Day: January 6, 2025

Thirty Years Later, The Windows 3.1 Video Driver You Needed

January 6, 2025 by 35 Comments

Over the course of the 1990s we saw huge developments in the world of PC graphics cards, going from little more than the original IBM VGA standard through super VGA and then so-called “Windows accelerator” cards which brought the kind of hardware acceleration the console and 16 bit home computer users had been used to for a while. At the end of the decade we had the first generation of 3D accelerator chipsets which are ancestors of today’s GPUs.

It was a great time to be a hardware enthusiast, but as anyone who was around at the time will tell you, the software for the drivers hadn’t caught up. Particularly for Windows 3.1 it could be something of a lottery, so [PluMGMK]’s modern generic SVGA driver could have been extremely useful had it appeared at the time.

As many of you will be aware, there is a set of VESA standardized BIOS extensions for video modes. There were generic VESA drivers back in the day, but they would only provide a disappointing selection of options for what the cards could do even then. The new driver provides support for all the available modes supported by a card, at all color depths. Windows 3.1 in true-color full HD? No problem!

It’s unexpected to see Program Manager and a selection of windows spread across so much real-estate, almost reminiscent of the uncluttered desktops from early ’90s workstations if you disregard the bright colors. We can’t help noticing it wins in one way over even the latest version of MacOS at these resolutions though, as anyone who has ever used a 4K screen on a Mac and found the menus remain miles away up in the top corner will tell you. Meanwhile if you’ve not had your fill of 16-bit Windows, how about sticking it in a ThinkPad BIOS?

Rethinking Your Jellybean Op Amps

January 6, 2025 by 33 Comments

Are your jellybeans getting stale? [lcamtuf] thinks so, and his guide to choosing op-amps makes a good case for rethinking what parts you should keep in stock.

For readers of a certain vintage, the term “operational amplifier” is almost synonymous with the LM741 or LM324, and with good reason. This is despite the limitations these chips have, including the need for bipolar power supplies at relatively high voltages and the need to limit the input voltage range lest clipping and distortion occur. These chips have appeared in countless designs over the nearly 60 years that they’ve been available, and the Internet is littered with examples of circuits using them.

For [lcamtuf], the abundance of designs for these dated chips is exactly the problem, as it leads to a “copy-paste” design culture despite the far more capable and modern op-amps that are readily available. His list of preferred jellybeans includes the OPA2323, favored thanks to its lower single-supply voltage range, rail-to-rail input and output, and decent output current. The article also discussed the pros and cons of FET input, frequency response and slew rate, and the relative unimportance of internal noise, pointing out that most modern op-amps will probably be the least thermally noisy part in your circuit.

None of this is to take away from how important the 741 and other early op-amps were, of course. They are venerable chips that still have their place, and we expect they’ll be showing up in designs for many decades to come. This is just food for thought, and [lcamtuf] makes a good case for rethinking your analog designs while cluing us in on what really matters when choosing an op-amp.

Is A Cheap Frequency Standard Worth It?

January 6, 2025 by 21 Comments

In the quest for an accurate frequency standard there are many options depending on your budget, but one of the most affordable is an oven controlled crystal oscillator (OCXO). [RF Burns] has a video looking at one of the cheapest of these, a sub ten dollar AliExpress module.

A crystal oven is a simple enough device — essentially just a small box containing a crystal oscillator and a thermostatic heater. By keeping the crystal at a constant temperature it has the aim of removing thermal drift from its output frequency, meaning that once it is calibrated it can be used as a reasonably good frequency standard. The one in question is a 10 MHz part on a small PCB with power supply regulator and frequency trimming voltage potentiometer, and aside from seeing it mounted in an old PSU case we also are treated to an evaluation of its adjustment and calibration.

Back in the day such an oscillator would have been calibrated by generating an audible beat with a broadcast standard such as WWV, but in 2024 he uses an off-air GPS standard to calibrate a counter before measuring the oven crystal. It’s pretty good out of the box, but still a fraction of a Hertz off, thus requiring a small modification to the trimmer circuit. We’d be happy with that.

For the price, we can see that one of these makes sense as a bench standard, and we say this from the standpoint of a recovering frequency standard nut.

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No Frills PCB Brings USB-C Power To The Breadboard

January 6, 2025 by 28 Comments

At this point, many of us have gone all-in on USB-C. It’s gotten to the point that when you occasionally run across a gadget that doesn’t support being powered USB-C, the whole experience seems somewhat ridiculous. If 90% of your devices using the same power supply, that last 10% starts feeling very antiquated.

So why should your breadboard be any different? [Axiometa] has recently unveiled a simple PCB that will plug into a standard solderless breadboard to provide 3.3 and 5 VDC when connected to a USB-C power supply. The device is going to start a crowdfunding campaign soon if you want to buy a completed one — but with the design files and Bill of Materials already up on GitHub, nothing stops you from spinning up your own version today.

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Schematic for progress of 3D integration. a, Schematic showing conventional 3D integration by TSV through wafers. b, M3D integration of single-crystalline Si devices by transfer, c, Growth-based M3D integration of polycrystalline devices. d, Growth-based seamless M3D integration of single-crystalline devices. (Credit: Ki Seok Kim et al., 2024, Nature)

Growing Semiconductor Layers Directly With TMDs

January 6, 2025 by 5 Comments

Transition-metal dichalcogenides (TMDs) are a class of material that’s been receiving significant attention as a possible successor of silicon. Recently, a team of researchers has demonstrated the use of TMDs as an alternative to through-silicon-vias (TSV), which is the current way that multiple layers of silicon semiconductor circuitry are stacked, as seen with, e.g., NAND Flash ICs and processors with stacked memory dice. The novelty here is that the new circuitry is grown directly on top of the existing circuitry, removing the need for approaches like TSV to turn 2D layers into 3D stacks.

As reported in the paper in Nature by [Ki Seok Kim] and colleagues (gift article), this technique of monolithic 3D (M3D) integration required overcoming a number of technological challenges, most of all enabling the new TMD single-crystals to grow at low enough temperatures that it doesn’t destroy the previously created circuitry. The progress is detailed in the paper’s schematic (pictured above): from TSV to M3D by transfer of layers and high- and low-temperature growth of single-crystal layers.

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Before GPS There Was LORAN

January 6, 2025 by 36 Comments

We found it nostalgic to watch [ve3iku] fire up an old Loran-A receiver and, as you can see in the video below, he got it working. If you aren’t familiar with LORAN, it was a common radio navigation technique before GPS took over everything.

LORAN — an acronym for Long Range Navigation — was a US byproduct of World War II and was similar in many ways to Britain’s Gee system. However, LORAN operated at lower frequencies to improve its range. It was instrumental in helping convoys cross the Atlantic and also found use in the Pacific theater.

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Cassette Tape Plays MP3s

January 6, 2025 by 65 Comments

Cassette tapes were a major way of listening to (and recording) music througout the 1980s and 1990s and were in every hi-fi stereo, boom box, and passenger vehicle of the era. Their decline was largely as a result of improvements in CD technology and the rise of the MP3 player, and as a result we live in a world largely absent of this once-ubiquitous technology. There are still a few places where these devices crop up, and thanks to some modern technology their capabilities as a music playback device can be greatly enhanced.

The build starts, as one might expect, by disassembling the cassette and removing the magnetic tape from the plastic casing. With the interior of the cassette empty it’s capable of holding a small battery, USB-C battery charger, and a Bluetooth module. The head of an old tape deck can be wired to the audio output of the Bluetooth module and then put back in place in the housing in place of the old tape. With the cassette casing reassembled, there’s nothing left to do but pair it to a smartphone or other music-playing device and push play on the nearest tape deck.

As smartphones continue to lose their 3.5 mm headphone jacks, builds like this can keep lots of older stereos relevant and usable again, including for those of us still driving older vehicles that have functioning tape decks. Of course, if you’re driving a classic antique auto with a tape technology even older than the compact cassette, there are still a few Bluetooth-enabled options for you as well.

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