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That's been a funny thing for me. I'm not an electrical engineer, at all. My electrical knowledge is an introductory electromagnetics course I had to take in co
by Teknoman117 4y ago
That's been a funny thing for me. I'm not an electrical engineer, at all. My electrical knowledge is an introductory electromagnetics course I had to take in college that I've mostly forgotten, reading/watching EEVblog, other internet sources, playing around with cheap and/or old parts, reading whatever I can find, etc.
I've made some retrocomputing boards (<= 50 MHz) (8051, 286, 68010, 68030, etc.) and haven't had much of a problem. No idea what the EMI looks like though. Greatest goof I had so far was an old part who's datasheet didn't mention that the signal output was open collector so I had to bodge a resistor in. Mostly just followed advice I found on the internet -> 4 layer boards can be had for very cheap these days (JLCPCB does 10 for $30 w/ ENIG boards up to 10cm x 10cm), so I followed the "just do yourself a favor and get the 4 layers boards so you can make ground and power planes" advice. Used a tool to compute minimum trace spacing to stay under a certain capacitance for a specific copper weight, board thickness, dielectric type, etc.
Probably my crowning achievement at this point is making an 1.8V LVDS to TMDS level shifter board so I can get HDMI 1.2a (4x 1.65 Gbps lanes + sidebands) out of an FPGA board I repurposed from some cryptomining hardware I bought on eBay. Had to learn how to do soldering using a stencil, paste, hot air station, and a hotplate because no one is hand soldering 0.4mm QFN packages. 0402 are the smallest thing I can do by hand.
Next thing I want to try is breaking out a small BGA. Managed to get a few Lattice iCE40HX8K's in the CT256 package (256 balls @ 0.8mm pitch BGA).
What hurts is how patent/royalty/industry interest group encumbered that nearly everything modern is. Want to do PCIe? Join PCIe SIG. Want to do USB? Join USB-IF. Want to support SD cards? Pay a bunch to SDA. Actually their patents expired so maybe you can do native SD mode now without much fear. HDMI is awful, DisplayPort requires you to join VESA, MIPI for CSI and DSI devices, etc.
- analog31 4y agoYeah, joining the clubs is burdensome. I'm lucky to be in an industry where there's enough value-add, that we just pay the piper and move on. Myself, I buy that kind of stuff pre-integrated.
- Teknoman117 4y agoI mean, it's the same for me, I'm just on the software side of the company (mostly, I'd say systems because occasionally I have to borrow the PCIe packet analyzer to figure out why something isn't working). The electronics are a thing I do as a hobby and I try my absolute hardest to ensure work and hobby resources are kept separate. Electronics is sufficiently different from my professional role that it doesn't feel draining as a thing to do on the side. I'm not one of those "spend 8 hours programming/architecting/designing at work only to go home and spend another 6 writing code for fun" kind of people. I definitely write software and learn at home from time to time, but the motivation for doing it on the side is certainly less than it was before I turned it into a full time job. So I tend to gravitate towards things that are interesting to me but not necessarily useful to others.
- phlipski 4y ago"Want to do PCIe? Join PCIe SIG. Want to do USB? Join USB-IF..." As someone who works for a large silicon vendor I can tell you that even with access to those industry groups the documentation still sucks!!!! I look at the amazing documentation available surrounding various software initiatives (OpenCV, machine learning, linux drivers, programming languages, etc...) with envy. It's all right there and out in the open with multiple blogs and forums and pages explaining shit. And actually I did try to learn PCIe. I gave up. 1000+ reference specs, about 3 random web pages and a half dozen marketing youtube video's. There's a reason why some guys manage to build niche careers around these HW topics!
- analog31 4y agoIt blew my mind that the microcontroller I'm now using has a 1000+ page datasheet.
- repiret 4y agoI recently came across a reference manual for an SoC that came in at over 24,000 pages - a new personal record. The tools for working with such large PDFs generally suck.
- synack 4y agoEvince on Linux is by far the best program I've found for reading large PDFs. It's worth the trouble to setup a VM or WSL just to run Evince if you're not natively on Linux.
- rsav 4y agoI've actually been using an (ancient) build of Evince for Windows [0] for quite some time now. [0] https://www.fosshub.com/Evince.html https://www.fosshub.com/Evince.html
- shriek 4y agoI've never had to read a large PDFs (probably, ~400 pages) but what's so great about Evince? Is it just speed or is it because of it's features?
- fleventynine 4y ago> "just do yourself a favor and get the 4 layers boards so you can make ground and power planes" In general, you should avoid power planes on 4 layer boards if you can. They tend to cause a lot of trouble with return currents when signals jump from the top layer to the bottom layer through a via. Prefer using ground planes for both inner layers and make sure you have ground return vias near every signal via. https://youtu.be/kdCJxdR7L_I https://youtu.be/kdCJxdR7L_I goes into more detail.
- Teknoman117 4y agoThanks! I'll check it out!