KiCad - Bus as input pin to a component

Question

Can a schematic component be created whereby a pin represents a bus (aka multi-bit) signal?

For example consider a case where you want to create a component for a 32-bit 16-to-1 multiplexer. Using a pin for each bit means that the component will have 516 input pins (32x16 + 4)!

My current approach is to create the component as such but place it inside a hierarchical sheet since the hiearchical sheet pins can take bus inputs. Is this the only approach available in KiCad? How do other programs like Altium and Eagle approach this issue?

Answer 1

Right now this is only supported for hierarchical pins (so you can pass a bus between hierarchies)

For v6 it is planned to have more powerful buses. It is also planned to switch to the new symbol file format. I am not sure if there is a plan to support bus pins.

Even if there are plans for it, i doubt it will be done by v6 as i suspect v6 will be the file format update without adding new features. My guess is that any more powerful symbol stuff will only come with v7. (So if you do not want to run development versions than this is at least 4 years away unless kicad gets a massive boost in development resources.)

Answer 2

CAD programs like KiCAD, Altium, and Eagle are intended to assist the user in making a PC Board based on a schematic diagram. To do that, the schematic must show all connections - what pins of this component connects to what pins of those other components - showing a bus as a single item does not allow that.

A block diagram could show a 32 bit bus as a "single" connection - but that is no help in specifying required connections on a PC board.

If you do have a single component that is a 32 bit 16-to-1 mux, (must be a huge FPGA in a BGA package!) then you will propbably need to show the component as several sub-components on a schematic.