Single-Board Z80 Computer Draws Inspiration From Picasso

May 1, 2025 by Lewin Day 19 Comments

Picasso and the Z80 microprocessor are not two things we often think about at the same time. One is a renowned artist born in the 19th century, the other, a popular CPU that helped launch the microcomputer movement. And yet, the latter has come to inspire a computer based on the former. Meet the RC2014 Mini II Picasso!

As [concretedog] tells the story, what you’re fundamentally looking at is an RC2014 Mini II. As we’ve discussed previously, it’s a single-board Z80 retrocomputer that you can use to do fun things like run BASIC, Forth, or CP/M. However, where it gets kind of fun is in the layout. It’s the same fundamental circuitry as the RC2014, but it’s been given a rather artistic flair. The ICs are twisted this way and that, as are the passive components; even some of the resistors are dancing all over the top of one another. The kit is a limited edition, too, with each coming with a unique combination of colors where the silkscreen and sockets and LED are concerned. Kits are available via Z80Kits for those interested.

We love a good artistic PCB design; indeed, we’ve supported the artform heavily at Supercon and beyond. It’s neat to see the RC2014 designers reminding us that components need not live on a rigid grid; they too can dance and sway and flop all over the place like the eyes and or nose on a classic Picasso.

It’s weird, though; in a way, despite the Picasso inspiration, the whole thing ends up looking distinctly of the 1990s. In any case, if you’re cooking up any such kooky builds of your own, modelled after Picasso or any other Spanish master, don’t hesitate to notify the tipsline.

A Birthday Cake For A Retrocomputer Designer

October 25, 2024 by Jenny List 6 Comments

When making a birthday cake a bit more personal, one can create a novelty themed confection appropriate for the lucky recipient. In the case of [Spencer Owen], who you may know as the creator of the RC2014 retrocomputing ecosystem, it was appropriate to have one of the little machines at work somewhere, so [peahen] did just that. The result is a cake in the shape of an IMSAI 8080 microcomputer, but it does more than just look the part. This is a working replica of the classic machine, powered as you might expect by an RC2014 sitting next to it.

The lights are a set of addressable LEDs, and the switches are made from appropriately colored sweets. Sadly the plan to make these capacitive touch switched failed as the wiring became buried in the icing, but the LEDs deserve a second look. They’re encased in translucent heatshrink sleeving which is embedded under a layer of white icing, which is translucent enough, but on top for the classic panel light look are a set of edible cake-maker’s jewels. Best of all while all except the electronics is edible, the front panel is robust enough to have been removed from the cake in one and thus will live on.

We rather like the idea of electronics meeting sugarcraft, because fondant is a surprisingly versatile medium that deserves attention much further than just confectionery. We remember it being a popular cheap way to experiment with 3D printing back at the dawn of open source printers, and it still has some potential. Meanwhile if you’ve not seen the RC2014 we reviewed its original version back in 2016, and since then it’s evolved to become an ecosystem in its own right.

No Z80? No Problem!

September 16, 2024 by Jenny List 17 Comments

Earlier this year Zilog stopped production of the classic 40-pin DIP Z80 microprocessor, a move that brought a tear to the eye of retro computing enthusiasts everywhere. This chip had a huge influence on both desktop and embedded computing that lingers to this day, but it’s fair to say that the market for it has dwindled. If you have a retrocomputer then, what’s to be done? If you’re [Dean Netherton], you create a processor card for the popular RC2014 retrocomputer backplane, carrying the eZ80, a successor chip that’s still in production.

The eZ80 can be thought of as a Z80 system-on-chip, with microcontroller-style peripherals, RAM, and Flash memory on board. It’s much faster than the original and can address a relatively huge 16MB of memory. For this board, he’s put the chip on a processor daughterboard that plugs into a CPU card with a set of latches to drive the slower RC2014 bus. We can’t help drawing analogies with some of the 16-bit upgrades to 8-bit platforms back in the day, which used similar tactics.

So this won’t save the Z80, but it might well give a new dimension to Z80 hacking. Meanwhile, we’re sure there remain enough of the 40-pin chips out there to keep hackers going for many years to come if you prefer the original. Meanwhile, read our coverage of the end-of-life announcement, even roll your own silicon if you want., or learn about the man who started it all, Federico Faggin.

Addressable LEDs From A Z80

January 19, 2023 by Jenny List 3 Comments

If you buy WS2812s under the Adafruit NeoPixel brand, you’ll receive the advice that “An 8 MHz processor” is required to drive them. “Challenge Accepted!“, says [ShielaDixon], and proceeded to first drive a set from the 7.3 MHz Z80 in an RC2014 retrocomputer, and then repeat the feat from a 3.5 MHz Sinclair ZX Spectrum.

The demos in the videos below the break are all programmed in BASIC, but she quickly reveals that they call a Z80 assembler library which does all the heavy lifting. There’s no microcontroller behind the scenes, save for some glue logic for address decoding, the Z80 is doing all the work. They’re all implemented on a pair of RC2014 extension cards, a bus that has become something of a standard for this type of retrocomputer project.

So the ubiquitous LEDs can be addressed from some surprisingly low-powered silicon, showing that while it might be long in the tooth the Z80 can still do things alongside the new kids. For those of us who had the Sinclair machines back in the day it’s particularly pleasing to see boundaries still being pushed at, as for example in when a Z80 was (almost) persuaded to have a protected mode.

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A homebrew computer built inside plexiglass cases with lots of LEDs

The Coleman Z80 Is A Modern Take On A 1970s Computer

December 20, 2022 by Robin Kearey 14 Comments

[Joshua Coleman] likes to design his own computers. Sometimes, that means drawing up bus architectures, memory maps and I/O port pinouts. Other times, he can focus his efforts more on the general aesthetics, as well as on building a great set of peripherals, as he shows in his latest ColemanZ80 project. Thanks to the RC2014 architecture defining most of the essential features of a classic Z80 computing platform, [Joshua] was able to design a modern retrocomputer that’s not only genuinely useful, but also looks as if it came off a production line yesterday.

The external design is a sight to behold: bright red laser-cut acrylic pieces form a neat, semi-transparent case with ventilation slots on the sides and lots of blinkenlights on the front. Inspired by 1970s classics like the Altair 8800, the front panel gives the user a direct view of the machine’s internal state and allows simple command inputs through a series of tumbler switches. The CPU, RAM and other basic devices are housed in one case, with all the expansion modules in a second one, linked to the mainboard through a 40-wire flatcable.

A hand-built Z80 computer's mainboard — Lots of classic chips, but also loads of hand-routed wires grace the ColemanZ80’s mainboard.

Although the mainboard closely follows the RC2014 design, [Joshua] went through a lot of effort to tune the system to his specific needs. The expansion boards he built include an NS16550 UART to replace the default 68B50, a battery-backed real-time clock, a YM2149-based sound card and even a speech synthesizer module built around the classic SP0256 chip, of Speak & Spell fame. An even more unusual feature is the presence of an AM9511, one of the earliest math coprocessors ever made, to speed up floating-point calculations. All of these modules were built entirely by hand on prototype boards: we can barely imagine how much time this must have taken.

Output devices include a VGA adapter courtesy of a Raspberry Pi Pico as well as a regular 4-digit 7-segment LED display and a set of classic HP “bubble” LEDs. [Joshua] runs several demos in his video (embedded below), ranging from computing the Mandelbrot set to playing chiptunes on the YM2149. There’s plenty of scope for further expansion, too: [Joshua] plans to build more peripherals including a floppy drive interface and a module to operate a robotic car.

This is not the first Coleman Z80 computer: the previous version ran on an architecture [Joshua] designed all by himself. We’ve seen several other impressive RC2014 derivatives, like a tiny micro version and this Altair-inspired case.

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Retro Serial Terminal Uses Modern Chips To Get CP/M Machine Talking

March 6, 2022 by Dan Maloney 26 Comments

The hobbyists of the early days of the home computer era worked wonders with the comparatively primitive chips of the day, and what couldn’t be accomplished with a Z80 or a 6502 was often relegated to complex designs based on logic chips and discrete components. One wonders what these hackers could have accomplished with the modern components we take for granted.

Perhaps it would be something like this minimal serial terminal for the current crop of homebrew retrocomputers. The board is by [Augusto Baffa] and is used in his Baffa-2 homebrew microcomputer, an RC2014-esque Z80 machine that runs CP/M. This terminal board is one of many peripheral boards that plug into the Baffa-2’s backplane, but it’s one of the few that seems to have taken the shortcut of using modern microcontrollers to get its job done. The board sports a pair of ATmega328s; one handles serial communication with the Baffa-2 backplane, while the other takes care of running the VGA interface. The card also has a PS/2 keyboard interface, and supports VT-100 ANSI escapes. The video below shows it in action with a 17″ LCD monitor in the old 4:3 aspect ratio.

We like the way this terminal card gets the job done simply and easily, and we really like the look of the Baffa-2 itself. We also spied an IMSAI 8080 and an Altair 8800 in the background of the video. We’d love to know more about those.

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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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