MATLAB: What block can I use to write data to a specific memory address in Simulink

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I would like to write data to a specific memory address using a Simulink block. However, I was not able to find a block that would enable me to do so.

Best Answer

The ability to write data to a specific memory address using a Simulink block is not available. To work around this issue, you can write a C/C++ file S-function and use the S-Function block in your Simulink model.

For more information on S-functions, refer to the documentation here:

https://www.mathworks.com/help/simulink/sfg/what-is-an-s-function.html

or use the following command in MATLAB 8.0 (R2012b):

 web([docroot '/simulink/sfg/how-to-implement-s-functions.html'])

Related Solutions

MATLAB: How to use Legacy Code Tool to include standard vectors, structures and functions in the S-function

I have included a small example which will demonstrate the workflow. This is through the usage of Legacy Code. Please see the link below for more details regarding the Legacy Code Tool.

https://www.mathworks.com/help/simulink/sfg/integrating-existing-c-functions-into-simulink-models-with-the-legacy-code-tool.html

First, include the definition of the structure by using this function: "Simulink.importExternalCTypes"

https://www.mathworks.com/help/simulink/slref/simulink.importexternalctypes.html

Then initialize the S function and define the Source and header files as described in the above example.

Then, specify that we intend to generate C++ code. This generates a MEX executable which can be used as an S-function block within your Simulink model. In order to prepare the data, I would suggest creating the structure data within Simulink and using this as the inputs to the S-function.

The example attached details the entire workflow. Please run the following attached script:

testLegacyStruct

Dynamic memory allocation is not supported yet by Simulink in MATLAB R2020b. Therefore the direct usage of "std::vector" is not supported in Simulink or connected externally by Legacy Code Tool up to this point.

The closest workaround to mimic this behavior is by modeling the dynamically allocated memory as a pointer work vector in the context of S-Functions. Note that S-Functions generated using Legacy Code Tool also support this pointer work vector workflow. The downside of this is that the data referenced by the pointer is opaque to Simulink and therefore cannot be operated on by blocks in the Simulink library. Instead, the user has to write more S-Functions that can accept this data, re-interpret it as the correct type, and then process it.

MATLAB: Creating a variable address

Hi,

i recommend you to use "fullfile" matlab function. This function allows you to build addresses from parts.

Thus, in your case:

variablecomponent = 'text';
fullfile('Data','Blocks',variablecomponent,'Input','MODEL_TYPE');

Thus, you vary in your for loop variablecomponent and you obtain a variable address.

Note that if variablecomponent is a cell array, where each cell contains a character array, remember to use {} brackets in your for loop. Otherwise the output of fullfile function is not a character array, but a cell array and maybe your function 'A.Application.Tree.FindNode' does not accept a cell array as input argument.

Hope this helps.

Best Answer

Related Solutions

MATLAB: How to use Legacy Code Tool to include standard vectors, structures and functions in the S-function

MATLAB: Creating a variable address

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