DS1820 khó quá....

[motu]

Mình đang làm mạch để điều khiển nhiệt độ hồ cá, không có thời gian làm mạch in nên lấy con EasyPIC chơi luôn, nhưng ác cái là con EasyPIC xài cảm biến DS1820, con này giao tiếp 1-wire khó chơi quá (mình là gà mà), search tá lả trên mạng cuôí cùng viết đoạn code sau:

#include <16F877A.h> 
#device *=16 
#device adc=8 
#include <def_877a.h>

#FUSES NOWDT, HS, PUT, NOPROTECT, NODEBUG, BROWNOUT, NOLVP, NOCPD, NOWRT      
#use delay(clock=20000000) 
#include <1wire.c> 
#include <ds1820.c>
int8 x0,x1,x2,x3;
int hms[6];

void tachso(int16 x)
{
x0=x%10;            //chu so hang don vi
x1=((x-x0)/10)%10;         //chu so hang chuc
x2=((x-10*x1-x0)/100)%10;      //chu so hang tram
x3=((x-100*x2-10*x1-x0)/1000)%10;   //chu so hang nghin
}

int BCD(int data)
   {                                 
      int xx;                     
      switch (data)
         {
         case 0:
            xx=0xC0;
            break;
         case 1:
            xx=0xF9;
            break;
         case 2:
            xx=0xA4;
            break;
         case 3:
            xx=0xB0;
            break;
         case 4:
            xx=0x99;
            break;
         case 5:
            xx=0x92;
            break;
         case 6:
            xx=0x82;
            break;
         case 7:
            xx=0xF8;
            break;
         case 8:
            xx=0x80;
            break;
         case 9:
            xx=0x90;
            break;
         default:
            xx=0x7F;
         }
      return(xx);    
   } 
   
void showLed(int data[6])
{
   int k,j,t;
   k=1;
   for (j=0;j<6;j++)
   {  
      PORTA = ~k;
      switch (j)
         {
         case 1:
            t=BCD(data[j]) & 0x7F;
            break;
         case 3:
            t=BCD(data[j]) & 0x7F;
            break;
         default:
            t=BCD(data[j]);
         }   
      PORTB = t;
      delay_us(600);    
      k=k<<1;
   }
}

void xulidulieu(int16 dt)
   {
      tachso(dt);
      hms[0] = 0x00;
      hms[1] = 0x00;
      hms[2] = x0;
      hms[3] = x1;
      hms[4] = x2;
      hms[5] = x3;
    }  
                  
void main() 
{ 
   int16 tem; 
   trisc=0x00;
   portc=0x00;
   TRISB = 0x00;    
   TRISA = 0b00000000;
   PORTB = 0xFF;    
   PORTA = 0;   
   tem = (int16) ds1820_read();
   delay_ms(10);
while (1)
{ 
  tem = (int16) ds1820_read();
  delay_ms(10);
  xulidulieu(tem);
  showLed(hms);
}
}

1wire.c (chôm trên mạng)

// (C) copyright 2003 j.d.sandoz / jds-pic !at! losdos.dyndns.org

// released under the GNU GENERAL PUBLIC LICENSE (GPL)
// refer to http://www.gnu.org/licenses/gpl.txt

// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

/***********************1Wire Class***********************/
/*Description: This class handles all communication */
/* between the processor and the 1wire */
/* sensors.
/*********************************************************/

/*-------1-wire definitions-------*/
#define ONE_WIRE_PIN PIN_E2       //mình dùng EasyPIC, set chân E2 nên sửa code lại chỗ này, file mặc định là #define ONE_WIRE_PIN PIN_A5

/*******************1-wire communication functions********************/

/************onewire_reset*************************************************/
/*This function initiates the 1wire bus */
/* */
/*PARAMETERS: */
/*RETURNS: */
/*********************************************************************/

void onewire_reset()  // OK if just using a single permanently connected device
{
 output_low(ONE_WIRE_PIN);
 delay_us( 500 ); // pull 1-wire low for reset pulse
 output_float(ONE_WIRE_PIN); // float 1-wire high
 delay_us( 500 ); // wait-out remaining initialisation window.
 output_float(ONE_WIRE_PIN);
}

/*********************** onewire_write() ********************************/
/*This function writes a byte to the sensor.*/
/* */
/*Parameters: byte - the byte to be written to the 1-wire */
/*Returns: */
/*********************************************************************/

void onewire_write(int data)
{
 int count;

 for (count=0; count<8; ++count)
 {
  output_low(ONE_WIRE_PIN);
  delay_us( 2 ); // pull 1-wire low to initiate write time-slot.
  output_bit(ONE_WIRE_PIN, shift_right(&data,1,0)); // set output bit on 1-wire
  delay_us( 60 ); // wait until end of write slot.
  output_float(ONE_WIRE_PIN); // set 1-wire high again,
  delay_us( 2 ); // for more than 1us minimum.
 }
}

/*********************** read1wire() *********************************/
/*This function reads the 8 -bit data via the 1-wire sensor. */
/* */
/*Parameters: */
/*Returns: 8-bit (1-byte) data from sensor */
/*********************************************************************/

int onewire_read()
{
 int count, data;

 for (count=0; count<8; ++count)
 {
  output_low(ONE_WIRE_PIN);
  delay_us( 2 ); // pull 1-wire low to initiate read time-slot.
  output_float(ONE_WIRE_PIN); // now let 1-wire float high,
  delay_us( 8 ); // let device state stabilise,
  shift_right(&data,1,input(ONE_WIRE_PIN)); // and load result.
  delay_us( 120 ); // wait until end of read slot.
 }

 return( data );
}

DS1820.c (cái này cũng là tài sản trên internet - chưa có tiền trả bản quyền )

float ds1820_read()
{
 int8 busy=0, temp1, temp2;
 signed int16 temp3;
 float result;

 onewire_reset();
 onewire_write(0xCC);
 onewire_write(0x44);

 while (busy == 0)
  busy = onewire_read();

 onewire_reset();
 onewire_write(0xCC);
 onewire_write(0xBE);
 temp1 = onewire_read();
 temp2 = onewire_read();
 temp3 = make16(temp2, temp1);
 
 result = (float) temp3 / 2.0;   //Calculation for DS18S20 with 0.5 deg C resolution
// result = (float) temp3 / 16.0;  //Calculation for DS18B20 with 0.1 deg C resolution
 
 delay_ms(200);
 return(result);
}

Nạp vô EasyPIC hiện lên sáu số 0 tròn trĩnh, ai đã từng test thực tế con DS1820 có thể giải thích lỗi trong code của mình hoặc cho mình 1 đoạn code đầy đủ để thử con DS1820 khó tính này (mình sử dụng EasyPIC nên dùng chân RE1 hoặc RA5 cho 1wire)
THk mọi người! không được chắc đổi qua LM35 cho dễ chơi quá!
P/S: Mấy đoạn code show led của mình hơi gà mọi người đừng cười