⑴ 求51单片机测量正弦波(20~100hz)的频率的c程序,最好是已经通过测试过的
首先使用电压比较器电路将正弦波转化成方波,以方便单片机接收,参考下图(该电路可接收峰峰值正负12V的正弦波),如果你的正弦波电路和单片机电路使用了不同的电源,则还需进行隔离处理
#include<AT89X51.H>
//********数码管位代码表(P0口)**********//
unsignedcharcodedispbit[]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f};
//********数码管段代码表(P2口,共阴且高位接a,低位接h笔段)**********//
unsignedcharcodedispcode[]={0xFC,0x60,0xDA,0xF2,0x66,0xB6,0xBE,0xE0,
0xFE,0xF6,0xEE,0x3E,0x9C,0x7A,0x9E,0x8E,0x00};
//********8位数据缓冲器**********//
unsignedchardispbuf[8];
unsignedchartemp[8];
unsignedchardispcount;
unsignedcharT0count;
unsignedchartimecount;
bitflag;
unsignedlongx;
//*********初始化模块**********//
voidinitial(void){
TMOD=0x15;
TH0=0;
TL0=0;
TH1=(65536-4000)/256;
TL1=(65536-4000)%256;
TR1=0;
TR0=0;
ET0=1;
ET1=1;
EA=1;
}
//******************************************************//
//*********显示模块**********//
voiddataDisplay(){
unsignedchari;
for(i=0;i<8;i++){
temp[i]=0;
}
i=0;
while(x/10){
temp[i]=x%10;
x=x/10;
i++;
}
temp[i]=x;
for(i=0;i<8;i++){
dispbuf[i]=temp[i];
}
P2=dispcode[dispbuf[dispcount]];
P0=dispbit[dispcount];
dispcount++;
if(dispcount==8){
dispcount=0;
}
}
//******************************************************//
//*********信号频率测量模块**********//
floatfrequency(floatfreq){
initial();
TR0=1;TR1=1;
if(timecount==250){
TR0=0;
freq=T0count*65536+TH0*256+TL0;
return(freq);
}
}
//******************************************************//
//*********信号周期测量模块**********//
floatcycle(floatcount){
initial();
if(P3_4==1){
TR0=1;TR1=1;
if(P3_4==0){
TR0=0;
count=1000000/(timecount*4000+TH1*256+TL1-61536);
}
}
return(count);
}
//******************************************************//
//*********定时中断服务程序1**********//
voidt1(void)interrupt3using0{
//initial();
//TR0=1;
//TR1=1;
TH1=(65536-4000)/256;
TL1=(65536-4000)%256;
timecount++;
}
//******************************************************//
//*********定时中断服务程序2**********//
voidt0(void)interrupt1using0{
//initial();
//TR0=1;
//TR1=1;
T0count++;
}
//******************************************************//
//*********主函数**********//
voidmain(void){
while(1){
x=frequency(x);
if(x<100){
x=cycle(x);
}
dataDisplay();
}
}
//******************************************************//