Retro computers are making a comeback, and not through emulation software with updated hardware, but with old school chips such as the Z80, 8080, 6802, and more. Some enthusiasts, such as physics professor Wichit Sirichote, are even offering DIY kits you can build that is specially made using new PCBs and old (or newly manufactured) 8-bit microcontrollers. Others, like Warren Toomey of the Unix Heritage Society, create their own 8-bit CPUs utilizing a series of readily available TTL chips.
Toomey’s CSCvon8 von Neumann-style 8-bit TTL CPU was inspired by Ben Eater’s video series on building an 8-bit computer from the ground up and wondered if he could accomplish the same feat using a slew of 7400-series chips. He succeeded by making the 4-bit CVCv2 Crazy Small CPU, using a minimum amount of TTL chips.
Toomey set out to accomplish the same goal again, only in an 8-bit form-factor, “With this project I’ve taken the same goal, a minimum number of 7400-series chips and built an 8-bit computer with 64K of address space. This time I’ve fabricated a PCB for the project and got it running at 3.57MHz.” The component list is pretty simple and includes several memory and logic ICs, along with a UM245R UART, register/counters, and a handful of miscellaneous electronics.
All the necessary schematics, CPU architecture, and design files are available on Toomey’s GitHub page for those who would like to take a stab at it themselves. He’s also uploaded an extensive build log of his CSCvon8, complete with bill of materials, tool list (EPROM burner, Minipro programmer, UV eraser), and much more.