Motorola DSP Developer's Kit

Output Objects

MOTDSP_Output objects are not used in S-functions. Instead, you create pointers to the output ports using specific Simulink macros.

    // Create real versions of output port pointers 
    // to output port 1
    // Real and Complex ...
   creal_T *y1 = (creal_T *)ssGetOutputPortSignal(S,0);
    // Real only ...
   real_T  *yr = ssGetOutputPortRealSignal(S,0);

You then "fill" these output signals with data returned from execution of the assembly or C program object file.

For a real array

    for (int k = 0; k < ssGetInputPortWidth(S,0); k++)
    {
       yr[k] = READ_MEM_SYM("OUT",a->GetSize(),M_FRACTYPE)[k];
    }

For real and imaginary parts of a single value complex output

//real part
y1[0].re = READ_REG("X1", M_FRACTYPE);
//imaginary part
y1[0].im = READ_REG("Y1", M_FRACTYPE);

For real and imaginary parts of a complex array output

for (int k = 0; k < ssGetInputPortWidth(S,0); k++)
{                 
    y1[k].re = READ_MEM_MAP_FRAC(X_MEM, StartAddress1, 
                                a->GetSizeReal())[k];
    y1[k].im = READ_MEM_MAP_FRAC(Y_MEM, StartAddress1, 
                                a->GetSizeImag())[k];
}

See Importing Data to DSP Simulator for more information on how to access the data returned from the simulator.

Validation:.   Inside the try block, a MOTDSP_FuncVar object is instantiated with the number of input ports and output ports as arguments. Use the supplied MOTDSP_FUNCVAR(NUM_INPORTS,NUM_OUTPORTS) macro. This class is used to validate access to input/output and create default or initial conditions.

Compared with MATLAB MEX-files, no MOTDSP_Config class is required for S-functions, since an argument list is not parsed. Instead, arguments are obtained from a parameter dialog box.

Input Objects

S-Function Blocks