Since the 1970s, a frequent project has been to take a microprocessor and build a computer system on a breadboard or board. These machines usually have a familiar 8-bit processor such as a 6502 or Z80 due to their board-friendly DIP packages, but there is surprisingly little reason why some of the newer silicon cannot can be treated in the same way. (FoxTech) is leading the way in this, making a board computer using an 80486DX.
A 1990-era 32-bit desktop CPU seems like unpromising territory for this application, but its architecture is surprisingly accessible. It needs a breakout board to access its various lines, but beyond that it can be wired in a very similar way to previous chips.
There are two videos in the series so far, which we’ve placed below the break. The first introduces the project and shows the basic configuration. A running 486 NOP can produce quite a light show, but as the second video starts to show, it’s capable of more. The ultimate goal is to have a simple but fully functional breadboard computer, so start with the logic to decode the 486’s 32-bit bus to the 8-bit bus it will use.
It’s fascinating to learn how the 32-bit 486 manages its interface and deals with four bytes at a time, and we’re really looking forward to seeing how this project develops. The 486 may be on life support here in 2023, but that doesn’t mean it can’t still get some love.
Thanks (Benny) for the tip!