ds18b20__.c

cvavr ds18b20源程序及仿真的例子,修正了cvavr中显示负温度时出的错误

/* 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

   PLEASE MAKE SURE THAT THE CKSEL0..3 FUSE
   BITS ARE PROGRAMMED TO USE THE EXTERNAL
   3.6864MHz CLOCK SOURCE OF THE STK500 AND NOT
   THE INTERNAL 1MHz OSCILLATOR.
   The ATmega8515 chip comes from the factory
   with CKSEL0..3 fuse bits set to use the
   internal 1 MHz oscillator.

   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.h> // LCD driver routines
#include <ds18b20.h>
#include <delay.h>
#include <stdio.h>

char lcd_buffer[33];

/* maximum number of DS18B20 connected to the 1 Wire bus */
#define MAX_DEVICES 8

/* DS18B20 devices ROM code storage area */
unsigned char rom_code[MAX_DEVICES][9];

main()
{
unsigned char i,j,devices;
float tmp;
lcd_init(16);
lcd_putsf("CodeVisionAVR\n1 Wire Bus Demo");
delay_ms(200);
lcd_clear();

/* detect how many DS18B20 devices
   are connected to the 1 Wire bus */
devices=w1_search(0xf0,rom_code);
sprintf(lcd_buffer,"%u DS18B20\nDevice detected",devices);
lcd_puts(lcd_buffer);
delay_ms(800);

/* display the ROM codes for each device */
if (devices)
   {
   for (i=0;i<devices;i++)
       {
       sprintf(lcd_buffer,"Device #%u ROM\nCode is:",i+1);
       lcd_clear();
       lcd_puts(lcd_buffer);
       delay_ms(800);
       lcd_clear();
       for (j=0;j<8;j++)
           {
           sprintf(lcd_buffer,"%02X ",rom_code[i][j]);
           lcd_puts(lcd_buffer);
           if (j==3) lcd_gotoxy(0,1);
           };
       delay_ms(800);
       };
   }
else
while (1); /* stop here if no devices were found */

/* configure each DS18B20 device for 12 bit temperature
   measurement resolution */
for (i=0;i<devices;)
    if (!ds18b20_init(&rom_code[i++][0],20,30,DS18B20_12BIT_RES))
       {
       sprintf(lcd_buffer,"Init error for\ndevice #%u",i);
       lcd_clear();
       lcd_puts(lcd_buffer);
       while (1); /* stop here if init error */
       };

/* measure and display the temperature(s) */
while (1)
      {
      //j=1;
      for (i=0;i<devices;i++)
          {
          tmp=ds18b20_temperature(&rom_code[i][0]);
          if(tmp>125)
          sprintf(lcd_buffer,"t%u=%+.3f\xdfC",i+1,tmp-4096);
          else
          sprintf(lcd_buffer,"t%u=%+.3f\xdfC",i+1,tmp);
          lcd_clear();
          lcd_puts(lcd_buffer);
          delay_ms(1000);
          };
      };
}