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For reasons far outside my control, I have now been thrust into doing MATLAB/Simulink/Stateflow work. I've done the On-Ramp training, and already I despise how unintuitive it is to do things that are just common and easy in any text-based programming language.

So here's my issue: I am trying to create Stateflow subcharts that I can reuse like a function, like a series of steps to take when requesting a series of responses from an SPI bus. I want to be able to use this subchart from within other subcharts in the same parent Stateflow diagram. My research has so far led me to Atomic Subcharts.

The problem is, my subchart relies on a number of Simulink Functions, which in turn call S-Functions to communicate with an STM32 target. I can make the subchart, no problem, with the Simulink Functions in the root Stateflow diagram. But when I convert the subchart into an Atomic Subchart, it can no longer detect the Simulink functions, giving me errors in the subchart for them.

All of this I am doing inside of a library as common code for a particular chip we use on a number of in-house circuit boards. As a final wrinkle, this whole thing is being used inside a much larger system and uses the "after()" transition between states so that the RTOS can go do other things. As far as I am aware, I cannot do the same thing inside of a Simulink or MATLAB function and HAVE to do this in Stateflow, which means I can't just make a normal "do all SPI reads" function but need a "Stateflow function".

  • Is there any way to access Simulink Functions from inside an Atomic Function?
  • Is there any other way to reuse a Stateflow diagram like a function, so that I can update the root diagram without having to modify the same copy/pasted diagram code in multiple places?
  • I also cannot use graphical functions because these diagrams have loops, and apparently you can't backtrack inside of a graphical function.
JustCallmeSPED
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1 Answers1

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So I found an answer while working through this problem with more Stateflow experience than me. He mentioned the idea of "concurrently running states".

What you do is, at the root state, group your normal state into a subchart. Then for any reusable code you want to call like a function, make that a separate state machine with its own substates that defaults to an Idle state. You can then declare a local event in your main state to move the "function" state from its idle state, and have your main state wait for the "function" to return to its idle condition.

Your "function calls" in your main states are going to always have 2 states as you want for the "function" to be in its idle state, and then wait again until it returns to its idle state, but if you've got a subchart of sufficient complexity, this is a lot more compact than trying to copy and paste the same behavior in multiple subcharts and having to modify them later. Plus, you get the function-like behavior of only having to modify your "function" subchart to modify the behavior all across your stateflow diagram.

Information about how to create parallel running states can be found here:

https://www.mathworks.com/help/stateflow/gs/parallelism.html https://www.mathworks.com/help/stateflow/gs/events.html

JustCallmeSPED
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