Avoid air wires if multiple pads have the same signal

Improvement Ideas
1

Good day everybody,

I’m currently working on a shield for the Arduino DUE. For this I recreated the Arduino in my library and - according to the guidelines - created GND and 5V only once in the schematic. The package itself has e.g. for GND but a total of 6 pads, all of which were assigned to GND in the device.

In the board editor I have wired all the other components accordingly, but the board editor continues to show me air wires to the GND points. Likewise for the 5V lines. Is this a bug or a feature?

GND-5V-Air-Wires
GND-5V-Air-Wires1110×632 92 KB

If it is a bug, then it might make sense to introduce a category “internally wired” when assigning pads to signals, so that the air wires are only displayed to me in the finished board layout if GND has not been connected at all.

But maybe I’m just missing something here?

Best regards,
Harry

2

Hi,

That’s actually a good question :slight_smile: If a device contains multiple pads for the same signal, it depends on the use-case or on the internal wiring of the device whether it is sufficient to connect one of these pins, or to connect all (or some) of them. Currently LibrePCB goes the safer way and expects that all pads need to be connected (“safer” because this way you get airwires).

I’m not sure if there is a good way to avoid such airwires. Or if we should keep it that way, but add a way to manually suppress specific airwires in the board…

3

Hi,

as mentioned above, I would suggest, that one should be able to tag signals as “internally wired”. That way one would have e.g. one gnd and the others are assigned “internally wired to signal” if suitable. If they are needed, they simply are not assigned that way. Seems to me more consistent and logical than suppressing specific airwires.

But I would definetly not leave it as it is, as air wires should only be visible if a connection has to be done.