ds18b20

#include

#include

#include

#include"./delay./delay.h"

#include "./1602/1602.h"

 

sbit ds = P0^0;

bit ack = 0;

void ds18b20_init()

{

  ds = 0;

  delay_us(200);

  delay_us(200);

  ds = 1;

  delay_us(30);

  if(ds == 0)  ack = 1;

  else   ack = 0;

   delay_us(200);

}

 

void ds18b20_send_byte(unsigned char byte)

{

     unsigned char i;

 for(i = 0;i < 8;i++)

 {

       ds = 1;

   ds = 0;

   _nop_();

   _nop_();

     ds = byte & 0x01;

   byte >>= 1;

   delay_us(30);

 

 }

 delay_us(30);

 ds = 1;

}

 

bit ds18b20_read_bit()

{

       bit tmp;

   ds = 1;

   ds = 0;

   _nop_();

   _nop_();

   ds = 1 ;

   tmp = ds;

   delay_us(30);

   return tmp;

 

 

}

 

unsigned char ds18b20_write_byte()

{

   unsigned char i,j,k = 0;

  

   for(i = 0;i < 8;i++)

   {

        j = ds18b20_read_bit();

 

    k = (j << 7) | (k >> 1) ;

   

   }

   return k;

   

 

 

}

 

void main()

{

     //ds18b20_init();

  //ds18b20_send_byte(0xcc);

 

  unsigned int temp,b;

  unsigned char a;

  float temp_f;

  unsigned char buf[16];

  LCD_Init();

  

 

  while(1)

  {

      ds18b20_init();

   ds18b20_send_byte(0xcc);

   ds18b20_send_byte(0x44);

   delay_ms(20);

   ds18b20_init();

   ds18b20_send_byte(0xcc);

   ds18b20_send_byte(0xbe);

   a = ds18b20_write_byte();

   b = ds18b20_write_byte();

   temp = (b << 8) + a;

   temp_f = (float)temp * 0.0625;

   sprintf(buf," Temp : %7.3f",temp_f);

   LCD_Write_String(0,0,buf);

 

 

  }

 

}