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如圖
單片機源程序如下:
#include<reg51.h>
#include<intrins.h>
#define uchar unsigned char
#define uint unsigned int
#define out P0
sbit smg1=out^4;
sbit smg2=out^5;
sbit DQ=P3^7;
void delay5(uchar);
void init_ds118b20(void);
uchar readbyte(void);
void writebyte(uchar);
uchar retemp(void);
void main(void)
{
uchar i,temp;
delay5(1000);
while(1)
{
temp=retemp();
for(i=0;i<10;i++)
{
out=(temp/10)&0x0f;
smg1=0;
smg2=1;
delay5(1000);
out=(temp%10)&0x0f;
smg1=1;
smg2=0;
delay5(1000);
}}}
void delay5(uchar n)
{
do
{
_nop_();
_nop_();
_nop_();
n--;
}
while(n);
}
void init_ds18b20(void)
{
uchar x=0;
DQ=0;
delay5(120);
DQ=1;
delay5(16);
delay5(80);
}
uchar readbyte(void)
{
uchar i=0;
uchar date=0;
for(i=8;i>0;i--)
{
DQ=0;
delay5(1);
DQ=1;
date>>=1;
if(DQ)
date|=0x80;
delay5(11);
}
return(date);
}
void writebyte(uchar dat)
{
uchar i=0;
for(i=8;i>0;i--)
{
DQ=0;
DQ=dat&0x01;
delay5(12);
DQ=1;
dat>>=1;
delay5(5);
}
}
uchar retemp(void) //讀取溫度函數(shù)
{
uchar a,b,tt;
uint t=0,t1=0;
EA=0;
init_ds18b20();
writebyte(0xCC);
writebyte(0x44);
EA=1;
while(!DQ);
EA=0;
init_ds18b20();
writebyte(0xCC);
writebyte(0xBE);
a=readbyte();
b=readbyte();
EA=1;
t=b;
t<<=8;
tt=t|a;
tt=t*0.0625;
return(tt);
}
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