MATLAB: Do I receive a warning regarding a word size mismatch when updating a model that contains a Stateflow chart in Simulink

datadiagramdifferentembeddedemlfunctionMATLABsizes"stateflowtypeupdate

I have a model that contains a Stateflow chart. The target hardware for this model is the TI C2000. When I update the Simulink diagram of this model, I get the following warning:

 The word size for "char" is specified as (16) in the "Hardware Implementation" section of Configuration Parameters. This is greater than the size (8) supported on the current machine. Results may be incorrect for signals of this type due to rounding/saturation effects.

I do not understand why this warning appears, since the choice of TI C2000 in the "Hardware Implementation" section is correctly specifying the word size for "char" as 16.

Best Answer

This error represented expected behavior in Simulink 7.0 (R2007b) and previous releases. However, the error message no longer appears in Simulink 7.1(R2008a).

Simulations performed in Simulink are typically done on a desktop machine where the default size of the "char" data type is 8. This could potentially differ from the default size of the "char" data type used on the target hardware.

If the size of the "char" data type specified in the "Hardware Implementation" section of the Configuration Parameters is different than that of the machine where simulations are performed, Simulink throws this warning to inform you that you may observe a difference between simulation results and actual code implementation.

Related Solutions

MATLAB: Do I receive a ‘skew was detected’ warning message when I open the model the with Stateflow chart containing Simulink functions in Simulink 7.4 (R2009b)

The warning message is displayed because the model has been corrupted. If you create a model with Simulink functions inside of Stateflow in R2008b and save the model once in R2009a or a later version, you will get this warning message if you open the model again in R2008b. After the model has been corrupted, this warning message will appear when you open the model in every version of MATLAB. The reason for this is that the code for Simulink functions was improved in R2009a and R2008b doesn't recognize these improvements.

If you need to open an R2009a or later model with Simulink functions inside Stateflow in R2008b, it is recommended that you use the File Menu \ Save As 'Simulink 7.2/R2008b Models' file type. If you open an R2009a or later model that contains Simulink functions inside of Stateflow in R2008b without using this Save As feature, it will corrupt the model.

MATLAB: How to load data/code to flash and run from RAM on a TI C2000 device

The TI compiler provides an easy mechanism to do this automatically using the "ramfuncs" attribute. Follow the steps below:

The shipping *.cmd (Linker command file) file of a specific processor already has allocation of sections of flash to store RAM data. Open the Configuration Parameters of your model, navigate the the "Hardware Implementation" settings, and click on the Edit button as shown below:

You can find the "ramfuncs" section details as below:

In the TI C2000 Hardware Support package provided by MathWorks, the custom storage class package labeled "tic2000demospkg" has been created to load the parameters/routines on the flash memory and run them from the RAM using this ramfuncs section. You can verify these built-in storage classes by executing the following command in the MATLAB command window:

>> cscdesigner

Select the tic2000demospkg package:

In the "Memory Sections" tab, you will find sections named "code_ramfuncs" and "const_data_ramfuncs" which can be used to store code and data in the ROM but copy them into RAM during execution.

If you cannot find the tic2000demospkg und "Select package," try clicking "Refresh package list" in the Configuration Parameters window in the Code Generation section:

To place a subsystem in the ramfuncs section, right-click on the subsystem, select Block Parameters and under the Code Generation tab, select the appropriate memory section as shown below:

Similarly, to allocate a Simulink parameter to ramfuncs section, type tic2000demospkg.Parameter in the MATLAB command prompt:

>> tic2000demospkg.Parameter

Then double-click on the parameter in the workspace and select const_data_ramfuncs as shown below:

Best Answer

Related Solutions

MATLAB: Do I receive a ‘skew was detected’ warning message when I open the model the with Stateflow chart containing Simulink functions in Simulink 7.4 (R2009b)

MATLAB: How to load data/code to flash and run from RAM on a TI C2000 device

Related Question