DSP Signal Generator Implementation On C6713 DSK - ComLab

1 include "dsk6713_aic23.h" //support file for codec, DSK
2 #define squareTableLen 800
3 Uint32 fs=DSK6713_AIC23_FREQ_96KHZ; //set sampling rate
4 short loop = 0; //table index
5 short gain =1;
6 short frequency = 1;
7 short square_table[squareTableLen]={0}; // table initialization
8 interrupt void c_int11() //interrupt service routine
9 {
10 output_sample(square_table[loop]*gain); //output square values
11 loop += frequency; //increment frequency index
12 loop = loop%squareTableLen; //reinitialize table if exceeds limit
13 return; //return from interrupt
14 } // end of interrpt routine
15 void main()
16 {
17 short i=0;
18 for(i=0; i < squareTableLen/2; i++)
19 {
20 square_table[i] = 300; // lookup table first half of waveform
21 }
22 for(i=squareTableLen/2; i < squareTableLen; i++)
23 {
24 square_table[i] = -300; // lookup table 2nd half of waveform
25 }
26 comm_intr(); //init DSK, codec, McBSP
27 while(1); //infinite loop
Figure 3.5: Source code for square wave generation
3.1.3 Triangular Wave Generation
Now we will discuss generation of triangular waves.
Figure 3.6: Triangular Wave obtained with the Scope
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