Schematic Trace Solver

Solve for the correct positions and routing for schematic traces and net labels. For use inside @tscircuit/core

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Overview

The Schematic Trace Solver is a pipeline that figures out how to route schematic traces and place net labels for a given schematic layout.

Chips are defined by their center point, width, and height and pins.

You then pass in direct connections and net connections. Direct connections are explicit pin-to-pin connections. When there's a direct connection between two pins, there is guaranteed to be a routed trace between them.

Net connections will not be routed, net labels are placed instead.

The solver first constructs minimum spanning tree to determine what pin-pairs to draw via the MspConnectionPairSolver. If there are two pins A and B that both connect to C, this phase will determine how to route traces to minimize overlap or crossings. e.g. we may decide to route a trace from A to B, then B to C OR we may decide to route a trace from A to C, then C to B. The pairs of traces are the mspConnectionPairs, these are used in future phases.

After the minimum spanning tree is constructed, we draw the schematic traces for each mspConnectionPair via the SchematicTraceLinesSolver. The TraceOverlapShiftSolver then shifts the schematic traces to make sure there are no parallel overlapping traces by shifting parallel traces orthogonally by a small amount.

Finally, the NetLabelPlacementSolver places net labels for each net connection. Often this requires drawing small traces to adapt to the availableFacingDirections of the net connection. If there is crowding at the pin, we look for an available spot along the trace connected to the pin.

Usage

import { SchematicTracePipelineSolver } from "@tscircuit/schematic-trace-solver"

type ChipId = string
type PinId = string

const solver = new SchematicTracePipelineSolver({
  chips: {
    chipId: "U1",
    center: { x: 0, y: 0 },
    width: 1.6,
    height: 0.6,
    pins: [
      {
        pinId: "U1.1",
        x: -0.8,
        y: 0.2,
      },
      // ...
    ],
  },
  directConnections: [
    {
      pinIds: ["U1.1", "C1.1"],
      netId: "VCC",
    },
    // ...
  ],
  netConnections: [
    {
      availableFacingDirections: ["y-"],
      netId: "GND",
      pinIds: ["U1.3", "C1.2", "C2.2"],
    },
    // ...
  ],
  availableNetLabelOrientations: {
    VCC: ["y+", "y-"],
    GND: ["y+", "y-"],
  },
})