Gorgeous Perfboard Build Puts 1-Bit Controller Back To Work

Eight-bit computers are all the retro rage these days, with people rushing to build computers either from chips like the 6502 or the Z80, or even recreating these chips from a collection of TTL logic chips. And while we respect and covet those builds immensely, 8-bit computers aren’t the only game going on. To wit we present this lovely single-board computer sporting a 1-bit CPU.

The machine, which creator [Simon Boak] cheekily dubs “the world’s least-powerful computer,” is based on the Motorola MC14500B, a chip from the 1970s that was aimed at the industrial controls market. There, the chip’s limited instruction set and narrow bus width were not as limiting as they would be in a general-purpose computer. In fact, since the chip requires an external program counter, it offers a great degree of design flexibility. [Simon] chose a 4-bit address space, but with a little wizardry he was able to get eight bits of input in the form of DIP switches and eight bits of output LEDs. It’s not good for much past making lights blink, but it does that with nary an Arduino in view — although it does sport a couple of 555s.

[Simon]’s goal for the build was simply to build cool from an unusual chip, and we think he succeeded. In fact, we can’t recall seeing a neater perfboard build — it’s almost to the level of circuit sculpture. We especially like the hybrid solder and wirewrap construction. We’ve seen builds based on this chip before, but never one so neat and attractive.

[via r/electronics]

Retro Computer Trainer Gets A Raspberry Pi Refit

We know what you’re thinking: this is yet another one of those “Gut the retro gear for its cool old case and then fill it up with IoT junk” projects. Well, rest assured that extending and enhancing this 1970s computer trainer is very much an exercise in respecting the original design, and while there’s a Pi inside,  it doesn’t come close to spoiling the retro goodness.

Like many of a similar vintage as [Scott M. Baker], the Heathkit catalog was perhaps only leafed through marginally less than the annual Radio Shack catalog. One particularly desirable Heathkit item was the ET-3400 microcomputer learning system, which was basically a 6800-based computer surrounded by a breadboarding area for experimentation. [Scott] got a hold of one of these, but without the optional expansion accessory that would allow it to do interesting things such as running BASIC or even supporting a serial port. So [Scott] decided to roll his own expansion board.

The expansion card that [Scott] designed is not strictly a faithful reproduction, at least in terms of the original BOM. He turned to more modern — and more readily available — components, but still managed to provide the serial port, cassette interface, and RAM/ROM expansion of the original unit. The Raspberry Pi is an optional add-on, which just allows him to connect wirelessly if he wants. The card fits into a 3D-printed case that sits below the ET-3400 and maintains the original trainer’s look and feel. The longish video below shows the build and gives a tour of the ET-3400, both before and after the mods.

It looks as though trainers like these and other artifacts from the early days of the PC revolution are getting quite collectible. Makes us wish we hadn’t thrown some things out.

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Run Java On An Amiga

In the modern world, we take certain tools for granted. High-level programming languages such as C or Python haven’t been around that long in the grand scheme of things, and Java has only existed since the ’90s. Getting these tools working on machines that predate them is more of a challenge than anything, and [Michael Kohn] was more than willing to tackle this one. He recently got Java running on a Commodore Amiga.

The Amgia predates Java itself by almost a decade, so this process wasn’t exactly straightforward. The platform has a number of coprocessors that were novel for their time but aren’t as commonplace now, taking care of such tasks such as graphics, sound, and memory handling. Any psoftware running on the Amiga needs to be in a specially formatted program as well, so that needed to be taken care of, even loading Java on the computer in the first place took some special work using a null modem cable rather than the floppy disk an Amiga would have used back in the day.

Loading Java on an antique Amiga is certainly a badge of honor, but [Michael] isn’t a stranger to Java and the Motorola 68000s found in Amigas. There’s a 68000 in the Sega Genesis as well, and we’ve seen how [Michael] was able to run Java on that too.

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Honoring Chuck Peddle; Father Of The 6502 And The Chips That Went With It

Chuck Peddle, the patriarch of the 6502 microprocessor, died recently. Most people don’t know the effect that he and his team of engineers had on their lives. We often take the world of microprocessor for granted as a commonplace component in computation device, yet there was a time when there were just processors, and they were the size of whole printed circuit boards.

Chuck had the wild idea while working at Motorola that they could shrink the expensive processor board down to an integrated circuit, a chip, and that it would cost much less, tens of dollars instead of ten thousand plus. To hear Chuck talk about it, he got a cease-and-desist letter from the part of Motorola that made their living selling $14,000 processor boards and to knock off all of the noise about a $25 alternative.

In Chuck’s mind this was permission to take his idea, and the engineering team, elsewhere. Chuck and his team started MOS Technologies in the 1970’s in Norristown PA, and re-purposed their work on the Motorola 6800 to become the MOS 6502. Lawsuits followed.

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Reverse Engineering An Ancient SBC With An Apple ][

We spend a lot of time in our community discussing the many home computers from the 8-bit era, while almost completely ignoring their industrial equivalents. While today a designer of a machine is more likely than not to reach for a microcontroller, four decades ago they would have used a single-board computer which might have shared a lot of silicon with the one you used to play Pac Man.

[Epooch] recently came into possession of a CMS 9619A Advanced Single Board Microcomputer, a rather unique Programmable Logic Controller intended for industrial applications. It’s powered by a Motorola 6809 CPU and features the usual array of peripheral chips. To unlock its secrets he reached not for an array of tools from 2019 but for a venerable Apple ][e microcomputer.

In this type of 8-bit machine the various peripherals are enabled through address decoding logic that toggles their chip select line when a particular I/O address is called. Sometimes this task is performed by a set of 74 or similar logic chips, but in the case of the CMS 9619A it falls upon a Programmable Array Logic (PAL). These chips, which could be thought of as a simple precursor to today’s FPGAs, were ideal for creating custom decoding logic.

As you might expect though, a PAL is an opaque device, so to deduce the address map it was necessary to reverse engineer it using the Apple ][‘s printer card and a bit of BASIC code. It then remained to do some ROM disassembly work and wire up the serial ports, before some ROM patching with the Apple ][ as an EPROM programmer to finally access the machine’s debugger.

The 6809 is famous as the brains of Radio Shack’s CoCo and the Dragon computers, but this isn’t the first time we’ve seen it in an SBC.

The Tiniest Working 68K System

68000 microprocessors appeared in the earliest Apple Macintoshes, the Commodore Amiga and Atari ST, and the Sega Genesis/Mega Drive among other familiar systems. If you were alive during the 16-bit era, there is a good chance that you will have owned a Motorola 68000 or one of its derivatives in a computer or game console. By the end of the 1990s it was clear that the 68K line had had its day on the desktop, but a new life for it at the consumer level was found in the PDA market. The first Motorola Dragonball was a 68000 series system-on-chip, and it was a few of these in a BGA package that [Plasmode] had in stock after ordering them in error believing them to be in a different package.

The Dragonball 68328 has an interesting bootstrap mode allowing it to run with no external ROM or RAM, and with only a serial connection to the outside world. Recognising this as having the potential for the smallest possible 68K system, he proceeded to make it happen with some impressive soldering direct to the solder balls of an upturned BGA package.

On a piece of PCB material are simply the 68328, a 32.768kHz crystal and capacitors, a MAX232 circuit for an RS232 serial connection, a reset button, and a power regulator. Using the Motorola DOS debug software which is still available for download after all these years, he was able to connect to his tiny 68K computer and run code. It’s not entirely useful, but of all the possible 68K configurations it has to be the smallest.

This isn’t the first minimal computer using only a processor chip and serial link, in the past we’ve shown you a PDP-11 in the same vein.

Ask Hackaday: Why Did Modular Smart Phones Fail?

Remember all the talk about modular smart phones? They sounded amazing! instead of upgrading your phone you would just upgrade the parts a bit like a computer but more simplistic. Well it seems modular phones are dead (video, embedded below) even after a lot of major phone manufacturers were jumping on the bandwagon. Even Google got on-board with Google Ara which was subsequently cancelled. LG released the G5 but it didn’t fare too well. The Moto Z from Motorola seemed to suffer from the same lack of interest. The buzz was there when the concept of these modular phones was announced, and people were genuinely exited about the possibilities. What went wrong?

For a start people expect their phones to have everything on board already, whether it be cameras, GPS, WiFi, high-capacity batteries or high-resolution screens. Consumers expect these things to come as standard. Why would they go out and buy a module when other phones on the market already have these things?

Sure you could get some weird and wonderful modules like extra loud speakers or perhaps a projector, but the demand for these items was small. And because these extras are already available as separate accessories not locked down to one device, it was a non starter from the beginning.

When we did our user studies. What we found is that most users don’t care about modularizing the core functions. They expect them all to be there, to always work and to be consistent. — Lead engineer Project Ara

The hackability of these phones would have been interesting to say the least, had they come to the mainstream. It just seems the public want thin sleek aluminum phones that they treat more as a status symbol than anything else. Modular phones have to be more bulky to accommodate the power/data rails and magnets for the modules, so they’ll lose out in pocketability. Still, we hope the idea is revisited in the future and not left on the scrap-heap of obsolescence.

Would you buy a modular smart phone? Even if it is bigger or more expensive? Is that really why they failed?
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