Read temperature maximum minimum ds1624

[MANEL]

Hi. I've had a circuit with PIC16f877 <--> Ds1624 connected by means I2C. The temperature is OK but the problem is that spent a certain time the temperature is sleep, is always the same one and it does not change although it changes the temperature of the surroundings. also I have a problem with the temperature minimum, the algorithm that I have created not shows minimum but 0�C always. Somebody finds the problem ?

The program:

#include <16f877.h>
#use delay (clock=4000000)
#use I2C(MASTER, SDA=PIN_C4, SCL=PIN_C3, fast)
#use fast_io(A)
#fuses XT, NOPROTECT, NOPUT, NOWDT, NOBROWNOUT, NOLVP, NOCPD

#include <lcd_lolo.c>

#define simbolo_grados 0b11011111
#define simbolo_coma 0b00101100
#define I2CWRITE 0b10010000
#define I2CREAD 0b10010001
#define I2CREAD2 0b10010011

#define DS1624_CMD_ACCESSCONFIG 0xAC
#define DS1624_CMD_INITIATECONVERT 0xEE
#define DS1624_CMD_ACCESSTEMPERATURE 0xAA
#define DS1624_CMD_ACCESSMEMORY 0x17

# byte port_a=6
int datah, datal;

void i2c_conversion()
{

i2c_start();
i2c_write(I2CWRITE);
i2c_write(DS1624_CMD_INITIATECONVERT);
i2c_stop();
}

void i2c_ds1624_inicia()
{
i2c_start();
i2c_write(I2CWRITE);
i2c_write(DS1624_CMD_ACCESSCONFIG);
i2c_write(0b01001011);
i2c_stop();
delay_ms(20);
i2c_conversion();
}

void i2c_ds1624_leer_temp_c()
{
i2c_start();
i2c_write(I2CWRITE);
i2c_write(DS1624_CMD_ACCESSTEMPERATURE);
i2c_start();
i2c_write(I2CREAD);
datah=i2c_read();
datal=i2c_read(0);
i2c_stop();
i2c_ds1624_inicia();
}


int read_ext_eeprom(int address)
{
int data;
i2c_start();
i2c_write(0x90);
i2c_write(0x17);
i2c_write(address);
i2c_start();
i2c_write(0x91);
data=i2c_read();
i2c_stop();
return data;


}


void write_ext_eeprom(int address, int data)
{
i2c_start();
i2c_write(0x90);
i2c_write(0x17);
i2c_write(address);
i2c_write(data);
i2c_stop();
delay_ms(50);
}
void main (void)
{
int temperatura;
int dec,decimal,max, maxd, auxi,auxi2,mini,mind,contador,conta,minimo;
lcd_inicia();
i2c_ds1624_inicia();
set_tris_a(0b111110);
lcd_ponc("\f");
port_a=0;
max=0;
maxd=0;
auxi=0;
mini=5;
mind=99;
auxi2=50;
contador=0;
conta=0;
while(1)
{
contador=contador+1;
if (conta<50) conta=conta+1;
i2c_ds1624_leer_temp_c();
lcd_ponc("\f");
switch(datal)
{
case 248: dec=98; break;
case 240: dec=94; break;
case 232: dec=90; break;
case 224: dec=87; break;
case 216: dec=83; break;
case 208: dec=80; break;
case 200: dec=77; break;
case 192: dec=75; break;
case 184: dec=72; break;
case 176: dec=70; break;
case 168: dec=68; break;
case 160: dec=66; break;
case 152: dec=62; break;
case 144: dec=60; break;
case 136: dec=58; break;
case 128: dec=55; break;
case 120: dec=53; break;
case 112: dec=50; break;
case 104: dec=48; break;
case 96: dec=44; break;
case 88: dec=40; break;
case 80: dec=37; break;
case 72: dec=34; break;
case 64: dec=30; break;
case 56: dec=28; break;
case 48: dec=23; break;
case 40: dec=20; break;
case 32: dec=17; break;
case 24: dec=13; break;
case 16: dec=10; break;
case 8: dec=05; break;
case 0: dec=0; break;
}
lcd_vaixy(1,1);

if (datah>max) max= datah;
if ((dec> maxd) && (auxi<=max))
{
maxd=dec;
auxi=max;
}
if ((dec<= maxd) && (auxi<max))
{
maxd=dec;
auxi=max;
}


if ((dec< mind) && (auxi2>=mini))
{
mind=dec;
auxi2=mini;
mini=datah;
}
if ((dec>= mind) && (auxi2>mini))
{
mind=dec;
auxi2=mini;
}
printf(lcd_ponc,"T= %d%2d%cC",datah,simbolo_coma,dec,simbolo_grados);
lcd_vaixy(1,2);
if (contador<100)
printf(lcd_ponc,"TMax=%d%c%2d%cC",max,simbolo_coma,maxd,simbolo_grados);
if (contador>=100)
printf(lcd_ponc,"TMin=%d%c%2d%cC",mini,simbolo_coma,mind,simbolo_grados);
if (contador>200) contador=0;
if (datah>20) output_high (PIN_A0);
if (datah<=20) output_low (PIN_A0);
}
}

[jds-pic]

(double posted; content in next post)

[Guest]

MANEL,

(note use of "Code" button below; makes reading much easier)

you are doing a lot of work outside of i2c_ds1624_leer_temp_c(), with the high and low bytes of the result carried back to main() as globals.

in my library code you cut-n-pasted from:

[padron70]

Thanks jds-pic, I have changed the function i2c_ds1624_leer_temp_c() since you have recommended and the results have been correct with the maximum and minimum temperatures perfectly shown.
The final code:

[jds-pic]

[Guest]

What would you suggest if i say that i need water temperature sensor that must be all the time, in the water ?

You stick it in the water and that's it. He should be all time in the water...