{
  "title": "Vehicle CAN FD topology",
  "source": "IO_MODULES/CAN_PHYSICAL_LAYER.md: Topology, termination, and service access",
  "nodes": {
    "title": {
      "label": "Vehicle CAN FD \u00b7 continuous linear trunk",
      "bounds": [
        30,
        20,
        1100,
        45
      ]
    },
    "subtitle": {
      "label": "500 kbit/s arbitration  \u00b7  2 Mbit/s data phase  \u00b7  approximately 2\u20132.5 m end-to-end",
      "bounds": [
        30,
        75,
        1100,
        40
      ]
    },
    "rear": {
      "label": "Rear endpoint\n120 \u03a9 across CAN_H / CAN_L",
      "bounds": [
        30,
        170,
        290,
        105
      ]
    },
    "ecu": {
      "label": "ECU \u00b7 local PCB junction\nMid-bus connection",
      "bounds": [
        440,
        170,
        280,
        105
      ]
    },
    "front": {
      "label": "Front endpoint\n120 \u03a9 across CAN_H / CAN_L",
      "bounds": [
        840,
        170,
        290,
        105
      ]
    },
    "distance1": {
      "label": "0.5\u20131 m",
      "bounds": [
        320,
        130,
        120,
        40
      ]
    },
    "distance2": {
      "label": "1\u20131.5 m",
      "bounds": [
        720,
        130,
        120,
        40
      ]
    },
    "ecu_note": {
      "label": "ECU transceiver joins locally on PCB.\nOptional ECU 120 \u03a9 termination: OPEN in V1;\nenable only if the ECU becomes an endpoint.",
      "bounds": [
        340,
        305,
        710,
        90
      ]
    },
    "service": {
      "label": "Debug / service connector\nCAN_H \u00b7 CAN_L \u00b7 CAN_0V\nVery short PCB branch\nNo termination",
      "bounds": [
        440,
        480,
        350,
        110
      ]
    },
    "busport": {
      "label": "Same local ECU bus",
      "bounds": [
        60,
        490,
        270,
        80
      ]
    },
    "foot": {
      "label": "Lines above represent the CAN_H / CAN_L twisted pair, not individual conductors.\nAll nodes also share the defined CAN_0V reference. Avoid a long attached service cable.",
      "bounds": [
        30,
        625,
        1100,
        55
      ]
    }
  },
  "connections": [
    {
      "from": "rear",
      "to": "ecu",
      "label": ""
    },
    {
      "from": "ecu",
      "to": "front",
      "label": ""
    },
    {
      "from": "busport",
      "to": "service",
      "label": ""
    }
  ],
  "continuations": {
    "busport": "ecu"
  },
  "bus_model": "Each trunk line represents the differential CAN_H/CAN_L pair. CAN_0V is a separate shared reference.",
  "termination": {
    "rear": "120 ohm across CAN_H/CAN_L",
    "front": "120 ohm across CAN_H/CAN_L",
    "ecu": "120 ohm option, solder jumper normally open; endpoint use only",
    "service": "none"
  }
}