I have a largish board full of stuff. I noticed that I have two ratsnest connections visible. They are connected, so they should not be there.
I see SCL pads and SCL0 tracks. A problem? But that should not be a problem.
What should I check or do next. Ignore them is an option.
I would not ignore them.
The router engine thinks they are not connected. I would try to understand why this is.
Have you checked for parity between your layout and the schematic?
ETA:
Oh. You have connected two nets: SDA and SDA0, and SCL and SCL0.
How did you manage to do that?
I think other is pad/pin name and other is a track name. Pin names are hard to change, but track names I can choose.
Have I misunderstood something.
Yes, I have ignored those ratsnests, but it would be better to know what is wrong.
Too bad that even if I select the whole track on the PCB, it is not selected on the Schematic.
This could be the reason
The small squares at the junctions indicate that there’s no connection. There should be connection dots.
Yes. I fixed those too.
An ERC would probably have warned you about dangling wires too. The fact that the pad was SCL and the track SCL0 was also a giveaway. One net name will win and the pad would have acquired the same net name as the track.
Well, why waste 10 seconds on ERC?
For some reason I didn’t see this on ERC. But I didn’t check ignore list either.
I am a bit carefull with ERC and such. It wants to fix things which are not broken. Like footprint outlines, some corners on tracks and so on.
Some day when I have time I’ll fix those, but not tonight.
By the way, my thanks to 3Dogs and retiredfeline
They helped
Just for future reference, SDA0 is not the same as SDA, they are different nets and, according to your schematic, should not be connected. I know you now know the cause but this kind of thing should jump out at you during layout, it’s also possible to set the interactive router to not allow you to make such connections.
PCB Editor / Inspect / Design Rules Checker
It’s a very important tool. Learn to uses it, and how to interpret it’s output.
