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lethalbit, to random
@lethalbit@chaos.social avatar

I don't see many KiCad projects with detailed notes in the board files or schematic, which is kinda sad because it's a great way to keep notes for reference and important design descriptions.

My KiCad schematics and board files are absolutely littered with notes, with things from calculations for things to why things are done they way they are.

I wish more people would do it, makes things easier on everyone.

lethalbit,
@lethalbit@chaos.social avatar

@gregdavill Yeah, I find a lot of people really don't use the hierarchical sheets to their full potential, if they even use them at all, they just bump the page size.

I also wish people would stop just smearing global labels over everything,.

I've been thinking about dedicating the root sheet to a block diagram and stuff like that, but I tend to to just interleave that stuff within the schematic pages. but having a dedicated overview page is not a bad idea.

azonenberg,
@azonenberg@ioc.exchange avatar

@lethalbit @gregdavill I normally have the first/top level page just be connections between other sheets and some high level notes, but not to that extent. Fab notes live separately.

lethalbit, to random
@lethalbit@chaos.social avatar

Has anyone used OpenEMS to calculate trace impedance profiles from a PCB stackup before?

I'm looking around for decent and fast 2d field solvers for that kinda thing but outside of like 4 HUGE and expensive software suites there really isn't anything for the at home catgirl

niconiconi,

@azonenberg @lethalbit The best free 2D transmission line field solver is TNT-MMTL. Developed during the 1980s by Mayo Clinic’s Special Purpose Processor Development Group, stopped development and GPL'd in 2004 - it's ancient but it still works. It can be difficult (but possible, after applying patches) to build it on a modern system so it's easier to use the Win32 installer (I was working on a WebAssembly port but didn't have time to finish it). You can find source code and installers on SourceForge, and a few tutorials on YouTube.

niconiconi,

@azonenberg @lethalbit full-wave 3D field solvers like openEMS can definitely be used for this purpose but it's massively overkill for simple transmission lines, and it can also be less accurate since it's extremely sensitive to meshing. Furthermore, FDTD in particular will have great trouble on modeling fine structures like solder masks - you have a 35 micrometer layer on top of a 1.6 mm board. So 2D solvers is strongly preferred to 3D.

lethalbit, to random
@lethalbit@chaos.social avatar

Suddenly I have the need to LaTeX math notation rendering in KiCad's eeschema / pcbnew text fields >.>

gsuberland,
@gsuberland@chaos.social avatar

@lethalbit first party support for that would be a pretty incredible feature. I don't think any of the commercial EDA products can do it either.

lethalbit, to random
@lethalbit@chaos.social avatar

Something that probably only I would find useful, but would be nice in KiCad is the ability to assign a nested sheet a schematic symbol, and have the pins match up to the sheet pins.

Would be nice for a few things i'm bapping at.

lethalbit,
@lethalbit@chaos.social avatar

I know that xschem can do it, and I /think/ Cadence Virtuoso can do it, and it's useful there.

Not so much in KiCad normally, but I still have a few things that could use it.

blinken,
@blinken@hachyderm.io avatar

@lethalbit i agree it'd be nice if at least the exposed hierarchical labels (and their positions) were saved with the sub-sheet, which would make a sheet more symbol-like. It would be nice to make re-use/DRY easier. Currently I have a folder of sub-sheet modules I maintain, but the workflow feels a bit hacky in places.

lethalbit, to random
@lethalbit@chaos.social avatar

Unable to focus so I spent a little bit and made some KiCad footprints for the @NGIZero hexagons.

You can find them on github in my KiCad libraries

https://github.com/lethalbit/aki-eda/blob/main/kicad/lib/lethalbit-graphics.pretty/NGI0-Hex.kicad_mod

https://github.com/lethalbit/aki-eda/blob/main/kicad/lib/lethalbit-graphics.pretty/NGI0-Hex-Alt.kicad_mod

lethalbit, to random
@lethalbit@chaos.social avatar

Spiral bound notebooks, like the ones with the big spiral on the top, common in sketch books, is a huge pain in the ass trying to draw all the way to the edge of the paper.

My hand always ends up bumping the spiral and jolting my lines >:(

gsuberland,
@gsuberland@chaos.social avatar

@lethalbit yeah I really hate them for technical drawings, especially being a leftie

azonenberg,
@azonenberg@ioc.exchange avatar

@gsuberland @lethalbit Spiral notebooks were clearly designed by a northpaw.

(is that a real word?)

lethalbit, to random
@lethalbit@chaos.social avatar

wake up babe, nix for lesbians just dropped

lethalbit, to random
@lethalbit@chaos.social avatar

I need me a logic analyzer that has like, 1024 channels,

gsuberland,
@gsuberland@chaos.social avatar

@lethalbit you can get them but they will cost you the GDP of a small island nation

lethalbit,
@lethalbit@chaos.social avatar
lethalbit, to random
@lethalbit@chaos.social avatar
lethalbit,
@lethalbit@chaos.social avatar

@byteborg that's an IBM 9348-002 9-track magnetic tape drive~

byteborg,
@byteborg@chaos.social avatar

@lethalbit
Wow, solid 😊

lethalbit, to random
@lethalbit@chaos.social avatar

Dear application developers, please please please stop throwing garbage into ~ we have .cache/.config/.local for a good reason, I don't need your garbage polluting my home directory making things a huge pain, thanks.

lethalbit, to random
@lethalbit@chaos.social avatar

So, it seems like IDC68 for internal SCSI connections was a common thing?

But as far as I can tell only the IDC50 header was ever actually standardized for internal unshielded connections (believe me, I check)

I wonder if they took the existing external HD68 or VHDCI68 pinouts and just used those, i've not checked that bit, but I suspect they did.

lethalbit,
@lethalbit@chaos.social avatar

@philpem I mean it is /kinda/ dsub, but it's still an IDC connector, just with a fine pitch,

Personally i've not seen any such devices but /supposedly/ they showed up on internal CD-ROM and HDD drives.

So maybe it's the same mating connector style but just crimped onto a ribbon cable :v

philpem,
@philpem@digipres.club avatar

@lethalbit ohhh! yeah, that's the HD68 and they do have an IDC variant. I thought you meant the big 0.1 pitch 2-row things.
They are indeed the same as the external plugs but crimp-on for convenience/mass-manufacture.
They might have turned up on CD drives but I've mostly seen them on later DDS tape drives and hard drives.

I have an Amphenol HD68 internal SCSI cable around here somewhere which is twisted-pair. The cables crimp onto an untwisted section that happens every few inches.

lethalbit, to random
@lethalbit@chaos.social avatar

I fixed my cohost bot, logicbot to allow for more than one output and also fixed the bug that was causing the netlists to be reduced to pure AOI netlists, so now we have things like muxes, and XOR gates and all that good stuff,

https://cohost.org/logic-bot/post/5748772-w-d-a-b

lethalbit,
@lethalbit@chaos.social avatar

The general gist of how it works is that it randomly picks a number of expressions to generate (1 to 4) then for each expression it randomly picks how many terms it will have.

Once that's done, it generates a LUT with that many columns and fills it out randomly.

The LUT is then converted into Algebraic Normal Form and then either expressly simplified or not.

Once that's done it generates Verilog which is cammed into Yosys with some processing, then the netlist SVG is generated from that.

jaseg,
@jaseg@chaos.social avatar

@lethalbit I wrote something very similar to generate assignments for the first semester digital design course I TA at work.

lethalbit, to random
@lethalbit@chaos.social avatar

Okay okay, so this made Lina grimace when I was joking about it, but.

So, you know how you can't really do a live update into a fully new kernel, because the structure and memory layout changes, but.

What if we first setup a lookaside buffer that we could /serialize/ the internal kernel structures into and write a small replacement stub.

gsuberland,
@gsuberland@chaos.social avatar

@lethalbit I read this and made a noise.

lethalbit,
@lethalbit@chaos.social avatar
lethalbit, to random
@lethalbit@chaos.social avatar

Who doesn't love to wiggle internal bits of things that you really shouldn't be touching :v

fell,
@fell@ma.fellr.net avatar

@lethalbit What's this from?

lethalbit, to random
@lethalbit@chaos.social avatar

ADHD is currently really kicking my ass, I'm just fidgety and can't focus on anything, and just aaaaaaaaaaa

gsuberland,
@gsuberland@chaos.social avatar

@lethalbit been struggling with that myself today. in the end I hyperfocused on a thing I was not supposed to be working on but still ended up being useful, but the thing I really really needed to get done did not get done and aaaaaaaaaaa

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