dingshiqi.c

51单片机定时器的初始化和用法

/*
在P10、P11、P12、P13口输出不同频率的方波
*/

#include<reg51.h>
#define uint  unsigned int
#define uchar unsigned char
#define ulong unsigned long
#define TRUE 1 
#define FALSE 0 

#define STH0 0x4c   //for(50ms)  0xdc for(10ms)
#define STL0 0x00  

sbit P10=P1^0;
sbit P11=P1^1;
sbit P12=P1^2;
sbit P13=P1^3;
sbit P14=P1^4;
sbit P15=P1^5;

uchar timeflag1=0;
uchar timeflag2=0;
uchar timeflag3=0;
	
//interrupt for 50ms
void interrupt_time0() interrupt 1  using 1
{
	TL0=STL0;
  	TH0=STH0;
	P10=!P10;
	timeflag1++;
	timeflag2++;
	timeflag3++;
}

void main()
{
	P10=0;
	P11=0;
	P12=0;
	P13=0;
	//setting for time1
	TL0=STL0;
  	TH0=STH0;
    TR0=1;	//time0 enable
	ET0=1;
    EA=1;
	while(1)
	{
		if(timeflag1==10)	
		{
			timeflag1=0;
			P11=!P11;
		}
		if(timeflag2==20)	
		{
			timeflag2=0;
			P12=!P12;
		}
		if(timeflag3==30)	
		{
			timeflag3=0;
			P13=!P13;
		}
	}
}