Annotation and custom chip references

I’m busy with a project reverse engineering a Apple II Card from the 80s

On the schematic Apple reference the chip numbers by their location.

For example the PCB has numbers 1-7 on the top, and A-F on the right. Then the chip reference is U7A


This is causing issues for the ERC in the schematic as if I reference the chip as U7A and run a ERC, KiCad reports that the component is not annotated. Looks like the chip reference needs to end in a number to keep the annotion check happy.

Is there a way to disable this or some kind of work around so that I can run ERC?

I would have to reference the chip as U7A1 and then disable the silkscreen for that on the PCB and create a text label for U7A - will get very confusion as there are lots of chips on the PCB.

?gnireenigne esrever ?tahw

Not as far as I know. You could assign A=1, B=2, etc and then U7A would become U71.

KiCad is a bit single minded concerning annotation, and it really wants it to end in a number.

I asked once (I think on gitlab) to reduce dependency on annotation to reduce it to something only used for human interaction (All internal stuff can and should e based on the UUID’s.) I think the response was “too much work, for too little benefit”.

The simplest workaround for you is to swap the columns. Instead of U7A, make it UA7.

Thanks. Had a feeling this might be the case.

I don’t like to complicate the reference annotation scheme (only benefit fo few projects, while this will for sure produce bugs during the transisiton period). But I will still point to the following already open gitlab wishlist issues:
general more flexibility for annotation: Allow more flexibility in annotation (reference designator) styles (#2403) · Issues · KiCad / KiCad Source Code / kicad · GitLab

someting a little bit like your apple board annotation: [Feature Request] Support for grid style refdes (#13706) · Issues · KiCad / KiCad Source Code / kicad · GitLab

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