LM75.cpp

/*
    LM75 - An arduino library for the LM75 temperature sensor
    Copyright (C) 2011  Dan Fekete <thefekete AT gmail DOT com>

    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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include <Wire.h>
#include "LM75.h"

LM75::LM75 () {
  address = LM75_ADDRESS;
}

LM75::LM75 (byte addr) {
  address = addr;
}

word LM75::float2regdata (float temp)
{
  // First multiply by 8 and coerce to integer to get +/- whole numbers
  // Then coerce to word and bitshift 5 to fill out MSB
  return (word)((int)(temp * 8) << 5);
}

float LM75::regdata2float (word regdata)
{
  return ((float)(int)regdata / 32) / 8;
}

word LM75::_register16 (byte reg) {
  Wire.beginTransmission(address);
  Wire.write(reg);	
  Wire.endTransmission();
  
  Wire.requestFrom(address, 2);
  word regdata = (Wire.read() << 8) | Wire.read();
  return regdata;
}

void LM75::_register16 (byte reg, word regdata) {
  byte msb = (byte)(regdata >> 8);
  byte lsb = (byte)(regdata);
  
  Wire.beginTransmission(address);
  Wire.write(reg);
  Wire.write(msb);
  Wire.write(lsb);
  Wire.endTransmission();
}

word LM75::_register8 (byte reg) {
  Wire.beginTransmission(address);
  Wire.write(reg);	
  Wire.endTransmission();
  
  Wire.requestFrom(address, 1);
  return Wire.read();
}

void LM75::_register8 (byte reg, byte regdata) {  
  Wire.beginTransmission(address);
  Wire.write(reg);
  Wire.write(regdata);
  Wire.endTransmission();
}

float LM75::temp (void) {
  return regdata2float(_register16(LM75_TEMP_REGISTER));
}

byte LM75::conf () {
  return _register8(LM75_CONF_REGISTER);
}

void LM75::conf (byte data) {
  _register8(LM75_CONF_REGISTER, data);
}

float LM75::tos () {
  return regdata2float(_register16(LM75_TOS_REGISTER));
}

void LM75::tos (float temp) {
  _register16(LM75_TOS_REGISTER, float2regdata(temp));
}

float LM75::thyst () {
  return regdata2float(_register16(LM75_THYST_REGISTER));
}

void LM75::thyst (float temp) {
  _register16(LM75_THYST_REGISTER, float2regdata(temp));
}

boolean LM75::shutdown () {
  return conf() & 0x01;
}

void LM75::shutdown (boolean val)	//sigmaeo: changed, because the old one changed the configuration (i.e. 12bit-RES).
{
  byte old;
  old = conf();
  if( val )
  	conf(old | (1<<LM75_CONF_SHUTDOWN));
  else
  	conf(old & ~(1<<LM75_CONF_SHUTDOWN));
}