avr8_dart

A Dart library that implements the AVR 8-bit architecture, enabling you to simulate Arduino and ATmega/ATtiny microcontrollers directly in Dart and Flutter.

This is a direct, 1-to-1 port of the official avr8js library (created by Uri Shaked), achieving 100% test coverage and parity with the original TypeScript project.

Features

Core CPU Simulation: Complete implementation of the AVR 8-bit instruction set.
Peripheral Simulation: Fully functional simulations for common AVR peripherals:
- GPIO
- Timers (8-bit and 16-bit, including ATtiny support)
- USART (Serial)
- SPI
- TWI (I2C)
- ADC
- EEPROM
- Watchdog
No Dependencies: Written in pure Dart. It works perfectly in Flutter web, mobile, and desktop applications.

How to Use This Library

This library simulates the inner workings of the AVR CPU core and its internal peripherals. To use it, you need to provide pre-compiled machine code (a .hex file compiled via avr-gcc or the Arduino IDE) and implement the functional simulations of any external hardware connected to the pins (like LEDs, buttons, or screens).

A rough conceptual diagram:

Compiled .hex code --> avr8_dart <--> Glue code <--> External hardware UI simulation

Basic Example

Here is a minimal example demonstrating how to set up the CPU, load a program, and execute it cycle by cycle.

import 'dart:typed_data';
import 'package:avr8_dart/avr8_dart.dart';

void main() {
  // 1. Create the CPU with 16KB of Flash memory
  final program = Uint16List(0x2000); 
  
  // (In a real app, you would load an Intel HEX file into `program` here)
  
  final cpu = CPU(program);

  // 2. Initialize peripherals (e.g., Timer and USART)
  AVRTimer(cpu, timer0Config);
  final usart = AVRUSART(cpu, usart0Config, 16000000);
  
  // Listen for serial output
  usart.onByteTransmit = (int byte) {
    print('Serial Output: ${String.fromCharCode(byte)}');
  };

  // 3. Run the simulation
  // Execute instructions in a loop
  for (int i = 0; i < 1000; i++) {
    avrInstruction(cpu);
    cpu.tick();
  }
}

Running the Tests

The project maintains 100% test parity with the original avr8js library, ensuring accurate behavioral simulation across all edge cases.

To run the full suite of tests (344 tests):

dart test

Project Status

avr8_dart is fully functional and covers the complete ATmega328p (Arduino Uno) simulation architecture. It also supports ATtiny85 hardware configurations.

See the CHANGELOG.md for detailed reference version tracking.

Acknowledgements

All architectural credit goes to Uri Shaked and the Wokwi team for the brilliant design of the original avr8js library.

License

This code is released under the terms of the MIT license.