You Can Use Visual Studio Code To Write Commodore 64 Assembly

April 29, 2024 by Lewin Day 18 Comments

Once upon a time, you might have developed for the Commodore 64 using the very machine itself. You’d use the chunky old keyboard, a tape drive, or the 1541 disk drive if you wanted to work faster. These days, though, we have more modern tools that provide a much more comfortable working environment. [My Developer Thoughts] has shared a guide on how to develop for the Commodore 64 using Visual Studio Code on Windows 11.

The video starts right at the beginning from a fresh Windows install, assuming you’ve got no dev tools to start with. It steps through installing git, Java, Kick Assembler, and Visual Studio Code. Beyond that, it even explains how to use these tools in partnership with VICE – the Versatile Commodore Emulator. That’s a key part of the whole shebang—using an emulator on the same machine is a far quicker way to develop than using real Commodore hardware. You can always truck your builds over to an actual C64 when you’ve worked the bugs out!

It’s a great primer for anyone who is new to C64 development and doesn’t know where to start. Plus, we love the idea of bringing modern version control and programming techniques to this ancient platform. Video after the break.

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You Can Run BASIC On An Old HP 4592 Protocol Analyzer

April 28, 2024 by Lewin Day 10 Comments

What do you do when you find an ancient piece of test gear and want to have fun? Well, you can always try getting BASIC running on it, and that’s precisely what [David Kuder] did.

The HP4952A Protocol Analyzer actually looks a lot like an old computer, even if it was never meant for general-purpose use. The heart of the machine is a Zilog Z80 CPU, though, so it shares a lot in common with microcomputers of its era.

Among other hacks, [David] worked to get Microsoft Basic-80 running on the machine. Initially, he was only able to get it up and running on the display, with no way to read the keyboard, disk, or access the serial port. Eventually, by diving into the nitty-gritty of the machine, he was able to at least get the keyboard working along with some basic BASIC programs. Usable memory is just 8KB, but you can do a fair bit with that when you’ve only got a 32×16 display for output anyway!

It’s a neat hack and one that was extendable to the HP4957A as well. We’ve seen similar machines on these pages before, too! If you’ve got your own neat retro hacks on the boil, don’t hesitate to drop us a line!

[Thanks to Christopher Zell for the tip!]

Pi Pico Gets A ZX Spectrum Emulator

April 27, 2024 by Lewin Day 9 Comments

The Pi Pico is a capable microcontroller that can do all kinds of fun and/or useful things. In the former vein, [antirez] has ported a ZX Spectrum emulator to the Pi Pico.

ZX2040, as it is known, is a port of [Andre Weissflog’s] existing ZX spectrum emulator. It’s designed for use on the compact embedded Pi Pico platform, using ST77xx TFT displays. To that end, it has a UI optimized for small, low resolution screens and minimal buttons. After all, very few Pi Picos come with a full QWERTY keyboard attached.

Certain hacks are necessary to make it all work; the chip is overclocked to get things humming fast enough. The emulator also runs upscaling or downscaling in realtime as needed. This allows the emulator to run with a variety of displays, almost none of which are a direct match for the ZX Spectrum’s original resolution of 256×192 pixels.

Code is on Github for the curious, including a great run down from [antirez] on everything that makes it tick. If you want to play ZX Spectrum games on a keychain, you’d do well to start here. There are other projects to emulate it on the Pico, too! Video after the break.

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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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Microsoft Updates MS-DOS GitHub Repo To 4.0

April 26, 2024 by Tom Nardi 30 Comments

We’re not 100% sure which phase of Microsoft’s “Embrace, Extend, and Extinguish” gameplan this represents, but just yesterday the Redmond software giant decided to grace us with the source code for MS-DOS v4.0.

To be clear, the GitHub repository itself has been around for several years, and previously contained the source and binaries for MS-DOS v1.25 and v2.0 under the MIT license. This latest update adds the source code for v4.0 (no binaries this time), which originally hit the market back in 1988. We can’t help but notice that DOS v3.0 didn’t get invited to the party — perhaps it was decided that it wasn’t historically significant enough to include.

That said, readers with sufficiently gray beards may recall that DOS 4.0 wasn’t particularly well received back in the day. It was the sort of thing where you either stuck with something in the 3.x line if you had older hardware, or waited it out and jumped to the greatly improved v5 when it was released. Modern equivalents would probably be the response to Windows Vista, Windows 8, and maybe even Windows 11. Hey, at least Microsoft keeps some things consistent.

It’s interesting that they would preserve what’s arguably the least popular version of MS-DOS in this way, but then again there’s something to be said for having a historical record on what not to do for future generations. If you’re waiting to take a look at what was under the hood in the final MS-DOS 6.22 release, sit tight. At this rate we should be seeing it sometime in the 2030s.

The First European Pocket Calculator Came From Yugoslavia

April 24, 2024 by Jenny List 10 Comments

At the start of the 1970s the pocket calculator was the last word in personal electronics, and consumers in Europe looked eagerly towards Japan or the USA for a glimpse of new products. Meanwhile the European manufacturers, perhaps Philips in the Netherlands, or Olivetti in Italy, would no doubt have been putting their best engineers on to the task of delivering the first domestic European models.

So who was first with a European-made calculator? Not the Dutch, the Italians, the Germans, or even the Brits, instead that honour went to the Yugoslavians. Digitron is a company located in Buje, in modern-day Croatia, and they pipped everyone else in Europe to the post back in 1971 with their DB800 model.

We read about the achievement through the above-linked exhibition, but perhaps the greatest surprise comes in finding relatively little technical information online about these machines. Other early calculators have been subjected to extensive teardowns, so we can see all manner of interesting period tech. This one however, other than references to using Japanese parts, has very little. Whose chip did it use, and were there any quirky design choices made? We hope that someone out there has one and is prepared to give the world a peek.

Meanwhile, we’ve looked at a few older calculators ourselves.

Ancient Cable Modem Reveals Its RF Secrets

April 22, 2024 by Dan Maloney 27 Comments

Most reverse engineering projects we see around here have some sort of practical endpoint in mind. Usually, but not always. Reverse-engineering a 40-year-old cable modem probably serves no practical end, except for the simple pleasure of understanding how 1980s tech worked.

You’ll be forgiven if the NABU Network, the source of the modem [Jared Boone] tears into, sounds unfamiliar; it only existed from 1982 to 1985 and primarily operated in Ottawa, Canada. It’s pretty interesting though, especially the Z80-based computer that was part of the package. The modem itself is a boxy affair bearing all the hallmarks of 1980s tech. [Jared]’s inspection revealed a power supply with a big transformer, a main logic board, and a mysterious shielded section with all the RF circuits, which is the focus of the video below.

Using a signal generator, a spectrum analyzer, and an oscilloscope, not to mention the PCB silkscreen and component markings, [Jared] built a block diagram of the circuit and determined the important frequencies for things like the local oscillator. He worked through the RF section, discovering what each compartment does, with the most interesting one probably being the quadrature demodulator. But things took a decidedly digital twist in the last compartment, where the modulated RF is turned into digital data with a couple of 7400-series chips, some comparators, and a crystal oscillator.

This tour of 80s tech and the methods [Jared] used to figure out what’s going on in this box were pretty impressive. There’s more to come on this project, including recreating the original signal with SDRs. In the mean time, if this put you in the mood for other videotext systems of the 80s, you might enjoy this Minitel terminal teardown.

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