There could also be no higher solution to study computer systems than to get your palms soiled and construct your individual. Wiring up the chips to 1 one other and contemplating how {the electrical} alerts stream between them is a good way to visualise how these elements work collectively to make a digital laptop. However trendy computer systems are tremendously complicated, and trying to wire these elements collectively on a breadboard or perfboard is totally futile. Save your self the hassle — it’s by no means going to work.
Because of this, folks that need to design and construct their very own laptop usually work with components from the early Eighties. These comparatively easy chips mostly use through-hole know-how, which makes them straightforward to work with. And the low clock speeds of those programs make them appropriate to be used with breadboards and jumper wires. However reality be instructed, when you construct a breadboard laptop, there’s usually little you can truly do with it.
Take into account Ben Eater’s highly regarded breadboard laptop constructed round a 6502 processor. With just some chips within the design, and solely a personality LCD to make use of for output, it isn’t particularly succesful. So numerous folks put them away of their spare components drawer quickly after getting the “howdy, world” code up and operating. Dr. Matt Regan observed that these computer systems truly do have numerous potential, nonetheless. They simply want a bit of little bit of assist.
Regan famous, for instance, that Eater’s breadboard laptop will not be all that distant from the design of a Commodore VIC-20 laptop, which might run all types of helpful applications and video games. However with the intention to convert the pc right into a VIC-20, a customized VIC chip is required. This chip has lengthy been out of manufacturing, and it’s getting tougher to return by with every passing 12 months.
There are FPGA-based drop-in replacements obtainable, however within the pursuits of training, Regan as an alternative determined to switch the performance of a VIC chip with a bunch of TTL logic chips and EPROMs which might be nonetheless in manufacturing. Between that and the 65C02 CPU and assist chips nonetheless being produced by Western Design Heart, it will be potential to make a clone of the VIC-20 utilizing all trendy components. And to make issues a bit of bit nicer for these of us that don’t need to observe down an outdated TV or conversion field, Regan additionally plans to change the customized VIC such that it could actually output a VGA sign.
To date, the primary video within the sequence has been launched. These preliminary steps set the stage for your complete undertaking by constructing a VIC-20-compatible circuit (minus the VIC alternative) on perfboard. However within the subsequent video, Regan guarantees to have the pc output a VGA sign from the newly-designed VIC circuit. Because the VIC chip additionally handles sound output, that must be coated in a future video as properly. If you wish to play alongside at dwelling, now could be the time to wire up the core of your trendy VIC-20. Try the video for some assist with getting began.
A VIC-20 clone with no VIC chip (📷: Dr. Matt Regan)
The core of the pc (📷: Dr. Matt Regan)
The VIC alternative circuit (📷: Dr. Matt Regan)
