emu is a general purpose, cross-platform emulator built in Rust. It is compatible with Mac OS, Windows, Linux, and web (via WASM).
Try it in your browser at https://emu.chrismoos.com
Supported Machines
Currently the emulator only supports Apple II (and it's variants). I'm hoping to add C64 support next.
The MOS 6502 processor is cycle accurate (or at least as close as possible given the emulator host environment). It passes the Klaus Dormann functional tests.
Architecture
emu uses the immediate-mode egui library for video display and input, and cpal for audio.
Download
Pre-built binaries for macOS, Linux, and Windows are available on the releases page.
Building from source
All platforms require Rust and cc65 (6502 cross-assembler for building Apple II firmware).
Linux (Debian/Ubuntu):
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh . "$HOME/.cargo/env" sudo apt-get install build-essential pkg-config cc65 libudev-dev libasound2-dev libxkbcommon-x11-0 git clone https://github.com/chrismoos/emu && cd emu cargo run --release
macOS:
brew install cc65 git clone https://github.com/chrismoos/emu && cd emu cargo run --release
Windows:
Install Rust and cc65, ensuring both are in your PATH.
git clone https://github.com/chrismoos/emu && cd emu cargo run --release
WASM:
trunk serve --features=wasm --no-default-features --release
Apple II
The following Apple II machines are supported:
- Apple II
- Apple II+
- Apple IIe (unenhanced)
- Apple IIe (enhanced, WDC65C02 processor)
The a2audit tests are passing for all supported machines.
Supported ROM files
- .dsk
- .po
- .woz
- .hdv
Peripherals and I/O
- Apple Disk ][
- Video (lores, hires, mixed mode, double hires, Video7 black and white)
- Mouse (limited, BASIC support still in progress)
- Audio
- Language Card
- Extended 80-column Text Card
- Smartport (rudimentary support, allows for loading .hdv)
- Super Serial Card
Super Serial Card
The emulator includes a full implementation of the Apple II Super Serial Card in slot 1. The card emulates the 6551 ACIA (Asynchronous Communications Interface Adapter) with support for configurable baud rates (50-19200), data bits (5-8), parity modes, and interrupt-driven I/O.
Serial Device Selection
On native targets (desktop), you can connect the Super Serial Card to either a physical serial port or the built-in Internet Modem:
# Use a physical serial port cargo run --release -- --serial-port /dev/ttyUSB0 # Use the Internet Modem (default when no --serial-port is specified) cargo run --release
The --serial-force-zero-baud flag can be used when testing with local socat bridges that don't require baud rate configuration.
Internet Modem (Default)
When no physical serial port is specified, the Super Serial Card connects to a virtual Internet Modem. This allows vintage Apple II terminal software (like ProTerm, Modem.MGR, etc.) to connect to modern TCP/IP services such as BBSes, MUDs, and other telnet-accessible systems.
AT Command Interface
The Internet Modem responds to Hayes-compatible AT commands. Characters are echoed as you type, and commands are terminated with Enter (CR or LF).
| Command | Description |
|---|---|
ATDT <host>:<port> |
Dial (connect) to a TCP host. Initiates a TCP connection to the specified address. |
Example Session:
ATDT bbs.example.com:23
Connecting to bbs.example.com:23...
OK: Connected to bbs.example.com:23
Once connected, the modem enters transparent data mode where all input/output is bridged directly to the TCP connection. The connection closes when the remote host disconnects or when DTR is disabled by the Apple II software.