There could also be no higher method to find out about computer systems than to get your arms soiled and construct your individual. Wiring up the chips to at least one one other and contemplating how {the electrical} alerts move between them is a good way to visualise how these parts work collectively to make a digital laptop. However fashionable computer systems are tremendously advanced, and trying to wire these parts collectively on a breadboard or perfboard is totally futile. Save your self the trouble — it’s by no means going to work.
Because of this, those that wish to design and construct their very own laptop usually work with components from the early Nineteen Eighties. These comparatively easy chips mostly use through-hole know-how, which makes them simple to work with. And the low clock speeds of those programs make them appropriate to be used with breadboards and jumper wires. However fact be instructed, when you construct a breadboard laptop, there may be usually little which you could truly do with it.
Contemplate Ben Eater’s extremely popular 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 a number of individuals put them away of their spare components drawer quickly after getting the “good day, world” code up and working. Dr. Matt Regan observed that these computer systems truly do have lots of potential, nonetheless. They simply want a bit of little bit of assist.
Regan famous, for instance, that Eater’s breadboard laptop just isn’t all that distant from the design of a Commodore VIC-20 laptop, which may run all kinds of helpful packages 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 more durable to return by with every passing 12 months.
There are FPGA-based drop-in replacements accessible, however within the pursuits of schooling, Regan as a substitute determined to switch the performance of a VIC chip with a bunch of TTL logic chips and EPROMs which are nonetheless in manufacturing. Between that and the 65C02 CPU and help chips nonetheless being produced by Western Design Middle, it might be potential to make a clone of the VIC-20 utilizing all fashionable components. And to make issues a bit of bit nicer for these of us that don’t wish to monitor down an previous TV or conversion field, Regan additionally plans to change the customized VIC such that it may well output a VGA sign.
To this point, the primary video within the collection has been launched. These preliminary steps set the stage for all the undertaking by constructing a VIC-20-compatible circuit (minus the VIC substitute) 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 lined in a future video as nicely. If you wish to play alongside at dwelling, now could be the time to wire up the core of your fashionable VIC-20. Take a look at 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 substitute circuit (📷: Dr. Matt Regan)