Yes — the Raspberry Pi RP2350 can emulate a Zilog Z80 CPU at real-time speed, with headroom to spare. The demo circulating on Adafruit's blog this week runs cycle-accurate Z80 opcodes at the original 4 MHz clock and drives a hobbyist LCD off-chip. That is a meaningful update because it puts a $6 microcontroller in the same execution class as a purpose-built retro-emulation SBC, and it hints at a broader shift in maker projects toward much cheaper substrates than the Raspberry Pi 4 8GB.
What happened
Adafruit's team posted a short write-up and video of a Z80 emulator running on the RP2350 — the newer sibling to the RP2040 that powers the Raspberry Pi Pico 2 line. The RP2350 has dual Cortex-M33 cores at 150 MHz, 520 KB of on-chip SRAM, and a pair of programmable I/O (PIO) blocks that can bit-bang bus signals with cycle-accurate timing. See the full post on the Adafruit blog.
The demo emulates the Z80 opcodes in the M33 core and uses the PIO blocks to drive an external LCD in the same timing envelope that an original Sinclair ZX Spectrum or Amstrad CPC used to hit. It is not new science — Z80 emulation has run on 200 MHz-class ARM cores for two decades — but it is the cleanest, cheapest, real-time implementation we have seen this year.
Why makers should care
The Z80 emulation demo is a proof point for a much larger question: what class of retro-emulation and teaching workloads can move off a full Linux SBC (like the Raspberry Pi 4 8GB or the Raspberry Pi Zero W Basic Starter Kit) onto a $6 microcontroller with an SD card slot? A lot, it turns out.
Anything that fits inside the class of "one CPU + a small amount of RAM + a bit-banged video signal" now fits on the RP2350. That is roughly:
- Z80 machines: ZX Spectrum, Amstrad CPC, MSX, Master System (if you skip the video coprocessor).
- 6502 machines: NES (without PPU), Commodore 64 CPU-only, Apple II CPU-only.
- Early 68k machines with heavy simplification.
The video-generation side is where things get creative. The RP2350's PIO blocks can bit-bang composite, VGA, or SPI-LCD timing without CPU intervention. That means you can dedicate one Cortex-M33 core entirely to the emulated CPU and use the other for I/O, sound, or a UI. It is a fundamentally different architecture from the Crucial BX500 1TB SSD-backed Raspberry Pi Linux boxes most people default to.
Key takeaways
- The RP2350 is a $6 microcontroller with enough headroom to emulate a Z80 in real time — and probably a 6502 too.
- For maker projects that only need one retro CPU, an LCD, and buttons, the RP2350 replaces a full Raspberry Pi at ~1/10th the total cost.
- The Raspberry Pi 4 8GB still wins if you want a full Linux userland — for RetroArch, for MAME, for anything that needs a filesystem and a proper display server.
- The Raspberry Pi Zero W Basic Starter Kit remains the right pick for beginners who want Linux + Wi-Fi + a friendly boot experience without soldering a PIO to a VGA connector.
- Per the official Raspberry Pi microcontroller docs, the RP2350 also supports RISC-V "Hazard3" cores in addition to the Cortex-M33 — so future emulators can pick their instruction set.
Why the RP2350 specifically
The RP2040 (the original Pico) could not do this comfortably. Dual Cortex-M0+ at 133 MHz did not have the instructions-per-cycle to hit real-time Z80 speed while also driving an LCD without dropping frames. The RP2350's M33 cores add DSP and integer-multiply instructions plus better branch prediction, and the boost to 150 MHz gives a real 30% single-thread uplift on emulation code paths. The PIO blocks are also faster in the new chip.
If you compare against a full Raspberry Pi like the Raspberry Pi 4 8GB, the tradeoff is stark. The Pi 4 wins on any Linux workload. The RP2350 wins on determinism, on power (100 mA vs 1.5 A), and on cost. For a portable Z80-based game console that runs on two AA batteries and boots in 50 milliseconds, the RP2350 is the right answer.
The pattern this fits into
For the last three years, the maker world has been slowly bifurcating. High-end projects (drone flight controllers, home-server clusters, ML edge inference) have moved to Raspberry Pi 4/5-class boards with real Linux distros. Small projects (weather stations, retro handhelds, MIDI controllers) have moved to microcontrollers with SD cards and displays.
The Z80 demo is a marker on the boundary. It shows that "small" now includes real-time emulation of vintage CPUs — a category that as recently as 2020 required at least a Raspberry Pi Zero. And because the RP2350 is $6 in single quantities, hobbyists can build one-off projects without the "I have to justify buying another Pi" hesitation.
The source
Adafruit's blog post is the primary reference for the demo. Their tutorial pipeline is unusually good — every project post comes with wiring diagrams, code, and a CircuitPython or MicroPython path. Their live-blog on the Adafruit blog covered the demo the day it broke.
For canonical RP2350 specs and the RISC-V/M33 dual-instruction-set positioning, see the Raspberry Pi products page and the official microcontroller documentation. Both are first-party primary sources.
Common gotchas for makers who want to try it
- PIO is not magic. Bit-banging cycle-accurate signals through PIO requires a mental model of state machines that is unfamiliar if you are coming from Arduino. Budget a weekend to work through the official PIO examples before you attempt the Z80 port.
- The M33 is faster than you think. Do not port everything to the second core just because you have one. The first core at 150 MHz is enough for Z80 opcode dispatch with headroom.
- Sound is the hard part. The demo does not (yet) drive PSG or SID chip audio. If you want a full ZX Spectrum, you need to add a small DAC or use another PIO block for square-wave generation.
- Storage is off-chip. 520 KB of SRAM is enough for the emulated machine's RAM plus a small ROM buffer. Anything larger (game files, save states) lives on an SD card, and the SD block reads add real latency you have to hide.
Adjacent projects worth building
If you have an RP2350 already and want to build against the Z80 demo, the natural next steps:
- Add PSG sound using another PIO block driving a 3.3V PWM output through a low-pass filter. Two channels of square-wave audio fit in the remaining CPU headroom.
- Port the 6502. The instruction set is simpler than the Z80, so a full 6502 core at 1 MHz is easy. A NES CPU (skipping the PPU entirely) is a reasonable first target.
- Build a QWERTY keyboard bracket using the same PIO trick with GPIO matrix scanning. The RP2350 has more than enough GPIOs.
- Wire it into a larger project — a portable ZX Spectrum in a 3D-printed case with a small LCD and battery pack costs under $30 in parts.
Why the news matters beyond the maker crowd
The bigger story here is a pattern we keep seeing in 2026: computation that used to require a "computer" now runs on a microcontroller. GPT-2-class language models run on ESP32-S3 boards. Full stereo audio DSP runs on the Teensy 4.1. Now cycle-accurate 1980s CPUs run on a $6 RP2350.
Every one of these moments makes projects cheaper, more accessible, and easier to teach. That is the practical outcome — a whole generation of "you can't do that on a microcontroller" projects is now within reach for a middle-school maker with a $10 budget.
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Citations and sources
- Adafruit blog — Z80 on RP2350 write-up — the primary demo coverage.
- Raspberry Pi products page — Pico 2 / RP2350 official product listing.
- Raspberry Pi microcontroller documentation — RP2350 datasheet and PIO examples.
Editorial commentary based on publicly available reporting. No first-party benchmarking is claimed here; the numbers cited come from the Adafruit and Raspberry Pi Foundation posts referenced above.
