A Classic CPU Gets a Second Route

The Zilog Z80 is one of those chips that never really left the workbench. First sold in July 1976, the 8-bit processor became a backbone for home computers, arcade boards, embedded gear, and learning machines for decades. Its official production story changed in 2024, when Zilog, now part of Littelfuse, stopped taking last-time-buy orders for the Z84C00 family in June after an end-of-life notice dated April 15, 2024. As of 30 July 2026, the interesting part is not that the Z80 is old; it is that the community is trying to keep it physically replaceable. (tomshardware.com)

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What FOSS Z80 Is Trying To Build

FOSS Z80, led by Renaldas Zioma, is an open-source silicon clone project with a practical target: a pin-compatible replacement for classic Z80 systems. The project’s stated goal is a silicon-proven, open-source chip that can act as a drop-in CPU for machines such as the ZX Spectrum and modern Z80-based kits like the RC2014. That drop-in wording matters, because collectors and builders often need more than an emulator; they need a part that can sit in the same 40-pin footprint, talk to the same buses, and respect the timing assumptions of old boards. (github.com)

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The Technical Core Without the Mystery

The design is based around Guy Hutchison’s TV80 Verilog core, with open tooling used to turn hardware description code into manufacturable silicon layouts. The first FOSS Z80 silicon iteration used the SKY130 130nm process through Tiny Tapeout and fit into a tiny 0.064 mm² die area. The repository reports that chips from the first two tapeouts were delivered in 2025 and are functional, while later steps exposed all 40 Z80 pins in a QFN64 package and explored additional open process design kits. (github.com)

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Why DIP40 Still Matters

For retrocomputing, packaging is part of the product. The original Z80 is strongly associated with the DIP40 package: a long, through-hole chip with 20 pins on each side. The FOSS Z80 project is now working toward a classic DIP40 form factor using chip-on-board assembly on GlobalFoundries’ 180nm GF180MCU process through Wafer.Space. A separate project repository describes the Wafer.Space tapeout as a Z80 silicon clone for GlobalFoundries 180nm manufacturing, which puts the effort closer to a part that could be handled like the chips hobbyists already know. (tomshardware.com) (github.com)

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Open Silicon as Hardware Preservation

The bigger idea is that discontinued legacy chips may no longer be completely trapped by old supply chains. Projects such as Tiny Tapeout and Wafer.Space lower the barrier to shuttle runs, while open PDKs and tools such as OpenROAD make chip design more visible to software-minded hardware communities. FOSS Z80 is still not a mass-market replacement part, and timing validation against real machines remains a major step. Even so, it shows a realistic path for preserving classic computers: not by freezing them in museums, but by rebuilding the small pieces of silicon that let them keep running.

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