dsjs.c

51定时器常用例子包括测频率测脉宽产生波形

	#include"at89x52.h"
	#define uchar unsigned char
	#define uint  unsigned int
	sbit m=P1^0;
    sbit key=P3^4;
	uchar code  tv[]={0xfe,0xfd,0xfb,0xf7};
	uchar code  a[]={0x3f,0x06,0x5b,0x4f,
                 0x66,0x6d,0x7d,0x07,0x7f,
                 0x6f,0x00,0x7c};
	uchar data  led[];
	uchar data  tvdata;

	
	void delay(void)
       {
		uint i;
		for(i=0;i<100;i++);
 	
       }

    ledxianshi()
       {
          uchar k,i;
     	  led[0]=tvdata/100;
		  led[1]=tvdata%100/10;
		  led[2]=tvdata%10;
		  led[3]=10;
		
		for(k=0;k<4;k++)
		 { 
		   i=led[k];
		   P0=a[i];
		   P2=tv[k];
	       delay();
		 }
		
	   }

	void main()
     {   uchar data l;
	     while(1)
	   {
	     TMOD=0X01;
	     TR0=1;
	     if(key==0)
	     {
	         TH0=(-2000)>>8;
		 	 TL0=-2000;
		       do{ledxianshi();}
		       while(TF0==0);
		   TF0=0;
		   l=l+1;
		   if(l==10)
		   {
		    m=!m;
		    l=0;
		    tvdata=tvdata+1;
		   }
	     }
	   }
     }