How to use custom C data types in Simulink S-Functions

Hi,

I am new to the whole MATLAB/Simulink programming environment and my boss is having us write firmware for our new product using this tool. I am essentially using the S-Functions as hardware drivers to call C code which I have written to carry out a specific hardware related task. I want to create libraries with these S-Functions in them so that it is easy for us to distribute among users. In some of the C functions that I'm calling using the S-Functions there are custom data types (for instance, one is called TIMER_TypeDef) that I not only need to be able to get Simulink to recognize, but also need to be able to assign as the input data type for an S-Function. I have read the support articles on the matter, chiefly this one:

Custom Data Types

In the article, it says that "the S-functions mdlInitializeSizes routine must..." and then gives an example of code that needs to be placed at the beginning of mdlInitializeSizes. My problem is being new to this programming environment I don't know where to define this routine. I don't even know if this is a MATLAB function or if it's something that's supposed to go in the C code that the model generates (which wouldn't make much sense, but the syntax in the example is very C code like, hence the confusion).

So, my question is where do I need to modify or define this S-function so that I can register my custom data type with Simulink?

Thank you in advance for your time.

-Chris Hack

Answer 1

[Sam Fishwick]

Mathworks provides templates for the S-functions.

https://uk.mathworks.com/help/simulink/sfg/templates-for-c-s-functions.html

I've seen mdlInitializeSizes within template sfuntmpl_doc.c

To find it either:

1:

Run this command by entering it in the MATLAB Command Window:

sfunddg_cb_edit('sfuntmpl_doc');

2:

Alternatively, sfuntmpl_doc.c can be found in your MATLAB installation path, most likely here:

MATLAB_ROOT\simulink\src