5-4.c

89c51的等精度频率计lcd1602显示

//proteus仿真论坛：http://proteus.5d6d.com
#include<reg51.h>
#include<stdio.h>
#include<lcd.c>
#include<math.h>
sbit p32=P3^2;
main()
{ 
 unsigned int period,k,j,i=0;
 unsigned long int f;
 char buff[30];
 init_LCD();
 P2=0x00;
 while(1)
 {
  TMOD=0X09;
  TH0=0;
  TL0=0;
  while(p32==1);
  TR0=1;
  while(p32==0);
  while(p32==1);
  TR0=0;
  period=TH0*256+TL0;
  while(period<=500)       /*判断是否分频及计算分频次数*/
  { P2++;
    i++;
	period=period*10;
    if(i==6)
    {P2=0x00;
	break;
	}
  }
  k=pow(10,i);             /* 10的i次方*/
  f=(1000000.0/(2*period))*k;
  sprintf(buff,"f=%ldhz",f);
  lcdprintf(0,0,buff);
 }
}