基于DS18B20的测温电路设计

ID:1061648 · 发表于 2023-8-21 10:33

功能要求：温度实时检测测量
代码：

#include <reg51.h>
#define uchar unsigned char
#define uint unsigned int
sbit DQ=P2^4;
unsigned char flag;
uchar code scan[8]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f};
uchar code table[13]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F,0x40,0x39,0x00};
uchar code ditab[16]={0x00,0x01,0x01,0x02,0x03,0x03,0x04,0x04,0x05,0x06,0x06,0x07,0x08,0x08,0x09,0x09};
uchar dispbuf[8];
uchar temper[2];
void delay(unsigned int us)
{
while(us--);
}
void reset(void)
{
uchar x=0;
DQ=1;
delay(8);
DQ=0;
delay(80);
DQ=1;
delay(14);
x=DQ;
delay(20);
}
uchar readbyte(void)
{
uchar i=0;
uchar dat=0;
for (i=8;i>0;i--)
{
DQ=0;
dat>>=1;
DQ=1;
if(DQ)
dat|=0x80;
delay(4);
}
return(dat);
}
void writebyte(unsigned char dat)
{
uchar i=0;
for (i=8;i>0;i--)
{
DQ=0;
DQ=dat&0x01;
delay(5);
DQ=1;
dat>>=1;
}
delay(4);
}
void readtemp(void)
{
uchar a=0,b=0;
reset();
writebyte(0xCC);
writebyte(0x44);
reset();
writebyte(0xCC);
writebyte(0xBE);
a=readbyte();
b=readbyte();
if(b>0x0f)
{
if(a==0)
b=~b+1;
else b=~b;
flag=10;
}
else flag=12;
temper[0]=a&0x0f;
a=a>>4;
temper[1]=b<<4;
temper[1]=temper[1]|a;
}
void scandisp()
{
unsigned char i,value;
for (i=0;i<8;i++)
{
P3=0xff;
value=table[dispbuf[i]];
if(i==3)
value|=0x80;
P0=value;
P3=scan[i];
delay(50);
}
}
void main()
{
uchar temp,temp1;
while(1)
{
scandisp();
readtemp();
temp1=temper[0];
temp=temper[1];
dispbuf[4]=ditab[temp1];
dispbuf[1]=temp/100;
dispbuf[3]=temp%10;
temp=temp/10;
dispbuf[2]=temp%10;
dispbuf[0]=flag;
dispbuf[5]=11;
}
}

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