粮仓温度巡检报警系统单片机多机通讯自动巡检程序和仿真 -

#include <reg52.h>
#include <18b20.h>
/*
sbit DS0=P1^0; //define interface
sbit DS1=P1^1; //define interface
sbit DS2=P1^2; //define interface
sbit DS3=P1^3; //define interface
sbit DS4=P1^4; //define interface
sbit DS5=P1^5; //define interface
*/
#define BIT1(x) (1<<x)
#define DS P1
#define NBIT1(x) ~BIT1(x)
uchar No_number;
//uchar DS;
uint temp; // variable of temperature
void dsreset(uchar m) //send reset and initialization command
{
uint i;
DS&=NBIT1(m);
//DS&=BIT0(x);
i=103;
while(i>0)i--;//>480us,reset
DS|=BIT1(m);//keep free
i=4;
while(i>0)i--;
}
bit tmpreadbit(uchar m) //read a bit
{
uint i;
// uchar a;
bit dat;
DS&=NBIT1(m);i++; //i++ for delay
DS|=BIT1(m);
//a=DS;
i++;i++;//读时间片，要大于60us
if(DS&BIT1(m))
dat=1;
else
dat=0;
i=8;while(i>0)i--;
return (dat);
}
uchar tmpread(uchar m) //read a byte date
{
uchar i,j,dat;
dat=0;
for(i=1;i<=8;i++)
{
j=tmpreadbit(m);
dat=(j<<7)|(dat>>1); //读出的数据最低位在最前面，这样刚好一个字节在DAT里
}
return(dat);
}
void tmpwritebyte(uchar dat,uchar m) //write a byte to ds18b20
{
uint i;
uchar j;
bit testb;
for(j=1;j<=8;j++)
{
testb=dat&0x01;//取最低位
dat=dat>>1;
if(testb) //write 1
{
//DS=0;
DS&=NBIT1(m);
i++;i++;
DS|=BIT1(m);
i=8;while(i>0)i--;
}
else
{
//DS=0; //write 0
DS&=NBIT1(m);
i=8;while(i>0)i--;//写0要保持低电平60us
//DS=1;
DS|=BIT1(m);
i++;i++;
}
}
}
void tmpchange(uchar m) //DS18B20 begin change
{
dsreset(m);
delay(1);
tmpwritebyte(0xcc,m); // address all drivers on bus
tmpwritebyte(0x44,m); // initiates a single temperature conversion
}
uint tmp(uchar m) //get the temperature
{
float tt;
uchar a,b;
dsreset(m);
delay(1);
tmpwritebyte(0xcc,m);
tmpwritebyte(0xbe,m);
a=tmpread(m);
b=tmpread(m);
temp=b;
temp<<=8; //two byte compose a int variable
temp=temp|a;
tt=temp*0.0625;
temp=tt*10+0.5;
return temp;
}

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