TI中文支持网aic23的采样率为48K，在程序中写下FFT后，听到的声音莎莎的，想问下是什么问题
#include <csl.h>
#include <csl_chip.h>
#include <csl_i2c.h>
#include <csl_pll.h>
#include <csl_mcbsp.h>
#include <csl_emif.h>
#include <csl_emifBhal.h>
#include <stdio.h>
#include <math.h>
//#include "5502_FLASH.h"
#include "E2PROM_Function.h"
#include "CODEC.h"
#include "i_cmplx.h" /* definition of the complex type */
#include "twiddle1024.h" /* quantised and scaled Twiddle factors */
#undef CODEC_ADDR
#define CODEC_ADDR 0x1A
short SourData1[65536]={0};
short SourData2[65536]={0};
short SourData3[65536]={0};
short OutData1[65536]={0};
short OutData2[65536]={0};
short OutData3[65536]={0};
Uint32 mod[256];
#pragma DATA_SECTION (SourData1,".Audio_in_data1");
#pragma DATA_SECTION (SourData2,".Audio_in_data2");
#pragma DATA_SECTION (SourData3,".Audio_in_data3");
#pragma DATA_SECTION (OutData1,".Audio_out_data1");
#pragma DATA_SECTION (OutData2,".Audio_out_data2");
#pragma DATA_SECTION (OutData3,".Audio_out_data3");
#define AUDIOTRY 0xAA0A//音频试听
#define AUDIOCOPY 0xAA07//音频存贮并回放
#define TESTCOMMAND 1 //操作命令选择
// 定义McBSP的句柄
MCBSP_Handle hMcbsp;
short OutFFT[256]={0};
COMPLEX DOutFFT[256];
void myFFT(COMPLEX *Y, int N);
/*————————————————————————————*/
//
// FUNCTION: MAIN
//
/*————————————————————————————*/
void main(void)
{
short DataTempLeft = 0; // 暂存采样数据
short DataTempRight = 0;
Uint16 i;
short TempData;
Uint16 TestCommand =0;
// long n;
// Uint16 m=0;
// short p,q;
Uint16 j=0;
// Initialize CSL library – This is REQUIRED !!!
CSL_init();
#if TESTCOMMAND==1
TestCommand =AUDIOTRY;//试听
#endif
#if TESTCOMMAND==2
TestCommand =AUDIOCOPY;//录音并回放
#endif
// The main frequency of system is 240MHz
// 该频率是为了设置IIC模块的需要设置的,为了使用I2C_setup函数
PLL_setFreq(1, 0xC, 0, 1, 3, 3, 0);
//EMIF初始化
Emif_Config();
// Open McBSP port 1 and get a McBSP type handle
hMcbsp = MCBSP_open(MCBSP_PORT1,MCBSP_OPEN_RESET);
// Config McBSP port 1 by use previously defined structure
Mcbsp_Config(hMcbsp);
//I2C初始化
I2C_cofig();
//CODEC寄存器初始化
inti_AIC();
/*————————————————————————————*/
// Receive the ADC output data of CODEC
// Then output the received data to DAC of CODEC
/*————————————————————————————*/
while(1)
{
switch(TestCommand)
{
/*音频试听*/
case AUDIOTRY:
/* 左通路数据 */
while(!MCBSP_rrdy(hMcbsp)){};
DataTempLeft = MCBSP_read16(hMcbsp);
for (j=0;j<255;j++)
{
OutFFT[j]=OutFFT[j+1];
OutFFT[255]=DataTempLeft;
// OutFFT[j]=DataTempLeft;
}
for (j=0;j<128;j++)
{
DOutFFT[j].real=OutFFT[2*j];
DOutFFT[j].imag=OutFFT[2*j+1];
}
/* for(j=0;j<128;j++)
{
p=OutFFT[j].real;
q=OutFFT[j].imag;
n=(long)p*(long)p+(long)q*(long)q;
mod[m]=sqrt(n);
m++;
}*/
/* 右通路数据 */
while(!MCBSP_rrdy(hMcbsp)){};
DataTempRight = MCBSP_read16(hMcbsp);
/* 左声道耳机输出 */
while(!MCBSP_xrdy(hMcbsp)) {};
MCBSP_write16(hMcbsp,DataTempLeft);
/* 右声道耳机输出 */
while(!MCBSP_xrdy(hMcbsp)) {};
MCBSP_write16(hMcbsp,DataTempRight);
myFFT(DOutFFT,256);
break;
/*音频存贮并回放*/
case AUDIOCOPY:
for(i=0;i<65535;i++)
{
while(!MCBSP_rrdy(hMcbsp)){};
//SourData[i] = MCBSP_read16(hMcbsp);
TempData=MCBSP_read16(hMcbsp);
SourData1[i]=TempData;
}
for(i=0;i<65535;i++)
{
while(!MCBSP_rrdy(hMcbsp)){};
//SourData[i] = MCBSP_read16(hMcbsp);
TempData=MCBSP_read16(hMcbsp);
SourData2[i]=TempData;
}
for(i=0;i<65535;i++)
{
while(!MCBSP_rrdy(hMcbsp)){};
//SourData[i] = MCBSP_read16(hMcbsp);
TempData=MCBSP_read16(hMcbsp);
SourData3[i]=TempData;
}
for(i=0;i<65535;i++)
{
OutData1[i] = SourData1[i];
}
for(i=0;i<65535;i++)
{
OutData2[i] = SourData2[i];
}
for(i=0;i<65535;i++)
{
OutData3[i] = SourData3[i];
}
for(i=0;i<65535;i++)
{
while(!MCBSP_xrdy(hMcbsp)) {};
MCBSP_write16(hMcbsp,OutData1[i]);
}
for(i=0;i<65535;i++)
{
while(!MCBSP_xrdy(hMcbsp)) {};
MCBSP_write16(hMcbsp,OutData2[i]);
}
for(i=0;i<65535;i++)
{
while(!MCBSP_xrdy(hMcbsp)) {};
MCBSP_write16(hMcbsp,OutData3[i]);
}
break;
default:
break;
}
}
}
void myFFT(COMPLEX *Y, int N)
{
Int32 temp1R, temp1I, temp2R,temp2I; /* 32 bits temporary storage for */
/* intermediate results */
short tempR, tempI, c, s; /* 16 bits temporary storages */
/* variables */
Int32 TwFStep, /* Step between twiddle factors *///旋转因子阶数
TwFIndex, /* Index of twiddle factors *///旋转因子指数
BLStep, /* Step for incrementing butterfly index */
BLdiff, /* Difference between upper and lower butterfly legs */ //碟形运算的长度（N点）
upperIdx,
lowerIdx, /* upper and lower indexes of buterfly leg */
i, j, k; /* loop control variables *///循环变量
BLdiff=N;
TwFStep=1;
for(k=N;k>1;k=(k>>1)) /* Do Log(base 2)(N) Stages */
{
BLStep=BLdiff;
BLdiff=BLdiff>>1;
TwFIndex=0;
for(j=0;j<BLdiff;j++)/* Nbr of twiddle factors to use=BLDiff */
{
c=w256[TwFIndex].real;
s=w256[TwFIndex].imag;
TwFIndex=TwFIndex+TwFStep;
/* Now do N/BLStep butterflies */
for(upperIdx=j;upperIdx<N;upperIdx+=BLStep)
{
/* Calculations inside this loop avoid overflow by shifting left once
the result of every adittion/substration and by shifting left 15
places the result of every multiplication. Double precision temporary
results (32-bit) are used in order to avoid losing information because
of overflow. Final DFT result is scaled by N (number of points), i.e.,
2^(Nbr of stages) =2^(log(base 2) N) = N */
lowerIdx=upperIdx+BLdiff;
temp1R = (Y[upperIdx].real – Y[lowerIdx].real)>>1;
temp2R = (Y[upperIdx].real + Y[lowerIdx].real)>>1;
Y[upperIdx].real = (short) temp2R;
temp1I = (Y[upperIdx].imag – Y[lowerIdx].imag)>>1;
temp2I = (Y[upperIdx].imag + Y[lowerIdx].imag)>>1;
Y[upperIdx].imag = (short) temp2I;
temp2R = (c*temp1R – s*temp1I)>>15;
Y[lowerIdx].real = (short) temp2R;
temp2I = (c*temp1I + s*temp1R)>>15;
Y[lowerIdx].imag = (short) temp2I;
}
}
TwFStep = TwFStep<<1; /* update separation of twiddle factors)*/
}
/* bit reversal for resequencing data *///变址运算
j=0;
for (i=1;i<(N-1);i++)
{
k=N/2;
while (k<=j)
{
j = j-k;
k=k/2;
}
j=j+k;
if (i<j)
{
tempR=Y[j].real;
tempI=Y[j].imag;
Y[j].real=Y[i].real;
Y[j].imag=Y[i].imag;
Y[i].real=tempR;
Y[i].imag=tempI;
}
}
return;
}
Shine：
是EVM板还是自己的板子？
如果不用FFT的话，有杂音吗？
kangni pang：
回复 Shine:
是教学的实验板，不用FFT就没有杂音，用上FFT就有，，是不是16bit跟32bit不合，，还是他们的采样率不一样
kangni pang：
回复 Shine:
FFT为什么在while（1）外听歌录音效果什么都很好 ，为什么FFT一进到while(1)里面就会有莎莎的声音。。。。。。。
Tony Tang：
回复 kangni pang:
我怎么没看到什么地方调用了myFFT函数？
