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stupid eagle polygon/routing question
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stupid eagle polygon/routing question

by ag3c on Sat Feb 05, 2011 7:31 pm

I'm designing a board in Eagle for a little project I made. It's just a two-layer board, and I was planning on doing a polygon fill top and bottom, connected to ground.

Now, if ground is available all over the place (with a suitably safe amount of isolation) ... it seems like this should greatly simplify the board wiring, right? All the components could just be connected to the ground fill by not isolating them from it. And then that's one less net that needs to be all over the board, so that should cut down on the amount of vias and circuitous routes.

But the board is already routed. (Some by me, some by the autorouter.) How do I get Eagle to just connect all the ground pads to the polygon? Should I just rip up the ground traces everywhere they exist? And then... use the ratsnest tool? Will that actually make the connections to the ground polygon?

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Re: stupid eagle polygon/routing question

by westfw on Sun Feb 06, 2011 5:00 am

If both the net and the polygon are named "GND", EAGLE will connect them. You don't need to rip-up the existing GND traces before making the polygon; they should just get "absorbed"; I like to leave them behind so that I have a board that will work with or without the polygon; for one thing it helps me be certain that I DO have nice thick ground connections in the relevant places. You can fool yourself into thinking that everything is fine because you have the polygon, when the only actual path to some heavy-current pin is some twisted path that narrows down to a tiny trace between dip pins (or something), which is not a good thing.

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Please be positive and constructive with your questions and comments.