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Thanks for the reply, Jeff. I believe that this is a CSS problem, as
somebody has posted about the same problem before (can't find the link now) and
fixed it by changing some linker settings in CCS. Here's an example of the code
that doesn't work:

    //sine8_intr.c Sine generation using 8 points, f=Fs/(# of points)
    //Comm routines and support files included in C6xdskinit.c

    short loop = 0;
    short sin_table[8] = {0,707,1000,707,0,-707,-1000,-707}; //sine values
    short amplitude = 10;     //gain factor

    interrupt void c_int11()  //interrupt service routine
    { 
     output_sample(sin_table[loop]*amplitude); //output each sine value
     if (loop < 7) ++loop;    //increment index loop
     else loop = 0;           //reinit index @ end of buffer
     return;                  //return from interrupt
    }

    void main()
    {
      comm_intr();            //init DSK, codec, McBSP
      while(1);               //infinite loop
    }

This is taken straight from the book and should work. However, using CCS's
"tone" example does work. The only difference between these two
examples appears to be the use of output_sample instead of DSK6713_AIC23_write.
Here's the fft256 code that also doesn't work. Both examples use the intterupt
routine that you described.

    //FFT256c.c FFT implementation calling a C-coded FFT function

    #include <math.h>                         
    #define PTS 256                //# of points for FFT
    #define PI 3.14159265358979
    typedef struct {float real,imag;} COMPLEX;
    void FFT(COMPLEX *Y, int n);        //FFT prototype
    float iobuffer[PTS];               //as input and output buffer
    float x1[PTS];                     //intermediate buffer
    short i;                           //general purpose index variable         
       
    short buffercount = 0;             //number of new samples in iobuffer      
 
    short flag = 0;                    //set to 1 by ISR when iobuffer full  
    COMPLEX w[PTS];                   //twiddle constants stored in w
    COMPLEX samples[PTS];              //primary working buffer                 
                           

    main()
    {
     for (i = 0 ; i<PTS ; i++)        // set up twiddle constants in w
      {
       w[i].real = cos(2*PI*i/512.0); //Re component of twiddle constants
       w[i].imag =-sin(2*PI*i/512.0); //Im component of twiddle constants
      }
     comm_intr();                //init DSK, codec, McBSP

     while(1)                    //infinite loop  
      {
       while (flag == 0) ;            //wait until iobuffer is full
       flag = 0;                      //reset flag
       for (i = 0 ; i < PTS ; i++)    //swap buffers
        {
         samples[i].real=iobuffer[i]; //buffer with new data
         iobuffer[i] = x1[i];         //processed frame to iobuffer
        }
       for (i = 0 ; i < PTS ; i++)
         samples[i].imag = 0.0;        //imag components = 0

       FFT(samples,PTS);              //call function FFT.c

       for (i = 0 ; i < PTS ; i++)    //compute magnitude
        {
         x1[i] = sqrt(samples[i].real*samples[i].real
             + samples[i].imag*samples[i].imag)/32;
        }
       x1[0] = 32000.0;               //negative spike(with AD535)for ref
      }                               //end of infinite loop
    }                         //end of main

    interrupt void c_int11()        //ISR
     {
      output_sample((int)(iobuffer[buffercount]));     //out from iobuffer
      iobuffer[buffercount++]=(float)(input_sample()); //input to iobuffer
      if (buffercount >= PTS)                   //if iobuffer full
      {
        buffercount = 0;                       //reinit buffercount
        flag = 1;                           //set flag
      }
    }
So is there any CCS-related reason that the sample_input and sample_output
functions wouldn't work but the DSK6713_AIC23_ ones would? I've hooked up an
oscilloscope to the output, and I've got some audio input. I've also tried to
plot the output from iobuffer using view->graphs but this gives nothing.

Cheers,

Mike

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Mike-

> So is there any CCS-related reason that the sample_input
> and sample_output functions wouldn't work but the
> DSK6713_AIC23_ ones would? I've hooked up an oscilloscope
> to the output, and I've got some audio input. I've also
> tried to plot the output from iobuffer using view->graphs
> but this gives nothing.

You'd have to debug.  What does sample_output() actually do?  What does
DSK6713_AIC23_write() actually do? 
sample_output() sounds generic so one guess might be that it doesn't know about
a specific board type, and doesn't
write the correct McBSP port and/or values.

In any case, this isn't a CSS issuec; CCS appears to be building and running
code fine.  The issue is which board and
which lib functions for that board.  If it turns out that sample_output() should
support the DSK 6713 but doesn't,
then you would want to ask Spectrum Digital (DSK provider) to explain.

-Jeff

> Thanks for the reply, Jeff. I believe that this is a CSS
> problem, as somebody has posted about the same problem before
> (can't find the link now) and fixed it by changing some linker settings in
CCS. Here's an example of the code that
> doesn't work:
>
>     //sine8_intr.c Sine generation using 8 points, f=Fs/(# of points)
>     //Comm routines and support files included in C6xdskinit.c
>
>     short loop = 0;
>     short sin_table[8] = {0,707,1000,707,0,-707,-1000,-707}; //sine values
>     short amplitude = 10;     //gain factor
>
>     interrupt void c_int11()  //interrupt service routine
>     {
>      output_sample(sin_table[loop]*amplitude); //output each sine value
>      if (loop < 7) ++loop;    //increment index loop
>      else loop = 0;           //reinit index @ end of buffer
>      return;                  //return from interrupt
>     }
>
>     void main()
>     {
>       comm_intr();            //init DSK, codec, McBSP
>       while(1);               //infinite loop
>     }
>
> This is taken straight from the book and should work. However, using CCS's
"tone" example does work. The only
> difference between these two examples appears to be the use of
output_sample instead of DSK6713_AIC23_write. Here's
> the fft256 code that also doesn't work. Both examples use the intterupt
routine that you described.
>
>     //FFT256c.c FFT implementation calling a C-coded FFT function
>
>     #include <math.h>
>     #define PTS 256                //# of points for FFT
>     #define PI 3.14159265358979
>     typedef struct {float real,imag;} COMPLEX;
>     void FFT(COMPLEX *Y, int n);        //FFT prototype
>     float iobuffer[PTS];               //as input and output buffer
>     float x1[PTS];                     //intermediate buffer
>     short i;                           //general purpose index variable
>     short buffercount = 0;             //number of new samples in iobuffer
>     short flag = 0;                    //set to 1 by ISR when iobuffer
full
>     COMPLEX w[PTS];                   //twiddle constants stored in w
>     COMPLEX samples[PTS];              //primary working buffer
>
>     main()
>     {
>      for (i = 0 ; i<PTS ; i++)        // set up twiddle constants in w
>       {
>        w[i].real = cos(2*PI*i/512.0); //Re component of twiddle constants
>        w[i].imag =-sin(2*PI*i/512.0); //Im component of twiddle constants
>       }
>      comm_intr();                //init DSK, codec, McBSP
>
>      while(1)                    //infinite loop
>       {
>        while (flag == 0) ;            //wait until iobuffer is full
>        flag = 0;                      //reset flag
>        for (i = 0 ; i < PTS ; i++)    //swap buffers
>         {
>          samples[i].real=iobuffer[i]; //buffer with new data
>          iobuffer[i] = x1[i];         //processed frame to iobuffer
>         }
>        for (i = 0 ; i < PTS ; i++)
>          samples[i].imag = 0.0;        //imag components = 0
>
>        FFT(samples,PTS);              //call function FFT.c
>
>        for (i = 0 ; i < PTS ; i++)    //compute magnitude
>         {
>          x1[i] = sqrt(samples[i].real*samples[i].real
>              + samples[i].imag*samples[i].imag)/32;
>         }
>        x1[0] = 32000.0;               //negative spike(with AD535)for ref
>       }                               //end of infinite loop
>     }                         //end of main
>
>     interrupt void c_int11()        //ISR
>      {
>       output_sample((int)(iobuffer[buffercount]));     //out from iobuffer
>       iobuffer[buffercount++]=(float)(input_sample()); //input to iobuffer
>       if (buffercount >= PTS)                   //if iobuffer full
>       {
>         buffercount = 0;                       //reinit buffercount
>         flag = 1;                           //set flag
>       }
>     }
> So is there any CCS-related reason that the sample_input and sample_output
functions wouldn't work but the
> DSK6713_AIC23_ ones would? I've hooked up an oscilloscope to the output,
and I've got some audio input. I've also
> tried to plot the output from iobuffer using view->graphs but this gives
nothing.
>
> Cheers,
>
> Mike

_____________________________________

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New Code Sharing Section now Live on DSPRelated.com. Learn about the Reward Program for Contributors here.



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