帶小數(shù)點(diǎn)DS18B20程序

#include REGX52.H>#define uchar unsigned charsbit DQ=P2^0;       //數(shù)據(jù)傳輸線接單片機(jī)的相應(yīng)的引腳unsigned char tempL=0;    //臨時(shí)變量低位（無(wú)符號(hào)字符變量）unsigned char tempH=0;   //臨時(shí)變量高位unsigned int tempa;      //溫度值（整型變量）uchar display_data[4]={0};void DS18_delay(int useconds)//延時(shí)函數(shù){int s;for (s=0; suseconds;s++);}unsigned char Init_DS18B20(void){unsigned char x=0;DQ=0;               //發(fā)送復(fù)位脈沖DS18_delay(29);           //延時(shí)（>480ms)DQ=1;             //拉高數(shù)據(jù)線DS18_delay(3);         //等待（15~60ms) 等待存在脈沖x=DQ;  //獲得存在信號(hào)(用于判斷是否有器件)DS18_delay(25);  // 等待時(shí)間隙結(jié)束return(x);  //返回存在信號(hào)，0 = 器件存在, 1 = 無(wú)器件}ReadOneChar(void)//讀一個(gè)字節(jié){unsigned char i=0;   unsigned char dat=0;for (i=8;i>0;i--)    {DQ=1;DS18_delay(1);DQ=0;      dat>>=1;//復(fù)合賦值運(yùn)算，等效dat=dat>>1(dat=dat右移一位后的值)DQ=1;if(DQ)dat|=0x80;DS18_delay(4);}return(dat);}WriteOneChar(unsigned char dat)//有參函數(shù)，功能是"寫"，而寫的內(nèi)容就是括號(hào)內(nèi)的參數(shù){ unsigned char i=0;   for(i=8;i>0;i--)   {DQ=0;     DQ=dat0x01;DS18_delay(5);DQ=1;dat>>=1;//復(fù)合賦值運(yùn)算，等效dat=dat>>1(dat=dat右移一位后的值)}DS18_delay(4);}unsigned int ReadTemperature(void)//返回讀取的溫度.{  Init_DS18B20();   //初始化，調(diào)用初始化函數(shù)WriteOneChar(0xcc);    //跳過(guò)讀序列號(hào)的操作，調(diào)用寫函數(shù)，寫0xcc指令碼（跳過(guò)讀序列號(hào)）WriteOneChar(0x44);   //啟動(dòng)溫度轉(zhuǎn)換，調(diào)用寫函數(shù)，寫0x44指令碼（啟動(dòng)溫度轉(zhuǎn)換）DS18_delay(125);       //轉(zhuǎn)換需要一點(diǎn)時(shí)間，延時(shí)Init_DS18B20();    //初始化，調(diào)用初始化函數(shù)WriteOneChar(0xcc);    //跳過(guò)讀序列號(hào)的操作，調(diào)用寫函數(shù)，寫0xcc指令碼（跳過(guò)讀序列號(hào)?WriteOneChar(0xbe);   //調(diào)用寫函數(shù)，寫0xbe指令碼，讀溫度寄存器（頭兩個(gè)值分別為溫度的低位和高位）tempL=ReadOneChar();   //讀出溫度的低位LSBtempH=ReadOneChar();   //讀出溫度的高位MSB  tempa=((tempH*256)+tempL)*6.25;  //溫度轉(zhuǎn)換,擴(kuò)大100返回//DS18_delay(10);//tempa=tempL+tempH;return(tempa);//運(yùn)算結(jié)果返回到函數(shù) }void display()//顯示函數(shù){unsigned char i,j,k=0x80;unsigned char code dis[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x39};for(i=0;i4;i++){P2=0x0f;if(i==1)P0=dis[display_data[i]]+0x80;elseP0=dis[display_data[i]];P2=k;k=k>>1;for(j=250;j>0;j--);}P2=0x0f;}void main(){unsigned int temp;uchar i;while(1){temp=ReadTemperature(); display_data[0]=temp/1000;display_data[1]=(temp/100)%10;display_data[2]=(temp/10)%10;display_data[3]=temp%10; for(i=0;i250;i++) display();}}