#include<reg52.h>
#define uint unsigned int
#define uchar unsigned char
sbit d=P3^7; //定义18B20数据脚
uchar code wu[]={0x7f,0xbf,0xdf,0xef,0xf7,0xfb,0xfd,0xfe}; //数码管位选
uchar code du[]={
0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90, //数码管段选
0x40,0x79,0x24,0x30,0x19,0x12,0x02,0x78,0x00,0x10,
0xff,0xbf
};
uchar str[5];
void delayms(int z)
{
uint y;
for(;z>0;z--)
for(y=110;y>0;y--);
}
void display(uchar d1,uchar d2) //显示函数
{
P1=wu[d1];
P0=du[d2];
delayms(1);
P0=0xff;
}
void delay(int z)
{
while(z--);
}
/************** 初始化b20********** */
void reset()
{
d=1;
delay(8);
d=0;
delay(85);
d=1;
delay(35);
}
/************** 写一个字节 ************/
void write_b20(uchar dat)
{
uchar i;
for(i=0;i<8;i++)
{
d=0;
d=dat&0x01;
delay(5);
d=1;
dat>>=1;
}
delay(4);
}
/*************** 读一个字节 *****************/
uchar read_b20()
{
uchar i,dat;
for(i=0;i<8;i++)
{
d=1;
d=0;
dat>>=1;
d=1;
if(d==1)
dat|=0x80;
delay(4);
}
return dat;
}
/********** 启动温度转换 ************/
void write_com()
{
reset();
write_b20(0xcc);
write_b20(0x44);
}
/*************** 读温度 *****************/
int read_temper()
{
int temper;
uchar a,b;
reset();
write_b20(0xcc);
write_b20(0xbe);
EA=0;
a=read_b20();
b=read_b20();
EA=1;
temper=b;
temper<<=8;
temper|=a;
temper*=0.625;
return temper;
}
void main()
{
int temper;
uchar i,j;
ES=1;
while(1)
{
write_com();
for(j=0;j<150;j++)
{
for(i=0;i<5;i++)
display(i,str[i]); //数码管扫描
}
temper=read_temper();
if(temper<0)
{
str[4]=21;
temper=~temper+1;
}
else
{
str[4]=20; //第五位数码管不显示
}
str[3]=temper/1000;
str[2]=temper/100%10;
str[1]=temper/10%10+10; //显示数字带小数点
str[0]=temper%10;
}
}
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