techmannih/nema34-mounted-stepper-controller

docs/decoupling-targets.json

[
  [
    "U1",
    10,
    "C2"
  ],
  [
    "U2",
    32,
    "C6"
  ],
  [
    "U2",
    1,
    "C7"
  ],
  [
    "U2",
    4,
    "C8"
  ],
  [
    "U3",
    8,
    "C9"
  ],
  [
    "U4",
    5,
    "C10"
  ],
  [
    "U5",
    2,
    "C12"
  ],
  [
    "U6",
    17,
    "C21"
  ],
  [
    "U7",
    3,
    "C25"
  ],
  [
    "U7",
    5,
    "C26"
  ],
  [
    "U7",
    29,
    "C27"
  ],
  [
    "U7",
    20,
    "C28"
  ],
  [
    "U7",
    33,
    "C29"
  ],
  [
    "U7",
    4,
    "C61"
  ],
  [
    "U10",
    5,
    "C38"
  ],
  [
    "U11",
    5,
    "C39"
  ],
  [
    "U13",
    5,
    "C40"
  ],
  [
    "U14",
    5,
    "C41"
  ],
  [
    "U15",
    1,
    "C43"
  ],
  [
    "U16",
    6,
    "C44",
    {
      "placement_limit_mm": 3.7,
      "reason": "UFQFPN48 lands move 0.875 mm inward from the previous LQFP row. C44/C45/C46 retain their proven ground returns and top-side branches; measured source paths remain 3.26/3.98/3.77 mm (all below the unchanged 5 mm native limit). This explicit 3.7 mm centre-distance bound preserves the local bypass placement without disturbing the adjacent crystal, USB and buzzer paths. Hardware rail ripple remains unqualified."
    }
  ],
  [
    "U16",
    5,
    "C45",
    {
      "placement_limit_mm": 3.7,
      "reason": "UFQFPN48 lands move 0.875 mm inward from the previous LQFP row. C44/C45/C46 retain their proven ground returns and top-side branches; measured source paths remain 3.26/3.98/3.77 mm (all below the unchanged 5 mm native limit). This explicit 3.7 mm centre-distance bound preserves the local bypass placement without disturbing the adjacent crystal, USB and buzzer paths. Hardware rail ripple remains unqualified."
    }
  ],
  [
    "U16",
    4,
    "C46",
    {
      "placement_limit_mm": 3.7,
      "reason": "UFQFPN48 lands move 0.875 mm inward from the previous LQFP row. C44/C45/C46 retain their proven ground returns and top-side branches; measured source paths remain 3.26/3.98/3.77 mm (all below the unchanged 5 mm native limit). This explicit 3.7 mm centre-distance bound preserves the local bypass placement without disturbing the adjacent crystal, USB and buzzer paths. Hardware rail ripple remains unqualified."
    }
  ],
  [
    "U17",
    8,
    "C51"
  ],
  [
    "U18",
    11,
    "C52",
    {
      "reason": "Only U18 is allowed on the bottom. C52 retains its XY pad centers on top, joined through one 0.60/0.30 mm V3V3 via at source (-0.6,-3.9), native (99.4,103.9). The 5 mm budget includes the 1.6 mm board thickness; all ordinary bypasses remain on the IC side. Encoder supply/ground ripple still requires powered qualification.",
      "layer_transition": {
        "from": "bottom",
        "to": "top",
        "source_xy_mm": [
          -0.6,
          -3.9
        ],
        "native_xy_mm": [
          99.4,
          103.9
        ],
        "pad_mm": 0.6,
        "drill_mm": 0.3,
        "barrel_mm": 1.6,
        "maximum_vias": 1
      }
    }
  ],
  [
    "U22",
    2,
    "C63"
  ],
  [
    "U23",
    1,
    "C69"
  ],
  [
    "U24",
    1,
    "C70"
  ],
  [
    "U28",
    1,
    "C74"
  ],
  [
    "U25",
    1,
    "C75"
  ],
  [
    "U25",
    5,
    "C76"
  ],
  [
    "U26",
    1,
    "C77"
  ],
  [
    "U27",
    1,
    "C78"
  ],
  [
    "U29",
    5,
    "C79"
  ],
  [
    "U30",
    8,
    "C80"
  ],
  [
    "U31",
    6,
    "C81"
  ],
  [
    "U32",
    6,
    "C82"
  ],
  [
    "U33",
    5,
    "C85"
  ],
  [
    "U34",
    2,
    "C87",
    {
      "placement_limit_mm": 3.3,
      "reason": "U34 VIN is the second pin of the PowerPAD package. C87 sits directly beside the package courtyard; the allowed 3.3 mm pad-center spacing clears PGND while retaining a <=5 mm top-layer connection. See docs/power-validation.md."
    }
  ],
  [
    "U34",
    6,
    "C88"
  ],
  [
    "U12",
    4,
    "C93"
  ],
  [
    "U12",
    6,
    "C94"
  ],
  [
    "U35",
    16,
    "C95"
  ],
  [
    "U36",
    8,
    "C97"
  ],
  [
    "U37",
    5,
    "C99"
  ]
]