It’s Raining Brand-new Commodore 64s

There’s never been a better time to build your own Commodore 64, apparently. Within a day of each other, we got tipped off on three (3!) separate C64 builds from two different hackers.

This has been made possible by a series of disparate projects that have individually recreated a piece of the full machine. Replacement motherboards exist, like the Ultimate 64 and the C64 Reloaded Mk2. New cases can be had courtesy of Pixelwizard. Even new keyboard bases can be had thanks to the Mechboard 64 project.

[Eric Hill] took all these parts and built his own C64 from scratch. And not content with one, he repeated the process and built another.

These two machines serve as demos for the two different motherboard options. Taken together, they serve to demonstrate how many of the vintage Commodore components have been remanufactured by the fan community: with the exception of the keycaps and possibly some of the silicon, all the parts in both machines are new.

Did we just say “keycaps?” This became the pet project of [Perifractic], who discovered that certain Lego Technic pieces had the same cross-shaped slot as the original Commodore 64 keys. After some experimentation, a full set of Lego keycaps was produced. (YouTube, embedded below.) Far from a thrown-together set of random pieces, the sets are available for order with printed tiles with recreation graphics. And this lets you build a C64 using precisely zero parts that came out of a Commodore factory. It’s a testament to the popularity of the world’s best selling computer that it is now once again possible to build one with brand new parts.

If you want to replicate this feat, [Perifractic]’s website is set up to make ordering everything you need easy. Things have certainly come a long way from the first reproduction cases launched on Kickstarter a few years ago.

[Thanks to Keith O for the tip!]

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Component Video For The Commodore 64

Of all the retro systems, the Commodore 64 had the best video system. The VIC-II chip in the C64 was the best example of why Commodore was the best, but in terms of video output, the C64 was still a consumer device: the only output was S-video, or composite video, or something like it. The professional stuff uses YPbPr, an RGB video signal that separates the red, green, and blue colors. On a modern LCD, the difference between composite and YPbPr is noticeable, and if you’re going to run your C64 on the big screen, it would be very helpful to use a professional video standard.

In an effort to bring the C64 into the future, [c0pperdragon] created an FPGA-based modification for the VIC-II chip. The end result is getting YPbPr signals directly from the computer, and outputting it to a TV in glorious 480p.

Inside the Commodore 64, the VIC-II creates the chrominance signal in a way that is impossible to convert it back to any form of RGB. The solution to get RGB out of this information is to listen in to 22 pins of the VIC-II to determine what signals it intends to generate. This is done with a smallish Altera FPGA connected to the VIC-II through a ribbon cable. On the FPGA, the luminescence and all the color information is generated, then converted into true YPbPr. For the complete mod, the RF modulator is removed, and the original A/V jack is still functional. This is effectively a very in-depth mod that rids the C64 of the TV connector and channel selector (that no one uses anymore) and replaces it with a professional-grade video output.

When it comes to C64 mods, we thought we’ve seen it all. We’ve seen C64s resurrected from the dead, and we’ve seen drop-in replacements for the SID that still don’t have working filters oh my god. This is on another level. This is using FPGAs to drag the C64 into the modern era, and if you don’t care about the rusting RF box, it’s a reversible mod.

Using Modern Nintendo Controllers On The C64

There are plenty of people out there who still enjoy playing games on vintage computers like the Commodore 64. But while they likely return to these classic games themselves out of a sense of nostalgia, the feeling doesn’t always extend to the hardware itself. For example, one can enjoy playing Impossible Mission without having to use a contemporary C64 joystick.

Thanks to an open source project developed by [Robert Grasböck], C64 owners who want to take advantage of the improvements made to gaming controllers in the nearly 40 years since the system’s release now have another option. Called Nunchuk64, it allows you to use various Nintendo controllers which make use of the Wii “Nunchuk” interface on original C64 hardware. This includes the controllers from the recent “Classic Edition” NES and SNES systems, which offer a decidedly retro feel with all the benefits of modern technology and construction techniques.

Both the hardware and software for Nunchuck64 are open source, and everything you need to build your own version is in the project’s repository. [Robert] even has assembly instructions, complete with images, which walk you through building your own copy of the hardware and flashing the firmware onto it. This is a nice touch that we very rarely see even in open source projects. The board is populated with a ATmega328P microcontroller and a handful of passive components, making assembly fairly straightforward assuming you are comfortable with SMD work.

Bringing more modern controllers to classic systems seems to be gaining popularity recently, within the last few months we’ve seen Xbox 360 controllers on the Nintendo 64, and newly manufactured pads for the Atari 5200.

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Sad Without a SID? This Comes Pretty Close

The MOS Technologies 6851, popularly known as the SID, is a legendary sound synthesiser integrated circuit from the early 1980s that is most famous for providing the Commodore 64 home computer with its ability to make noise. At the time it was significantly better than what could be found in competitor machines, making it a popular choice for today’s chiptune and demo scene artists.

There’s a snag for a modern-day SID-jockey though, the chip has been out of production for a quarter century and is thus in short supply. Emulation is a choice, but of little use for owners of original hardware so it’s fortunate that [Petros Kokotis] has produced a SID replacement using a Teensy 3.6.

The operation is simple enough, the Teensy provides all the requisite SID data lines via some level shifters for the host microcomputer, and uses [Frank Boesing]’s ReSID library to do the heavy lifting part of being a SID. You can download the code from a GitHub repository, and he’s posted a video we’ve put below the break showing a prototype in action with a real Commodore 64. The audio quality isn’t brilliant due to a phone camera recording from a very tinny speaker, but notwithstanding that it has the air of the real thing.

This isn’t the first SID we’ve seen here. How about a MIDI synth using one?

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Raspberry Pi Becomes Cycle Exact Commodore Drive Emulator

The Commodore 1541 disk drive is unlike anything you’ll ever see in modern computer hardware. At launch, the 1541 cost almost as much as the Commodore 64 it was attached to ($400, or about $1040 at today’s value). This drive had a CPU, and had its own built-in operating system. Of course, anyone using a Commodore 64 now doesn’t deal with this drive these days — you can buy an SD2IEC for twenty dollars and load all your C64 games off an SD card. If you’re cheap, there’s always the tape drive interface and a ten dollar Apple Lightning to 3.5mm headphone adapter.

But the SD2IEC isn’t compatible with everything, and hacking something together using the tape drive doesn’t have the panache required of serious Commodoring. What’s really needed is a cycle-accurate emulation of the 1541 disk drive, emulating the 6502 CPU and the two 6522 VIAs in this ancient disk drive. The Raspberry Pi comes to the rescue. [Steve White] created the Pi1541, an emulation of the Commodore 1541 disk drive that runs on the Raspberry Pi 3B.

Pi1541 is a complete emulation of the 6502 and two 6522s found inside the Commodore 1541 disk drive. It runs the same code the disk drive does, and supports all the fast loaders, demos, and copy protected original disk images that can be used with an original drive.

The only hardware required to turn a Raspberry Pi 3 into a 1541 are a few transistors in the form of a bi-directional logic level shifter, and a plug for a six-pin serial port cable. This can easily be constructed out of some Sparkfun, Adafruit, Amazon, or AliExpress parts, although we suspect anyone could whip up a Raspberry Pi hat with the same circuit in under an hour. The binaries necessary to run Pi1541 on the Raspberry Pi are available on [Steve]’s website, and he’ll be releasing the source soon.

This is a great project for the retrocomputing scene, although there is one slight drawback. Pi1541 requires a Raspberry Pi 3, and doesn’t work on the Raspberry Pi Zero. That would be an amazing bit of software, as ten dollars in parts could serve as a complete emulation of a Commodore disk drive. That said, you’re still likely to be under $50 in parts and you’re not going to find a better drive emulator around.

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Emulating A Complete Commodore 64

When the Commodore 64 was released in 1982, it was a masterpiece of engineering. It had capabilities far outstripping other home computers, and that was all due to two fancy chips inside the C64. The VIC-II, the video chip for the C64, had sprites and scrolling, all stuffed into a single bit of silicon. The SID chip was a complete synthesizer on a chip. These bits of silicon made the C64 the best selling computer of all time, but have also stymied efforts to emulate a complete C64 system on a microcontroller.

[Frank Bösing] has just managed to emulate an entire C64 on a Teensy 3.6. The Teensy uses an exceptionally powerful microcontroller, but this is a labor of love and code.

The inspiration for this project comes from a reverse-engineered SID chip that was ported to the Teensy 3.2. The SID chip is the make it or break it feature of any C64 emulation, but the Teensy 3.2 didn’t have enough RAM for the most recent versions of reSID. With the release of the Teensy 3.6, [Frank] figured the increased amount of RAM would allow a complete C64 system, so he built it.

The new C64 emulator uses a Teensy 3.6, with a small add-on ‘shield’ (or whetever we’re calling them) to provide connectors for joysticks and the Commodore IEC bus. There’s audio out, support for USB keyboards, and support for an IL9341 SPI display or a regular ‘ol VGA display.

The entire development of this Commodore emulator has been documented over on the PJRC forums, and all the code is over on GitHub. It’s a fantastic piece of work, and as the video (below) shows, this is a real Commodore 64 that fits in your pocket.

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Can This Commodore 64 Be Saved?

If you are a certain age, there’s a fair chance your first computer was a Commodore 64. These machines are antiques now, and [RetroManCave] received one from a friend’s loft in unknown condition. He’s made two out of three videos covering the machine, its history, and its internals. Assisting is Commodore 64 expert [Jan Beta] who apparently owned one way back when. You can see the first two videos, below.

The machine isn’t as old as you might think — it is the “newer” case style (circa 1987). [Jan] gives a great overview of the different motherboards you might encounter if you are lucky enough to come across one of these in a dumpster somewhere.

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