The ColecoVision Homebrew Cartridge PCB designed by Pixels Past (Joe Grand) and distributed as an assembled, socketed kit via the AtariAge Store is a commercial-grade development circuit board. It is engineered specifically for retro-gaming hobbyists, homebrew developers, and preservationists to assemble physical game cartridges for the standard ColecoVision console and the Coleco ADAM home computer system.
By providing a brand-new, clean board, it eliminates the messy practice of harvesting and destroying original 1980s retail game cartridges just to reuse their PCBs for homebrew projects.
Technical Architecture & Logic
The layout is optimized for high electrical reliability and simple chip swaps:
- The Sockets: The "Assembled with Socket" retail tier pre-solders logic retention sockets onto the board. This allows creators to plug in or swap programmed memory chips instantly. It eliminates the risk of overheating delicate semiconductor traces with a soldering iron during testing cycles.
- Storage Framework: It features standard DIP configurations designed to interface with 8 KB, 16 KB, 24 KB, or 32 KB unmapped game binaries.
- Target EPROMs: The layout maps directly to standard, widely accessible non-volatile memory ICs like the 27C256 EPROM or standard EEPROM alternatives.
- Address Decoding Hardware: To mirror classic 1980s cartridge bank layouts, the PCB pairs the memory chip socket with a secondary logic chip slot running a 74LS21 dual 4-input positive-AND gate or a custom-configured PLD (Programmable Logic Device) chip. This secondary component reads inputs from the system's address line pins to accurately map the data tracks across the host console's memory map blocks.
Shell and Cartridge Fitment
The board’s external layout and screw-hole positions are cut exactly to the original 1982 factory blueprints. It drops neatly into standard, genuine Coleco retail plastic cartridge shells, or high-quality, modern 3D-printed replica cartridge casings.
Crucial Software Compilation Rules
Because the board relies on linear address selection rather than dynamic page mappers, developers must account for distinct size requirements:
- Maximum File Constraints: The base design tops out at a 32 KB file limit. Complex modern homebrews exceeding 32 KB (like massive 128 KB MegaCart configurations or setups requiring non-volatile NVRAM saves) are not natively supported by this unmapped layout.
- Padding Smaller Binaries: If you are deploying smaller retro game files—such as an 8 KB or 16 KB game (e.g., BurgerTime)—the raw file cannot be flashed raw onto a 32 KB chip. You must duplicate the code blocks using a file concatenation program or a tool like Bin Wizard to fill out the file length. This ensures the address lines route properly and prevents the system from locking up on a blank screen on boot.
