commodore

127 Articles

[Linus] playing his instrument

The Qweremin Is A QWERTY Theremin With A C-64 Heart

August 30, 2025 by 5 Comments

While we have nothing against other 1980s 8-bit machines, the Commodore 64 has always been something special. A case in point: another new instrument using the C-64 and its beloved SID chip. Not just new to retrocomputing, either, but new entirely. [Linus Åkesson] has invented the QWERTY Theremin, and there’s a Commodore at its core.

If this project sounds vaguely familiar, it’s because it’s based off of the C-64 Theremin [Linus] built a couple of years back. According to [Linus], there were a few issues with the instrument. A real thereminist told him there were issues with the volume response; his own experience taught him that theremins are very, very hard to play for the uninitiated.

This model fixes both problems: first, the volume circuit now includes a pair of digital-analog-converters (DACs) connected to the Commodore’s user port, allowing smooth and responsive volume control.In this case the DAC is being used solely for volume control: SID provides the analog reference voltage, while the 12-bit digital input served as volume control. That proved noisy, however, thanks to the DC bias voltage of the audio output being scaled by the DAC even when the SID was silent. A second DAC was the answer, providing a signal to cancel out the scaled bias voltage. That in and of itself is a clever hack.

The biggest change is that this instrument no longer plays like a theremin. Pitch has been taken out of the 555-based antenna circuit entirely; while vertical distance from the spoon-antenna still controls volume as in a regular theremin and the last version, the horizontal distance from the second antenna (still a clamp) now controls vibrato. Pitch is now controlled by the QWERTY keyboard. That’s a much easier arrangement for [Linus] — this isn’t his first chiptune QWERTY instrument, after all.

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VIC-20 Gets ISA Slot, Networking

August 26, 2025 by 22 Comments

There are few computing collapses more spectacular than the downfall of Commodore, but its rise as a home computer powerhouse in the early 80s was equally impressive. Driven initially by the VIC-20, this was the first home computer model to sell over a million units thanks to its low cost and accessibility for people outside of niche markets and hobbyist communities.

The VIC-20 would quickly be eclipsed by the much more famous Commodore 64, but for those still using these older machines there are a few tweaks to give it some extra functionality it was never originally designed for like this build which gives it an ISA bus.

To begin adapting the VIC-20 to the ISA standard, [Lee] built a fixed interrupt line handled with a simple transistor circuit. From there he started mapping memory and timing signals. The first attempt to find a portion of memory to use failed as it wasn’t as unused as he had thought, but eventually he settled on using the I/O area instead although still had to solve some problems with quirky ISA timing. There’s also a programmable logic chip which was needed to generate three additional signals for proper communication.

After solving some other issues around interrupts [Lee] was finally able to get the ISA bus working, specifically so he could add a 3Com networking card and get his VIC-20 on his LAN. Although the ISA bus has since gone out of fashion on modern computers, if you still have a computer with one (or build one onto your VIC-20), it is a surprisingly versatile expansion port.

Thanks to [Stephen] for the tip!

Commodore Is Back Selling New C64s, But Should You Buy Them?

August 17, 2025 by 107 Comments

It’s hard to argue with nostalgia, but you can toss a bucket of cold facts over it. In the case of the recent rescuing of the Commodore brand from the clutches of relabeling of generic electronics by [Perifractic] of Retro Recipes, we got [The Retro Shack] doing the proverbial bucket dumping in a new video. Basically the question is whether the fresh Commodore 64 offerings by the new-and-improved Commodore are what you really want, or need.

The thing is that over the decades many people have created all the bits that you need to build your own classical C64, or even buy one off-the-shelf, with people like [bwack] having reverse-engineered the various C64 mainboards. These can be populated with drop-in replacements for chips like the SID, VIC-II, CIAs and others that are readily available, along with replica cases and keyboards. If you crave something less bulky and complex, you can run a bare metal C64 emulator like BMC64 on a Raspberry Pi, or just run the VICE emulator on your platform of choice. There’re also options like the full-sized TheC64 and Ultimate 64 Elite II systems that you can buy ready to go.

Basically, there is a whole gamut of ways to get some part of the C64 experience, ranging from emulator-only to a full hardware DIY or pre-assembled format. Each of which come with their own price tag, starting at $0 for running VICE on your existing system. With so much choice we can only hope that the renewed Commodore company will become something more than Yet Another C64 Experience.

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Software Defined Retro ROM Makes 8-bit Easy

July 5, 2025 by 28 Comments

Like the rest of us, 8-bit hardware is not getting any newer, and failed ROMs are just a fact of life. Of course you can’t call up Commadore corporation for replacement parts anymore, so something is needed. [Peirs Rocks] wasn’t satisfied with the existing options, so he came up with the Software Defined Retro ROM to serve as a drop-in replacement for 2364, 2332, and 2316 ROM chips.

Physically, the Software Defined Retro ROM is a PCB that matches the footprint of the original ROM chip, and holds an STM32F4 family microcontroller with a number of extra pins facing upwards. Some of those pins are for programming, so you can flash the board in-situ without removing it from the system using a Pi Pico. The others pins are jumpers for image selection or chip configuration. Depending which STM32 you use, you can have upto 16 ROM images on the board, at whatever chip select behaviour you require. The ROM’s chip select lines could be configured at the factory to answer to HIGH or LOW, and this board can handle either with a jumper swap.

The documentation on the GitHub is very well done, for which we applaud [Piers]. Instructions and demos are also available in the video embedded below. We could certainly see this hack becoming popular in the retrocomputer community, especially as everything ages and memories continue to, uh, y’know. What were we talking about, again?

Oh, right, ROMs. You might think an mask ROM would last a very long time, but it’s been a very long time since some of these were made. Best to dump them while you still can. If the chip is really far gone electrically, you might try decoding a photograph of the die.

 

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Let’s Buy Commodore! Well, Somebody Is.

June 7, 2025 by 62 Comments

When a man wearing an Atari T-shirt tells you he’s buying Commodore it sounds like the plot for an improbable 1980s movie in which Nolan Bushnell and Jack Tramiel do battle before a neon synthwave sunset to a pulsating chiptune soundtrack. But here on the screen there’s that guy doing just that, It’s [Retro Recipes], and in the video below he’s assembling a licensing deal for the Commodore brand portfolio from the distant descendant of the Commodore of old.

It’s a fascinating story and we commend him for tracing a path through the mess that unfolded for Commodore in the 1990s. We tried the same research path with a friend a few years ago and ended up with an anonymous Dutch paper company that wouldn’t answer our calls, so we’re impressed. In conjunction with several other players in the Commodore retrocomputing world he’s trying to assemble a favourable percentage deal for manufacturers of new parts, computers, and other goodies, and we’re pleased to see that it’s for the smaller player as much as for the industry giant.

When looking at a story like this though, it’s important not to let your view become clouded by those rose tinted glasses. While it’s great that we’re likely to see a bunch of new Commodore-branded Commodore 64s and parts, there are many pitfalls in taking it beyond that. We’ve seen the Commodore logo on too many regrettable licensed products in the past, and we fear it might be too tempting for it to end up on yet another disappointing all-in-one video game or just another budget PC. If something new comes out under the Commodore brand we’d like it to be really special, exploiting new ground in the way the Amiga did back in the day. We can hope, because the alternative has dragged other famous brands through the mud in recent years.

If you want an insight into the roots of the original Commodore’s demise, have a read of our Hackaday colleague [Bil Herd]’s autobiography.

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A New Mechanical Keyboard For An Old Computer

April 10, 2025 by 9 Comments

As computers age, a dedicated few work towards keeping some of the more interesting ones running. This is often a losing battle of sorts, as the relentless march of time comes for us all, human and machine alike. So as fewer and fewer of these machines remain new methods are needed to keep them running as best they can. [CallousCoder] demonstrates a way of building up a new keyboard for a Commodore 64 which both preserves the original look and feel of the retro computer but also adds some modern touches.

One of the main design differences between many computers of the 80s and modern computers is that the keyboard was often built in to the case of the computer itself. For this project, that means a custom 3D printed plate that can attach to the points where the original keyboard would have been mounted inside the case of the Commodore. [CallousCoder] is using a print from [Wolfgang] to get this done, and with the plate printed and a PCB for the keys it was time to start soldering. The keyboard uses modern switches and assembles like most modern keyboards do, with the exception of the unique layout for some of the C64 keys including a latching shift key, is fairly recognizable for anyone who has put together a mechanical keyboard before.

[CallousCoder] is using the original keycaps from a Commodore 64, so there is an additional step of adding a small adapter between the new switches and the old keycaps. But with that done and some amount of configuring, he has a modern keyboard that looks like the original. If you’re more a fan of the original hardware, though, you can always take an original C64 keyboard and convert it to USB to use it on your modern machines instead.

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Copying Commodore Data Tapes, 40 Years Late

February 28, 2025 by 41 Comments

Unless you handle the backups for a large corporation, bank, or government entity, you likely haven’t stored much data to tape recently. But magnetic storage used to be fairly mainstream back in the 1980s for all kinds of computer programs. Plenty of computers used standard cassette tapes for this too but you couldn’t just copy them with standard audio equipment. You’d need something like this 1560 datasette from [Jan].

The core problem with using Hi-Fi equipment to copy tapes storing data instead of audio is that data tapes need to be much more precise in order to avoid losses that might not be noticeable in an audio recording. In the 80s computer companies like Commodore built tape drives specifically for their computers, so [Jan]’s project uses two of these 1530 drives to build this “1560” datasette. (No working 1530 hardware was harmed in this build.) An inverter circuit in one tape deck is used to provide the signal to write the data to the other tape, reliably copying data from these data tapes in a way Hi-Fi never could.

[Jan] does lament not having something like this back in the 80s when the Commodore was in its heyday, but there’s still a dedicated retrocomputing scene for these machines that will get plenty of use out of projects like this. If you need to go the other direction in time, there are also interfaces that allow data tapes from old Commodores to be read by modern computers with USB.

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