@tscircuit/schematic-match-adapt

An automatic layout system for schematics that uses the PMARS pattern:

• Partition the input schematic
• Match partitions with close, pregenerated templates
• Adapt the template until the netlist matches the partition
• Refine the layout to fix overlapping or clutter caused by adaptation
• Stitch the laid-out partitions together

Test Online · tscircuit

Motivation

Creating a schematic layout algorithm is difficult. Schematics can't easily use existing flow-diagram layout algorithms because readable schematics require using common conventions, such as orienting ground net labels down and V+ labels up.

The PMARS layout system is designed to be an extensible way to build a complex layout system that adheres to common conventions. We do this by pre-processing a large set of schematic templates that represent many common scenarios for partial or full representation of a schematic to create a large lookup table of schematic layouts. We then process a netlist against this lookup table to find the closest layout for a given netlist, considering factors such as the net labels and passive components.

Because the algorithm is extended by adding new templates, it is simple to extend to algorithm to handle new scenarios as users need them or as edge cases are found.

Usage

You should create an InputNetlist to describe your schematic input. You can then call getLayoutForNetlist to get CircuitBuilder instance with the layout applied.

import { SchematicLayoutPipelineSolver } from "@tscircuit/pmars-layout"

const solver = new SchematicLayoutPipelineSolver({
  inputNetlist: {
    boxes: [
      {
        boxId: "U1",
        leftPinCount: 2,
        rightPinCount: 2,
        topPinCount: 0,
        bottomPinCount: 0,
      },
      {
        boxId: "R1",
        leftPinCount: 1,
        rightPinCount: 1,
        topPinCount: 0,
        bottomPinCount: 0,
      },
    ],
    connections: [
      {
        connectedPorts: [
          { boxId: "U1", pinNumber: 1 },
          { boxId: "R1", pinNumber: 1 },
        ],
      },
      {
        connectedPorts: [{ boxId: "U1", pinNumber: 4 }, { netId: "VCC" }],
      },
    ],
    nets: [{ netId: "VCC" }, { netId: "GND" }],
  },
})

solver.solve()

console.log(solver.toAsciiString())

// You can access the position of each box via circuitBuilder.chips

Great Reference Schematics

• https://cdn.sparkfun.com/assets/7/7/2/1/9/SparkFun_STM32_Thing_Plus.pdf