A crazy small 8-bit CPU built with only seventeen 7400-series chips.
This repository holds the files for my 8-bit "big brother" CPU to the 4-bit Crazy Small CPU. This is a von Neumann style CPU designed with 7400-style logic chips, 32K of RAM, 32K of ROM and a UART. The CPU requires only seventeen chips, not including the clock circuitry. A short video is here.
The overall design of the CPU is covered in Docs/CSCvon8_design.md. Also read the getting started guide and the guide to building the PCB version.
As at the 18th May 2019 I have the CPU running solidly at 3.57MHz on the PCBs that I ordered from the PCB design in the Schematics folder. I've kept a journal with details of my progress from the initial design phase through to the successful build.
The files and folders in this repository are:
There is also a Verilog version with the top-level file being ttlcsvon8.v, the testbench is icarus_tb.v and the Makefile will build and run the Verilog testbench. Some notes on this implementation are in the Docs/implementation_notes.md file.