DS18B20 temperature display demonstration program (6-digit digital tube display)

#include

sbit DQ = P3^3; //define DS18B20 port DQ 

sbit BEEP=P3^7 ;

unsigned char presence ;

unsigned char code  LEDData[ ]   = {0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,

                                                          0x80,0x90,0xff};

unsigned char data  temp_data[2] = {0x00,0x00};

unsigned char data  display[5] =  {0x00,0x00,0x00,0x00,0x00};

unsigned char code  ditab[16] =   {0x00,0x01,0x01,0x02,0x03,0x03,0x04,0x04,

                                                       0x05,0x06,0x06,0x07,0x08,0x08,0x09,0x09};

void beep();

sbit DIN = P0^7; //decimal point

bit flash=0; //display switch mark

/**********************************************************/

void Delay(unsigned int num)//delay function

{

  while( --num );

}

/**********************************************************/

 Init_DS18B20(void) // Initialize DS1820

{

     DQ = 1; //DQ reset

     Delay(8); //Slight delay

     DQ = 0; //MCU pulls DQ low

     Delay(90); //Precise delay greater than 480us

     DQ = 1; //Pull the bus high

     Delay(8);

     presence = DQ; //If = 0, initialization is successful, = 1, initialization fails

     Delay(100);

     DQ = 1;

     return(presence); //Return signal, 0=presence, 1= no presence

}

/**********************************************************/

ReadOneChar(void) //Read one byte

{

unsigned char i = 0;

unsigned char dat = 0;

for (i = 8; i > 0; i--)

  {

    DQ = 0; // Give pulse signal

    that >>= 1;

    DQ = 1; // Give pulse signal

    if(DQ)

     that |= 0x80;

    Delay(4);

  }

    return (that);

}

/**********************************************************/

WriteOneChar(unsigned char dat) //write one byte

{

  unsigned char i = 0;

  for (i = 8; i > 0; i--)

  {

    DQ = 0;

    DQ = dat&0x01;

    Delay(5);

    DQ = 1;

    that>>=1;

  }

}

/*********************************************************/

Read_Temperature(void) //Read temperature

{

  Init_DS18B20();

  if(presence==1)       

   { beep(); flash=1;} //DS18B20 is abnormal, buzzer alarm

   else

   {

     flash=0;

     WriteOneChar(0xCC); // Skip reading the serial number and column number

     WriteOneChar(0x44); // Start temperature conversion

     Init_DS18B20();

     WriteOneChar(0xCC); //Skip the operation of reading the serial number and column number

     WriteOneChar(0xBE); //Read temperature register

     temp_data[0] = ReadOneChar(); //lower 8 bits of temperature

     temp_data[1] = ReadOneChar(); //high 8 bits of temperature

   }

}

/*********************************************************/

Disp_Temperature() //Display temperature

{

  unsigned char  n=0;

  display[4]=temp_data[0]&0x0f;

  display[0]=ditab[display[4]]; //Look up the table to get the decimal value

  display[4]=((temp_data[0]&0xf0)>>4)|((temp_data[1]&0x0f)<<4);

  display[3]=display[4]/100;

  display[1]=display[4]%100;

  display[2]=display[1]/10;

  display[1]=display[1]%10;

  if(!display[3]) //high bit is 0, not displayed

  {

    display[3]=0x0a;           

    if(!display[2]) //The second highest bit is 0, not displayed

     display[2]=0x0a;

  }

P0 = 0xc6; //Display C

P2 = 0x7f;

Delay(300);

P0 = 0x9c; //display ° 

P2 = 0xbf;

Delay(300);

P0 =LEDData[display[0]]; //Display decimal places

P2 = 0xdf;

Delay(300);

P0 =LEDData[display[1]]; //Display the unit digit

DIN = 0;

P2 = 0xef;

Delay(300);

P0 =LEDData[display[2]]; //Display the tens digit

P2 = 0xf7;

Delay(300);

P0 =LEDData[display[3]]; //Display the tens digit

P2 = 0xfb;

Delay(300);

P2 = 0xff; // Turn off display

}

/*********************************************************/

void beep()

  {

    unsigned char i;

    for (i=0;i<100;i++)

    {

      Delay(60);

      BEEP=!BEEP;                 //BEEP取反

    }

    BEEP=1; //Turn off the buzzer

  }

/*********************************************************/

void main(void)

{

  while(1)

  {

    Read_Temperature();

 if(flash==0)             

 {Disp_Temperature();}

 else P2 = 0xff ; //DS18B20 is abnormal, turn off the display

  }

}