MATLAB SIMULINK 7 - DEVELOPING S-FUNCTIONS Guía de usuario descargar pdf (Pagina 190)

4 Guidelines for Writing C MEX S-Functions

4-24

mxGetPr MATLAB API function. This results in a slight increase in

performance.

mdlRTW Usage

The Real-Time Workshop calls the mdlRTW routine while it (the Real-Time

Workshop) generates the

model.rtw file. You can add information to the

model.rtw file about the mode in which your S-function block is operating to

produce optimal code for your Simulink model.

This example adds the following information to the

model.rtw file:

• Parameters — these are items that can be modified during execution by

external mode. In this example, the

XData and YData S-function parameters

can change during execution and are written using the function

ssWriteRTWParameters.

• Parameter settings — t hese are items that do not change during execution.

In this case the

XDataEvenlySpaced S-function parameter cannot change

during execution (

ssSetSFcnParamNotTunable was s pecified for it in

mdlInitializeSizes). This example writes it out as a parameter setting

(

XSpacing) using the function ssWriteRTWParamSettings.

Example Model

Before examini ng the S-function and the inlined TLC file, consider the

generated code f or the following model.

1 2 ... 185 186 187 188 189 190 191 192 193 194 195 ... 209 210

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MATLAB SIMULINK 7 - DEVELOPING S-FUNCTIONS Guía de usuario Pagina 190