#include
unsigned char t=0,yichu=0,fenpin;
sbit B153=P2^0;
sbit A153=P2^1;
sbit GATE=P2^6;
sbit CLR=P2^7;
sbit P33=P3^3;

void t0(void)interrupt 1
{t++;
yichu=2;????????//定時器0溢出，yichu=2
}

void t1(void)interrupt 3????//計數器1溢出，yichu=1
{TCON=0;
yichu=1;
TH1=0xff;
TL1=0xff;
}

void delay(void)??????//1s軟件延時
{unsigned int i=500,j;
while(i)
?{i--;
?j=250;
?while(j)
??{j--;}
?}
}
unsigned char table(unsigned char x)?//軟件查表輸出
{unsigned char code n[10]={0xee,0x82,0xdc,0xd6,0xb2,0x76,0x7e,0xc2,0xfe,0xf6};
return(n[x]);
}

display(float f)??????//以測出的頻率串行輸出
{unsigned long x;
unsigned char a[5]={0,0,0,0,0},i=0,j;
if(f!=0){
if((f<10000)&&(f>1))?????//正常顯示
?{if(f>1000)f=f-1;?????//軟件修正頻率偏差
?while(f<1000)
??{f=f*10;
??i++;
??}
?x=f*10;
?a[4]=x%10;
?if(a[4]>=5)f=f+1;;
?x=f;
?a[1]=x%10;
?a[2]=(x/10)%10;
?a[3]=(x/100)%10;
?a[4]=(x/1000)%10;
?for(j=0;j<5;j++)
??{a[j]=table(a[j]);}
?a[i+1]++;
?a[0]=0;
?}
else if(f>=10000)??????//以科學計數法顯示
?{while(f>=1000)
??{f=f/10;
??i++;
??}
?x=f;
?a[4]=(unsigned char)((float)((f-x))*10);
?if(a[4]>=5)x++;??????//四舍五入
?a[2]=x%10;
?a[3]=(x/10)%10;
?a[4]=(x/100)%10;
?a[0]=i+2;
?for(j=0;j<5;j++)
??{a[j]=table(a[j]);}
?a[4]++;
?a[1]=0x7c;
?}
else
?{x=f*10000;???????//頻率值小于1
?if((x%10)>=5)x=x+10;?//四舍五入
?x=x/10;
?a[1]=x%10;
?a[2]=(x/10)%10;
?a[3]=(x/100)%10;
?a[4]=(x/1000)%10;
?for(j=0;j<5;j++)??
??{a[j]=table(a[j]);}
?a[4]++;
?a[0]=0;
?}
?
}
for(j=0;j<5;j++)???//串行
?{SBUF=a[j];
?while(TI==0);}

}

cepin()
{unsigned char i;
float sj;
unsigned long js;//時間、計數的拼音首字母
float f;??//f為頻率
TMOD=0xd9;
t=0;
TH0=0;
TL0=0;
TH1=0;
TL1=0;
GATE=0;
TCON=0x50;
GATE=1;
delay();
GATE=0;
for(i=0;i<250;i++){}????//延時1ms
sj=((float)(TH0*256+t*65536+TL0))/1000000.0;
js=(long)TH1*256+TL1+1;
f=(js/sj)*fenpin;
display(f);
}

panduan()
{float zhouqi;
B153=1;
A153=1;
TMOD=0x51;??
TH0=0xce;??//定時器0=12.8ms
TL0=0;
TH1=0xff;??//計數器1=100個脈沖
TL1=0x9c;
TCON=0x50;
while(yichu==0);
TCON=0;
if(yichu==1)?//計數器先溢出：在12.8ms內測得的脈沖過多，說明頻率較高
?{fenpin=128;//轉為測128分頻后的頻率
?cepin();}
else ???//計時器先溢出：100個脈沖的時間比較短，即頻率較低，可以減少分頻數
?{yichu=0;
?B153=1;
?A153=0;
?TH0=0xc1;?//定時器0=16ms
?TL0=0x80;
?TH1=0xff;?//計數器1=100個脈沖
?TL1=0x9c;
?TCON=0x50;
?while(yichu==0);
?TCON=0;
?if(yichu==1)?? //計數器先溢出：在16ms內測得的脈沖過多，說明頻率較高
??{fenpin=16;//轉為測16分頻后的頻率
??cepin();}
?else?? //計時器先溢出：100個脈沖的時間比較短，即頻率較低，用2分頻測周期
??{B153=0; //以下是測周期部分
??A153=0;
??TH0=0;
??TL0=0;
??t=0;
??TMOD=0x09;
??TR0=1;
??GATE=1;
??while(P33==0);
??GATE=0;
??while(P33==1);
??TR0=0;
??zhouqi=(TH0*256+t*65536+TL0)/1000000.0;
??if(zhouqi<0.001)?//若周期太小，則轉為測原頻率
???{fenpin=1;
???B153=0;
???A153=0;
???cepin();}
??else{display((1.0/zhouqi));}
??}
?}
}

main()
{
IE=0x8a;
while(1)
?{
?panduan();?//判斷原頻率屬于哪個范圍，并調用相應函數測其頻率
?delay();
?}

}