The story for this one starts a few months ago, when [John Green] released his PICO-GB project. His code allowed the Raspberry Pi Pico to stand in for a Game Boy cartridge, complete with a simple text menu that let the user select between ROMs that had been baked into the microcontroller’s firmware. The project was particularly notable for the fact that it was entirely a software solution; while a custom breakout cartridge made for a handy temporary solution, you could have permanently wired the Pico’s pins directly to the Game Boy’s cartridge connector if you wanted to.
Then in early June, the RP2040 chip that powers the Pi Pico went up for sale in single unit quantities. That opened up the possibility of building the PICO-GB functionality into a cartridge small enough to actually fit inside the Game Boy. So [Martin “HDR” Refseth] got to work creating the slick cartridge PCB you’re seeing now.
The RP2040 is joined by a trio of Texas Instruments TXB0108 level shifters, and there’s a spot for adding a SPI flash chip. The RP2040 supports a maximum of 16 MB of external flash, but given the size of Game Boy games were generally measured in kilobytes, that shouldn’t pose much of a problem.
Looking ahead, the original PICO-GB documentation mentions enhancements like loading ROMs from SD card, as well as hardware additions like a real-time-clock for the more advanced games that supported it. We assume those concepts will become part of [Martin]’s PCB eventually, but these are still early days.
We’ve seen Game Boy cartridge emulation with a microcontroller in the past, but we’re exited to see how the unique capabilities of the Raspberry Pi Foundation’s custom silicon can improve the state-of-the-art.
[Thanks to Itay for the tip.]