[STM32F0] M0生成正弦波，波形很差怎么办？

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <math.h>



int main(int argc,char *argv[])

{

    int entries, entries_2PI, phase, amplitude, offset, data_per_line;

    int i, j;

    int max, min, max_digits;



    if (argc != 7) {

        fprintf(stderr,"Generate C source code for sine table\n");

        fprintf(stderr,"Usage:\n");

        fprintf(stderr,"sinus_gen entries entries_per_2PI phase amplitude offset data_per_line >outputfile\n\n");

        fprintf(stderr,"entries         : number of entries in sine table\n");

        fprintf(stderr,"entries_per_2PI : number of samples within full 360 degree\n");

        fprintf(stderr,"phase           : phase offset in samples\n");

        fprintf(stderr,"amplitude       : amplitude of sine wave, integer\n");

        fprintf(stderr,"offset          : offset of sine wave, integer\n");

        fprintf(stderr,"data_per_line   : number of samples per line in source file\n");

        fprintf(stderr,">outputfile     : redirect output form terminal to file\n");

        return 1;

    }



    entries = atoi(argv[1]);       //180

    entries_2PI = atoi(argv[2]);   //180

    phase = atoi(argv[3]);        // 0

    amplitude = atoi(argv[4]);     // 20

    offset = atoi(argv[5]);        // 20

    data_per_line = atoi(argv[6]); // 输出多少行



    min = abs(offset - amplitude);

    max = abs(offset + amplitude);



    max_digits=2;

    if (min > 99   || max > 99)   max_digits=3;

    if (min > 999  || max > 999)  max_digits=4;

    if (min > 9999 || max > 9999) max_digits=5;



    // header

    printf("const int sinus[%d] = {\n\t", entries);



    for (i=0, j=0; i<entries; i++) {

        switch(max_digits) {

            case 2: printf("%3d", (int)(offset + amplitude*sin((phase+i)*2*3.1415927/*3))); break;

            case 3: printf("%4d", (int)(offset + amplitude*sin((phase+i)*2*3.1415927/entries_2PI))); break;

            case 4: printf("%5d", (int)(offset + amplitude*sin((phase+i)*2*3.1415927/entries_2PI))); break;

            case 5: printf("%6d", (int)(offset + amplitude*sin((phase+i)*2*3.1415927/entries_2PI))); break;

        }

        if (i < (entries-1)) {

            printf(", ");

        }

        j++;

        if (j==data_per_line) {

            if (i < (entries-1)) {

                printf("\n\t");

            } else {

                printf("\n");

            }

            j=0;

        }

    }

    if (j !=0) printf("\n");



    // footer

    printf("};\n");



    return 0;

}

#include "cordic-16bit.h"

#include <math.h> // for testing only!



//Print out sin(x) vs fp CORDIC sin(x)

int main(int argc, char **argv)

{

    double p;

    int s,c;

    int i;    

    for(i=0;i<50;i++)

    {

        p = (i/50.0)*M_PI/2;        

        //use 32 iterations

        cordic((p*MUL), &s, &c, 16);

        //these values should be nearly equal

        printf("%f : %f\n", s/MUL, sin(p));

    }       

}

//Cordic in 16 bit signed fixed point math

//Function is valid for arguments in range -pi/2 -- pi/2

//for values pi/2--pi: value = half_pi-(theta-half_pi) and similarly for values -pi---pi/2

//

// 1.0 = 16384

// 1/k = 0.6072529350088812561694

// pi = 3.1415926536897932384626

//Constants

#define cordic_1K 10000

#define half_pi 0x00006487

#define MUL 16384.000000

#define CORDIC_NTAB 16

int cordic_ctab [] = {0x00003243, 0x00001DAC, 0x00000FAD, 0x000007F5, 0x000003FE, 0x000001FF, 0x000000FF, 0x0000007F, 0x0000003F, 0x0000001F, 0x0000000F, 0x00000007, 0x00000003, 0x00000001, 0x00000000, 0x00000000, };



void cordic(int theta, int *s, int *c, int n)

{

  int k, d, tx, ty, tz;

  int x=cordic_1K,y=0,z=theta;

  n = (n>CORDIC_NTAB) ? CORDIC_NTAB : n;

  for (k=0; k<n; ++k)

  {

    d = z>>15;

    //get sign. for other architectures, you might want to use the more portable version

    //d = z>=0 ? 0 : -1;

    tx = x - (((y>>k) ^ d) - d);

    ty = y + (((x>>k) ^ d) - d);

    tz = z - ((cordic_ctab[k] ^ d) - d);

    x = tx; y = ty; z = tz;

  }  

 *c = x; *s = y;

}