基于51单片机和FFT算法的音频频谱程序分享

李欣

2018-7-19 07:54:57 6967 51单片机 FFT算法

#include
typedef unsigned char uint8;
typedef unsigned int uint16;
#define channel 0x01 //设置AD通道为 P1.0
#define ADC_POWER (1<<7)
#define ADC_SPEEDHH (0x03<<5)
#define ADC_START (1<<3)
#define PADCH (1<<5)
#define ADC_FLAG (1<<4)
#define P_3 P3 //32列扫描控制
***it sw=P1^2;//74HC154组切换控制位
//放大128倍后的sin整数表（128）
code char SIN_TAB[128]={0,6,12,18,24,30,36,42,48,54,59,65,70,75,80,85,89,94,98,102,
105,108,112,114,117,119,121,123,124,125,126,126,126,126,126,
125,124,123,121,119,117,114,112,108,105,102,98,94,89,85,80,75,
70,65,59,54,48,42,36,30,24,18,12,6,0,-6,-12,-18,-24,-30,-36,-42,
-48,-54,-59,-65,-70,-75,-80,-85,-89,-94,-98,-102,-105,-108,-112,
-114,-117,-119,-121,-123,-124,-125,-126,-126,-126,-126,-126,-125,
-124,-123,-121,-119,-117,-114,-112,-108,-105,-102,-98,-94,-89,-85,
-80,-75,-70,-65,-59,-54,-48,-42,-36,-30,-24,-18,-12,-6};
//放大128倍后的cos整数表（128）
code char COS_TAB[128]={127,126,126,125,124,123,121,119,117,114,112,108,105,102,98,94,
89,85,80,75,70,65,59,54,48,42,36,30,24,18,12,6,0,-6,-12,-18,-24,
-30,-36,-42,-48,-54,-59,-65,-70,-75,-80,-85,-89,-94,-98,-102,
-105,-108,-112,-114,-117,-119,-121,-123,-124,-125,-126,-126,-126,
-126,-126,-125,-124,-123,-121,-119,-117,-114,-112,-108,-105,-102,
-98,-94,-89,-85,-80,-75,-70,-65,-59,-54,-48,-42,-36,-30,-24,-18,
-12,-6,0,6,12,18,24,30,36,42,48,54,59,65,70,75,80,85,89,94,98,102,
105,108,112,114,117,119,121,123,124,125,126,126};
//采样存储序列表
code char LIST_TAB[128] = {0,64,32,96,16,80,48,112,8,72,40,104,24,88,56,120,4,68,36,100,20,84,52,116,
12,76,44,108,28,92,60,124,2,66,34,98,18,82,50,114,10,74,42,106,26,90,58,
122,6,70,38,102,22,86,54,118,14,78,46,110,30,94,62,126,1,65,33,97,17,81,49,
113,9,73,41,105,25,89,57,121,5,69,37,101,21,85,53,117,13,77,45,109,29,93,61,
125,3,67,35,99,19,83,51,115,11,75,43,107,27,91,59,123,7,71,39,103,23,87,55,
119,15,79,47,111,31,95,63,127};
uint8 LED[32]={0x80,0x00,0xC0,0x00,0xE0,0x00,0xF0,0x00,
0xF8,0x00,0xFC,0x00,0xFE,0x00,0xFF,0x00,
0xff,0x80,0xff,0xC0,0xff,0xE0,0xff,0xF0,
0xff,0xF8,0xff,0xFC,0xff,0xFE,0xff,0xFF,};
uint8 COUNT=15,COUNT1=0,ADC_Count=0,LINE=15,G=0,T;
uint8 i,j,k,b,p,anum,led=0;
int Temp_Real,Temp_Imag,temp; // 中间临时变量
uint16 TEMP1,max=0;
int xdata Fft_Real[128];
int xdata Fft_Image[128]; // fft的虚部
uint8 xdata LED_TAB2[16]; //记录漂浮物是否需要停顿一下
uint8 xdata LED_TAB[16]; //记录红色柱状
uint8 xdata LED_TAB1[16]; //记录漂浮点
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void FFT()//基2fft
{
for( i=1; i<=7; i++) /* for(1) */
{
b=1;
b <<=(i-1); //碟式运算，用于计算隔多少行计算例如第一极 1和2行计算
for( j=0; j<=b-1; j++) /* for (2) */
{
p=1;
p <<= (7-i);
p = p*j;
for( k=j; k<128; k=k+2*b) /* for (3) */
{
Temp_Real=Fft_Real[k];
Temp_Imag=Fft_Image[k];
temp=Fft_Real[k+b];
Fft_Real[k]=Fft_Real[k]+((Fft_Real[k+b]*COS_TAB[p])>>7)+((Fft_Image[k+b]*SIN_TAB[p])>>7);
Fft_Image[k]=Fft_Image[k]-((Fft_Real[k+b]*SIN_TAB[p])>>7)+((Fft_Image[k+b]*COS_TAB[p])>>7);
Fft_Real[k+b]=Temp_Real-((Fft_Real[k+b]*COS_TAB[p])>>7)-((Fft_Image[k+b]*SIN_TAB[p])>>7);
Fft_Image[k+b]=Temp_Imag+((temp*SIN_TAB[p])>>7)-((Fft_Image[k+b]*COS_TAB[p])>>7); // 移位.防止溢出. 结果已经是本值的 1/64
Fft_Real[k] >>= 1;
Fft_Image[k] >>= 1;
Fft_Real[k+b] >>= 1;
Fft_Image[k+b] >>= 1;
}
}
}
for(j=0;j<16;j++)//16分频
{
TEMP1=((((Fft_Real[j+1]* Fft_Real[j+1]))+((Fft_Image[j+1]*Fft_Image[j+1])))>>1);//求各频段幅值
if(TEMP1<1)TEMP1=0;
LED_TAB[j]=TEMP1;
if(LED_TAB[j]>max)max=LED_TAB[j];
}
if(max>16)//分级量化
{
max/=16;
for(j=0;j<16;j++)LED_TAB[j]/=max;
}
}
void delay2us(void) //2us延时
{
unsigned char a,b;
for(b=1;b>0;b--)
for(a=3;a>0;a--);
}
void Init()
{
//-----------------------------------------------------------------------------------
P1ASF = 0x02; //0000,0010, 将 P1.1 置成模拟口
AUXR1 &=0xFB; //1111,1011, 令 ADRJ=0
EADC=1; //AD中断打开
ADC_CONTR = ADC_POWER | ADC_SPEEDHH | ADC_START | channel;//1110 1001 1打开 A/D （ADC_POWER）转换电源；11速度为90周期一次；
//0中断标志清零；1启动adc(ADC_START);001AD通道打开（这里为P1.1）;
//-----------------------------------------------------------------------------------
P2M0=1;
TMOD=0X12;
TH0=0xb0;
TL0=0xb0;
TH1=0xfe;
TL1=0Xd4;
ET0=1; //定时器0 打开
TR0=0; //关闭定时器
ET1=1;
TR1=1;
PT1=0;
PT0=1;
IPH=PADCH;
IP=PADC; //中断优先级
EA=1; //总中断打开
}
//----------------------------------------------------------------------------------------
void ADC_Finish() interrupt 5
{ ADC_CONTR &= !ADC_FLAG;
Fft_Real
[LIST_TAB[ADC_Count]]=(int)((ADC_RES)<<1)+(ADC_RESL>>1)*2;//按LIST_TAB表里的顺序，进行存储采样值
if(ADC_Count<=127)ADC_Count++;
else {EADC=0;TR0=0;}
}
//---------------------------------------------------------------------------------------
void LED_Display() interrupt 3 //中断一次显示一列
{
TH1=0xfe;
TL1=0Xd4;
G++;
if(G==33)G=1;
switch(G) //往点阵屏填充一列的数据
{
case 1:sw=1;anum=LED_TAB[0];P_3=0x00;break;
case 2:anum=LED_TAB[0];P_3=0x01;break;
case 3:anum=LED_TAB[1];P_3=0x02;break;
case 4:anum=LED_TAB[1];P_3=0x03;break;
case 5:anum=LED_TAB[2];P_3=0x04;break;
case 6:anum=LED_TAB[2];P_3=0x05;break;
case 7:anum=LED_TAB[3];P_3=0x06;break;
case 8:anum=LED_TAB[3];P_3=0x07;break;
case 9:anum=LED_TAB[4];P_3=0x08;break;
case 10:anum=LED_TAB[4];P_3=0x09;break;
case 11:anum=LED_TAB[5];P_3=0x0a;break;
case 12:anum=LED_TAB[5];P_3=0x0b;break;
case 13:anum=LED_TAB[6];P_3=0x0c;break;
case 14:anum=LED_TAB[6];P_3=0x0d;break;
case 15:anum=LED_TAB[7];P_3=0x0e;break;
case 16:anum=LED_TAB[7];P_3=0x0f;break;
case 17:sw=0;anum=LED_TAB[8];P_3=0x00;break;
case 18:anum=LED_TAB[8];P_3=0x10;break;
case 19:anum=LED_TAB[9];P_3=0x20;break;
case 20:anum=LED_TAB[9];P_3=0x30;break;
case 21:anum=LED_TAB[10];P_3=0x40;break;
case 22:anum=LED_TAB[10];P_3=0x50;break;
case 23:anum=LED_TAB[11];P_3=0x60;break;
case 24:anum=LED_TAB[11];P_3=0x70;break;
case 25:anum=LED_TAB[12];P_3=0x80;break;
case 26:anum=LED_TAB[12];P_3=0x90;break;
case 27:anum=LED_TAB[13];P_3=0xa0;break;
case 28:anum=LED_TAB[13];P_3=0xb0;break;
case 29:anum=LED_TAB[14];P_3=0xc0;break;
case 30:anum=LED_TAB[14];P_3=0xd0;break;
case 31:anum=LED_TAB[15];P_3=0xe0;break;
case 32:anum=LED_TAB[15];P_3=0xf0;break;
}
for(led=0;led<=anum;led++) //递增
{ P0=LED[2*led+1];
P2=LED[2*led];
delay2us();
} //递减
for(;led>=0;led--)
{ P0=LED[2*led+1];
P2=LED[2*led];
delay2us();
}
}
//------------------------------------------------------------------------------------------------------------
void Ad_Control() interrupt 1 //控制采样率
{
ADC_CONTR = ADC_POWER | ADC_SPEEDHH| ADC_START | channel; //开始AD采集
}
//===============================================================================================================
void main()
{
uint8 i;
Init();
while(1)
{
ADC_Count=0;
TR0=1;
EADC=1; //开启定时器中断0，开启ADC
while(ADC_Count<128);
for(i=0;i<128;i++)
{
Fft_Image=0;
}
FFT();//FFT运算并转换为各频段幅值
}
}