mlx90614.cpp

00001  
00002 #include "mlx90614.h"
00003 
00004 
00005 
00006 
00007 MLX90614::MLX90614(I2C* i2c,int addr){
00008 
00009     this->i2caddress = addr;
00010     this->i2c = i2c; 
00011     
00012 }
00013 
00014 
00015 bool MLX90614::getTemp(float* temp_val){
00016 
00017     char p1,p2,p3;
00018     float temp_thermo;
00019     bool ch;
00020 
00021     i2c->stop();                            //stop i2c if not ack
00022     wait(0.01);
00023     i2c->start();                           //start I2C                   
00024     ch=i2c->write(i2caddress);              //device address with write condition
00025     
00026     if(!ch)return false;                    //No Ack, return False
00027     
00028     ch=i2c->write(0x07);                    //device ram address where Tobj value is present
00029 
00030     if(!ch)return false;                    //No Ack, return False
00031 
00032 
00033     i2c->start();                           //repeat start
00034     ch=i2c->write(i2caddress|0x01);         //device address with read condition 
00035     if(!ch)return false;                    //No Ack, return False
00036 
00037     p1=i2c->read(1);     //Tobj low byte
00038     p2=i2c->read(1);     //Tobj heigh byte
00039     p3=i2c->read(0);     //PEC
00040     
00041     i2c->stop();                            //stop condition
00042      
00043     
00044     temp_thermo=((((p2&0x007f)<<8)+p1)*0.02)-0.01;      //degree centigrate conversion
00045     *temp_val=temp_thermo-273;                          //Convert kelvin to degree Celsius
00046     
00047     return true;                            //load data successfully, return true 
00048 }