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Topic: Eagle, logically connecting Pinheaders? (Read 2142 times) previous topic - next topic

Demonic69

Feb 16, 2012, 02:51 pm Last Edit: Feb 16, 2012, 03:08 pm by Demonic69 Reason: 1
Hi All
I've recently started learning Eagle and I think it's going reasonably well. One PCB I'm designing should be fairly simple, but the project will have 6 separate circuits on one board to minimise cost (If the suppliers will do as I ask at least) and they'll be separated upon arrival.
all 6 individual boards will be connected by ribbon cables, providing signals, power and ground (from LEDs to TCL5940 etc)
I'd like to be able to check that the pin headers logically match up, even though there's no direct route between them, is this possible?

Also, I've calculated .6mil for power traces to LEDs, but I've seen recommendations for 24mil, is this right?

Cheers

CrossRoads

Trace width, I doubt any suppliers will go that small. Perhaps you mean 6.0mil?

If you plan to have 6 of the same board, then draw it once in the schematic.  Make the layout you want on the board.
Then close the schematic, make a copy of the board file, open that up and copy the layout as you want.
Might work. Or it might give all the components new names.

Other option is to make 6 copies of the diagram on the schematic, using unique signal names for each group.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Demonic69

Hi Crossroads
Yeah, I thought .6mil was a wee bit tiny, this is based on a calculator in the ElectroDroid app. 24mil seems massive though, they're only 20ma RGB LEDs.

I've already got the board designed, mostly. There are 4 parts mostly the same, and 2 totally different. I've copied the parts individually in the schematic and got them connected and laid out how I want, that was the easy bit :D
I was hoping there was a way to make a connection between pins that doesn't require an air wire or trace, to check for continuity.
I have TLC - Pin header - Ribbon Cable between boards - Pinheader - LED, repeated 36 times more or less.
I was hoping there was an easy way to check if the net from the LED leads all the way back to the correct pin on the TLC, even though there's a break in the trace which would be covered by the ribbon cable.
It's fine if not, I can just manually double-check. Just would have been nice if ERC could have done if for me :D

Thanks for the reply.

KirAsh4

Most, if not all production houses will not allow you to tile different designs on the same board.  You can tile the same design a few times, but not different ones.  Now, there are exceptions of course, and perhaps your board house will allow you to do that for a cost.  I don't know.

For Seeedstudio and ITeadstudio, both allow tiling of the same design, no more than 5 times (even if you can add more, they won't allow it.)
BatchPCB will allow you to tile it as many times as you want as they charge by the sq inch, not set sizes like the two above.  I suppose it's possible to have completely different designs on a single board if you're going through BatchPCB.  But then why bother, you can submit multiple designs and they fit things for you (again, as opposed to the previous two where you have specific board sizes to work with.)

As for logically checking pin headers, there is no way to do that that I'm aware of.  However, if you're duplicating your board design, then all of them will have the same exact wiring.  You shouldn't have to test the pins because EagleCAD won't magically change pin 2 for pin 6, pin 4 for pin 1 when you copy/paste a board layout

Maybe I'm just not understanding what you're trying to do.

CrossRoads

Sure, you can show parts with just signal names, and have the same signal names on other parts elsewhere.
To check continuity, Tools:ERC, or click the bottom left symbol that looks like a magnifying glass over a logic gate.

If you're laying out similar circuits, be sure to give them different names or eagle will want to show them all connected in the .brd file.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Demonic69

OK, I think I'm starting to understand a bit better, thanks.

I've attached an image of the board I was hoping to get produced (once it's finished). Do you think the PCB manufacturers would take issue with it? I didn't think about having it panellized, I just designed it like this to save on costs, I planned to split it myself afterwards.

CrossRoads

Its possible, won't know for sure until you send in gerbers.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Demonic69

I'm probably a way from that at the minute :D
I'm just deciding if I've made things more difficult for myself by using a 1mm grid with a 1mm routing grid, rather than a 1.27mm grid. I can get a bit OCD and I hate working with dodgy numbers (1.yadayadayada instead of just 1), but I also hate when things don't line up perfectly. I also hate imperial measurements!
But... alas, it seems that the whole electronics world is against me and insists on sticking with this archaic form of measurement.
So am I just causing myself and the manufacturers more pain by sticking to my belligerent guns?

jwatte

1mm routing grid is fine. Especially if you use European component footprints. You can mix-and-match with imperial fractions, but getting to the exact center of pads when routing becomes painful.
6 mil is super tiny for traces. Most cheap places don't want you to go below 8, and I'd rather use 12 or 16 by default. You can still run a 16 mil trace between the pins of a DIP socket (with 100 mil spacing) just fine.
Unless you're doing high-frequency radio stuff, wider traces are entirely a Good Thing in my mind :-) Less resistance, less mechanical risk of cracks, less worry about etching eating into the traces.

Demonic69

That's great, thanks.
The traces are 10mil at the minute, I'll try bumping them up gradually to see what I can get away with.

Thanks for all of your help guys 'n gals, I'll be back soon with more Noob questions  :smiley-mr-green:

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