18b20.c

自制实验DS18b20.rar实现温度精确显示

#include  <reg51.h> 
#include <intrins.h>
#include"7219.h"

#define uint unsigned int
#define uchar unsigned char
uint qian,bai,shi,ge;
float temps;//距离的个位、十位、百位
uchar k[]={0x7e,0x30,0x6d,0x79,0x33,0x5b,0x5f,0x70,0x7f,0x7b};


sbit temp=P0^6;
bit yes;

void delay1820(uchar w)
{
	unsigned char k;
  for(k=w;k>0;k--)
  {}//延时计算方法 w*8+19
}

void delay13us1820()
{
	_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();
}
void init1820()
{
	temp=0;
	delay1820(90);
	temp=1;
	delay13us1820();
	while(temp);

	delay1820(4);
	temp=1;
	delay1820(60);
		
}

void write1820(uchar wdata)
{
	char i,t;
	for(i=8;i>0;i--)
	{
		
		t=wdata&0x01;
		temp=0;
		_nop_();
		_nop_();
        if(t)
		temp=t;
		delay1820(6);
		temp=1;		  
		wdata=wdata>>1;
		delay1820(3);
	}	
}

uchar read1820()
{
	char i;
	uchar dat;
	for(i=8;i>0;i--)
	{
		dat>>=1;
		temp=0;
		_nop_();
		temp=1;
		delay13us1820();
		if(temp)
			dat|=0x80;
			temp=1;
	    delay1820(6);	
	}
	return(dat);
}
void max7219show()
 {
	Write(0x04,k[ge]);
	Write(0x03,k[shi]);
    Write(0x02,k[bai]);
	Write(0x01,k[qian]);
}

void readtemp()
{
		uint templ,temph;
	    init1820();
   		write1820(0xcc);
		write1820(0x44);   
		init1820();
		write1820(0xcc);
		write1820(0xbe);
		templ=read1820();
		temph=read1820();
		//templ=(templ>>4)&0x0f;
		temph=(temph<<8);//&0x07;
		temps=templ|temph;
		temps=temps*0.0625;
		temps=temps*100;
}
void work(void)
{ uint value;
  value=temps;
  qian=value/1000;
  bai=(value-qian*1000)/100;
  shi=(value-qian*1000-bai*100)/10;
  ge=value-qian*1000-bai*100-shi*10;
 
}
void main()
{
	
	init7219();
	while(1)
	{
		readtemp();    
		work();
		max7219show();
	        delay1820(50000);
			delay1820(50000);
			delay1820(50000);
			delay1820(50000);
			delay1820(50000);
			delay1820(50000);
			delay1820(50000);
		
	}
}