DSP Applications and Student Projects - Digital Signal Processing and Applications with the C6713 and C6416 DSK - page 356

#include "dsk6713_aic23.h"
#include <rtdx.h>
#define RTDX_BUFFER_SIZE 256 //change for higher order
Uint32 fs = DSK6713_AIC23_FREQ_8KHZ;
RTDX_CreateInputChannel(control_channel); //create input channel
short* pFir; //->filter's Impulse response
short RtdxBuffer[RTDX_BUFFER_SIZE]={0}; //buffer for RTDX
short dly[RTDX_BUFFER_SIZE] = {0}; //buffer for input samples
short i;
short N; //order of filter
int yn;
interrupt void c_int11()
{
dly[0] = input_sample();
yn = 0;
for(i = 0; i < N; i++)
yn += pFir[i]*dly[i];
for(i = N - 1; i > 0; i--)
dly[i] = dly[i-1];
output_sample(yn >> 15);
}
void main()
{
N = 0; //initial filter order
pFir = &RtdxBuffer[1]; //-> 2nd element in buffer

comm_intr();
RTDX_enableInput(&control_channel); //enable RTDX input channel
while(1) //infinite loop
{
if(!RTDX_channelBusy(&control_channel)) //if free, read->buffer
{ //read N and coefficients
RTDX_read(&control_channel,&RtdxBuffer,sizeof(RtdxBuffer));
N = RtdxBuffer[0]; //extract filter order
}
}
}

FIGURE 10.7. C source program that runs on the DSK to implement an FIR filter using
RTDX with Visual C ++ to transfer the coefficients from the PC to the DSK

( rtdx_vc_FIR.c ).

FIGURE 10.8. Visual C message to load a file with the FIR coefficients to be transferred

through RTDX from the PC to the DSK.

++