I have created a footprint with nothing but a PTH pad that an M3 screw will fit through. That pad has a big fat exposed amount of copper than a screw and a serrated washer will connect to and I want to connect this pad to earth from the IEC inlet.
However, no matter what I do, PCBnew will simply not allow me to attach a net to it. Other parts I can select the pad and attach nets, but not this one.
I have kind of got round it by creating a schematic symbol as well and taken it through to the PCB, but that’s not really what I want.
Is there something funky with single pad parts or do you simply have to have a symbol and footprint if you want nets attached to a pad?
What is your problem with putting mounting holes on the schematic?
They’re just a few small dots in a corner, and Eeschema has predefined mounting holes with pins, which makes everything work normally and as it should be done.
Connection of the PCB to the case via screws is also important information which simply also belongs on the schematic. And that is why Pcbnew tries really hard to prevent you from making mistakes.
If you want to be stubborn, there are a few options.
1). you can start drawing a track from the center of your mounting hole, this will attach a track to that footprint, but it will not be connected to a net.
Then hover over a section of the track you just drew and press e to edit it. Now you can select a net from the Track & Via Properties.
This information will probably be lost again as soon as you update the pcb from the schematic. It may make your life a bit easier if you also put a V in the [ ] Locked checkbox for the track segment that connects to your mounting hole.
But still: Just put the holes in your schematic. The schematic is the source of the netlist, and should contain the whole netlist (& footprint links etc).
If you have footprints on the PCB which are not in the schematic you also have to lock them to prevent them from “disapearing” in some circumstances.
