Though the phrase “I constructed my individual computer” could possibly audio amazing to the uninitiated, anyone with an interest in modern day computer system components is familiar with that there’s really not considerably to it: invest in a circumstance, a motherboard with a CPU, some RAM and peripherals, and you are pretty much there. What’s way much more spectacular is developing a complete personal computer technique from the ground up, as [Joshua Coleman] just did when he crafted the Coleman Z80.
And when we say “from the ground up”, we signify it: every thing down to the program bus was hand-drawn by [Joshua] himself. It does share anything with fashionable PCs nevertheless: a strictly modular layout. There’s a Z80 CPU board, a ROM and RAM board, and even two modules that you could explain as a movie card and a seem card. All of these are designed on prototyping boards with a 40-pin edge connector and hooked up to a one backplane carrying the primary method bus.
Built as an experimentation platform, the Coleman Z80 has several functions that permit testing and debugging, this sort of as an adjustable clock generator and a handful of gorgeous classic LED displays that show the status of the main bus. Input and output are mainly by means of a serial link and a 16×2 Lcd, but [Joshua] is previously scheduling a keyboard interface and composite online video output to give it that good 1980s home laptop or computer vibe. The application is at this time limited to a ROM check that enables basic I/O instructions, but with 256 KB of RAM there’s lots of probable for crafting handy software.
Just as impressive as the style itself is the reality that this was [Joshua]’s initial digital style venture we’ve undoubtedly found worse initially jobs! In excess of the decades we have featured many interesting homebrew Z80 pcs, these as a super-minimalistic board, a modular method dependent on the effective eZ80, and this adorable minor one particular that fits inside an Altoids tin.