Gearcoleco

COLECO COLECOVISION EMULATOR CORE

Gearcoleco

Gearcoleco is the libretro core (and a standalone emulator project) that accurately emulates the ColecoVision console and Coleco ADAM computer. It is open-source, actively maintained, distributed as a Libretro core for RetroArch and as standalone desktop builds and platform packages.

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Gearcoleco emulator screenshot.

Coleco ColecoVisionPRIMARY SYSTEM

History documentedPROJECT BEGAN

Open sourcePROJECT MODEL

WHY IT MATTERS

Why Gearcoleco matters

Gearcoleco provides a high-accuracy ColecoVision and ADAM emulation option with features beyond basic cores: a precise Z80 CPU implementation, TMS9918A VDP, SN76489/AY-3-8910 sound emulation, Super Game Module (SGM) and ADAM support, save states, rewind, run-ahead, and an integrated debugger/MCP server for advanced testing and AI-assisted debugging. It is available both as a libretro core (for RetroArch and libretro frontends) and as standalone desktop builds.

BEST FOR

Notable strengths

Accuracy and feature set (SGM, ADAM media and firmware support), broad platform coverage (standalone desktop builds plus libretro core for many systems), integrated debugger and MCP server, active releases and GitHub development with packaged binaries and platform-specific installers.

The people behind Gearcoleco

Project history and status

Gearcoleco is an actively developed open-source emulator whose primary public development repository is hosted on GitHub (drhelius/Gearcoleco). The project provides both a libretro core and standalone builds with official releases published on the repository's Releases page. The repo README documents features, platform targets, and detailed desktop/ADAM usage notes. Community documentation (Libretro core list and docs) lists Gearcoleco as the ColecoVision libretro core. The project history (commits and releases) shows ongoing maintenance and recent releases and build artifacts; for precise commit history consult the repository. Users should be aware that original console BIOS/firmware files are required for ColecoVision and ADAM emulation and are not included with the core or binaries.

What Gearcoleco supports

ColecoVision cartridges (standard .rom / .col / .bin formats, compressed ZIP)
Coleco ADAM computer images (.ddp, .dsk and supported ADAM media formats)
Super Game Module (SGM) and MegaCart ROMs
Standalone desktop: Windows, macOS, Linux, BSD
Libretro core: RetroArch platforms including Windows, Linux, macOS, Raspberry Pi, Android, iOS, various consoles and embedded platforms (platform list in repository README)

Download and availability

OFFICIAL DOWNLOADS

Get Gearcoleco

Official downloads: GitHub releases (standalone builds and platform packages) and the libretro core distribution (downloadable via RetroArch online updater or the Libretro core list). The project README and Releases page are the authoritative download locations; RetroArch users can install the 'game.libretro.gearcoleco' core through RetroArch's Online Updater.

Get Gearcoleco ↗

DOCUMENTATION

Official documentation

Read the official configuration, compatibility, and troubleshooting material before changing advanced options.

Read official documentation ↗

Broken or missing download? Emulator projects move and official links sometimes change. Please contact Retro Replay so the source can be verified and updated.

Gearcoleco setup guide

Setup note: This guide covers both using Gearcoleco as a libretro core within RetroArch and running the standalone desktop builds. It focuses on verified, practical steps: obtaining the core/binaries, required BIOS/firmware files and naming/placement, essential configuration for controllers and ADAM media, and troubleshooting common 'No BIOS' and core-selection issues.

1) Get the core or standalone build: RetroArch: open RetroArch → Main Menu → Online Updater → Core Updater → find and download 'Gearcoleco' (game.libretro.gearcoleco). Standalone: download the platform build from the project's GitHub Releases page (desktop zips and platform packages are provided); the README lists platform-specific install notes (Homebrew taps, PPAs, RPMs).
2) Obtain the required BIOS/firmware files: Gearcoleco does not include proprietary BIOS/firmware. For ColecoVision the core looks for the ColecoVision BIOS (OS-7). Common filenames accepted include colecovision.rom, coleco.rom or os7.u2; the README documents expected CRC32 values for verification. For ADAM emulation you will also need EOS and SmartWriter ROMs (e.g., eos.rom and writer.rom/wp.rom) with the sizes and CRCs noted in the README. Place BIOS files in RetroArch's system directory (or the location configured for cores) when using the libretro core; for standalone builds place them in the 'system' or same directory as the binary as described in the project's tips.
3) Put BIOS files in the right place and check names: RetroArch: copy colecovision.rom (or the filename documented by the core) into RetroArch's 'system' folder (often /sdcard/retroarch/system on Android or the 'system' subfolder of RetroArch on desktop). Standalone: place BIOS files in the 'system' folder next to the Gearcoleco binary or where the README indicates. If you see a 'NO BIOS' message, verify filenames and CRCs against the core docs — renaming or moving files to the core/system folder is a frequent fix.
4) Loading cartridges and ADAM media: Standalone: use the emulator menu (Gearcoleco > Open ROM…) to open cartridge images. ADAM: insert disk or data pack images through the ADAM menu, then Power On; supported formats include .ddp, .dsk and ZIP archives containing a single valid image. RetroArch: load a ColecoVision cartridge ROM via RetroArch's Load Content → select the ROM and choose 'Run' with Gearcoleco as the core. Use playlists for bundles or multi-file content.
5) Controllers and special inputs: Configure controllers in RetroArch Input settings for the core; Gearcoleco supports modern gamepads and reads a gamecontrollerdb.txt when present for accurate button mappings. For spinners/roller controls use the core's spinner capture features (mouse capture or mapped joystick axes) as described in the README. ADAM keyboard and special ADAM keys are configurable in the standalone build's ADAM > Keyboard menu.
6) Using advanced features: save states, rewind, run-ahead, debugger: Save states and rewind are supported by the core and standalone. Run-ahead is available through the libretro/RetroArch run-ahead feature and the core's settings. The standalone builds include a full debugger and an MCP server for external tooling and AI-assisted debugging — consult MCP_README.md in the repository for setup and usage directions for the MCP server and debugger features.
7) Common troubleshooting: If games fail to boot: confirm you're using the Gearcoleco core and not a different Coleco or MSX core (BlueMSX can show an MSX BASIC screen). Verify BIOS filenames and CRCs and check that BIOS files are in the correct 'system' or core folder. Update the core to the latest release via RetroArch Online Updater or download the latest GitHub release. On desktop builds ensure required runtime dependencies are installed (README notes items such as SDL or Visual C++ redistributables on Windows).

Software reminder: The libretro core and standalone binaries do not include proprietary ColecoVision or ADAM BIOS/firmware. Obtain firmware legally from your own hardware dumps or other legal sources before using the core.

Sources and further reading

Detailed guides and tutorials

Explore step-by-step guides for Gearcoleco as they are published.

Use Gearcoleco on Android

An Android ARM64 Libretro build exists for Gearcoleco. Run the core through RetroArch for Android; the standalone desktop download and Android core may have different menus and features.

Emulates: ColecoVision.

Verified Android core build ↗ · Browse all Android emulators →