Identical hierarchical sheets with busses assign wrong netclasses

[Stefan-Olt]

Hello,
I’m designing a board with 2 identical ADC channels. For those I created a single sheet that I added twice to the main sheet. For the ADC output I created a bus D[0..11]. When I connect these busses on the main sheet to the parts that should connect to the two ADCs, these parts are connected instead. The ADCs from the hierarchical sheets will remain unconnected. Normal signals are working fine. What am I doing wrong? Are busses in hierarchical sheets special somehow?
Best regerds
Stefan

Kicad 7.0.9 on Ubuntu 22.04 LTS

[paulvdh]

I took the liberty to edit your post and put the bus labels in a “Preformatted text” section, because this forum software maims your text and shows three dots instead, and that won’t work wiith KiCad.

Buses though hierarchical sheets do work, but they are a bit finicky to use. In the post below, I posted an example with a bus connecting though a hierarchy (also to two instances of a single sheet).

Where is the documentation for how to define a bus in 6.x?

I’ve been playing a bit more with these buses. If you have a bus with named members, then you can right click on the bus, and choose “Unfold from Bus” and select a name from the list, and I think this is new in KiCad V6. [image] I’ve also added some aliases to my example, and grouped them under the name “BBUUSS”. And these aliases can be used as a separate bus, or as a part in a group bus. Note the: Music.Gretl name. The example is just two instances of a hierarchical sheet, connected on th…

If you’re still stuck after that, you can zip up your project (or a simplified version of it) and post it here, and there will be several people willing to have a look at it and give some advice.

[Stefan-Olt]

Thanks. I couldn’t figure it out. I attached the entire project. It should be quite obvious: D0 of both input sheets are connected, but the input of the drivers are connected and not the the sheet output to driver input.
adc_usb3.zip (250.1 KB)
Best regards
Stefan

[paulvdh]

You have to name the bus itself (put a simple local label on it).
After that you can right click and use the Unfold from bus function to get one of it’s members.

If a bus has no name at all then (I guess, I’m not totally sure) KiCad defaults to the old behavior, in which a bus is only a graphical item and therefore local labels with the same name are connected on the schematic.

There is quite a lot in Buses in KiCad. I highly recommend to read the manual and do some studying and experimenting before you use them in an actual project.