@embedded32/j1939

Educational SAE J1939 helpers for Embedded32: 29-bit ID parsing, a partial PGN catalog, message decoding, diagnostics subset, and CAN gateway bindings.

Scope: This is a learning-oriented subset - not a complete or certified J1939 stack.

Installation

npm install @embedded32/j1939 @embedded32/can

Minimum runnable example

import { parseJ1939Id, decodeJ1939, buildJ1939Id } from '@embedded32/j1939';

const parsed = parseJ1939Id(0x18f00401);
console.log(parsed.pgn, parsed.sa);

const msg = decodeJ1939({
  id: 0x18f00401,
  data: [0, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70],
  extended: true,
});
console.log(msg.name);

const id = buildJ1939Id({ priority: 6, pgn: 0xf004, sa: 0x00 });

Full walkthrough: examples/j1939-basic.ts - npx tsx examples/j1939-basic.ts

Public API overview

Export	Role
`parseJ1939Id`, `buildJ1939Id`	29-bit identifier math
`decodeJ1939`, `formatJ1939Message`	Frame → structured message
`getPGNInfo`	Catalog metadata for known PGNs
`J1939TransportProtocol`	Multi-packet subset (BAM/RTS - partial coverage)
`DiagnosticsManager`	DM1/DM2-oriented helpers
`J1939CANBinding`	Connect CAN traffic to a runtime message bus
`AddressClaimManager`	Address-claim teaching utilities

Runtime requirements

Node.js 18+
ESM imports
@embedded32/can when using CAN bindings or examples with frames

Hardware requirements

None for parse/decode examples. SocketCAN optional when using J1939CANBinding with real interfaces.

Browser compatibility

Decode functions are pure TypeScript and may be bundled for browser demos. SocketCAN and Node-only bindings are not browser-compatible.

Common errors

Error	Fix
`unknown PGN` / sparse decode	PGN not in catalog - check `getPGNInfo`
Wrong priority/SA	Confirm hex ID (`0x18F00401`) and `extended: true` on frames
Import `J1939Id` namespace	Use `parseJ1939Id` / `buildJ1939Id` functions instead

@embedded32/can - frame transport
@embedded32/sim - ECUs that emit J1939 traffic
@embedded32/tools - simulate and j1939 monitor commands
@embedded32/sdk-js - application-level J1939 client

Version compatibility

Use @embedded32/j1939@1.0.0 with matching @embedded32/can@1.0.0. Transport and diagnostics APIs may expand in minor releases without breaking parse/decode.