To demonstrate the functionality of an 8-bit computer processor at a very basic level, [Mazen Gomaa] assembled a Homemade 8-Bit Educational Computer using common CMOS logic chips, a handful of prototyping boards, and an impressive number of carefully connected wires. [Mazen] was inspired by Ben Eater’s 8-bit TTL Breadboard Computer but opted to solder the chips and other components onto proto boards instead of using solderless breadboards.
The 8-Bit computer is based on the Simple-As-Possible (SAP) computer architecture described in the book “Digital Computer Electronics” by [Paul Malvino] and [Jerald Brown]. These useful educational examples demonstrate data, computer logic, and even programming in the context of basic electronic components. Tinkering with such simple computers provides a real “zeros and ones” exposure to computation.
[Mazen] added some additional features and functionality to his computer, including an instruction keypad, an address keypad, a dot matrix memory data viewer, a Schottky diode matrix ROM, and a boot loader that initializes the RAM with data stored in ROM. With clock speeds up to 100 Hz, the computer consumes around 300-500 mA of current.
Future plans include expanding the memory and instruction set from the present 128-bit (8×16) RAM, 64-bit (8×8) ROM, and a set of ten instructions. Already, this project is a great addition to an ever-growing catalog of homemade solderless breadboard computers, LCD snake games, and VGA video cards.