OLED Display Lets Vintage PC Engage Turbo Mode In Style

Back in the 486 days, it was common to see a “Turbo” button on the front panel of many PCs, which was used to toggle between the CPU’s maximum speed and a slower clock rate that was sometimes necessary for compatibility with older software. Usually an LED would light up to show you were running at this higher speed, or if your machine was very fancy, it might even have a numerical display that would show the current CPU frequency.

[Joshua Woehlke] wanted to add a similar display to his 486, but figured that with modern technology, he could do something a bit more interesting. Especially when he realized that the spot on his case where the two-digit LED display would have originally been mounted was the perfect size to hold a common 0.96″ SSD1306 OLED. From there it was just a matter of wiring it up to an Arduino and writing some code to display different graphics depending on the computer’s current CPU speed.

Just like the frequency indicators of yore, the Arduino doesn’t actually measure the CPU’s frequency, it’s simply reading the state of the Turbo LED on the front panel. When the LED is off the Arduino shows an image of a i8088 CPU on the screen to indicate the computer is running in compatibility mode, and when the LED is on, the screen shows the Cyrix Cx486 DX2 logo. When the button hasn’t been pressed in awhile, the display defaults to a star field screensaver.

Regular readers may recall we recently covered a similar project that used an Arduino to add a little flair to an era appropriate seven-segment LED display. We’d say there’s still a good deal of romanticism about computers having a big “TURBO” button you can smash whenever you feel the need for speed.

486 Gets Animated Turbo Button Thanks To Arduino

There was a point in time, excruciatingly brief, in which desktop computers often had a large “TURBO” button on their front panel. Some even featured an LED display that would indicate the current CPU frequency, providing visual conformation that your machine had leaped to a blistering 66 MHz.

The 486 that [someyob] is restoring had the Turbo button, but sadly there was just a simple LED to show whether or not it was engaged. But there was a window in the front panel where it seemed like a numerical display was intended to go, so they decided to wire up their own CPU indicator by sensing the state of the Turbo LED with an Arduino Pro Mini.

Now to modern audiences, this might seem like cheating. After all, the Arduino isn’t actually measuring the CPU speed, nor is it directly controlling it (that’s still done by the original Turbo button wiring). But the truth is, even back in the day, the CPU frequency displays faked it — they just toggled between showing two predefined frequencies depending on the state of the button. The arrangement [someyob] has come up with does the same thing, except now there’s some extra processing power in the mix, so the display can show some slick animations as it switches between 33 and 66 Mhz.

In the GitHub repository, [someyob] has provided the Arduino source code and schematics showing how the microcontroller was shoehorned into the existing front panel wiring without compromising its functionality. There’s even a brief video below that shows the display in operation.

Like the idea but don’t have a 486 laying around? Don’t worry. We’ve seen a similar panel built for modern machines that  just doesn’t look the part, it actually manages to be functional.

Continue reading “486 Gets Animated Turbo Button Thanks To Arduino”

A miniature 486 desktop PC running Lemmings

Tiny 3D Printed Gaming PC Contains Real Retro Hardware

Emulators are easy and convenient, but for some retrocomputing enthusiasts nothing comes close to running classic software on actual era-appropriate hardware. This can become a problem, though, for those into vintage PC gaming: old PCs and their monitors are notoriously large and heavy, meaning that even a modest collection will quickly fill up a decent family home. There is a solution however, as [The Eric Experiment] demonstrates in his latest video. He designed and built a 3D-printed mini PC that runs on an actual 486 processor.

An ordinary desktop motherboard would have required a rather large case to begin with, so [Eric] started his project by buying an old industrial PC board. Such a device has the processor and all main motherboard components sitting on an ISA card, which then connects to other ISA cards through a backplane. This way, a complete system with expansion cards can be made way more compact than even the sleekest desktop PCs of the time. An SD-card-to-IDE converter makes for an extremely slim hard drive replacement, while a Gotek floppy emulator allows the system to boot as if there’s actually a floppy drive present.

A small 486 tower case being assembled
Even the side panels slide in exactly like they do on real PC cases.

All of this is pretty neat to begin with, but by far the most impressive parts of the Tiny 486 project are the enclosures that [Eric] designed for the PC and its accompanying monitor. Both were modelled off real-world examples and are accurate down to the smallest details: the tilting stand that clips onto the base of the monitor for instance, or the moving latch on the faux 5.25″ floppy drive. That latch operates a cleverly hidden door that reveals the USB connector for the floppy emulator. The compulsory seven-segment LED display on the mini tower’s front panel now finally serves a useful purpose – indicating which floppy image is currently active.

Sporting an Intel 486-DX4 100 MHz processor, 32 MB of RAM, a Tseng ET4000 video card and an ESS Audiodrive for sound, the tiny 486 can run DOS or Windows 95, although performance in the latter is a bit limited due to the lack of a local-bus video card. It’s perfectly fine for most DOS games though, and a lot more practical than a full-sized desktop PC.

There are several ways to make a tiny game PC, like using PC/104 standard boards or repurposing old network equipment. The crucial part needed to turn it into a gaming machine is a proper sound card, which you can even build from scratch if needed. Thanks for the tip, [Nathan]!

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It’s A 486 Computer, On A Breadboard

Ever since the 1970s, a frequent project has been to take a microprocessor and construct a computer system on a breadboard or stripboard. Usually these machines feature a familiar 8-bit processor such as a 6502 or a Z80 because of their breadboard-friendly DIP packages, but there is surprisingly little reason why some of the more recent silicon can’t be treated in the same way. [FoxTech] is leading the way on this, by making a breadboard computer using an 80486DX.

A 1990-era 32-bit desktop CPU seems unpromising territory for this application, but its architecture is surprisingly accessible. It needs a breakout board to gain access to its various lines, but beyond that it can be interfaced to in a very similar way to those earlier chips.

So far there are two videos in the series, which we’ve placed below the break. The first one introduces the project and shows the basic set-up. A 486 running NOPs may produce a pretty light show, but as he starts to show in the second video, it’s capable of more. The eventual aim is to have a simple but fully functional breadboard computer, so he’s starting with logic to decode the 32-bit bus on the 486 into the 8-bit bus he’s going to use.

It’s fascinating to learn about how the 32-bit 486 handles its interfacing and deals with four bytes at once, and we’re very much looking forward to seeing this project play out. The 486 may be on life support here in 2023, but that doesn’t mean it can’t still receive some love.

Continue reading “It’s A 486 Computer, On A Breadboard”

A smartphone-sized PCB is in a person's hand. A large blue chip package houses a 486 and the board has a SoundBlaster card and a 40 PIN Raspberry Pi Connector along one edge for attaching a Raspberry Pi Zero.

TinyLlama Is A 486 In Your Pocket

We love retrocomputing and tiny computers here at Hackaday, so it’s always nice to see projects that combine the two. [Eivind]’s TinyLlama lets you play DOS games on a board that fits in your hand.

Using the 486 SOM from the 86Duino, the TinyLlama adds an integrated Crystal Semiconductor audio chip for AdLib and SoundBlaster support. If you populate the 40 PIN Raspberry Pi connector, you can also use a Pi Zero 2 to give the system MIDI capabilities when coupled with a GY-PCM5102 I²S DAC module.

Audio has been one of the trickier things to get running on these small 486s, so its nice to see a simple, integrated solution available. [Eivind] shows the machine running DOOM (in the video below the break) and starts up Monkey Island at the end. There is a breakout board for serial and PS/2 mouse/keyboard, but he says that USB peripherals work well if you don’t want to drag your Model M out of the closet.

Looking for more projects using the 86Duino? Checkout ISA Sound Cards on 86Duino or Using an 86Duino with a Graphics Card.

Continue reading “TinyLlama Is A 486 In Your Pocket”

Bye Bye Linux On The 486. Will We Miss You?

A footnote in the week’s technology news came from Linus Torvalds, as he floated the idea of abandoning support for the Intel 80486 architecture in a Linux kernel mailing list post. That an old and little-used architecture might be abandoned should come as no surprise, it’s a decade since the same fate was meted out to Linux’s first platform, the 80386. The 486 line may be long-dead on the desktop, but since they are not entirely gone from the embedded space and remain a favourite among the retrocomputer crowd it’s worth taking a minute to examine what consequences if any there might be from this move.

Is A 486 Even Still A Thing?

Block diagram of the ZFx86 SoC
An entire 486 PC in a chip that only uses 1W, that would have been amazing in 1994!

The Intel 80486 was released in 1989, and was substantially an improved version of their previous 80386 line of 32-bit microprocessors with an on-chip cache, more efficient pipelining, and a built-in mathematical co-processor. It had a 32-bit address space, though in practice the RAM and motherboard constraints of the 1990s meant that a typical 486 system would have RAM in megabyte quantities. There were a range of versions in clock speeds from 16 MHz to 100 MHz over its lifetime, and a low-end “SX” range with the co-processor disabled. It would have been the object of desire as a processor on which to run WIndows 3.1 and it remained a competent platform for Windows 95, but by the end of the ’90s its days on the desktop were over. Intel continued the line as an embedded processor range into the 2000s, finally pulling the plug in 2007. The 486 story was by no means over though, as a range of competitors had produced their own take on the 486 throughout its active lifetime. The non-Intel 486 chips have outlived the originals, and even today in 2022 there is more than one company making 486-compatible devices. RDC produce a range of RISC SoCs that run 486 code, and according to the ZF Micro Solutions website they still boast of an SoC that is a descendant of the Cyrix 486 range. There is some confusion online as to whether DM&P’s Vortex86 line are also 486 derivatives, however we understand them to be descendants of Rise Technology’s Pentium clone. Continue reading “Bye Bye Linux On The 486. Will We Miss You?”

Building A Serial Bus To Save An Old Hard Drive

Universal Serial Bus has been the de facto standard for sending information to and from computer peripherals for almost two decades, but despite the word “universal” in the name this wasn’t always the case. Plenty of competing standards, including USB, existed in the computing world in the decades before it came to dominance, and if you’re trying to recover data from a computer without USB you might have to get creative with how it’s done.

[Ben] recently came across a 80486 with this problem, so he had to get creative to recover the contents of the drive. He calls it the “lunchbox” computer due to its form factor, and while it doesn’t have USB it does have a tried-and-trusted serial port to communicate with other computers. [Ben] wrote up a piece of software for both the receiving computer and the sending computer in order to copy the drive sectors one by one across a serial link to a standalone computer running Windows XP, and was able to recover the contents of the drive that way instead.

All of the code [Ben] wrote is available on his GitHub page for anyone looking to boot up a 30-year-old computer again. While it might sound uncommon, computers of this vintage are still around running things like CNC machines or old mainframes.