参考一下 函数
#include <csl.h>
#include <csl_pll.h>
#include <csl_emif.h>
#include <csl_chip.h>
#include <csl_mcbsp.h>
#include <stdio.h>
#include "fpga_offset_addr.h"
#include <math.h>
#define CESECT2 0x400000
#define R_AD9280 (CESECT2 + RE_AD9280_OFFSET) //
#define Length 128 //FFT的点数
Uint16 *R_AD9280_Addr;
int in_x[Length]; //数据缓冲数组 128
int i = 0;
int s,m = 0;
int intnum = 0;
int flag = 0; //采集128点的标志
double xavg;
double x[128],pr[128],pi[128],fr[128],fi[128],mo[128];
int n,k,l,il;
PLL_Config myConfig = {
0, //IAI: the PLL locks using the same process that was underway
//before the idle mode was entered
1, //IOB: If the PLL indicates a break in the phase lock,
//it switches to its bypass mode and restarts the PLL phase-locking
//sequence
12 , //PLL multiply value; multiply 12 times
0 //Divide by 2 PLL divide value; it can be either PLL divide value
//(when PLL is enabled), or Bypass-mode divide value
//(PLL in bypass mode, if PLL multiply value is set to 1)
};
/*SDRAM的EMIF设置*/
EMIF_Config emiffig = {
0x221, //EGCR : the MEMFREQ = 00,the clock for the memory is equal to cpu frequence
// the WPE = 0 ,forbiden the writing posting when we debug the EMIF
// the MEMCEN = 1,the memory clock is reflected on the CLKMEM pin
// the NOHOLD = 1,HOLD requests are not recognized by the EMIF
0xFFFF, //EMI_RST: any write to this register resets the EMIF state machine
0x3FFF, //CE0_1: CE0 space control register 1
// MTYPE = 011,Synchronous DRAM(SDRAM),16-bit data bus width
0xFFFF, //CE0_2: CE0 space control register 2
0x00FF, //CE0_3: CE0 space control register 3
// TIMEOUT = 0xFF;
0x1FFF, //CE1_1: CE0 space control register 1
// Asynchronous, 16Bit
0xFFFF, //CE1_2: CE0 space control register 2
0x00FF, //CE1_3: CE0 space control register 3
0x1FFF, //CE2_1: CE0 space control register 1
// Asynchronous, 16Bit
0xFFFF, //CE2_2: CE0 space control register 2
0x00FF, //CE2_3: CE0 space control register 3
0x1FFF, //CE3_1: CE0 space control register 1
// Asynchronous, 16Bit
0xFFFF, //CE3_2: CE0 space control register 2
0x00FF, //CE3_3: CE0 space control register 3
0x2911, //SDC1: SDRAM control register 1
// TRC = 8
// SDSIZE = 0;SDWID = 0
// RFEN = 1
// TRCD = 2
// TRP = 2
0x0410, //SDPER : SDRAM period register
// 7ns *4096
0x07FF, //SDINIT: SDRAM initialization register
// any write to this register to init the all CE spaces,
// do it after hardware reset or power up the C55x device
0x0131 //SDC2: SDRAM control register 2
// SDACC = 0;
// TMRD = 01;
// TRAS = 0101;
// TACTV2ACTV = 0001;
};
void delay(Uint16 k)
{
while(k>0)
{
k--;
}
}
//--------------------------------------------------------------------
// 函数名称 : void kfft(double pr[128],double pi[128],int n,int k,double fr[128],double fi[128],int l,int il)
// 函数说明 : 基2快速傅立叶变换子程序
// 输入参数 :
// 输出参数 : 无
//--------------------------------------------------------------------
void kfft(double pr[128],double pi[128],int n,int k,double fr[128],double fi[128],int l,int il)
{
int it,m,is,i,j,nv,l0;
double p,q,s,vr,vi,poddr,poddi;
for (it=0; it<=n-1; it++)
{ m=it; is=0;
for (i=0; i<=k-1; i++)
{ j=m/2; is=2*is+(m-2*j); m=j;}
fr[it]=pr[is]; fi[it]=pi[is];
}
pr[0]=1.0; pi[0]=0.0;
p=6.283185306/(1.0*n);
pr[1]=cos(p); pi[1]=-sin(p);
if (l!=0) pi[1]=-pi[1];
for (i=2; i<=n-1; i++)
{ p=pr[i-1]*pr[1]; q=pi[i-1]*pi[1];
s=(pr[i-1]+pi[i-1])*(pr[1]+pi[1]);
pr[i]=p-q; pi[i]=s-p-q;
}
for (it=0; it<=n-2; it=it+2)
{ vr=fr[it]; vi=fi[it];
fr[it]=vr+fr[it+1]; fi[it]=vi+fi[it+1];
fr[it+1]=vr-fr[it+1]; fi[it+1]=vi-fi[it+1];
}
m=n/2; nv=2;
for (l0=k-2; l0>=0; l0--)
{ m=m/2; nv=2*nv;
for (it=0; it<=(m-1)*nv; it=it+nv)
for (j=0; j<=(nv/2)-1; j++)
{ p=pr[m*j]*fr[it+j+nv/2];
q=pi[m*j]*fi[it+j+nv/2];
s=pr[m*j]+pi[m*j];
s=s*(fr[it+j+nv/2]+fi[it+j+nv/2]);
poddr=p-q; poddi=s-p-q;
fr[it+j+nv/2]=fr[it+j]-poddr;
fi[it+j+nv/2]=fi[it+j]-poddi;
fr[it+j]=fr[it+j]+poddr;
fi[it+j]=fi[it+j]+poddi;
}
}
if (l!=0)
for (i=0; i<=n-1; i++)
{ fr[i]=fr[i]/(1.0*n);
fi[i]=fi[i]/(1.0*n);
}
if (il!=0)
for (i=0; i<=n-1; i++)
{ pr[i]=sqrt(fr[i]*fr[i]+fi[i]*fi[i]);
if (fabs(fr[i])<0.000001*fabs(fi[i]))
{ if ((fi[i]*fr[i])>0) pi[i]=90.0;
else pi[i]=-90.0;
}
else
pi[i]=atan(fi[i]/fr[i])*360.0/6.283185306;
}
}
void main()
{
/*初始化CSL库*/
CSL_init();
/*EMIF为全EMIF接口*/
CHIP_RSET(XBSR,0x0a01);
/*设置系统的运行速度为144MHz*/
PLL_config(&myConfig);
/*初始化DSP的外部SDRAM*/
EMIF_config(&emiffig);
R_AD9280_Addr = (Uint16 *)R_AD9280;
//--------初始化数组in_x[i] =0---------------------
for(i=0;i<128;i++)
in_x[i] = 0;
asm(" nop ");
while(!flag)
{
in_x[m] = (*R_AD9280_Addr & 0x00ff)*5;
m++;
intnum = m;
if (intnum == Length) //采集到128个点了吗？是，进行FFT分析
{
intnum = 0;
xavg = 0.0;
for (s=0; s<Length; s++)
{
xavg = in_x[s] + xavg; //归一化处理
}
xavg = xavg/Length;
for (s=0; s<Length; s++)
{
x[s] = 1.0*(in_x[s] - xavg);
pr[s] = x[s]; //输入实部
pi[s] = 0; //输入虚部
}
kfft(pr,pi,128,7,fr,fi,0,1); //调用FFT分析程序
for (s=0;s<Length;s++)
{ mo[s] = sqrt(fr[s]*fr[s]+fi[s]*fi[s]);} //求输出模值
m=0;
flag = 1; //改变标志位
}
}
while(1)
{
asm(" nop "); //在此设置断点
}
}
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