por cierto, si a alguien le interesa la libreria del protocolo 1 wire para las EEPROM y sensores de temp de dallas semiconductor, son las siguientes, una para el protocolo y otra para el sensor DS18S20/DS18B20
Libreria 1 wire
// (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_B5
/*******************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_byte(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_byte()
{
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);
}
Libreria DS18S20/DS18B20
float ds1820_read()
{
int8 busy=0,temp1,temp2;
signed int16 temp3;
float result;
onewire_reset();
onewire_write_byte(0xCC);
onewire_write_byte(0x44);
while (busy == 0) busy = onewire_read_byte();
onewire_reset();
onewire_write_byte(0xCC);
onewire_write_byte(0xBE);
temp1=onewire_read_byte();
temp2=onewire_read_byte();
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);
}
Funciona de maravillas!
