How to create union in simulink

Hellow.

I have a question about how to union in simulink in simulink coder.

I know how to create the bus of struct using the 'Simulink bus' in dictionary file. (*.sldd)

However, i can't see the part that creates the union.

Does Mathoworks support the method of generating code an union as shown below?

If so, could you tell me how?

thank you

**************************************************************************************

typedef union
{
    uint32 R;
    uint16 H;
} Test_u;

**************************************************************************************

Answer 1

[Angelo Yeo]

Hi @WJKIM,

Current Simulink bus does not support union. Could we get a clearer understanding of why you want to realize the Simulink.Bus object as a union in the generated code? Is there any particular use case for this request?

[WJKIM]

Hi.

I respond to that.

If there are many flags (for example, Fault Flags), i can save memory space by using union.

This is only my opinion.

[rikro]

I am looking for the same purpose for fault flags . Is there a way we can use Union ?

Answer 2

[Anurag Ojha]

Hello

You can refer to following file exchange link to get more information:

https://www.mathworks.com/matlabcentral/fileexchange/116520-use-union-datatype-in-simulink

I hope this helps you resolve your query

[WJKIM]

Thank you for feedback.

I will try it

[WJKIM]

Hello,

I have a question about your link.

I found the 'TempBus' in *.m file. And its configuration of code generation is as follow:

Data scope : Imported

Header file : DataTypeImport.h

However, i don't find the DataTypeImport.h file.

Could you tell me where it is? How can i get that?

[Meghna]

Hello,

Following up on this as well, how is the header supposed to look/are there any examples?

Thanks!

[安晏]

Hello,

I have try this way: I defined union type in my *.h file, and union name is xx_TypeDef. And I Create Bus, Which DataScope is 'Imported', and special *.h file. Then, I Create Simulink.Signal with data Type is The Bus. After Code Generation, I found The union object generated. But!!! union object init is illegal, which init both member in union object. This mean, simulink coder always treat bus object as c-struct.