How to remove Airwires in Eagle ?

[3Deye]

Hello,

I need to remove some airwires from the board in Eagle. These airwires are connecting ground pins in an FPGA even I didn't connect them in the schematics!

How can I do this ?

 

[keith1200rs]

It would be useful to see your Eagle files to answer that. Airwires are usually unconnected nets. It could be Vdd & GND nets which are automatically connected to other nets with the same name even if the physical connection i snot shown in the schematic. In which case, you should route them.

Keith.

 

[3Deye]

Hello Keith,

This is a picture of the FPGA chip from the .brd file :

I manually routed all IOs to the memory, but left the airwires connecting the GND pins. I think I could connect them directly to the ground plane through vias so no need to connect (route) them to each other !

 

[keith1200rs]

Hello Keith,

I manually routed all IOs to the memory, but left the airwires connecting the GND pins. I think I could connect them directly to the ground plane through vias so no need to connect (route) them to each other !

Yes. Connect them to vias, define a power plane with the correct name and hit "ratsnest" and they should disappear.

Keith.

 

[3Deye]

Great.... Helped +1

Another question popped up ! Could I add vias to the GND pins at the left side of the FPGA? (those pins which are surrounded by traces)

 

[keith1200rs]

Normally you would try to put them as close as possible to the pad (if there is room). For the ones which you have already routed (but still need connecting to ground) - add a via, then make sure it is named GND (or whatever your ground is called). You can do this before you place the via by typing VIA 'GND' or afterwards (using "NAME"). It will then create another airwire from the track to the via which you will need to connect. If you drop it directly on the wire (assuming the tracks and via are on the same grid) it will connect without any extra work as soon as you hit "ratsnest". That is the quickest way if you have stuck to a grid and you don't even need to name it - it will take the name 'GND' if you place it directly on the GND track.

I hope that all makes sense!

Keith.

 

[3Deye]

Yes, I understand how to add the GND plane and connect these air wires to it but the problem now as you said is:

(if there is room)

I think I will not be able to add vias in these crowded areas ! can I control the size of via to fit in these areas ?

 

[keith1200rs]

You can make the via any size you like provided it fits within the manufacturing capability of your PCB manufacturer. You can have as many different sizes as you like.

Keith

 

[3Deye]

Thanks Mr. Keith.

Btw, nice avatar

 

[keith1200rs]

Thanks. I did just has my logo but my name seems to cause some confusion about my gender in certain countries, so I thought I would try to clarify it!

Keith.