chepin.rar_51单片机测频_单片机 测频_单片机测频_测频 单片机

#include <reg52.H> unsigned char code Tab[]={ 0xFC,0x60,0xDA,0xF2,0x66,0xB6,0xBE,0xE0,0xFE, 0xF6,0xEE,0x3E,0x9C,0x7A,0x9E,0x8E,0x00,}; unsigned char cfDispPos=0; unsigned long ifTimes=0; unsigned long Freq=0; unsigned long DispNow; bit bfComplete=0; bit bfTesting=0; unsigned char Method=0; sbit KEY=P3^7; void Delay(int t) { while(t--); } void StartFreq(unsigned char Method) { switch(Method) { case 0: { EX0=1; //从中断开定时器，测周法 IT0=1; TMOD=0x51; //Timer0 for precise Time EA=1; break; } case 1: { //计数测频法 TH0=0xf8;TL0=0x30; //1ms ifTimes=0; TMOD=0x51; //Time0 for precise Time ,Timer1 for counter TH1=0;TL1=0; EA=1; ET0=1; TR0=1;TR1=1;ET1=1; PT1=1; } default:break; } } void timer0 (void) interrupt 1 { switch(Method) { case 0: //用于计数功能 ifTimes++; break; case 1: //work with T1 TH0=0xf8; TL0=0x30; //1ms ifTimes++; if(ifTimes>2000) //2s { TR1=0; TR0=0; EA=0; ET0=0; ET1=0; Freq+=(TH1*256+TL1); Freq=Freq*10/2; //Keep One bit for '.' if(Freq>900000)Freq=0; bfComplete=1; } break; default:break; } } void timer1(void) interrupt 3 { Freq+=65536; } void EX0_IRQ(void) interrupt 0 //测周法使用 { if(!bfTesting) //first falling edge { TH0=0x0;TL0=0x0; //1ms ifTimes=0; ET0=1; TR0=1; //Timer0 for Time bfTesting=1; } else //second falling edge { EA=0;TR0=0; ET0=0; EX0=0; Freq=(ifTimes*65536+256*TH0+TL0)*1/2;// us S Freq=10000000/Freq; //Keep one bit for '.' bfComplete=1; } } void SystemInitial(void) { SCON=0X00; //TH0=0xfc;TL0=0x18; //0.5ms StartFreq(Method); } void main(void) { SystemInitial(); while(1) { if(!KEY) { Delay(2000); if(!KEY) { while(!KEY); if(Method) Method=0; else Method=1; DispNow=0; StartFreq(Method); } } if(bfComplete)//开始测量 { DispNow=Freq; Freq=0; bfComplete=0; bfTesting=0; StartFreq(Method); } {//显示 switch(cfDispPos) { case 0:P2=0x6E; P0=0xFE;break; case 1:P2=Tab[DispNow/1%10]; P0=0xFD;break; case 2:P2=Tab[DispNow/10%10]|(~Tab[8]); P0=0xFB;break; case 3:P2=Tab[DispNow/100%10]; P0=0xF7;break; case 4:P2=Tab[DispNow/1000%10]; P0=0xEF;break; case 5:P2=Tab[DispNow/10000%10]; P0=0xDF;break; case 6:P2=Tab[DispNow/100000%10]; P0=0xBF;break; case 7:if(Method)P2=0x02;else P2=0; P0=0x7F;break; } Delay(100);cfDispPos++; if(cfDispPos>=8){cfDispPos=0;} } } }