www.pudn.com > DS18B20.rar > ds18b20__.c

/* Multipoint thermometer with LCD display 
   using the Maxim DS18B20 
   1 Wire bus temperature sensors 
 
   CodeVisionAVR C Compiler 
   (C) 2000-2005 HP InfoTech S.R.L. 
   www.hpinfotech.ro 
 
   Chip: ATmega8515 
   Memory Model: SMALL 
   Data Stack Size: 128 bytes 
 
   THE ATmega8515 CLOCK FREQUENCY MUST BE 3.6864 MHz 
 
   The DS18B20 sensors are connected to 
   bit 6 of PORTA of the ATmega8515 as follows: 
 
   [DS18B20]     [STK500 PORTA HEADER] 
    1 GND         -   9  GND 
    2 DQ          -   7  PA6 
    3 VDD         -  10 +5V 
 
   All the temperature sensors must be connected 
   in parallel 
 
   AN 4.7k PULLUP RESISTOR MUST BE CONNECTED 
   BETWEEN DQ (PA6) AND +5V ! 
*/ 
#asm 
    .equ __w1_port=0x1b 
    .equ __w1_bit=6 
#endasm 
 
/* Use an 2x16 alphanumeric LCD connected 
   to PORTC as follows: 
 
  [LCD]   [STK500 PORTC HEADER] 
   1 GND- 9  GND 
   2 +5V- 10 VCC 
   3 VLC- LCD contrast control voltage 0..1V 
   4 RS - 1  PC0 
   5 RD - 2  PC1 
   6 EN - 3  PC2 
  11 D4 - 5  PC4 
  12 D5 - 6  PC5 
  13 D6 - 7  PC6 
  14 D7 - 8  PC7 
*/ 
 
#asm 
    .equ __lcd_port=0x15 
#endasm 
 
#include  // LCD driver routines 
#include  
#include  
#include  
 
char lcd_buffer[33]; 
 
 
main() 
{ 
//unsigned char i,j,devices; 
float aa; 
lcd_init(16); 
lcd_putsf("CodeVisionAVR\n1 Wire Bus Demo"); 
delay_ms(2000); 
lcd_clear(); 
 
    if(ds18b20_init(0,25,35,DS18B20_12BIT_RES)==0) 
       { 
 
       while (1); /* stop here if init error */ 
       }; 
 
 
while (1) 
      { 
      //j=1; 
      //for (i=0;i<1;i++) 
        //  { 
        aa=ds18b20_temperature(0); 
        if(aa>125) 
        sprintf(lcd_buffer,"t=%+.1f\xdfC",aa-4096); 
        else 
          sprintf(lcd_buffer,"t=%+.1f\xdfC",aa); 
          lcd_clear(); 
          lcd_puts(lcd_buffer); 
          delay_ms(500); 
          //}; 
      }; 
}