Whilst the phrase “I crafted my individual computer” could seem outstanding to the uninitiated, everyone with an curiosity in modern-day personal computer hardware is aware that there is genuinely not considerably to it: acquire a circumstance, a motherboard with a CPU, some RAM and peripherals, and you’re pretty considerably there. What is way additional amazing is coming up with a total laptop program from the ground up, as [Joshua Coleman] just did when he crafted the Coleman Z80.
And when we say “from the floor up”, we necessarily mean it: everything down to the method bus was hand-drawn by [Joshua] himself. It does share a thing with modern PCs nevertheless: a strictly modular layout. There is a Z80 CPU board, a ROM and RAM board, and even two modules that you could explain as a online video card and a sound card. All of these are designed on prototyping boards with a 40-pin edge connector and hooked up to a single backplane carrying the major technique bus.
Made as an experimentation system, the Coleman Z80 has several functions that permit screening and debugging, this kind of as an adjustable clock generator and a few stunning classic LED shows that present the status of the main bus. Enter and output are predominantly by a serial backlink and a 16×2 Liquid crystal display, but [Joshua] is by now arranging a keyboard interface and composite online video output to give it that proper 1980s property computer system vibe. The program is at this time restricted to a ROM keep an eye on that enables primary I/O commands, but with 256 KB of RAM there’s a great deal of probable for creating practical software program.
Just as extraordinary as the style by itself is the simple fact that this was [Joshua]’s very first electronic structure venture we’ve absolutely observed even worse very first assignments! Over the decades we’ve showcased various great homebrew Z80 computers, these kinds of as a super-minimalistic board, a modular procedure dependent on the powerful eZ80, and this cute little 1 that fits inside of an Altoids tin.