main.c

本源代码是在这款TMS320LF2407的DSP上的FFT算法程序

#include "LF2407regs.h"
#include "math.h"
#define	N	32                  //FFT变换的点数  
extern void fft(void);
extern void resave(void);
void interrupt nothing(void);
void sysinit(void);
extern int input[2*N];          //输入数据的存储数组 
int indati[N]={0};
//    -----------------------------------------------------------------------------------
//    128 点 FFT所需的数据
//    采样函数： x=1/4+1/4cos(3*2*pi*f*t)+1/4cos(6*2*pi*f*t)+1/4cos(9*2*pi*f*t)；
//    f=50Hz
//    -----------------------------------------------------------------------------------
/*int indatr[N]=
{
 16394, 15871, 14425, 12398, 10276,  8584,  7767,  8088,  9557, 11913,
 14660, 17155, 18724, 18802, 17044, 13411,  8197,  1995, -4389,-10071,
-14231,-16255,-15844,-13057, -8309, -2296,  4125, 10079, 14819, 17843,
 18969, 18342, 16394, 13739, 11055,  8950,  7848,  7921,  9070, 10961,
 13110, 14992, 16159, 16334,  5479, 13792, 11675,  9640,  8197,  7741,
  8457, 10264, 12815, 15554, 17812, 18939, 18429, 16034, 11825,  6203,
  -156, -6405,-11662,-15165,-16394,-15165,-11662, -6405,  -156,  6203,
 11825, 16034, 18429, 18939, 17812, 15554, 12815, 10264,  8457,  7741,
  8197,  9640, 11675, 13792, 15479, 16334, 16159, 14992, 13110, 10961,
  9070,  7921,  7848,  8950, 11055, 13739, 16393, 18342, 18969, 17843,
 14819, 10079,  4125, -2296, -8309,-13057,-15844,-16255,-14231,-10071,
 -4389,  1995,  8197, 13411, 17044, 18802, 18724, 17155, 14660, 11913,
  9557,  8088,  7767,  8584, 10276, 12398, 14425, 15871,
};*/
//   -----------------------------------------------------------------------------------
//   32点FFT所需的数据 
//   采样函数： x=1/4+1/4cos(3*2*pi*f*t)+1/4cos(6*2*pi*f*t)+1/4cos(9*2*pi*f*t)；
//   f=50Hz ；pi=π；
//   -----------------------------------------------------------------------------------
/*int indatr[N]=
{
 16384, 10270,  9551, 18713,  8192,-14222, -8304, 14810, 16384,  7843,
 13102, 15469,  8192, 12807, 18418, -0156,-16384, -0156, 18418, 12807,
  8192, 15469, 13102,  7843, 16383, 14810, -8304,-14222,  8192, 18713,
  9551, 10270,
};*/
int indatr[N]=
{
 0x07ff, 0x07ff, 0x07ff, 0x07ff, 0x07ff, 0x07ff, 0x07ff, 0x07ff, 0x07ff, 0x07ff,
 0x07ff, 0x07ff, 0x07ff, 0x07ff, 0x07ff, 0x07ff,0x0F801,0x0F801,0x0F801,0x0F801,
0x0F801,0x0F801,0x0F801,0x0F801,0x0F801,0x0F801,0x0F801,0x0F801,0x0F801,0x0F801,
0x0F801,0x0F801,
};        
//   -----------------------------------------------------------------------------------
//    64点 FFT所需的数据
//   采样函数： x=1/4+1/4cos(3*2*pi*f*t)+1/4cos(6*2*pi*f*t)+1/4cos(9*2*pi*f*t)；
//   f=50Hz
//   -----------------------------------------------------------------------------------
/*int indatr[N]=
{
 16384, 14416, 10270,  7762,  9551, 14651, 18713, 17034,  8192, -4387,
-14222,-15834, -8304,  4123, 14810, 18957, 16384, 11049,  7843,  9064,
 13102, 16149, 15469, 11668,  8192,  8452, 12807, 17801, 18418, 11818,
 -0156,-11655,-16384,-11655, -0156, 11818, 18418, 17801, 12807,  8452,
  8192, 11668, 15469, 16149, 13102,  9064,  7843, 11049, 16383, 18957,
 14810,  4123, -8304,-15834,-14222, -4387,  8192, 17034, 18713, 14651,
  9551,  7762, 10270, 14416,
};*/
//   ---------------------------------------------------------------
//    128 点 FFT的sin 和 cos值存储表
//   ---------------------------------------------------------------
/*const int sintab[N]=
{
    	0x07fff，0x00000，0x07fd9，0x0f9b9，0x07f62，0x0f375，0x07e9d，0x0ed38，
        0x07d8a，0x0e708，0x07c2a，0x0e0e7，0x07a7d，0x0dad8，0x07885，0x0d4e1，
        0x07642，0x0cf05，0x073b6，0x0c946，0x070e3，0x0c3aa，0x06dca，0x0be32，
        0x06A6C，0x0B8E4，0x066CE，0x0B3C1，0x062F1，0x0AECD，0x05ED6，0x0AA0C，
        0x05A81，0x0A57F，0x055F4，0x0A12A，0x05133，0x09D0F，0x04C3F，0x09932，
        0x0471C，0x09594，0x041CD，0x09237，0x03C56，0x08F1F，0x036B9，0x08C4B，
        0x030FB，0x089C0，0x02B1E，0x0877D，0x02527，0x08584，0x01F19，0x083D7，
        0x018F8，0x08277，0x012C7，0x08164，0x00C8B，0x0809F，0x00647，0x08029，
        0x00000，0x08001，0x0F9B9，0x08029，0x0F375，0x0809F，0x0ED39，0x08164，
        0x0E708，0x08277，0x0E0E7，0x083D7，0x0DAD9，0x08584，0x0D4E2，0x0877D，
        0x0CF05，0x089C0，0x0C947，0x08C4B，0x0C3AA，0x08F1F，0x0BE33，0x09237，
        0x0B8E4，0x09594，0x0B3C1，0x09932，0x0AECD，0x09D0F，0x0AA0C，0x0A12A，
        0x0A57F，0x0A57F，0x0A12A，0x0AA0C，0x09D0F，0x0AECD，0x09932，0x0B3C1，
        0x09594，0x0B8E4，0x09237，0x0BE33，0x08F1F，0x0C3AA，0x08C4B，0x0C947，
        0x089C0，0x0CF05，0x0877D，0x0D4E2，0x08584，0x0DAD9，0x083D7，0x0E0E7，
        0x08277，0x0E708，0x08164，0x0ED39，0x0809F，0x0F375，0x08029，0x0F9B9
};*/
//   ---------------------------------------------------------------
//   64点 FFT的sin 和 cos值存储表
//   ---------------------------------------------------------------                        
/*const int sintab[N]=
{
        0x7FFF，0x0000，0x7F61，0xF375，0x7D89，0xE708，0x7A7C，0xDAD9，
	    0x7640，0xCF05，0x70E1，0xC3AA，0x6A6C，0xB8E4，0x62F1，0xAECD,
	    0x5A81，0xA57F，0x5133，0x9D0F，0x471C，0x9594，0x3C56，0x8F1F，
	    0x30FB，0x89C0，0x2527，0x8584，0x18F8，0x8277，0x0C8B，0x809F，
	    0x0000，0x8001，0xF375，0x809F，0xE708，0x8277，0xDAD9，0x8584，
	    0xCF05，0x89C0，0xC3AA，0x8F1F，0xB8E4，0x9594，0xAECD，0x9D0F，
	    0xA57F，0xA57F，0x9D0F，0xAECD，0x9594，0xB8E4，0x8F1F，0xC3AA，
	    0x89C0，0xCF05，0x8584，0xDAD9，0x8277，0xE708，0x809F，0xF375，
};*/
//   ---------------------------------------------------------------
//   32 点 FFT的sin 和 cos值存储表
//   ---------------------------------------------------------------
const int sintab[N]=
{
         0x7FFF,0x0000,0x7D89,0xE708,0x7640,0xCF05,0x6A6C,0xB8E4,
         0x5A81,0xA57F,0x471C,0x9594,0x30FB,0x89C0,0x18F8,0x8277,
         0x0000,0x8001,0xE708,0x8277,0xCF05,0x89C0,0xB8E4,0x9594,
         0xA57F,0xA57F,0x9594,0xB8E4,0x89C0,0xCF05,0x8277,0xE708,
};

//extern int table128[];
extern int nom;            					//当nom=1时， FFT 需要归一化处理
main()
{
    int i;
    double x=0,y;
    nom=1;                                  //需要归一化处理
    sysinit();
    for(i=0;i<=255;i++)input[i]=0;          //清除输入数据
    resave();                               //把原始的输入数据反序排列
    *PCDATDIR=(*PCDATDIR&0x0FF00)|0x01;
    fft();                                  //进行FFT运算
    *PCDATDIR=*PCDATDIR&0x0FF00;
}

void interrupt nothing(void)
{        
    return;
}                

void sysinit(void)
{        
    *SCSR1=0x81FE;
    *WDCR=0x0E8;
    *IFR=0x0FF;
    *IMR=0x0;
    WSGR=0;
    *MCRB=0;
    *PCDATDIR=0x100;
}