USB-C connector with unconnected pads in PCB editor

[Stephane_Muller]

Hi,

I’m having an issue with a USB-C connector. On my schematic I have connected every pin and yet, on the layout the GND and VBUS pads look like they are unconnected (there’s no net name on them and no ratsnest coming out of them).

I have tried deleting the footprint and updating the layout from schematic, changing footprint and then back again… nothing’s working. It’s started happening with KiCAD 8 (I have downloaded 8.02 to see if the bug was fixed but it’s not).

Anyone else has had this issue? Or found a way to fix it?

[paulvdh]

Why do you think it’s a bug?

KiCad is quite straight forward in pin mapping. It maps pin S1 on the schematic to pad S1 of the footprint. S2 through S4 are not in the schematic, and therefore KiCad does not know what you want do do with it.

There are two quite simple solutions.

1. You can modify the footprint, and renumber some pads, so all four mechanical pads have the pad name S1
2. You can add S2 through S4 to the schematic symbol. You can either make these visible, or use “pin stacking”.

[Stephane_Muller]

I think it’s a bug because it has worked in the past… same symbol, same footprint.

[paulvdh]

It’s definitely not a bug. You can compare it with your other project to find the differences.

[mousey]

With what version of Kicad was it working ok ? out of interest

[eelik]

There’s this annoying feature in KiCad that you can stack invisible symbol pins. I think that’s the only way this situation could be a bug.

[gschelotto]

According to the KiCad Library Conventions for pin stacking…
Note that if SH1…SH4 are defined as Power pins the stacking should be avoided.

[Stephane_Muller]

I could not find the issue so I made a new footprint and now it’s working…

I did notice a real bug since kicad 8 though. Sometimes footprints just don’t appear in the footprint editor or in the preview (when assigning footprints). I have to quit and restart kicad for it to work again.

Thanks for all your inputs!

[paulvdh]

@Stephane_Muller

I did notice a real bug since kicad 8 though. Sometimes footprints just don’t appear in the footprint editor or in the preview (when assigning footprints).

I am using an older Linux Mint (I think 20.2) version, and this has an annoying bug in file handling. I use XFCE (or was it LXDE, I always mix those up), and in the Thunar file browser, it does not always show all files. It tends to toggle between showing a file and “hiding” it on each file save.

[iabarry]

The schematic Symbol and the PCB Footprint don’t have matching pin names.
In sch: VBUS is on pin A4. There is no A4 in the footprint. Possibly the lib items were created by different people who may not have referenced a manufacturer datasheet for pin names. Pin names MUST MATCH.

[paulvdh]

@iabarry

Pin names MUST MATCH.

That is clear to me, and I already posted that in my first response.
I also unmarked the last post from IP as “the solution”, because creating a new footprint is a daft solution to this minor problem. Just renumbering some pads is all that was needed.