Gearcoleco

Gearcoleco is a very accurate, cross-platform ColecoVision and Coleco ADAM emulator written in C++ that runs on Windows, macOS, Linux, BSD and RetroArch, with an embedded MCP server for AI debugging and development.

This is an open source project with its ongoing development made possible thanks to the support by these awesome backers. If you find it useful, please consider sponsoring.

Don't hesitate to report bugs or ask for new features by opening an issue.

Downloads

Notes:

• Windows: May need Visual C++ Redistributable and OpenGL Compatibility Pack
• Homebrew: If Homebrew asks you to trust the third-party tap, run brew trust --tap drhelius/geardome
• Linux: May need libsdl3

Features

• Very accurate Z80 core, TMS9918A VDP, SN76489 PSG and AY-3-8910 SGM emulation.
• Support for ColecoVision Super Game Module (SGM) and MegaCart ROMs.
• Coleco ADAM computer and cartridge boot modes, full keyboard, ADAMnet, printer, Digital Data Pack and floppy support.
• Optional F18A v1.9 emulation.
• Support for Super Action Controller (SAC), Wheel Controller and Roller Controller.
• Save states with preview and rewind support.
• Run-ahead support to reduce input latency.
• Compressed ROM support (ZIP).
• VGM recorder.
• Supported platforms (standalone): Windows, Linux, BSD and macOS.
• Supported platforms (libretro): Windows, Linux, macOS, Raspberry Pi, Android, iOS, tvOS, webOS, PlayStation Vita, PlayStation 3, Nintendo 3DS, Nintendo GameCube, Nintendo Wii, Nintendo WiiU, Nintendo Switch, Emscripten, Classic Mini systems (NES, SNES, C64, ...), OpenDingux, RetroFW and QNX.
• Full debugger with just-in-time disassembler, CPU breakpoints, memory access breakpoints, code navigation (goto address, JP JR and CALL double clicking), debug symbols, automatic labels, memory editor, trace logger, IO inspector and VRAM viewer including registers, tiles, sprites and backgrounds.
• MCP server for AI-assisted debugging with Claude Code, Codex and similar, exposing tools for execution control, memory inspection, hardware status, rewind and more.
• Windows, Linux and macOS Portable Mode.
• Programmable Shader Chain.
• Content loading from the command line by adding the cartridge, ADAM media or playlist path as an argument.
• Content loading using drag & drop.
• Support for modern game controllers through gamecontrollerdb.txt file located in the same directory as the application binary.

Tips

Basic Usage

• BIOS and ADAM Firmware: Firmware is not included. Select the ColecoVision BIOS (OS-7) under Emulator > BIOS; the original BIOS is recommended (CRC32 3aa93ef3; filenames colecovision.rom, coleco.rom or os7.u2). ADAM additionally needs ADAM > EOS ROM (eos.rom, 8192 bytes, common CRC32 05a37a34) and ADAM > SmartWriter ROM (writer.rom, wp.rom or wp_r80.rom, 32768 bytes, common CRC32 58d86a2a).
• ADAM Startup and Media: Insert images through the ADAM menu's disk or data pack submenus, then select Power On. Supported formats are 256 KiB .ddp, 160/320 KiB .dsk, ZIP archives containing one valid ADAM image, and .m3u playlists containing images of the same type. Each drive has its own recent images, playlist and write protection controls. Insert/eject affects only that drive; dropped images use an available matching drive or prompt for a destination. Gearcoleco > Open ROM... starts ColecoVision cartridges.
• ADAM Power and Saves: Power Off saves modified media and keeps it inserted. Firmware changes apply at the next Power On; Computer Reset retains the current firmware and mounted media. Changes are stored as complete images under Save Files, leaving source files untouched. Drive menus also provide Save Changes and Save As; a failed save keeps the modified image mounted.
• ADAM Input: Type directly into ADAM; in debug mode, focus Output to type or a debugger tool to use its shortcuts. Configure special keys under ADAM > Keyboard (see defaults below); F12 toggles fullscreen. ADAM > Controller 1 / Controller 2 selects gamepad (default), keyboard or no hand controller per port. Bindings come from Input > Gamepads or Input > Keyboard Configuration; keys mapped to a hand controller do not type into ADAM. ADAM controller choices are saved separately from ColecoVision settings.
• Spinners: Use Input > Spinners > Capture Mouse or the configured Capture Mouse shortcut. Disable spinners for software that does not use them.
• Rewind: Hold the configured rewind hotkey (Backspace by default) or a mapped gamepad shortcut to step backwards through recent gameplay.
• Overscan: For a precise representation of the original image, select Overscan Top+Bottom and Aspect Ratio Standard (4:3 DAR) in the Video menu.
• Mouse Cursor: Automatically hides when hovering over the main output window or when Main Menu is disabled.
• Portable Mode: Run with --portable, or create an empty file named portable.ini in the same directory as the application binary. On macOS, place the file next to the .app bundle.

Desktop ADAM Keyboard

Normal letters, digits, punctuation, Return, Escape, Backspace, Tab, Shift, Control, Caps Lock and arrow keys map directly. The dedicated ADAM keys use these defaults: