Bare Metal STM32: Increasing The System Clock And Running Dhrystone

When you start an STM32 MCU with its default configuration, its CPU will tick along at a leisurely number of cycles on the order of 8 to 16 MHz, using the high-speed internal (HSI) clock source as a safe default to bootstrap from. After this phase, we are free to go wild with the system clock, as well as the various clock sources that are available beyond the HSI.

Increasing the system clock doesn’t just affect the CPU either, but also affects the MCU’s internal buses via its prescalers and with it the peripherals like timers on that bus. Hence it’s essential to understand the clock fabric of the target MCU. This article will focus on the general case of increasing the system clock on an STM32F103 MCU from the default to the maximum rated clock speed using the relevant registers, taking into account aspects like Flash wait states and the APB and AHB prescalers.

Although the Dhrystone benchmark is rather old-fashioned now, it’ll be used to demonstrate the difference that a faster CPU makes, as well as how complex accurately benchmarking is. Plus it’s just interesting to get an idea of how a lowly Cortex-M3 based MCU compares to a once top-of-the line Intel Pentium 90 CPU.

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FLOSS Weekly Episode 859: OpenShot: Simple And Fast

This week Jonathan chats with Jonathan Thomas about OpenShot, the cross-platform video editor that aims to be simple to use, without sacrificing functionality. We did the video edit with OpenShot for this episode, and can confirm it gets the job done. What led to the creation of this project, and what’s the direction it’s going? Watch to find out!

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Curious Keyboards

I love first builds! They say so much about a person, because you see what’s paramount to them in a keyboard. You can almost feel their frustration at other keyboards come through their design choices. And the Lobo by [no-restarts] is no exception to any of this.

There’s just something about this Corne-like object with its custom case and highly-tappable and variously tilted keycaps. The list of reasons for being begins innocently enough with [no-restarts] wanting a picture of their dog on the case.

A nicely-tented split keyboard with really interesting, 3D-printed keycap profiles.
Image by [no-restarts] via reddit
From there, things get really personal. You may notice the thumb cluster is slightly different — [no-restarts] doesn’t like the thumb tuck required by the Corne to reach the innermost keys. I really dig the homing bumps on the middle thumb keys. Another difference is the splayed layout, as [no-restarts] is especially prone to pinky splay. Finally, there are a pair of OLEDs hiding on the inner sides of the case, which are designed to be visible when tented.

Overall, [no-restarts] is happy with it, but has some ideas for revision. Yep, that sounds about right. The Lobo is all hand-wired, and there’s a PCB with hot swap sockets in its future. If you’re interested in the case files, GitHub is your friend.

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Pufferfish Venom Can Kill, Or It Can Relieve Pain

Tetrodotoxin (TTX) is best known as the neurotoxin of the puffer fish, though it also appears in a range of other marine species. You might remember it from an episode of The Simpsons involving a poorly prepared dish at a sushi restaurant. Indeed, it’s a potent thing, as ingesting even tiny amounts can lead to death in short order.

Given its fatal reputation, it might be the last thing you’d expect to be used in a therapeutic context. And yet, tetrodotoxin is proving potentially valuable as a treatment option for dealing with cancer-related pain. It’s a dangerous thing to play with, but it could yet hold promise where other pain relievers simply can’t deliver. Continue reading “Pufferfish Venom Can Kill, Or It Can Relieve Pain”

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Hackaday Links: December 14, 2025

Fix stuff, earn big awards? Maybe, if this idea for repair bounties takes off. The group is dubbed the FULU Foundation, for “Freedom from Unethical Limitations on Users,” and was co-founded by right-to-repair activist Kevin O’Reilly and perennial Big Tech thorn-in-the-side Louis Rossman. The operating model works a bit like the bug bounty system, but in reverse: FULU posts cash bounties on consumer-hostile products, like refrigerators that DRM their water filters or bricked thermostats. The bounty starts at $10,000, but can increase based on donations from the public. FULU will match those donations up to $10,000, potentially making a very rich pot for the person or team that fixes the problem.

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User Serviceable Parts

Al and I were talking on the podcast about the Home Assistant home automation hub software. In particular, about how devilishly well designed it is for extensibility. It’s designed to be added on to, and that makes all of the difference.
That doesn’t mean that it’s trivial to add your own wacky control or sensor elements to the system, but that it’s relatively straightforward, and that it accommodates you. If your use case isn’t already covered, there is probably good documentation available to help guide you in the right direction, and that’s all a hacker really needs. As evidence for why you might care, take the RTL-HAOS project that we covered this week, which adds nearly arbitrary software-defined radio functionality to your setup.

And contrast this with many commercial systems that are hard to hack on because they are instead focused on making sure that the least-common-denominator user is able to get stuff working without even reading a single page of documentation. They are so focused on making everything that’s in-scope easy that they spend no thought on expansion, or worse they actively prevent it.

Of course, it’s not trivial to make a system that’s both extremely flexible and relatively easy to use. We all know examples where the configuration of even the most basic cases is a nightmare simply because the designer wanted to accommodate everything. Somehow, Home Assistant has managed to walk the fine line in the middle, where it’s easy enough to use that you don’t have to be a wizard, but that you can make it do what you want if you are, and hence it got spontaneous hat-tips from both Al and myself. Food for thought if you’re working on a complex system that’s aimed at the DIY / hacker crowd.

Hackaday Podcast Episode 349: Clocks, AI, And A New 3D Printer Guy

Hackaday Editors Elliot Williams and Al Williams met up to cover the best of Hackaday this week, and they want you to listen in. There were a hodgepodge of hacks this week, ranging from home automation with RF, volumetric displays in glass, and some crazy clocks, too.

Ever see a typewriter that uses an ink pen? Elliot and Al hadn’t either. Want time on a supercomputer? It isn’t free, but it is pretty cheap these days. Finally, the guys discussed how to focus on a project like Dan Maloney, who finally got a 3D printer, and talked about Maya Posch’s take on LLM intelligence.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download the human-generated podcast in mostly mono, but sometimes stereo, MP3.

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