pcb layout

There's a bunch retiring now. Cheers

Might be an opportunity for unemployed CE grads.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

There's quite a strong visual element in the job. Computer science engineering doesn't call for that. Artificial intelligence might step in. Automatic layout programs never worked all that well, and human layout specialists were rarely as careful about stray capacitances and inductance as they needed to be, though some of them were quick to learn,

The best pcb layout people rarely understand electronics. But CE grads rarely understand electronics either.

We explain the rules to them and check their work. If something is especially critical, I sometime find it easier to do that bit of the layout myself; that's easier than trying to explain all the consraints.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Me too, but I've never had much trouble explaining to a layout person what the electronic constraints are, and the better ones could see what I meant and cleaned up extra stuff I hadn't got around to objecting to.

At least one of them was the daughter of one of the very clever technicians who worked at Cambridge Instruments. In a more egalitarian country he would have been doing my job. The UK sucked from time to time.

The three best layout people that I ever worked with were all female.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

The words out there's absolutely no future in this profession. AI can do so much better and so much more than any human. AI can evaluate prospective partial layouts for things like signal integrity and inter-trace coupling in real time during the layout process. It's only a matter of time for the right people to be needy enough to develop the specialized training algorithms. Or, even more spectacular, for AI systems to develop training algorithms for AI applications like this.

What CAD tools is everyone using for schematic capture through PCB layout?

We currently use Altium at work. I used to use the Cadence suite of tools which were very comprehensive, very expensive, and in my opinion very buggy.

Are any of the open source tools decent?

We use PADS, mainly because we used it in the DOS days when there wasn't much else, and we have thousands of files and a lot of learning invested. Actually, it works fine.

My big complaint is jaggies on my schematics. Varous people ceated library parts on diffferent grid centers, and the pins don't always line up on schematics.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Am 01.04.26 um 19:51 schrieb Buzz McCool:

Altium here. I stopped the yearly support fee when they would not help me at all when they heard that my Windows runs under VMware on a Linux host. Their excuse was that VMware could not handle networks. ROTFL! That's what earns them their money.

The real problem for Altium as I see it is, that a full installation with local license file can simply be copied and you can run as many incarnations of the VM as long as the virtual machines cannot see each other.

Not a real argument for me as a one man band, but I don't want to allow access to Internet for the Windows VM. If I crash the VM badly, I can simply fetch a new copy from an external drive.

Other than that, the VM sees only C: which is just system & tools and d: for the user data which is /d under Linux, mapped by VMware.

BTW, my problem was that I had renamed an old Protel library from .lib to .pcblib. Altium reads libraries completely without checking the contents and dies 500ms after startup. That bug must have been in Altium since the very beginning, never ever corrected.

For some time we used PADS layout with Orcad STD schematics. I even wrote a converter to augment the netlist with the decals, but an island solution. Never use a CAD program without access to a large user base.

Sometimes I use Genesys / ADS when the customer has a license, mostly for microstrip filter design / Electromagnetics etc, but never for board production. Transfer to Altium is not without problems but can be done. I managed to transfer some optimized comb line filters so that they looked like standard PCB decals in Altium.

KICAD ia said to be quite OK, but I have never tried it. There seems to be a bridge from Qucs Studio / usimmics to Kicad, (Verilog-A, spice, s-parameters, harmonic balance...) <

Click on the English flag. I have played with that a bit, no complaints from my side.

Gerhard

I stopped when things (bugs) started going BACKWARDS. Rolling back to an earlier release (a problem most tools have is they think you NEED to "keep up")

This is a flaw in many license schemes. I recall ancient SLOWARIS boxes chatting up on some high port number to look for duplicates. (so, a well designed firewall fixes that "problem")

Exactly. I don't let any of my work machines talk to the outside world. No worries about malware slipping in, my IP leaking out, time consuming upgrades (and their unexpected consequences) etc.

You can still exploit *local* connectivity to move stuff onto and off of the machine. But, the application is blind.

I used to use whatever the client required. As a result, have a boatload of tools available to choose from (even DASH-PCB!). It was a very deliberate act to pick which to embrace as my own. Some older tools were much more usable than the newer stuff (which often seems to be designed by someone who is just trying to map every action into an icon).

STRIDES was, by far, the most productive tool for schematic capture (assuming you had an adequate library). OrCAD's Layout was annoying when you tried to manually fix a routing (it would rip it up and put it back where *it* wanted it to be!) Tools change owners so it's hard to keep track of each pedigree.

"Layout" was one of the earliest "electronics" activities to see benefits from AI. Think about how you used to lay out a board in the 80's -- with tape or an "electronic etch-a-sketch". Then, autorouters with human assist. Then a *variety* of autorouters that you could selectively deploy on portions of a design. DRCs. Specifying propagation times for individual nets. Current handling requirements. Mechanical aspects of the components *on* those traces.

And, available on commodity hardware (no more Mentor/Computervision PROPRIETARY workstations!)

Folks who think they are "manually" laying out boards today are deluding themselves.

Have you done any AI board layouts?

I guess that enough KWH dumped into enough Nvidia chips could finally create some good autoplace and autoroute programs. But a real, non-trivial board will need a lot of input definition.

The Flux examples, so far, seem trivial and low density.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Am 01.04.26 um 23:23 schrieb Don Y:

I don't know STRIDES but I liked DOS Orcad schematics. Somehow I still miss it. We must have been one of the very first customers. They had just tiny ads in EDN.

I did this board in DOS Orcad on a Compaq-286, but only the schematics & firmware part. I had some unlucky guy to do the layout under time pressure. It is a complete PC-AT in Multibus2 format with 386/387, SCSI, floppy, transputer link, 2*com:, LPT:, cache and a whopping 8 MBytes of DRAM, dual ported to the Multibus2. The router routed happily across existing vias etc...

=:( )

At that time we cracked Racal RedBoard that used a laser- mutilated floppy as copy protection. That was hard because RedBoard claimed ALL available RAM for itself--- but we had extra RAM above the video card. The Microsoft CodeView debugger could be loaded high, so we saw the RMW cycles on the floppy and could skip them. That took an entire Easter weekend which was a _very_ bad investment of time. The software was sooo ugly.

You just draw whatever you want with a resist pen and etch the rest off.

No, use a Dremel and remove the parts you don't want.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Nostalgia:

KiCad looks okay, and some people seem to like it. It came from CERN. I've got it on my computer and used it a bit, but didn't get very far. I didn't have any problems with the software, but the project stopped being quite as attractive as it had been when I'd started work on it.

Windows made a lot of tools clumsy. They coerced developers into implementing "toolbars" and other widgets instead of a good combination of keyboard and mouse.

STRIDES used a three-button mouse effectively. And, you could call up a "screen" of all of the keyboard shortcuts so you could click on the one you wanted as well as refreshing your memory about it (to skip that screen callup).

It's biggest downside was the symbol editor as it wasn't graphical. Well, the *display* was graphical but you had to type "primitives" at the prompt and it would add those to the graphical depiction. It would have been nicer if you could just DRAW the symbol.

The quality of tools varies (varied?) tremendously. DASH-PCB was released around the time SMT was just *starting* to see use (when most boards were still thru-hole). It's design pardigm didn't fit well with SMT so it was a kludge to make it work. Best to stick with thru-hole designs for that.

My problems with autorouters was always getting them to let ME override their decisions as there were times when I wanted to route specific signals in specific ways that conflicted with its notion of the "best" route (given other signals present).

But, *knowing* their limitations, they could be exploited to shave layers off of a board (e.g., do something in 4 layers that SHOULD have been done in 6, etc.)

My current designs are far too dense for me to think I can be smarter than the layout and routing tools. E.g., 400 pins in 0.25 sq in?? And, hoping there's no components that will interfere on the back side of the board...

The DASH product line was protected with hardware keys. They shipped with an ISA board that implemented the mouse interface (just an extra UART with proprietary connector) and had sockets for up to 8 "keys".

Each key was a PAL -- something like a 16R8 (mid 1980's). Each implemented a state machine whose characteristics were known to the software. It would read the current state and then apply a stimulus and check the next state to see if it corresponded with it's expectations.

I wrote a small piece of code to explore all transitions from all states and tabulate them (this isn't as easy as it seems as you need to be able to "steer" the state machine to a state that you haven't fully characterized instead of just chasing it around).

They (DASH) made another product that would reduce such state tables to a set of equations for a PLD. So, it seemed amusing to use *their* tools to crack their keys! :>

Nowadays, EDA tools have a very high bar to entry. You need to invest in libraries that have been augmented with all sorts of additional information (beyond schematic symbol and PCB footprint) so they can determine how to swap "gates" in a package, back-annotate the schematic based on decisions made in layout, etc.