ddsFreq.c
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#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <math.h>
#include "ddsFreq.h"
#include "ad9915.h"
//#define debug
long double pgcd ( long double m , long double n)
{
if (fmod(m,n) ==0)
return n;
return pgcd(n,fmod(m,n));
}
int setddsFreq(int fd, int f_dds, long double f0, long double fs)
{
#ifdef debug
printf("f0=%Le\tfs=%Le\n",f0,fs);
#endif
if (fs<0 || f0<0) return EXIT_FAILURE;
struct frac f1;
f1.numerator = f0;
f1.denominator = fs;
long double d1 = pgcd (f1.numerator , f1.denominator );
//printf(" d1 = %24.16Lf\n",d1);
long double M = f0 / d1 ;
long double N = fs / d1 ;
//printf(" M = f0 / d1 = %24.16Lf\n",M);
//printf(" N = fs / d1 = %24.16Lf\n",N);
long double ftw = M * scalbn(1.0,32);
ftw /= N;
//printf("ftw = %24.16Lf\n",ftw);
//printf("X=floor(ftw) = %24.16Lf\n",(long double)floor(ftw));
long double Y = M * scalbn(1.0,32);
Y -= N * floor(ftw);
//printf("Y=M*2**32-X*N = %24.16Lf\n",Y);
long double d2 = pgcd (Y,N);
//printf(" d2 = %24.16Lf\n",d2);
long double A = Y / d2;
long double B = N / d2;
//printf("A = Y/d2 = %24.16Lf\n",A);
//printf("B = N/d2 = %24.16Lf\n",B);
//printf("f0 = (M/N) * fclk= %24.32Lf\n",fs*M/N);
//printf("f0 = (X+A/B)2**32= %24.32Lf\n",fs*(floor(ftw)+A/B)/scalbn(1.0,32));
#ifdef debug
printf("\n so finally the programmed registers are :\n"
"ftw= 0x%08x A= 0x%08x B= 0x%08x\n"
"",(unsigned int)ftw,(unsigned int)A,(unsigned int)B);
printf("uint ftw = %d\n",(unsigned int)ftw);
printf("\n 0x%08x 0x%08x 0x%08x \n\n",(unsigned int)ftw,(unsigned int)A,(unsigned int)B);
//setFreqMM(fd,f_dds,(unsigned int)ftw, (unsigned int)A, (unsigned int)B);
#endif
setFreqMM(fd,f_dds,(unsigned int)ftw, 2*(unsigned int)B, 2*(unsigned int)A); //??why *2??
return EXIT_SUCCESS;
}
int ddsFreq(int fd, int f_dds)
{
checkSize();
long double f0,fs;
//printf("long = %lu\n",sizeof (long));
//printf("float = %lu\n",sizeof (float));
//printf("double = %lu\n",sizeof (double));
//printf("long double = %lu\n",sizeof (long double));
printf("\nDesired output Frequency (MHz) : ");
scanf("%Lf",&f0);
printf("DDS frequency Clock (MHz) : ");
scanf("%Lf",&fs);
//long double f0=atof(argv[1]); //desired output freq
//long double fs=atof(argv[2]); //dds_clk
//int toto = (int)strtol(argv[3],NULL,0);
//printf("toto=%d\t%x\n",toto,toto);
if (fs<0 || f0<0) return EXIT_FAILURE;
struct frac f1;
f1.numerator = f0;
f1.denominator = fs;
long double d1 = pgcd (f1.numerator , f1.denominator );
printf(" d1 = %24.16Lf\n",d1);
long double M = f0 / d1 ;
long double N = fs / d1 ;
printf(" M = f0 / d1 = %24.16Lf\n",M);
printf(" N = fs / d1 = %24.16Lf\n",N);
long double ftw = M * scalbn(1.0,32);
ftw /= N;
printf("ftw = %24.16Lf\n",ftw);
printf("X=floor(ftw) = %24.16Lf\n",(long double)floor(ftw));
long double Y = M * scalbn(1.0,32);
Y -= N * floor(ftw);
printf("Y=M*2**32-X*N = %24.16Lf\n",Y);
long double d2 = pgcd (Y,N);
printf(" d2 = %24.16Lf\n",d2);
long double A = Y / d2;
long double B = N / d2;
printf("A = Y/d2 = %24.16Lf\n",A);
printf("B = N/d2 = %24.16Lf\n",B);
printf("f0 = (M/N) * fclk= %24.32Lf\n",fs*M/N);
printf("f0 = (X+A/B)2**32= %24.32Lf\n",fs*(floor(ftw)+A/B)/scalbn(1.0,32));
printf("\n so finally the programmed registers are :\n"
"ftw= 0x%08x A= 0x%08x B= 0x%08x\n"
"",(unsigned int)ftw,(unsigned int)A,(unsigned int)B);
//printf("uint ftw = %d\n",(unsigned int)ftw);
printf("\n 0x%08x 0x%08x 0x%08x \n\n",(unsigned int)ftw,(unsigned int)A,(unsigned int)B);
//setFreqMM(fd,f_dds,(unsigned int)ftw, (unsigned int)A, (unsigned int)B);
setFreqMM(fd,f_dds,(unsigned int)ftw, 2*(unsigned int)B, 2*(unsigned int)A);
return EXIT_SUCCESS;
}