Squareboi Is the Open Source Game Boy Color Cartridge System You Need
If you have Nintendo Game Boy and want a DIY-friendly “flash cart” option, then Squareboi is the solution for you.
There is only one thing that the entire retrogaming community agrees on: the best experience comes from playing on original hardware. But even if you get your hands on a vintage console or handheld, you may end up resorting to emulation because of the cost and difficulty of building a physical game library. For that reason, there are various storage solutions for many consoles. They often let you copy game ROMs onto an SD card that the console can access. But if you have Nintendo Game Boy and want a hackable option, then Squareboi is the solution for you.
ALXCO-Hardware developed Squreboi to be “as accessible and DIY-friendly as possible.” Unlike most of the flash cartridges on the market that are closed source, Squareboi is an open source project that you can hack to your heart’s content. You can copy game ROMs to the device to play them on your Game Boy, Game Boy Color, or Game Boy Advance. It stores game saves without requiring a battery and lets you copy those game saves back to your computer if you like. It also serves as a cartridge reader if you want to dump a ROM. Max storage space is 4MB of ROM and 32KB of RAM. It is Arduino-compatible so you can tweak the firmware if you like.
The Squareboi design utilizes a few different PCBs that you select based on your needs. To start, you will need at least the mainboard and the Writeboi programmer board. You’ll need a JTAG programmer to flash the firmware and an Arduino Mega 2560 development board to connect the Writeboi board to your computer. There are optional daughter boards to add RAM or ROM if necessary for the game/program you want to run, which is really helpful if you’re in the homebrew scene. A donor cartridge (aftermarket is fine) is necessary for the case.
The various boards require a handful of different chips for memory, but the chip that does the heavy lifting is a Microchip ATF1502ASL CPLD (complex programmable logic device). A CPLD is a bit like a simple FPGA and it eliminates the need for original ICs that are hard to find. Full build instructions are available on the Squareboi GitHub page.