Over the past ~1.5 years, I built an open-source FPGA retro emulation handheld that can play Game Boy, Game Boy Color, and Game Boy Advance cartridges. To my knowledge, there isn't an existing open-source FPGA emulator that can play physical cartridges like this.

One of my main goals was to do all of the pieces myself, and be able to understand every component of it, so I designed my own PCB, wrote the firmware, wrote a Game Boy and Game Boy Advance emulator for the FPGA (using the Chisel HDL), and designed a 3D-printed case.

I detailed the design and development process in the linked post. It's quite long, but there are a lot of pictures and videos.

Code and design files available on GitHub: https://github.com/elipsitz/gamebub, and an overview of the architecture: https://github.com/elipsitz/gamebub/blob/handheld/docs/archi...