New Processor Project Compatible with Z80

After termination on April 15, Zilog ceased production of 8-bit processors such as the Z80. In response, enthusiasts have launched an initiative to develop an open clone of the processor. The goal of this project is to create a replacement for Z80 processors that is interchangeable with the original Z80 CPU, compatible at the pin level, and suitable for use in devices like the ZX Spectrum computer. Schematics, hardware block descriptions in Verilog, and necessary production documentation are available under the Apache 2.0 license. The production of the first trial batch of Foss Z80 processors is expected to begin in June 2024.

Development of the Foss Z80 chip involves the use of Openroad framework, designed to automate the creation of open microcircuits, as well as the process design kit that describes the technology used at the Skywater factory and helps prepare necessary production files. This collaboration aims to reduce costs and streamline the chip testing process for the project.

The accelerated development timeline of the Foss Z80 chip is attributed to the utilization of an existing open project tv80 as the foundation, providing Verilog-based core compatibility with the Z80 CPU under the MIT license. Following the initial batch, project developers plan to compare the chip with other implementations, such as a-z80 on FPGA platforms (Altera, Xilinx, and Lattice) under the GPLV2 license, and z80explorer, a simulator for the Zilog Z-80