DFX to Gerber?

And you imagine what it would be like today if noone had bothered to reinvent wheels?

Can you see wooden slabs on a Corvette? Or a 747?

print version

When they can do that we will all go that way. But until then paper is still handier. And sometimes has other uses too.

Yeah, I sometimes make the tracks as wide as possible & neck them down between the pads. I'm not sure hpw much of this you've done, but IC sockets are cheap, especially for one offs or low volume stuff. They make it easy to solder both sides if needed (pseudo vias) and also for fault finding/debugging. Maybe instead of replating just tin or hand tin with solder the tracks that need to be heavier or alternately use heavier weight copper cladding to begin with. Have fun!

Ah, got it. Haven't played with them myself (you stick with what you know for as long as possible -- in my case, that means HC11).

The last time I looked at CCI there was plenty of non PIC content.

Mostly to avoid problems. Everybody in the business uses a laser photoplotter to make the master artwork. All decent PCB CAD software can produce "Gerber" files, which are actually a variant form of "G code", ie RS-274D. It is a modal code, where an X and Y coordinate specify where to do "something", which is to either draw to or flash an aperture at that location. The aperture wheel is turned by a tool selection (D) code, and selects the size of the spot projected on the film. All newer machines are raster instead of vector, but the code is the same.

Anyway, if you give them a Gerber file, and their plotter accepts it and makes a plot, the chances of your saying "Oh, no, the board came out half the size it was supposed to be!" is extremely low.

The drill file (also known as an Excellon file) is ALSO a variant of RS-274D. One of them is leading zero suppressed, the other is trailing zero suppressed, both have the decimal points suppressed. (I forget which is which on the leading/trailing.)

Jon

If all else fails, I could probably re-do the whole thing in my PCB cad package. I don't think there's any way it could be imported into the package, but maybe there would be a way. I can generate RS-274D and X photoplot files and Excellon drill files. (I have Protel 99, which was a $7000 package when they moved on to the next system. It is very flexible and powerful.) I'd have to charge you, though, as re-entering the whole thing would be fairly time-consuming. Less than 2K$, however!

Jon

Sure, but I don't know if it is on the net. I got Gerber Scientific to send me a book "Gerber Format Guide" that has every variant and option. But, it is a VERY simple format.

Jon

Signals tracks this short seldom need extra metal, but power and especially ground sometimes do.

What we did back in the good old days was simply remove the solder resist from a ground trace and solder on a piece of wire.

Well, all elee pretty well failed, Jon.

I'm redrawing the whole thing with PCB Artist. Half liking it - pretty cool PDB design features, and half hating it - sloppy CAD functionality.

In a CAD program, I want...

To be able to access and easily manipulate individual points.

Points that make up a single object, or even selected points of several objects at the same time. And not necessarily have to manipulate the whole object.

A way to lock down cursor motion to one axis at a time. In DC, the Shift and Control keys do that. For 2D shift lockes out the X (moves along Y), ctrl locks out the Y, and in 3D use both to lock out X and Y (move along Z only)

And - a gravity select for the nearest point. (right click for instance)

There is more, but that's the worst of it.

It dawns on me that I just might be a bit spoiled.

Well, Protel is a powerful package designed specifically for PCB design, with schematic entry and cross-checking between the schematic and PCB. I've never had a bad board where the schematic was right. (Had more than a few where I screwed up the schematic, and the board was dutifully cross-checked against the bad schematic!) It has a very mediocre autorouter, but I sometimes still try to use it.

You might check out Autotrax, a free download that was the Protel product several generations ago.

I design pretty much with all surface mount parts now, up to 8 layers, and super-fine line parts down to .4mm lead pitch. other than some trickery you need to use for boards with multiple identical "channels" of circuits, there really isn't much in Protel 99 that I'd change.

Jon

Why on EARTH do you want 4 Oz copper on that digital board? What would be the resistance of those traces on 1 Oz Cu, .1" corner to corner? I use 2 Oz on a servo amp board that runs 20 A, otherwise I NEVER ask for anything over 1 Oz.

Jon

You could probably replace all of that except the memory with a Xilinx Spartan 3 FPGA for $12. It would probably be a 4-chip system. The FPGA, a download EPROm for the FPGA, the memory and the RS-232 translator. And, it could run at 50 MHz, too.

Jon

That's pretty small stuff, Jon.

It's amazing how far micro electronics have come.

Are those FPGAs erasable?

I've got 512k of eprom on this thing.

Some stuff will run in situ, with slight modification to relocate the stack and data storage to RAM. Other stuff may need to be relocated to RAM (512K also) to run.

I figure I've got equevelant room of one good 360k Floppy, the BIOS, monitor, and BASIC interpreter.

I suspect I'll be making a lot of trips to the eprom programmer.

Point taken and conceeded. That's just the way we did them 20 years back. Didn't know not to I guess.

I've had a number of gerber files plotted by my local photoplotter service from some commercial software and the PCD package that I wrote myself. They have said that due to the variations and the number of PCD packages out there, that is is often useful to have a printout of what the end result should look like. They said they frequently had to alter settings in their gerber to raster software in order to get the correct result.

Yes, just turn the power off, they have to be reloaded every time you power up. The Xilinx ones have a reloader function built in, so all you have to do is hook up one of the serial EPROMS to a couple pins and the chip does the rest. I'm using SST memories, $0.89 for one megabit.

There should be some open-source 8088 definitions available, as well as the other stuff that isn't dead simple. I recently picked up a UART definition off the web and it worked fine right away. All i had to do was edit away the features I didn't need.

Jon

I meant to say .1 OHM corner to corner. good enough for < 30 MHz stuff, for sure.

Jon