Open source test and measurement equipment, high speed digital design, and more
Backstory Back in January, the ThunderScope team sent me a PCIe card version of their prototype open hardware oscilloscope. I was very excited about this, because I was already testing ngscopeclient with a Thunderbolt version of the ThunderScope but the only machines I had with Thunderbolt were laptops. The PCIe card version would be usable with my (much more powerful) desktops, allowing me to…
For the second time, what started out as a silly comment on Mastodon turned into a slightly longer micro-SF story. In this case, it’s one of the most unlikely alternate history crossover fan fics imaginable. I won’t spoil it, read on! July 11, 2029 - Cheyenne Mountain, Colorado The sounds of gunfire and explosions grew louder as the humans’ assault pushed closer to Skynet’s base. T-1000 3310…
If you have a large, well-equipped electronics lab you’re going to have a lot of instrumentation with trigger input and output ports. In my case all three oscilloscopes, the vector signal generator, and even my VNAs have trigger sync capability, and there’s probably more things I’m missing. And that doesn’t even count the ThunderScope or the two Siglent AWGs I have on loan for ThunderScope R&D.…
If you’ve been following this blog for a while, you probably know that I do almost all of my high-end embedded work by pairing a STM32H735 with a Xilinx FPGA using the external parallel memory controller (FMC) in PSRAM mode. It works great, you can get 128 MB of off-chip address space bridged pretty directly to the internal AXI bus and if you set the MPU right you can make it behave as strongly…
This is part 3 of my ongoing series about LATENTRED, my project to create an open source 1U managed Ethernet switch from scratch. Here’s a quick, or maybe not-so-quick, update about the PHY on the line card and some of my troubles (and solutions). And probably more internal details than you want to know, but hey - maybe this will be useful to somebody. Not a lot of pretty pictures either. One day…
This is part 2 of my ongoing series about LATENTRED, my project to create an open source 1U managed Ethernet switch from scratch. Today, we’re going to be talking about the 24-port QSGMII line card. Two of these will provide all of the front panel connectivity for the edge-facing side of the switch (i.e. everything but uplink and management ports). Overview Here’s the line card before heatsink…
One of my longest-running projects has been an open hardware Ethernet switch. This has been one of the key driving forces behind many of my other projects, such as ngscopeclient and the high speed probes. It was also the project that got me into high speed digital design. So I figured it’s time to kick off a series with a short writeup of where things are now, how we got there, and what’s coming…
This is a bit of a change from my usual content, but I’ve been sitting on this idea for a short SF story for a long time and I had to try actually writing it. I’m mostly a technical writer not a creative one so hopefully this turned out decently :) Arrival BEEP BEEP BEEP BEEP It took Dr. Lynn Clarke a minute to wake up enough to register that the noise was her alarm clock. She was not a morning…
I realized a while back that I haven’t put any silicon reverse engineering content on the new blog yet. It’s time to change that! Today, we’ll be doing a teardown of the ST STM32L431. Why? Because it’s a part I use a lot, it’s my go-to for “I want enough flash for A/B firmware images and a bootloader and a nontrivial amount of code, but a H735 is overkill”. And, most importantly, I had one on a…
(Sorry for the slow updates… I’ve been busy with a lot of stuff, like getting ngscopeclient ready for the full v0.1 release at the end of the year. I haven’t stopped working on projects, just been too busy to do long-form writeups.) When I started out with digital electronics, most of my designs ran on 5V from a barrel jack. This was fine for simple stuff, but I rapidly ran into two problems: 5V…