Re: Seen Some Good PCB Training Video's?

I do practice that stuff.. I'm interested in seeing a style and use of tools such as alignment tools, part shoving and partial autorouting.

D from BC

I'd like to see those things just to see what you get for your $10k/seat tools vs the cheap/free stuff.

--
Ben Jackson AD7GD

http://www.ben.com/

I think it doesn't even compare. Granted, the commercial stuff is criminally overpriced and looks like it has stagnated since the 70s. I'm always a bit surprised at how little the software does given the tremendous computer resources we have now.

I've used some of the free stuff. Some of it is quite good even, but can't handle the complex stuff. 14+ layers, 4 levels of blind vias, differential pairs that alternate between microstrip and stripline, heterogeneous material stack ups, etc..

And even Allegro can't handle the simple (IMHO) task of re-sizing diff pairs when the rules change. To me, this should be simple. Yet all it does is flag some DRCs and waits like the Secretary of Education in Idiocracy for me to fix them.

But the commercial stuff has never blown up in my face at a critical time, and when it does wet its pants I'm a phone call away from talking to support. Cadence support is quite good. It has to be given their documentation. I call it negative documentation, because the more I read it, the dumber I get.

I'm surprised that, as far as I'm aware, there's not one PCB CAD program out there that has the placement features of any modern CAD program (such as SolidWorks) or even high-end drawing programs (such as CorelDraw). I'm thinking of features such as automatic snapping to lines at pre-defined intervals (e.g., 0%, 25%, 50%, 75%, 100%) or, say, circles (at, say, 30 degree intervals), alginment of one object based off of the, e.g., edges, centers, etc. of other objects, and so on.

I feel confident that few PCB software designers have ever actually used a good CAD or drawing program like that...

Heck, a lot of packages won't even let you view the board from the opposite side! Many won't let you see a true 3D view of the PCB either.

Good points.

Agreed... Cadence seems to have a corporate priority of producing *more* documentation, but they don't realize (at least in the case of ORCAD, that I'm familiar with) that what they've been adding is simply *quantity* and not

*quality*. Another thing I feel confident about: The folks who've written most of the ORCAD documentation in the past handful of years are *not* regular users of the software.

---Joel

Not always. What if you have a constraint that all lines in a bus have to be within 500ps of each other and be a certain length? That's when you have to start planning where you're gonna pile up the accordions.

Not always, sometimes the power track is purposely made to be inductive, as in the power leads to MMICs.

That's just a side-effect of reduced inter-plane inductance. That's why you want power planes, and close to each other, ZBC be damned.

The world of PCB is so complex and encompasses everything from cheap commodity punch-and-crunch wall-wart DC power supplies to exotic materials and multi GHz operation, as in LNBs. Not to mention high voltages, etc... No single set of rules can hope to cover everything. Not saying your rules are wrong, just that if you stop there, you're missing the point.

I wonder how much money it would take to make a credible start at creating a MODERN commercial (say, Solidworks price range) 3-D PCB CAD program with commercial-quality libraries and features.

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

Allegro has flexible grids. You can define a grid to have points at

5,5,5,10,23,21 mils for example. Basically random. Also has a polar grid. Not used a lot.

I think few PCB software designers know what a PCB is, or have enough hardware hacking background.

I know, it's terrible. Video games give you photo realistic movies rendered in real time, but I can't see a rectangle with 12 resistors on it spin in space. Ridiculous.

Concept is even worse. I just use it by rote, I still don't know quite how it works.

I've made a few circuit boards in Corel just so I can get really fancy.

Heck, if Corel was turned into a pcb app. I'd try it out.

D from BC

How is this different than a plain grid?

One of the PCB users wrote an alignment plugin to do that.

PCB has that. Automatically changes drawing and visible layers accordingly, too. You can even choose vertical or horizontal flip. I'd think this would be a must-have on any pcb cad package, given how much SMT stuff goes on the back side of modern boards.

Kicad has that, I think.

Well..Linear Tech. released Switchercad for free... But..I don't think releasing a pcb CAD program will also help sell LT chips.. :P

But,let's say LTSpice transferred a netlist to a fictional "LT SwitcherPCB" program... LT might sell even more chips. :P Imagine...LT pads, LT holes, LT footprints...etc..

D from BC

It's more productive in that you don't have to define a new grid just because you need some one-off placement of, say, a handful of holes based off of, say, some metric dimensioning line when in general you're perfectly happy with, say, a 25mil grid. Grids force you to know (calculate) the physical dimensions of what it is you're doing, which slows you down when all you really want is, e.g., 4 mounting holes spaced equally between two points on the PCB.

Programs like CorelDraw have grids as well, although once you get used to referencing placement of one object off of another you tend to not use the grid itself so much except when you're first placing large "anchor" objects. They make it trivial to do something like placing an object centered horizontally between two other items but vertically between still two more, all just using various mouse strokes and clicks. It's of course also trivial to do something like line up all the left edges of a bunch of objects as you're placing them, rather than using the method that most PCB packages support of dropping them somewhere reasonably close to each other, selecting them all, and then selecting "align left."

Yeah, Pulsonix does that too... although as far as I can tell PADS (which is definitely one of the more expensive packages out there) doesn't. Nor does PADS give you a 3D board view, which Pulsonix and some other packages do.

3D board views are most useful for looking at the layer stackup... being able to see the entire board in 3D is cool eye candy, although to make it really look nice you have to enter the height & shape information for parts, which does require a little more time when building your parts library. (Plus you have the usual problem that, if the program doesn't include the 3D shape for a part you're using -- such as, say, some oddball connector -- either you have to live with a more generic rectangular "blob" for the rendering of go make or find a proper 3D model, which can be quite time-consuming.)

---Joel