DS18B20

ID:256430 · 发表于 2018-1-3 15:11

#include "reg51.h"
#include " intrins.h"
#define uchar unsigned char
#define uint unsigned int
sbit dq=P3^7;
bit flag;
sbit sm1=P1^3;
sbit  sm2=P1^4;

uchar d1[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90};
uchar d2[]={0x40,0x79,0x24,0x30,0x19,0x12,0x02,0x78,0x00,0x10};

void delay(uchar n)
{
do
{
_nop_();
_nop_();
_nop_();
n--;
}
while(n);
}

void chushi()
{
dq=1;
delay(10);
dq=0;
delay(120);
dq=1;
delay(30);
if(dq==0)
flag==1;
else
flag==0;
delay(40);
}

uchar readbyte()
{
uchar i;
uchar date=0;
for(i=8;i>0;i--)
{
dq=0;
delay(1);
dq=1;
date>>=1;
if(dq)
date|=0x80;
delay(11);

}
return date;
}

void writebyte(uchar dat)
{
uchar i;
for(i=0;i<8;i++)
   {
   dq=0;
   delay(1);
   dat=dat&0x01;
   delay(14);
   dq=1;
dat=dat>>1;
   delay(20);
   }
}
uint readtemp()
{
uchar a,b;
uint temp;
chushi();
writebyte(0xcc);
writebyte(0xbe);
a=readbyte();
b=readbyte();
temp=b;
temp=temp<<8;
temp=temp|a;
temp=temp*0.0625;
return temp;
}
   display(uint temp)
   {


   sm1=1;
   sm2=0;

   P2=d1[(temp/10)&0x0f];
   delay(1000);
   sm1=0;
   sm2=1;


   P2=d1[(temp%10)&0x0f];

   delay(1000);

   }
   void main()
   {
   while(1)
   {
   chushi();
   writebyte(0xcc);
   writebyte(0x44);
   display(readtemp());
   }
   }

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