18b20.c

用51单片机做数字温度计PCB资料

#include<reg51.h>


#define uchar unsigned char
#define uint unsigned int

sbit DQ=P1^0;

uchar temperature,tl,th;

void delay(uint n)
{
	uint x,y;
	for(x=n;x>0;x--)
		for(y=112;y>0;y--)
				;
}

void init()
{
	uchar x=0;
    DQ=1;
	delay(5);
	DQ=0;
	delay(500);
	DQ=1;
	delay(15);
}

uchar read()
{
	uchar i=0;
	uchar dat=0;
	for(i=8;i>0;i--)
	{
		DQ=1;
		delay(2);
		DQ=0;
		dat>>=1;
		DQ=1;
		if(DQ!=0)
			dat|=0x80;
		delay(4);
	}
	return(dat);
}

void write(uchar dat)
{
	uchar i=0;
	for(i=8;i>0;i--)
	{
		DQ=0;
		DQ=dat&0x01;
		delay(5);
		DQ=1;
		dat>>=1;
	}
	delay(5);
}
uchar readtemperature()
{
	init();
	write(0xcc);
	write(0x44);
	delay(150);
	init();
	write(0xcc);
	write(0xbe);
	tl=read();
	th=read();
	temperature=(th*256+tl)*0.0625;
	delay(200);
	return (temperature);	
}