How to generate code that accepts Simulink block parameters as an argument to the model step function?

I have a complex project that I am generating code for. The Simulink model uses block paramters that are defined in the matlab workspace by configuration files. The config files look like the following:

config.param1 = 1
config.param2 = 2
assignin('caller','config',config)

The generated C++ code declare these param1 and param2 as global variables and the step function has the following declaration:

void Model_step(void);

The parameters are declared in Model_private.h like this:

/* Imported (extern) block paramters */
extern real_T param1;
extern real_T param2;

I want the code generated so that I can pass param1 and param2 to the step function so that the declaration looks like this:

struct {
param1
param2
} param_type
void Model_step(param_type);

How can I do that?

Answer 1

[Abhas]

Hi @Mohammed Afandi,

To modify the generated C++ code so that parameters are passed to the "Model_step" function as a structured type using Simulink and Embedded Coder, follow these steps:

Part 1: Environment Setup

• Open your Simulink model.
• In the Apps gallery, select "Embedded Coder".
• On the "C++" Code tab, choose "Embedded Code - C++".

Part 2: Configure Code Mappings

• Go to "Code Interface > Code Mappings".
• In the "Functions" tab, find "model_step".
• Click the hyperlink in "Function Preview" to edit the function signature.
• Define a "param_type" struct with your parameters and set it as the input argument for "model_step".

You may also refer the below documentation to Configure Parameters for C++ Interface Code Generation: https://www.mathworks.com/help/ecoder/ug/configure-parameters-for-c-code-generation.html

Part 3: Define Parameter Structure

• Create a header file (model.h) and define the struct:

typedef struct {
    real_T param1;
    real_T param2;
} param_type;

• Ensure "model.h" is included in relevant files.

Part 4: Generate and Verify Code

1. Click "Generate Code" in the Embedded Coder app.
2. Check "model.cpp" to confirm "Model_step" uses "param_type":

void Model_step(param_type params) {
    // Use params.param1 and params.param2
}

This approach ensures parameters are passed as a structured type, enhancing code clarity and organization.

You may refer to the below MathWorks documentation links to know more about the same:

1. https://www.mathworks.com/help/ecoder/ref/codemappingsceditor.html
2. https://www.mathworks.com/help/rtw/ref/model_step.html

I hope this helps!