Overview :: A-Z80 CPU :: OpenCores
A-Z80 is a conceptual implementation of the venerable Zilog Z80 processor targeted to synthesize and run on a modern FPGA device. It differs from the existing (mostly Verilog) Z80 implementations in that it is designed from the ground-up through the schematics and low-level gates. It is a result of a research and tedious reverse-engineering of Z80 at all levels, including micro-photographs of a die.
Project includes a fully working Sinclair ZX Spectrum implementation based on this CPU. It has been described in more details at BaltazarStudios.
In addition, project files contain a number of readme's to help you understand, recreate it and/or add A-Z80 to your own project.
Framework is also developed around the Fuse tests (low-level Z80 CPU) that run each Z80 instruction on the ModelSim and automatically compare to the expected Fuse test result files. Mis-matches are flagged.
ZMAC assember is used to generate Z80 program test snippets which are then run in the simulation and on the actual FPGA hardware. The resulting files should match. This level of tests adds UART to the ModelSim and FPGA implementation so the tests can be run and outputs compared.
