As a new user of KiCad, I must say that the power flag thing is the most incomprehensible part of KiCad! Nothing about it makes any sense. The symbol used doesn’t make sense. None of the discussions nor questions and answers about it make any sense. There are no sensible examples of how to us it. IMHO it should be gotten rid of as it only seem to be some inconvenient hack in order to do something that should be an editable option of any of the already available power parts. Adding these horrible things to you schematic only confuses the reader and clutters multi source circuits. Look at any professional schematic (i.e. from Samsung, Qualcomm etc.) and you will…guess what? Not find any!
Please rid this nuisance or at least put some proper effort in explaining how to use it. Yes, lots of example pictures would be helpful.
Reading through the forums, it is also clear that this is an issue that is both overwhleming and will clearly not go away any time soon.
How is a ‘power part’ defined? On my board I have an RJ-45 connector (symbol from outside of the KiCad library, as well), where power and data connections arrive. Short of editing that connector’s symbol to mark the relevant pins as ‘power output’, PWR_FLAG is the only solution, since this part is not a ‘power part’ by any reasonable definition.
That is a good point, but my point is that you should not have to edit the part in your library to be able to set one or more of it’s pins to be a power source. So in this regard, I suppose there are only 2 solutions, either:
rewrite the part libraries
or make part pins editable so that they can be marked as powersource
Anyway, what do I know. I’m just re-new’ed to KiCad since >5 years.
One of the main points of confusions might be that a normal symbol is used to communicate this sort of thing. If it would be similar to the no connect flag then i think it might be a lot more intuitive.
Atomic part might not be the correct term here. A fully specified symbol represent exactly one part number and has all its fields filled out accordingly. But it still points to a generic footprint. Only if the assigned footprint is also only meant to represent that same component can the pair be called “atomic”.
Nothing suggested here would require even a fully specified yet alone an atomic asset.
The term you are looking for is a “project specific” symbol. This is a symbol of any type (generic, fully specified or atomic) that is changed to represent special requirements for the current project. (Non standard use of a rj connector, pin setup of an mcu representing how it is configured in software, …)
Each pin should have an option to add attributes. Like symbols now have where you can add custom fields. Then we could standardize a few of the attributes for this purpose. This would enable automating DC power analysis using FEM.
Hopefully the option to add attributes to pins will be added in V6.