A Z80 Computer At The Next Level

February 23, 2020 by Jenny List 40 Comments

At the close of the 8-bit home computer era there were some machines produced that attempted to bridge the gap between the 8- and 16-bit worlds, either by providing a 16-bit device with a backwards compatibility mode, or an 8-bit one with enhanced capabilities to compete with its newer rivals. These products largely fell by the wayside in the face of new 16-bit only platforms, but they and the various enhanced versions of 8-bit processors that appeared over subsequent decades present a fascinating glimpse of what might have been. It’s a theme [Konstantin Dimitrov] explores with his Z20X computer project, a machine using the Zilog eZ80 processor running at 20 MHz, with 512 kB of external memory, and an interface for a 7″ TFT screen module.

The eZ80 is a more recent development, a pipelined processor capable of much higher clock speeds and addressing up to 16 MB of memory while maintaining software compatibility with the Z80. Had it come to market in the late 1980s it would have been a sensation, but instead it has appeared in embedded computers and perhaps of most interest to Hackaday readers, in TI’s line of programmable calculators.

The Z20X is designed to be a through-hole board, with the only SMD component the eZ80 itself. We can understand the motivation behind this, but at the same time wonder whether its likely builders in 2020 will be people unfazed by SMD assembly. It has a system of processor modules in case of future upgrades, and an expansion backplane with an option of an RC2014-compatible bus. There are also PS/2 keyboard and mouse connectors, a serial bus, and an on-board sound chip. The website is short on details of any software, but we’d expect it to work with the typical Z80 retrocomputer offerings such as a BASIC interpreter and the CP/M operating system.

This machine is likely to appeal to retrocomputing enthusiasts, but had it appeared even without the display in a previous decade it would no doubt have become an object of desire. It does however serve as a reminder that the Z80 line has been updated, and though most of us will have moved on it still offers a few chips that could be of interest. Meanwhile for a comparison, take a look at last year’s review of the latest in the range of RC2014 retrocomputer boards.

Thanks [yNos] for the tip.

Catch The Old School BASIC Bug With This Computer Kit

December 12, 2019 by Tom Nardi 27 Comments

Does the complexity of modern computing ever get you down? Do you find yourself longing for the old days, where you could actually understand what your desktop machine’s hardware and software was doing at any given moment? You aren’t alone, but unfortunately running a 40+ year old computer as your daily driver isn’t really a viable option.

But that doesn’t mean you don’t have options. [Kostas] writes in to tell us about the “CB2 micro”: a diminutive open source retrocomputer kit that can be built in as little as 30 minutes thanks to its through-hole construction and exceptionally low parts count. When completed the miniature computer is an all-in-one BASIC development platform; just connect up a display and a PS/2 keyboard, and you’ve got everything you need to write you own programs or run games and applications developed by the community. You don’t even need a floppy, as the ATmega644P powered board has enough internal flash to store eight programs for easy access through its graphical menu system.

For many in the audience, a cheap little board that you can assemble yourself and use as a stand-alone BASIC experimentation platform is appealing enough. But thanks to a collection of hardware add-on boards, the CB2 micro can be augmented with some interesting capabilities.

Some are fairly obvious such as adding additional flash storage or RAM, but you can also run the computer on AA or AAA batteries, or add an S-Video port. [Kostas] even explains how to assemble a special serial cable that allows you to network multiple boards together. If you take the plunge and start building your own hardware modules, the sky’s the limit.

Of course, purists may balk because the CB2 micro isn’t using a “real” computer processor. Fair enough. For those that want a more authentic retro experience, you could always pick up a kit like the RC2014, or go all out and cram a Z80 into an Altoids tin so you can carry it around with you.

Building A Front Panel For The RC2014 Computer

November 21, 2019 by Tom Nardi 6 Comments

The RC2014 is a slick Z80 computer kit that’s graced these pages a number of times in the past. It allows anyone with a soldering iron and a USB-to-serial adapter to experience the thrill of early 1980s desktop computing. But what if you’re looking for an even more vintage experience? In that case, this custom RC2014 front panel from [James Stanley] might be just the thing to scratch that Altair itch.

The front panel allows you to view and alter the contents of memory with nothing more complex than toggle switches and LEDs, just like on the early microcomputers of the 1970s. If you’ve ever wanted to learn how a computer works on the most basic level, single-stepping through instructions and reading them out in binary is a great way to do it.

[James] says he was inspired to take on this project after reading a 1978 issue of Kilobaud Magazine (as one does), and seeing an article about building a homebrew Z80 machine with a front panel. Obviously he had to modify the approach a bit to mate up with this relatively modern variation on the venerable CPU, but the idea was essentially the same.

His documentation for the project is sure to be fascinating for anyone enamored with those iconic computers of yesteryear, but even readers with more modern sensibilities will likely find some interesting details. The way [James] coaxes the data and various status states out of the kit computer takes up the bulk of the write-up, but afterwards he talks about how he designed the PCB and wraps up with his tips for creating a professional looking front panel.

This isn’t the first time we’ve seen a modern Z80 computer kitted out with blinkenlights, but it’s certainly one of the most professional looking. If you combine the RC2014 kits available on Tindie with the details provided by [James], you’ll soon be learning the fine art of programming a computer with toggle switches.

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Teardown: VTech PreComputer 1000

November 19, 2019 by Tom Nardi 46 Comments

Back in the days before kids could be placated with a $50 Android burner phone, many a youngster was gifted a so-called “educational computer” to keep them occupied. Invariably looking like a fever dream version of the real computer their parents didn’t want to let them use, these gadgets offered monochromatic exploits that would make Zork look like Fortnite. Due equally to their inherent hardware limitations and the premise of being an educational toy, the “games” on these computers often took the form of completing mathematical equations or answering history questions.

The VTech PreComputer 1000 is a perfect specimen of this particular style of educational toy. Released in 1988, it was advertised as a way for pre-teens to become more comfortable with operating a real computer; since at that point, it had become abundantly clear that the coming decade would see a beige box on every professional’s desk. Its full-size QWERTY keyboard was specifically mentioned in the product’s accompanying literature as a way to get young hands accustomed to the ways of touch typing.

Words of wisdom from the PreComputer 1000’s manual.

By the mid-1990s these devices would have progressed far enough to include passable text-to-speech capabilities and primitive graphics, but the junior professional who found him or herself seated in front of the PreComputer 1000 was treated to a far more spartan experience. It’s perhaps just as well that this particular educational computer was listed as a training tool, because even in 1988, surely a session with this toy must have felt very much like work.

But that’s not to say the PreComputer 1000 is without its own unique charms. In an effort to help cement its role as a “trainer” for more conventional computers, VTech saw fit to equip the PreComputer with its own BASIC interpreter. They even included generous written documentation that walked young programmers through the various commands and functions. Even today, there’s something oddly appealing about a mobile device with a full keyboard that can run BASIC programs for better than 24 hours on batteries (even if they’re alkaline “C” cells).

Let’s take a look inside this more than 30 year old mobile device, and see how the designers managed to create a reasonable facsimile of actual computing on a kid-friendly budget.

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The Book Of Dreams Brings Back All Your Memories

November 16, 2019 by Jenny List 16 Comments

The retro-facing side of British social media has been abuzz for the last few days with a very neat piece of marketing form the catalogue retailer Argos: they’ve digitised all their catalogues since 1975 and put them online. While this contains a cross-section of over four decades’ styles, fads, and ephemera, it also gives the browser a fascinating look at a host of retrotechnology from a contemporary viewpoint rather than through the rose-tinted glasses of 2019. It may not be a hack, but we guarantee you’ll spend a while browsing it!

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Atari Tape Drive Turned Security DVR

November 1, 2019 by Tom Nardi 11 Comments

We know that a lot of our beloved readers don’t take kindly to abuse of vintage hardware, so the Atari fans in the audience may want to avert their eyes for this one. Especially if they’re particularly keen on spinning up their Jawbreaker cassette on authentic hardware, as [iot4c] has gutted an Atari XC12 Program Recorder to turn it into an enclosure for a Raspberry Pi video storage device.

Step one of this conversion was, as you might expect, removing all the original hardware from the cassette recorder case. From there, [iot4c] fitted the Raspberry Pi, a USB hard drive, and a YDS-5A DC-DC converter to power them. Depending on what the drive setup looks like, it might also make sense to add a USB powered hub. A length of Ethernet cable was left hanging out the back of the Atari XC12 so it could be plugged into the network, but a panel mount RJ45 connector could spruce things up a bit.

Of course, gutting an old piece of hardware and sticking a Pi into it isn’t exactly breaking any new ground at this point. But we did appreciate that [iot4c] went the extra mile to wire it up so the “Save” LED now doubles as a network activity indicator. Which pretty much brings it full circle in terms of functionality for a network-attached video recorder.

Earlier in the year [iot4c] converted a 65XE into a USB keyboard with the help of an Arduino Leonardo, but the vintage Atari aficionados will be happy to note that at least in that case the donor machine remained fully functional.

Vintage Speech Synthesizer Croons The Oldies

June 11, 2019 by Dan Maloney 33 Comments

If you listened to the National Weather Service Weather Radio in the US about 25 years ago, you’ll no doubt remember [Perfect Paul], one of the synthesized voices used to read current conditions and weather forecasts. The voice came from a DECtalk DTC01, a not inexpensive voice synthesizer first made in 1984 that also gave voice to [Stephen Hawking] for many years.

Long obsolete, the DECtalk boxes have a devoted following with hobbyists who like to stretch what the device can do. Some even like to make it sing, after a fashion, and [Michael] decided that making a DECtalk sing “Xanadu”, the theme song from the 1980 [Olivia Newton-John] musical extravaganza, was a good idea. Whether it actually was is debatable, and we’ll take exception with having that particular ditty stuck in our head as a result, but we don’t judge except on the merits of the hack.

It’s actually easy if you have a DECtalk; the song is a straight ASCII file with remarkably concise instructions on which phonemes the box needs to generate. Along with inflection, tone, and timing instructions, the text file looks almost completely unlike English while still somehow being readable. The DECtalk accepts the file over RS-232, which would be easy enough to do with a modern computer, but [Michael] upped his game a bit by using a TRS-80 Model 100 computer as a serial terminal. The synthesized song is in the video below, with the original included for reference by those who didn’t ~~experience~~ endure the late disco-era glory days.

DECtalks seem pretty rare in the wild, so we appreciate this glimpse at what they can do. There are other retro speech synthesizer hacks, though: the simulated walnut goodness of the Votrax and the MicroVox come to mind, as does the venerable TI Speak and Spell.

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