Building your own CPU is arguably the best way to truly wrap your head around how all those ones and zeros get flung around inside of a computer, but as you can probably imagine even a relatively simple processor takes an incredible amount of time and patience to put together. Plus, more often than not you’re then left with a maze of wires and perfboards that takes up half your desk and doesn’t do a whole lot more than blink some LEDs.
But the Pineapple ONE, built by [Filip Szkandera] isn’t your average homebrew computer. Oh sure, it still took two years for him to design, debug, and assemble, his 32-bit RISC-V CPU and all its associated hardware; but the end result is a gorgeous looking machine that runs C programs and offers a basic interactive shell over VGA. In fact with its slick 3D printed enclosure, vertically stacked construction, and modular peripheral connections, it looks more like some kind of high-tech scientific instrument than a computer; homebrew or otherwise.
[Filip] says he was inspired to build this 500 kHz (yes, kilohertz) beauty using only discrete logic components by [Ben Eater]’s well known 8-bit breadboard computer and [David Baruch]’s LMARV-1 (Learn Me A RISC-V, version 1). He spent six months simulating the machine before he even started creating the schematics, let alone design the individual boards. He tried to keep all of his PCB’s under 100 x 100 mm to take advantage of discounts from the fabricator, which ultimately lead to the decision to align the nine boards vertically and connect them together with pin headers.
In the video below you can see [Filip] start up the computer, call up a bit of system information, and even play a rudimentary game of snake before peeking and poking some of the machine’s 512 kB of RAM. It sounds like there’s still some work to be done and bugs to squash, but we’ve already seen enough to say this machine has more than earned entry into the pantheon of master-crafted homebrew computers.