[LIVE] How to Achieve Proper Grounding - Rick Hartley - Expert Live Training (US)

Admittedly I ended up building a board with a microcontroller rather than a microprocessor because I could interface with the modem over spi too. However, this YouTube channel was great to work through: link It has some high speed stuff with ddr memory, fpga’s gigabit Ethernet and usb3 too so I’m pretty sure you could use the same concepts to build a board with a microprocessor on it. Proper grounding, emi, impedance control and length matching are well explained. I think he has some more advanced courses via his website too. Additionally, this was an ah-ha moment video for me: ▶ this video

Not directly answering your question, but on preventing emission in the first place (and the best video I've ever seen on electrical engineering): ▶ this video

For anyone who cares enough to watch a 2 hour video on it and hasn’t seen it yet, this Rick Hartley video is the recent gold standard of explaining the issues at play: ▶ this video

My recommendation would be to search YouTube for "Rick Hartley". The guy is extremely knowledgeable, yet humble, and presents things like grandpa reciting a war story. It's easy to listen to, and I'd take him being on any kind of program as an endorsement that it'll be high quality content. The most important talk for beginners getting into high-speed is probably this one: ▶ this video because without proper grounding, interference and EMI is going to destroy your HF signals (for example CPU to RAM bus).

Some kinds of "expert" are a commodity: you can hire an astronomy PhD or a registered nurse. Entrepreneurs traffic in a special expertise: valuable, unique and defensible IP. All Roy Kroc had to know was how to teach people to teach other people how to run a McDonald's restaurant. A business that achieves "product-market fit" has a very specific and path-dependent situation. Sometimes you find this "one weird trick" that lets you make money hand-over-fist for a while and you want most of all to keep that a secret. Other times the knowledge is so specific (how do you grow the most rice you possibly can in this valley?) that it's not of interest to outsiders. "Expert networks" are notoriously promiscuous so firms have a lot of fear that they'll bring in an expert who walks out with more valuable information (e.g. "one weird trick") than the they can bring into it. My favorite kind of expert is this kind of guy ▶ this video who grew continuously through a 40+ year career and went from being in the dark about noise in circuit boards to an inspiring vision of how electrical energy flows not in the wires but through the space between the wires that makes everything I thought mysterious about antennas seem obvious.

I have some further video recommendations: ▶ this video ("How to achieve proper grounding") link ("Keys to control noise, interference, and EMI in PCBs") link ("What your differential pairs wish you knew") link ("Secrets of PCB optimization") These are all by Rick Hartley (from GP's comment) and they are all worth watching in this order.

That video is good for the water like wave explanation that is a very useful lens. If you want a more in-depth explanation, particularly how the field is in the dielectric and the wires/traces are simply the wave guide, this long presentation by Rick Hartley will help move to the next level. ▶ this video The dramatic shift in behavior above the audio frequency range is where the water wave lens starts to fall down IMHO. I was looking at my brothers memory card from a Cray 1a the other day and that video popped in my head. They had the timing traces snaking through several flat-pack chips legs. No wonder they had to move from parity to Hamming code even with exclusively using differential twisted pairs between modules.

This is advanced level PCB design. You need to know proper grounding and differential pairs and length matching to accomplish what is listed in this article. These are very difficult topics, but this 2 hour video should give you an idea of what's going on here: ▶ this video -------- If this is too much for you, then instead stick to microcontrollers and other sub-100Mhz or sub-20Mhz projects. But 500MHz and above that requires length matching with controlled impedances is waaaayyyyy outside the scope for a beginner designer. --------- Beginner design is easier at 20MHz or so. The faster your signals, the more susceptible to noise they are. Those 500MHz+ Linux MPUs may fail to boot or fail spuriously if you make grounding / noise / EMC errors. And it's pretty difficult to explain to a beginner what is going on physically. The PCB board itself needs to be seen as parasitic capacitors, inductors and resistors (especially around Vias, between layers and other elements). But these 500Mhz or so processors here in this blogpost are still easier than Ghz+ chips. ------ The example I always like to point out: 2.4GHz wavelength is just a couple of cm long. That means any trace of ~centimeters can accidentally turn into a Bluetooth / WiFi antenna, which would inject a ton of noise into your circuit (or conversely: 'Throw' your electrons out like a Bluetooth / WiFi antenna). That's why faster speeds are harder. 900Mhz and slower needs an antenna over 30cm long, so staying below this means eve

The professionals use PCB-design software with physical modeling / FEA to calculate estimates to all of the important parameters of the circuit board (including how much trace lengths matter... but also board-capacitance, resistances, and resonance frequencies of the board itself, etc. etc.) In contrast, we hobbyists deal with "rules of thumb", because none of us will spend $4000+ on professional PCB software that run these calculations for us. And furthermore, we aim very conservative because its very difficult to debug a PCB layout issue... as we hobbyists are functionally blind to all of these issues (ex: trace inductance, trace capacitance, or other issues). I think spending a good bit of time on PDN / grounding / etc. etc. study is very worth your while. ▶ this video 2+ hour talk on just the issue of good "grounding" design in PCBs, but it does relate to this issue of capacitors, trace-lengths and the like. I feel like you'd benefit from this talk. The "correct" way of thinking is exceptionally complex, far more complex than what is taught in colleges. But you have all the basic ideas thanks to the old rules of thumb. You just need to take the next step to see what the problems are. -------- And as you'll see, traces on the same side of a board are cake. Its things like vias that actually wreck you.

The article is not that good, but whatever. I am new to electronics myself and quite fascinated how has the art progressed in the past hundred or so years. There are people remembering "we were doing it wrong". Incredible. Anyway, if you are interested in signals traveling inside those cute green multi-GHz boards you make your living off, go watch Rick Hartley. ▶ this video (How to Achieve Proper Grounding) link (What your Differential Pairs Wish You Knew)

> so wouldn't it be better to put power/ground on the outer layers and keep signals in the middle? Signals must never cross a break or split in the plane they're referencing (usually 0V or ""ground""). This creates huge EMI problems. Your proposal would have signals on layer 2 crossing a split in the ground plane on layer 1 (that split caused by power traces). Some interesting material on the subject: link link ▶ this video link