How do you generate a PWM signal through S function in C.I am facing a build error while building.Could anyone help me in this issue.

#define S_FUNCTION_NAME pwm_sfunction

#define S_FUNCTION_LEVEL 2

#include "simstruc.h"

#define PARAM_FREQUENCY 0

#define PARAM_DUTY_CYCLE 1

static void mdlInitializeSizes(SimStruct *S)

{

ssSetNumSFcnParams(S,2);

if (ssGetNumSFcnParams(S) != ssGetSFcnParamsCount(S))

{

return;

}

ssSetNumContStates(S,0);

ssSetNumDiscStates(S,0);

if (!ssSetNumInputPorts(S,0)) return;

if (!ssSetNumOutputPorts(S,1)) return;

ssSetOutputPortWidth(S,0,1);

ssSetNumSampleTimes(S,1);

ssSetSimStateCompliance(S,USE_DEFAULT_SIM_STATE);

ssSetOptions(S,0);

}

static void mdlInitializeSampleTimes(SimStruct *S)

{

ssSetSampleTime(S,0,INHERITED_SAMPLE_TIME);

ssSetOffsetTime(S,0,0.0);

}

static void mdlStart(SimStruct *S)

{

}

static void mdlOutputs(SimStruct *S,int_T tid)

{

real_T *y=ssGetOutputPortRealSignal(S,0);

real_T frequency = *mxGetPr(ssGetSFcnParam(S,PARAM_FREQUENCY));

real_T duty_cycle = *mxGetPr(ssGetSFcnParam(S,PARAM_DUTY_CYCLE));

double T_pwm =1.0/frequency;

double time = fmod(ssGetT(S),T_pwm);

*y =(time < T_pwm * duty_cycle)? 1.0:0.0;

}

static void mdlTerminate(SimStruct *S)

{

}

#ifdef MATLAB_MEX_FILE

#include "simulink.c"

#else

#include "cg_sfun.h"

#endif

Answer 1

[Mark McBroom]

Why are you writing an S-Function for this simple C algorithm. If you must write this in C, I suggest using the C Function block. https://www.mathworks.com/help/simulink/slref/cfunction.html

Or even easier, just write this code in MATLAB using a MATLAB Function Block: https://www.mathworks.com/help/simulink/ug/what-is-a-matlab-function-block.html#