8-Bit Computers Crunch Advanced Scientific Computations

December 1, 2024 by Bryan Cockfield 37 Comments

Although largely relegated to retrocomputing enthusiasts and embedded systems or microcontrollers now, there was a time when there were no other computers available other than those with 8-bit processors. The late 70s and early 80s would have seen computers with processors like the Motorola 6800 or Intel 8080 as the top-of-the-line equipment and, while underpowered by modern standards, these machines can do quite a bit of useful work even today. Mathematician [Jean Michel Sellier] wanted to demonstrate this so he set up a Commodore 64 to study some concepts like simulating a quantum computer.

The computer programs he’s written to do this work are in BASIC, a common high-level language of the era designed for ease of use. To simulate the quantum computer he sets up a matrix-vector multiplication but simplifies it using conditional logic. Everything is shown using the LIST command so those with access to older hardware like this can follow along. From there this quantum computer even goes as far as demonstrating a quantum full adder.

There are a number of other videos on other topics available as well. For example, there’s an AmigaBasic program that simulates quantum wave packets and a QBasic program that helps visualize the statistical likelihood of finding an electron at various locations around a hydrogen nucleus. While not likely to displace any supercomputing platforms anytime soon, it’s a good look at how you don’t need a lot of computing power in all situations. And, if you need a refresher on some of these concepts, there’s an overview on how modern quantum computers work here.

Using AI To Help With Assembly

November 7, 2024 by Bryan Cockfield 30 Comments

Although generative AI and large language models have been pushed as direct replacements for certain kinds of workers, plenty of businesses actually doing this have found that using this new technology can cause more problems than it solves when it is given free reign over tasks. While this might not be true indefinitely, the real use case for these tools right now is as a kind of assistant to certain kinds of work. For this they can be incredibly powerful as [Ricardo] demonstrates here, using Amazon Q to help with game development on the Commodore 64.

The first step here was to generate code that would show a sprite moving across the screen. The AI first generated code in all caps, as was the style at the time of the C64, but in [Ricardo]’s development environment this caused some major problems, so the code was converted to lowercase. A more impressive conversion was done in the next steps, as the program needed to take advantage of the optimizations found in the Assembly language. With the code converted to 6502 Assembly that can run on the virtual Commodore, [Ricardo] was eventually able to show four sprites moving across the screen after several iterations with the AI, as well as change the style of the sprites to arbitrary designs.

Although the post is a bit over-optimistic on Amazon Q as a tool specifically for developers, it might have some benefits over other generative AIs especially if it’s capable at the chore of programming in Assembly language. We’d love to hear anyone with real-world experience with this and whether it is truly worth the extra cost over something like Copilot or GPT 4. For any of these generative AI models, though, it’s probably worth trying them out while they’re in their early stages. Keep in mind that there’s a lot more than programming that can be done with some of them as well.

Another Commodore Portable We Never (Quite) Received

October 29, 2024 by Jenny List 7 Comments

The story of Commodore computers is one of some truly great machines for their time, and of the truly woeful marketing that arguably spelled their doom. But there’s another Commodore computing story, that of the machines we never received, many of which came close enough to production that they might have made it.

[Old VCR] has the story of one of these, and it’s a portable. It’s not a C64 like the luggable which did emerge, neither is it the legendary LCD portable prototype in the possession of our Hackaday colleague [Bil Herd]. Instead it’s a palmtop branded under licence from Toshiba, and since it’s a rare device even its home country of Japan the article gives us perhaps the only one we’ll ever see with either badge.

The Commodore HHC-4 was announced at Winter CES 1983, and since it was never seen again it’s aroused some curiosity among enthusiasts. The article goes to some lengths to cross-reference the visible features and deduce that it’s in fact a Toshiba Pasopia Mini, a typical palmtop computer of the era with not much in the way of processing power, a small alphanumeric display, and a calculator-style QWERTY keyboard. We’re treated to a teardown of a Toshiba unit and its dock, revealing some uncertainty about which processor architecture lurks in those Toshiba custom chips.

Looking at the magazine reviews and adverts it seems as though Commodore may have had some machines with their branding on even if they never sold them, so there exists the tantalizing possibility of one still lurking forgotten in the possession of a former staffer. We can hope.

If Commodore history interests you, you really should read [Bil]’s autobiographical account of the company in the 1980s.

C64 Gets A Graphics Upgrade Courtesy Of Your Favorite Piano Manufacturer

October 11, 2024 by Lewin Day 39 Comments

The Commodore 64 was quite a machine in its time, though a modern assessment would say that it’s severely lacking in the graphical department. [Vossi] has whipped up a bit of an upgrade for the C64 and C128, in the form of a graphics expansion card running Yamaha hardware.

As you might expect, the expansion is designed to fit neatly into a C64 cartridge slot. The card runs the Yamaha V9958—the video display processor known for its appearance in the MSX2+ computers. In this case, it’s paired with a healthy 128 kB of video RAM so it can really do its thing. The V9958 has an analog RGB output that can be set for PAL or NTSC operation, and can perform at resolutions up to 512×212 or even 512×424 interlaced. Naturally, it needs to be hooked directly up to a compatible screen, like a 1084, or one with SCART input. [Vossi] took the time to create some demos of the chip’s capabilities, drawing various graphics in a way that the C64 couldn’t readily achieve on its own.

It’s a build that almost feels like its from an alternate universe, where Yamaha decided to whip up a third-party graphics upgrade for the C64. That didn’t happen, but stranger team ups have occurred over the years.

[Thanks to Stephen Walters for the tip!]

Nearly-Destroyed Commodore Gets New Life

April 26, 2024 by Bryan Cockfield 10 Comments

We all have our shiny, modern computers for interacting with the modern world, but at times they can seem a little monochromatic. Even the differences between something like macOS and Windows for the average user often boil down to which operating system loads an Internet browser. There are obviously more differences than that, but back in the 80s it was much more extreme with interoperability a pipe dream in most cases. What keeps drawing people to maintaining and using computers from that chaotic era is more tangible compared to modern machines, and that is meant quite literally; computers from this era can be saved from an extreme amount of degradation like this Commodore that was nearly completely destroyed before it was re-discovered.

The first step was to restore the case of this Commodore PC20-III, but the restoration of the computer’s internals took a bit more time. First, the entire board was de-soldered, with any rare chips being set aside for future use. Unfortunately the board itself was too corroded and otherwise damaged to be used, but since these were just two-layer boards it could be photographed and then re-created in CAD software to make a near-perfect duplicate of the original. The team at [The Cave] took the opportunity to add patch wires which would have been present in the original machine into the PCB, and made some other upgrades as well like adding sockets to various chips that would have been originally soldered to the board.

The passive components, especially capacitors, were brand new as well and some period-correct components such as a monitor and keyboard finish out the build. The computer boots on the first try, and is quickly put through its paces testing the hard disk drive, using the old floppy drive, and even playing a few video games from the era. The fact that retrocomputers like these are easy (by modern standards) to reverse engineer and restore surely leads to their continued popularity, and we’ve seen everything from C64s to this 128DCR get a similar full restoration.

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Drop-In Switch Mode Regulators

March 31, 2024 by Bryan Cockfield 30 Comments

Perhaps the simplest way to regulate a DC voltage is using a voltage divider and/or an active device like a Zener diode. Besides simplicity, they have the additional advantage of not being particularly noisy, but with a major caveat: they are terribly inefficient. To solve this problem a switching regulator can be used instead, but that generally increases complexity and noise. With careful design, though, a switching regulator can be constructed to almost completely replicate a linear regulator like this drop-in TO3 replacement. (Google Translate from German)

While the replacement regulator was built by [Mr. Floppy], the units are being put to the test in the linked video below by [root42]. The major problem these solve compared to other switching regulators is the suppression of ripple, which is a high-frequency artifact that appears on the DC voltage. Reducing ripple in this situation involved designing low-inductance circuit traces on the PCB as well as implementing a number of EMI filters on both input and output. The final result is an efficient voltage supply for retrocomputers which has a ripple lower than their oscilloscopes can measure without special tools.

[root42] is not only testing these, but the linked video also has him using the modules to repair a Commodore 1541 which originally had the linear TO3 voltage regulators. It’s definitely a non-trivial task to build a switching power supply that meets the requirements of sensitive electronics like these. Switch mode power supplies aren’t new ideas, either, and surprisingly pre-date the first commercially-available transistor although modern ones like these are much less expensive to build.

Continue reading “Drop-In Switch Mode Regulators” →

Commodore CHESSmate Replica Runs On The ESP32

March 20, 2024 by Maya Posch 9 Comments

The Commodore CHESSmate chess computer might not be terribly well known, but that doesn’t make it any less worthy of being reproduced. If anything it is more important, as it gives more people an opportunity to use one of these devices, yet beyond a purely emulated experience the real user interface is harder to experience.

This is where [Michael Gardi]’s modernized replica provides a highly accessible version, consisting of a custom PCB with an ESP32 as the brains of the system. Although decidedly overkill next to the 6502 in the original CHESSmate, it makes the project far easier for others to assemble as it contains few components that shouldn’t be readily available.

The ESP32 is mounted on a small daughterboard which plugs into the main PCB with the buttons, LEDs and indicators. The whole stack is then inserted into the 3D printed reproduction case. These 3D models along with the ESP32 port of the CHESSmate firmware can be found in the GitHub repository, along with a minimalist frame and a ‘CHESSmate Lite’ version as alternative enclosure options for those who somehow don’t appreciate the delightful 1980s aesthetics.

We covered the Commodore CHESSmate last year, including a highly faithful reproduction built by [Hans Otten], which [Michael] read the day after meeting [Peter Jennings], the author of MicroChess (which the CHESSmate uses internally) at an event at York University. Taking this as a sign, he set to work on this particular project.

We’re not sure if there’s really a cosmic force directing [Michael] towards his next project, but if there is, we’d like to take this opportunity to thank it for doing a fantastic job so far.