Emulate ROMs at 12MHz with Raspberry Pi Pico2 PIO | Retro Computing Hack (2026)

Here’s a bold truth: the heart of your retrocomputer—its ROM—is ticking away, destined to fail. And if you’re crafting your own firmware, finding period-accurate EPROMs and programmers can feel like hunting for a needle in a digital haystack. But here’s where it gets controversial: what if you could bypass this entirely with a modern solution? Enter [Kyo-ta04], whose ingenious Pico2ROMEmu project (https://hackaday.io/project/203946-pico2romemu-pico2rp2350-rom-emulator) does just that, using the Raspberry Pi Pico2 to emulate ROMs at speeds up to 12MHz.

This isn’t just a theoretical exercise—it’s been battle-tested. The emulator runs smoothly at 10MHz with a Z80 processor and pushes to 12MHz with an MC68000. And this is the part most people miss: instead of relying on the RP2350’s RISC-V or ARM cores, [Kyo-ta04] leverages the chip’s Programmable I/O (PIO) subsystem to handle the heavy lifting. If you’re unfamiliar with PIO, think of it as a hardware accelerator for I/O tasks—a deep dive into its capabilities can be found here (https://hackaday.com/2025/11/30/a-deep-dive-into-using-pio-and-dma-on-the-rp2350/). By offloading the work to PIO, the main microcontroller core stays free, resulting in a faster, more efficient ROM emulator.

Now, you might be thinking, ‘Haven’t we seen ROM emulators before?’ Yes, projects like OneROM (https://hackaday.com/2025/09/03/one-rom-the-latest-incarnation-of-the-software-defined-rom/) come to mind, but they’re often tailored for slower, older systems. While OneROM also uses the RP2350 and its PIOs, it hasn’t prioritized high-speed performance—though that could change in future revisions (https://github.com/piersfinlayson/one-rom/issues/19). What makes Pico2ROMEmu stand out is its focus on slightly higher-performance retrocomputers, filling a gap in the community.