S2K51 - Retro 8051 Computer

Introduction

Here's an evergreen industry standard microcontroller / microprocessor from 1980. Just like the Z-80 and 6502. This CPU is long obsolete, but it lives on in 2026. We're going to not only breadboard a small computer, but we're going to make it run some kind of home-rolled OS, and make it do things. What exactly? Well, imagination can take us anywhere...

The point is to dabble in a bit of lost art, to deal with a CPU that has an external bus for a change. These days most processors do not have exposed buses (for good technical reasons). This little computer is packed with important concepts and design principles that are not being taught anymore. I have encountered an entire generation of engineers and computer science graduates who do not have a cooking clue about buses, peripherals, clocks, bus latency, capacitance, or even a bus cycle, or even memory mapping and how all that actually works.

To be continued...