MATLAB SIMULINK 7 - DEVELOPING S-FUNCTIONS Guide de l'utilisateur télécharger pdf (Page 53)

Writing Basic C MEX S-Functions

3-9

• mdlOutput:

- The numerical calculation.

mdlOutputs tells S imulink to multiply the

input signal by 2.0 and place the result in the output sig nal.

- To access the input signal, use:

InputRealPtrsType uPtrs = ssGetInputPortRealSignalPtrs(S,0);

where uPtrs is a vector of pointers and must be accessed using:

*uPtrs[i]

For more details, see “Data View of S-Functions” on page 3–19.

- To a ccess the output signal, use

real_T *y = ssGetOutputPortRealSignal(S,0);

This returns a contiguous a rray for the block’s outputs.

- The S -function loops o ver the width of the signal passing through the

block. To access the width, you can check the input or output port width.

Here the output port width was evaluated.

•

mdlTerminate:

- This is a mandatoryS-function routine. However, the

timestwo S-function

doesn’t need to perform any termination actions, so this routine is empty.

• Atthe end ofthe S-function,specifycode thatattaches this exampleto either

Simulink or the Real-Time Workshop:

#ifdef MATLAB_MEX_FILE

#include "simulink.c"

#else

#include "cg_sfun.h"

#endif

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MATLAB SIMULINK 7 - DEVELOPING S-FUNCTIONS Guide de l'utilisateur Page 53