Open Source Z80 Chip Set to Replace End-of-Line Processor

An exciting development is underway in the world of microcontrollers as an open-source version of the Z80 microcontroller is being constructed to fill the void left by the discontinuation of the original Z80 dual in line package (DIP) microcontroller. Zilog, now under the umbrella of Ixys and Littelfuse, recently announced the end of life for the original DIP version of the Z80, prompting the need for a new solution.

Renaldas Zioma, a prominent chip designer, emphasized the importance of the open-source and hardware preservation community stepping in to provide a Free and Open Source Silicon (FOSS) replacement for the Zilog Z80. This initiative aims to ensure the continued availability of a key component in the world of microcontrollers, which has powered numerous chips over the years.

The first fabrication of the FOSS design is slated for June 2024, utilizing the next round of the Tiny Tapeout multi-project wafer on a 130nm process. This cutting-edge fabrication process will result in a remarkably compact die measuring just 0.064 mm2. Tiny Tapeout 7, the platform for this groundbreaking project, is scheduled to enter the fabrication phase in June.

What sets this new design apart is its utilization of a modern, free, and open-source silicon clone of the Z80 that is not only silicon proven but also pin-compatible with existing systems. Leveraging the OpenROAD open-source EDA chip design flow and the FOSS 130 nm Skywater PDK, the project aims to synthesize production-ready silicon that meets the highest standards of quality and compatibility. The open-source design is readily accessible on Github at github.com/rejunity/z80-open-silicon.

The Tiny Tapeout infrastructure plays a crucial role in testing and pooling designs with numerous other projects, effectively reducing the overall cost of physical chip fabrication at Skywater. By collaborating and sharing resources through platforms like app.tinytapeout.com, the community is driving innovation and accessibility in the realm of microcontroller development.