INDRBT / Reading room

Electronics circuit review

Retained digital evidence · results/validation/electronics_circuit_review.json · SHA-256 02ab20807deb1e75184fc98df15dface1f1c91e30511e9bee200038c0ebb52c0

This readable record comes from the engineering project. Its assumptions, sampling and rule scope remain part of the result.

{
  "scope": "28 October 2026 native MCP inspection of the exact saved INDRBT joint-interface source, plus native KiCad CLI ERC/DRC/parity/export execution. No editor/IPC session was running; unsaved editor changes are excluded.",
  "source_revision": "INDRBT branded working tree; exact saved native source SHA-256 bindings below",
  "board_sha256": "1046bd78d82cd37f4eb656b654840edead73e625d1d94488c067a607fa495aba",
  "schematic_sha256": "17d7f75f067bb735ad2a5a8c1007acfb8115b868c983112e39b75b617fe1129e",
  "power_audit_dispositions": [
    {
      "finding": "No >=10 uF bulk on +3V3",
      "disposition": "Advisory heuristic, not a circuit failure: AP2112 minimum effective output requirement is 1 uF; C2 is 4.7 uF nominal and C7 adds 100 nF. Effective capacitance/load transient performance remain physical selection checks."
    },
    {
      "finding": "No bypass capacitor on +5V_IN / +5V_FUSED",
      "disposition": "These are the short source/fuse segments before the reverse-polarity diode; they feed no IC. C1 provides 10 uF at U1 VIN on the protected rail. Duplicating caps ahead of reverse protection is not required by this architecture."
    },
    {
      "finding": "No dedicated test points on four supply rails",
      "disposition": "Optional physical-debug recommendation. J1/J2/J3 expose input/logic supply and ground, and intermediate pad lands can be probed. Dedicated production fixtures/test points were not part of the digital interface brief."
    }
  ],
  "circuit_review": [
    {
      "area": "Power path",
      "result": "No required circuit edit found",
      "evidence": "Fuse then correctly oriented SS14 then U1 input and EN; 10 uF input and 4.7 uF output. Shared 150 mA budget explicit. LDO heat calculation corrected separately to include quiescent current; temperature/headroom claims remain conditional."
    },
    {
      "area": "Input conditioning",
      "result": "Matches declared low-voltage short-cable contract",
      "evidence": "3 channels with 1 kOhm / 100 pF and correctly oriented upper/lower BAT54H clamps; 1 kOhm / 10 kOhm / 100 nF NC limit filter. External Schmitt inputs and power sequencing are required; no field transient or 5 V immunity claim."
    },
    {
      "area": "External drive",
      "result": "Matches external-drive interface scope",
      "evidence": "330 Ohm STEP/DIR/ENABLE paths, pull-down disabling ENABLE when disconnected, 10 kOhm pull-up for a 3.3 V open-drain fault. No motor current/power stage implemented."
    },
    {
      "area": "RS485",
      "result": "Pinout and declared topology coherent",
      "evidence": "LTC2850IS8 /RE and DE tied to pulled-low direction input; 100 nF decoupling has 3.562 mm local copper path. Switchable 120 Ohm endpoint termination and optional single-node 330/330 Ohm bias. Manufacturer confirms internal failsafe for open, shorted and terminated-undriven input. No cable EMC/isolation qualification."
    },
    {
      "area": "F1 land pattern",
      "result": "Manufacturer nominal drawing agrees",
      "evidence": "Native MCP saved-board pad readback shows 1.0 x 1.6 mm pads at board x=33.5/36.5 mm, giving 2.0 mm inner gap. MF-NSMF025X-2 selected; no manufacturer-specific 3D body or solder-process approval asserted."
    }
  ],
  "primary_sources": {
    "regulator": "https://www.diodes.com/assets/Datasheets/AP2112.pdf",
    "rs485": "https://www.analog.com/media/en/technical-documentation/data-sheets/285012fe.pdf",
    "fuse": "https://www.bourns.com/docs/product-datasheets/mf-nsmf.pdf"
  },
  "library_comparison_summary": {
    "footprint_pad_contracts": 48,
    "embedded_symbol_pin_contracts": 14,
    "mismatches": 0
  },
  "status": "PASS",
  "checked_at_utc": "2026-10-28T13:08:20.966267+00:00",
  "native_application_version": "10.0.6",
  "source_evidence": {
    "board_state": "saved_file",
    "gui_running": false,
    "excludes_unsaved_editor_state": true
  },
  "native_findings": {
    "mcp_erc_errors": 0,
    "mcp_erc_warnings": 0,
    "native_cli_erc_findings": 0,
    "native_cli_drc_findings": 0,
    "native_cli_unconnected": 0,
    "native_cli_schematic_parity": 0
  },
  "mcp_tools_used": [
    "check_kicad_ui",
    "get_board_info",
    "get_component_pads",
    "run_erc",
    "get_schematic_component",
    "get_component_nets",
    "audit_connections",
    "audit_decoupling",
    "audit_power_rails"
  ],
  "rename_invariance": {
    "scope": "Complete parsed native board and schematic equal the archived original after normalizing only the project name and local library alias. All other fields and values remain unchanged.",
    "checks": {
      "whole_board": {
        "expected": "c6e9ba0cee41656733b1dc1dd1427daff1fce7a97914debf46fecab2c9eb57b6",
        "actual": "c6e9ba0cee41656733b1dc1dd1427daff1fce7a97914debf46fecab2c9eb57b6",
        "matches": true
      },
      "whole_schematic": {
        "expected": "03a8da4c963c07f6fb843ef991948deec6c000c1174271ca812dbe454cee7f2f",
        "actual": "03a8da4c963c07f6fb843ef991948deec6c000c1174271ca812dbe454cee7f2f",
        "matches": true
      },
      "copper_and_zones": {
        "expected": "1fd8e0c557c984d57bd55a158a18c0f318995bf41bbd1a4ea56f31a6ff943d5d",
        "actual": "1fd8e0c557c984d57bd55a158a18c0f318995bf41bbd1a4ea56f31a6ff943d5d",
        "matches": true
      },
      "footprints_with_pad_geometry_and_net_assignments": {
        "expected": "dfe5d080b5cd73fdac32ca89bfae7129eae59981e61137d33d3e085d8e5db504",
        "actual": "dfe5d080b5cd73fdac32ca89bfae7129eae59981e61137d33d3e085d8e5db504",
        "matches": true
      },
      "board_settings_and_layers": {
        "expected": "7a4755740ecb39a7d06daab8baf1aadb93c72d40e9bb852f7bfd76c49889199d",
        "actual": "7a4755740ecb39a7d06daab8baf1aadb93c72d40e9bb852f7bfd76c49889199d",
        "matches": true
      }
    },
    "counts": {
      "footprint": 48,
      "segment": 265,
      "via": 32,
      "zone": 2
    },
    "unchanged_inputs": [
      "pin_contract.json",
      "joint_interface.kicad_pro",
      "joint_interface.kicad_dru",
      "sym-lib-table",
      "local F1 footprint geometry"
    ]
  },
  "canonical_proof_sha256": {
    "erc_report.json": "a7f6c2dd4d7e062b2de1de08a4e61e3d3f1a85033fd3810ea75fb4b6a88b3aac",
    "pcb_drc_report.json": "295e527e505e5ccad630e0fcfa63394753e84208e8afa102a1d0dd06c1f3e010",
    "pcb_verification.json": "2f4763645c1bc934e1e92fa58b5a4877024c85e5b88b1a8abf9d13b2fbcdc792",
    "pin_contract.json": "f964f42f6c746b9edde86030eaaf766f3679cf2e9fab22e903129eb435d2d81d",
    "joint_interface.kicad_pro": "1cbe4d95a46fe4c8e8a28a635cd5d81d293c97451c79740726e6cffe839bdd1a",
    "joint_interface.kicad_dru": "72afecaf275113ea1933885f575e19720a433f4028c2282d8bdac265d51b80cd"
  }
}