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-"],
  },
})

solver.solve()

Development

Running locally

Every *.page.tsx file in the site directory automatically appears in the browser when you run bun run start. You should add pages to help you debug various solvers.

By clicking the solver name at the top of the page, you can download specific inputs for each solver. This can help to reproduce bugs in the solvers that only appear at certain iterations.

Downloading input problems from tscircuit

1. Create a test in tscircuit/core
2. Set DEBUG=Group_doInitialSchematicTraceRender
3. Run the test with bun test
4. The console output will show the location of the input problem
5. Copy the input problem and paste it into the input debugger
6. Download the page.tsx or test.tsx file and put it in the site or tests directories.

Updating Test Snapshots

1. export BUN_UPDATE_SNAPSHOTS=1
2. bun test