I need to draw software code like they did for hardware in circuit schematic diagrams.

Suppose we have function A, function B.

Function B calls function A...

Can we draw blocks with inputs & outputs, and connect these blocks together ?

Is there any software, which can generate such diagrams ?

It does not have to draw complicated UML diagrams, the diagram simply represent the function block inputs & outputs, that is enough, plus, it also represent the calling hierarchy through input & output lines connected, like they did in circuit schematic diagrams.

(output pin of chip A connects to input pin of chip B)

example drawing

  • What OS must the software run on? How much would you spend if it comes to paid software?
    – Izzy
    Apr 14, 2020 at 8:32
  • Do you expect the software to draw the diagrams, or are you simply looking for a GUI which allows you to draw such schematics manually? (For the latter I'm thinking Dia though it's been many years since I used it; you can also use any general SVG drawing program like Inkscape. See further en.wikipedia.org/wiki/Comparison_of_vector_graphics_editors)
    – tripleee
    Apr 14, 2020 at 8:49

1 Answer 1


For such a task I use yEd. yEd is and available for Windows, MacOS and Linux, since it's based on Java.

The company, yWorks, makes money by selling the library which is the basis for such an editor. So there's nothing specifically bad about it. No ads, no other treatments.

While I think it can do real UML diagrams, you needn't use it like that. (And, to be honest, sometimes you don't need UML to communicate a thing.)

Here's what I have created in ~2 minutes:


Usability is a bit of an issue. yEd does not behave the way you think it would. I now use it for some years and I have adapted to it. In the beginning you'll likely draw more boxes than you attempted to, because clicking does not select and creates a new box instead.

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