |
|---|---|---|
| USB 2.0 / 3.x | 90 Ω | Intra-pair matching matters from USB 2.0 HS up |
| LVDS | 100 Ω | |
| Ethernet (MDI) | 100 Ω | |
| HDMI / TMDS | 100 Ω | |
| PCIe | 85 Ω | AC coupling caps in-line on TX |
| SATA | 90 Ω | |
| MIPI D-PHY | 100 Ω | |
| DDR (DQS, CK) | 100 Ω typical | Check the memory datasheet |
| CAN | 120 Ω | Low speed; tolerances relaxed |
From the impedance, derive the routing flags:
--impedance <Z> computes per-layer widths and gap from the stackup (preferred when the stackup is realistic — see /recommend-stackup), or set --track-width/--diff-pair-gap explicitly.--diff-pair-intra-match for interfaces fast enough that P/N skew matters (USB HS+, PCIe, SATA, HDMI, LVDS at high rates).polarity_swappable: yes|no|unknown. yes = an endpoint can compensate a P/N swap (FPGA/CPLD generic I/O pin pairs, PCIe lanes, SerDes with RX/TX polarity-invert, 1000BASE-T MDI); no = polarity-critical (USB D+/D-, MIPI, TMDS/HDMI/DP, CAN, RS-485/422, DDR CK/DQS, fixed-function receivers, connectors to unknown hardware, or an asymmetric attachment like a single-sided pull-up on one net); unknown = treat as no. Feed the yes pairs into route_diff.py --polarity-swap-nets <patterns> (swaps are denied by default, #279).# USB is polarity-critical: no --polarity-swap-nets (swaps denied by default)
python3 -X utf8 py_router/route_diff.py board.kicad_pcb board_usb.kicad_pcb \
--nets "USB_DP" "USB_DM" \
--impedance 90 --diff-pair-intra-match \
2>&1 | tee /tmp/route_usb.txt
# FPGA generic-I/O pairs CAN swap (pin functions reassigned in gateware)
python3 -X utf8 py_router/route_diff.py board.kicad_pcb board_lvds.kicad_pcb \
--nets "lvds_*" --impedance 100 \
--polarity-swap-nets "lvds_*" \
2>&1 | tee /tmp/route_lvds.txt
Suspected pairs with the evidence (matching pin functions but unverified part, name-only pairing), asking the user to confirm before routing them as pairs.
A note of any pairs found by Step 1 but not corroborated by pin function — possible false positives of name matching (e.g. unrelated nets that happen to end in P/N).