18B20温度传感器数码管显示当前温度

ID:129422 · 发表于 2016-7-6 14:19

#include <reg52.h>
#define uchar unsigned char
#define uint unsigned int
sbit DS=P2^2;          //define interface
uint temp;          // variable of temperature
uchar flag1;          // sign of the result positive or negative
sbit dula=P2^6;
sbit wela=P2^7;
unsigned char code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,
                     0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
unsigned char code table1[]={0xbf,0x86,0xdb,0xcf,0xe6,0xed,0xfd,
                     0x87,0xff,0xef};

void delay(uint count)    //delay
{
  uint i;
  while(count)
  {
i=200;
while(i>0)
i--;
count--;
  }
}
///////TheNeXT:串口初始化,波特率9600，方式1///////
void Init_Com(void)
{
   TMOD = 0x20;
   PCON = 0x00;
   SCON = 0x50;
   TH1 = 0xFd;
   TL1 = 0xFd;
   TR1 = 1;
}

void dsreset(void)    //send reset and initialization command
{
  uint i;
  DS=0;
  i=103;
  while(i>0)i--;
  DS=1;
  i=4;
  while(i>0)i--;
}

bit tmpreadbit(void)    //read a bit
{
uint i;
bit dat;
DS=0;i++;       //i++ for delay
DS=1;i++;i++;
dat=DS;
i=8;while(i>0)i--;
return (dat);
}

uchar tmpread(void) //read a byte date
{
  uchar i,j,dat;
  dat=0;
  for(i=1;i<=8;i++)
  {
j=tmpreadbit();
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) //write a byte to ds18b20
{
  uint i;
  uchar j;
  bit testb;
  for(j=1;j<=8;j++)
  {
testb=dat&0x01;
dat=dat>>1;
if(testb)    //write 1
{
   DS=0;
   i++;i++;
   DS=1;
   i=8;while(i>0)i--;
}
else
{
   DS=0;    //write 0
   i=8;while(i>0)i--;
   DS=1;
   i++;i++;
}

  }
}

void tmpchange(void)  //DS18B20 begin change
{
  dsreset();
  delay(1);
  tmpwritebyte(0xcc);  // address all drivers on bus
  tmpwritebyte(0x44);  //  initiates a single temperature conversion
}

uint tmp()             //get the temperature
{
  float tt;
  uchar a,b;
  dsreset();
  delay(1);
  tmpwritebyte(0xcc);
  tmpwritebyte(0xbe);
  a=tmpread();
  b=tmpread();
  temp=b;
  temp<<=8;          //two byte  compose a int variable
  temp=temp|a;
  tt=temp*0.0625;
  temp=tt*10+0.5;
  return temp;
}

void readrom()       //read the serial
{
  uchar sn1,sn2;
  dsreset();
  delay(1);
  tmpwritebyte(0x33);
  sn1=tmpread();
  sn2=tmpread();
}

void delay10ms()          //delay
  {
uchar a,b;
for(a=10;a>0;a--)
   for(b=60;b>0;b--);
}

void display(uint temp) //显示程序
{
uchar A1,A2,A2t,A3,ser;
ser=temp/10;
SBUF=ser;
A1=temp/100;
A2t=temp%100;
A2=A2t/10;
A3=A2t%10;
dula=0;
P0=table[A1]; //显示百位
dula=1;
dula=0;

wela=0;
P0=0xfe;
wela=1;
wela=0;
delay(1);

dula=0;
P0=table1[A2]; //显示十位
dula=1;
dula=0;

wela=0;
P0=0xfd;
wela=1;
wela=0;
delay(1);

P0=table[A3]; //显示个位
dula=1;
dula=0;

P0=0xfb;
wela=1;
wela=0;
delay(1);
}

void main()
{
uchar a;
Init_Com();
  do
  {
tmpchange();
// delay(200);
for(a=10;a>0;a--)
  { display(tmp());
  }
  }             while(1);
}

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