rp2040_dart

A pure Dart port of rp2040js, Wokwi's Raspberry Pi RP2040 (Pico) emulator: the Cortex-M0+ core, SIO, PIO, DMA, USB, UART, I²C, SPI, PWM, ADC, timers and the rest of the chip, with no native dependency. It runs on the Dart VM, compiled to JavaScript and to WebAssembly, so the same emulator works in Flutter apps on desktop, mobile and the web.

Its sibling avr8_dart does the same for AVR (Arduino Uno).

Status

A line-by-line port of rp2040js v1.4.0 (commit a304c74); the rules it follows, above all for 32-bit arithmetic, are in PORTING.md.

• Tests: all 315 rp2040js spec cases, same names, pass on the Dart VM, compiled to JavaScript and compiled to WebAssembly.

• Identical to rp2040js: booting MicroPython v1.20.0 for 3 simulated seconds ends in the same CPU and RAM state (hash 9893d66b, 3,990,398 instructions) on rp2040js and on every Dart target, and the MicroPython REPL runs over emulated USB (example/micropython_run.dart).

• Speed, in million emulated instructions per second (Apple M-series, medians of three runs). Workload: MicroPython running one line of pure computation typed over emulated USB (tool/bench_py.dart, and reference/bench_py.ts for rp2040js). Boot: 3 simulated seconds from reset (tool/bench.dart). Both end in the same state as rp2040js on every target.

  	Workload	vs rp2040js	Boot	vs rp2040js
  rp2040js (Node)	34.1	1.00x	22.1	1.00x
  dart2wasm	~80	2.3x	~46	2.1x
  Dart AOT	52.3	1.53x	53.2	2.41x
  dart2js	40.3	1.18x	30.5	1.38x

  Startup (RP2040() plus loadBootrom) takes 2 ms native, 3 ms dart2js and 8 ms Wasm.

Usage

import 'package:rp2040_dart/bootrom.dart';
import 'package:rp2040_dart/rp2040_dart.dart';

void main() {
  final simulator = Simulator();
  final mcu = simulator.rp2040..loadBootrom(bootromB1);
  // Copy a program into mcu.flash (example/load_flash.dart reads UF2 and
  // Intel HEX), then start it from flash:
  mcu.core.PC = 0x10000000;
  mcu.uart[0].onByte = (byte) => print(String.fromCharCode(byte));
  simulator.execute();
}

example/ runs a Pico SDK binary (emulator_run.dart, with a GDB server on port 3333) and the MicroPython REPL (micropython_run.dart).

Licence

MIT, like rp2040js. The boot ROM image in lib/src/bootrom.dart is Raspberry Pi's, under BSD-3-Clause.