Slightly OT: accessible circuit/logic diagramming tools?

[Bill Dengler <codeofdusk@xxxxxxxxxxx>]

Hello,
I’m about a week away from starting university (studying computer science). Part of my coursework involves the creation and manipulation of logic/circuit diagrams.
In the past, I have given verbal descriptions of logic gaits and the connections between them (inputs/outputs), but this system quickly becomes unwieldy for even tens of gaits.
How have others dealt with this? Are there accessible circuit/logic diagramming tools that allow the user to create a component made up of logic gaits, connect the components, then “zoom out” for a higher-level overview? Or is there another method that works better for this sort of thing? Maybe something within Emacs, to take advantage of Emacs/Emacspeak’s outlining capabilities?

Thanks,
Bill