Eli Lipsitz's Game Bub Puts an Open Source Nintendo Game Boy, GBC, GBA Emulator in Your Palm

Software engineer and vintage gaming enthusiast Eli Lipsitz has designed a slick handheld console for Nintendo Game Boy-family emulation, driven by an FPGA and compatible with both ROM images and original cartridges: the Game Bub.

"Game Bub [is] an open-source FPGA based retro emulation handheld, with support for Game Boy, Game Boy Color, and Game Boy Advance games," Lipsitz explains of his creation. "While there are open-source FPGA retrogaming projects (e.g. MiSTer), there doesn't appear to be anything open-source that supports physical Game Boy and Game Boy Advance cartridges, let alone an open-source handheld device. Thus I somewhat naively set out to design what would become by far my most complex electrical engineering and hardware design project to date."

Looking not entirely dissimilar to the FPGA-driven proprietary Analogue Pocket, the Game Bub is a modernized take on Nintendo's original Game Boy layout: a portrait-format handheld with an upper display and lower control area with four-way D-pad, four fire buttons, Select and Start buttons, and a menu button.

Inside its housing is a custom-designed six-layer circuit board housing an AMD XC7A100T FPGA and an Espressif ESP32-S3 microcontroller. There are stereo speakers, a built-in rumble motor for haptic feedback, real-time clock, a cartridge reader for original games, microSD card slot for ROM images, support for the Game Link Cable to either original Nintendo devices or other Game Bubs, and a docking port with HDMI video output for big-screen gaming.

"I believe that FPGA emulators have only one real advantage over software emulators: they can more easily interface with original hardware, such as physical cartridges or other consoles via link cables," Lipsitz explains of his decision to use an FPGA rather than a general-purpose processor emulating the Game Boy in software, as a way to counteract what he calls "misleading marketing and hype" surrounding FPGA-based emulation. "I did this project not because I think that FPGA emulators are inherently better than software emulators, but because I think they’re interesting and fun to build."

Lipsitz's highly-detailed project write-up is available on his website, where he is also seeking to gauge interest in the production of a kit; for those looking to go their own way and DIY it, hardware design files and firmware/gateware/software source code are available on GitHub under the reciprocal GNU General Public License 3.