嵌入式系统设计报告英文含代码文档格式.docx
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5.CoreCodeandExplanationofSystem
Thecodeofthesystemislistedasfollows:
//record.crecord/playinputusingexternalmemory
#include<
stdio.h>
#include"
math.h"
dsk6416_aic23.h"
//codecsupport
Uint32fs=DSK6416_AIC23_FREQ_8KHZ;
//setsamplingrate
Uint16inputsource=DSK6416_AIC23_INPUT_MIC;
//selectinput
unsignedlongi,count,s;
shortbuffer[N];
shortbuffer1[SAMPLENUMBER];
longm;
floatmax;
voidInitForFFT（）;
intINPUT[SAMPLENUMBER],DATA[SAMPLENUMBER];
floatfWaveR[SAMPLENUMBER],fWaveI[SAMPLENUMBER],w[SAMPLENUMBER];
floatsin_tab[SAMPLENUMBER],cos_tab[SAMPLENUMBER];
#pragmaDATA_SECTION（buffer,"
.EXT_RAM"
）//buffer->
externalmemory
voidmain（）
{
intq,t,n,m,l,tt=0;
shortplaying=0;
DSK6416_DIP_init（）;
DSK6416_LED_init（）;
comm_poll（）;
//initDSK,codec,McBSP
InitForFFT（）;
count=0;
while
（1）//infiniteloop
{
if（DSK6416_DIP_get（3）==0）//ifSW#3ispressed
{
DSK6416_LED_on（3）;
//turnonLED#3
buffer[count++]=input_left_sample（）;
}
if（DSK6416_DIP_get（3）==1||（count>
=N-1））//ifSW#3ispressed
DSK6416_LED_off（3）;
}
if（DSK6416_DIP_get（0）==0）//ifSW#0pressed
playing=1;
while（playing==1）
DSK6416_LED_on（0）;
//turnonLED#0
output_left_sample（buffer[count++]）;
if（count>
=N-1）
DSK6416_LED_off（0）;
for（s=50;
s<
N/SAMPLENUMBER;
s++）
n=0;
for（l=SAMPLENUMBER*（s-1）;
l<
s*512;
l++）
{
n=l-SAMPLENUMBER*（s-1）;
buffer1[n]=buffer[l];
for（q=0;
q<
SAMPLENUMBER;
q++）
fWaveR[q]=buffer1[q];
fWaveI[q]=0.0f;
FFT（fWaveR,fWaveI）;
max=w[0];
m=0;
for（t=0;
t<
SAMPLENUMBER/2;
t++）
{
if（max<
w[t]）
{
max=w[t];
m=t;
}
}
}//for（l=SAMPLENUMBER*（s-1）;
tt=m*8000/SAMPLENUMBER;
if（tt>
=1046&
&
tt<
=1975）
{DSK6416_LED_on
（1）;
DSK6416_LED_on
（2）;
}
elseif（tt>
513）DSK6416_LED_on
（2）;
0）DSK6416_LED_on
（1）;
else
DSK6416_LED_on（3）;
DSK6416_LED_on
（1）;
if（tt>
25）
printf（"
%d\n"
tt）;
DSK6416_LED_off
（1）;
DSK6416_LED_off
（2）;
DSK6416_LED_off（3）;
}//for（s=1;
}//if（count>
}//while（playing==1）
playing=0;
}//if（DSK6416_DIP_get（0）==0）
}//while
（1）
}//main
voidFFT（floatdataR[SAMPLENUMBER],floatdataI[SAMPLENUMBER]）
intx0,x1,x2,x3,x4,x5,x6,x7,x8,xx;
inti,j,k,b,p,L;
floatTR,TI,temp;
/**********followingcodeinvertsequence************/
for（i=0;
i<
i++）
x0=x1=x2=x3=x4=x5=x6=x7=x8=0;
x0=i&
0x01;
x1=（i/2）&
x2=（i/4）&
x3=（i/8）&
x4=（i/16）&
x5=（i/32）&
x6=（i/64）&
x7=（i/128）&
x8=（i/256）&
//x=x0*1024+x1*512+x2*256+x3*128+x4*64+x5*32+x6*16+x7*8+x8*4+x9*2+x10;
xx=x0*256+x1*128+x2*64+x3*32+x4*16+x5*8+x6*4+x7*2+x8;
dataI[xx]=dataR[i];
dataR[i]=dataI[i];
dataI[i]=0;
/**************followingcodeFFT*******************/
for（L=1;
L<
=9;
L++）
{/*for
（1）*/
b=1;
i=L-1;
while（i>
0）
b=b*2;
i--;
}/*b=2^（L-1）*/
for（j=0;
j<
=b-1;
j++）/*for
（2）*/
p=1;
i=9-L;
while（i>
0）/*p=pow（2,7-L）*j;
*/
p=p*2;
p=p*j;
for（k=j;
k<
k=k+2*b）/*for（3）*/
TR=dataR[k];
TI=dataI[k];
temp=dataR[k+b];
dataR[k]=dataR[k]+dataR[k+b]*cos_tab[p]+dataI[k+b]*sin_tab[p];
dataI[k]=dataI[k]-dataR[k+b]*sin_tab[p]+dataI[k+b]*cos_tab[p];
dataR[k+b]=TR-dataR[k+b]*cos_tab[p]-dataI[k+b]*sin_tab[p];
dataI[k+b]=TI+temp*sin_tab[p]-dataI[k+b]*cos_tab[p];
}/*ENDfor（3）*/
}/*ENDfor
（2）*/
}/*ENDfor
（1）*/
w[i]=sqrt（dataR[i]*dataR[i]+dataI[i]*dataI[i]）;
}/*ENDFFT*/
Firstly,Isetthesamplingfruquencyas8Khz,andthetotalbuffernumberis512000whichmeansthatitcanrecordthevoiceaslongas64seconds.Thecoreofthecodeincludesthreeparts.Oneistherecordingpart,andthesecondisplayingpart,andthethirdistheFFTanalysispart.WhiletheDSPchipdetecttheswitchthreewaspressed,thenrecordingstarts.Recordingisaccomplishedbythefuctioncalledinput_sample.,whichcancompletetheADsamplingandstorethesampledvalueintobuffer.LEDthreewillturnoffwhilethebufferhasbeenfilledortheswitchthreeisuplifted.Thenifyoupressswitchzero,thenplayingstarts,whichcanpalywhathasbeenrecorded.Andtheplayingpartisaccomplishedbythefunctioncalledoutput_sample,whichcanreadthediscretevalueinthebufferandturnintoanalogyspeechsignal.Afterthepalyingisover,LEDzerowillturnoff,andLEDonewillturnonindicatingthatFFTwiththeradix-2analysisbegins.FFTalgorithmcomputingisaccomplishedbylookinguptotable,andthetableismadeupbythesinefunctionandcosinefuction,wewillgettherealandimaginarypartsofmagnitudes.Andthenbythewayofergodicalgorithmtofindtheaccuratenumberoflocationofthemaxmummagnitude.Wewillgetthefrequencybyequationof
AftertheFFTfinished,LEDonewillturnoff,andthespeechsignalspectrumanalyzerhasfulfilledallfunction.
6.DebuggingRecordingofSystemandTestingIllustration
Eachtime,FFTanalyze512points.SoIdividethewholebufferintolotsoflittlebuffercontaining512points.Thedebuggingprocessingmainlydependsonthelocationofbreakpoints.IsetthebreakpointinthelocationofFFTanalyzeofeachlittlebuffercalledbuffer1,andwhenthecodeexecutethelo
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