ARITH-MATIC has considered the idea of building a 4-bit 7400 series-based CPU for some time. Like many projects, however, life (and perhaps other projects) got in the way, but with the Retro Computer Festival in Cambridge, England coming up, he decided to just go for it and see what could be made in 30 days!
With this rushed production schedule, he created the Cambridge-1 breadboard computer, which implements a 4-bit word size, but can do 8-bit calculations via bit slicing if needed. The main components consist of 74HC273 registers for storage during calculations, along with other 7400 series components for counters, buffers, an adder, and a comparator. A non-7400 SRAM chip is used to for program storage, and there’s also Arduino Micro onboard, which dwarfs the C-1’s computing power as it runs at a tepid 40 Hz clock speed. A variety of LEDs that blink away to tell the status of the machine, plus a huge number of wires, spread out on an epic breadboard setup.
The Arduino used here is actually implemented to programs onto the RAM chip, which certainly saved time when developing and building the rig in a 30-day time frame. It’s an amazing build, as seen in the video below below, and it will be exciting to see how this project continues to develop!
Go to Source
Author: Jeremy S. Cook