Recently I played around with multi sheet diagrams and hierarchical schematic and found that I like the root sheet symbols with placement of hierarchical pins much.
Compared to any ordinary symbol what can be considered as “frozen”, the behavior of hierarchical pins on a root symbol box could solve many aesthetic problems of schematic design.
E.g. a 555 timer has only 8 pins and every circuit prefers a diffrent arrangement. One prefers to count the pin numbers clockwise, another likes VCC in north and GND in south direction or a third design inpus left and outputs right. Whats about the idea of a “move” or “frozen” property flag what may switch any normal IC symbol to the behaviour of a sheet symbol. Ratio of the box may be modified free an the available pins with pin names may be selected from available pool ? Comparing to sheet symbols, Kicad already has everything on board for this feature ?
Don’t use hierarchical sheets for a component. Create a new library symbol.
Here is how i do it for ICs:
Power pins have their own block. Usually placed at the bottom of the shematic. The bypass capacitors are placed next to them. When you want to understand the function of a circuit, you normally don’t care about the supply pins, but they have to be visible in the schematic (just like everything from the PCB). And it is mostly clear which capacitor is for with pair of power pins.
For simple IC’s, i draw a symbol in a personal global library and use it for all projects needed. This are transceivers, logic gate, motor drivers and a 555 would probably also belong to this, but if it changes too much see next paragraph. The pins are placed by their function and how they are related to the other pins (completely independent of pin numbers). Normally input is on the left and output on the right, but they can be mirrored and rotated when placed if needed.
For more complex or more flexible IC’s, i use project specific libraries and draw a symbol just for this schematic. This are mostly programmable controllers.
Whether to do this or not, may depend on your use case a little bit. If you use 555 alot and you find that your projects always have 3 or 4 components with the same values, than you may consider grouping them in a sheet. That is especially useful because you can use the sheet to store footprints and vendor numbers.
I even have a sheet for my voltage regulator which just have 3 components. Thay may look excessive it, I think it is usefull. Readability does not really change.
On other benefit that I can think of, is that you are free to re-arrange the label pins of your sheet to your liking for every project. Just keep in mind, readability is key
Agree completely, i also use sheets for things like a single LDO + a few capacitors and a testpoint at least for GND.
But i wouldn’t use a hierarchical sheet to replace a symbol for a single component, just because creating a new symbol in a project specific library is annoying. You can store additional information such as part number, vendor number, datasheet link, … at a symbol library level.
There is a clear diffrence between using component symbols and sheet symbols. Its only the idea to enable similar pin shoove capability from sheet symbols also inside component symbols. This could improve schematic readability and/or shrink the library size. Maybe there is already any issue for this in the tracker ?
I don’t understand what your problem is. You can use a project specific symbol library to arrange the pints how they are needed in this project. You could also double click on the symbol and click “Edit Symbol …” to edit the symbol in your schematic (without touching the symbol in the library).
