Read temperature from MCP9808

read-temperature-from-MCP9808.cpp

#include "MCP9808.h"

MCP9808::MCP9808(PinName sda, PinName scl) : i2c(sda, scl)
{
}

// read temperature from MCP9808    
float MCP9808::readTemp()
{
   data_write[0] = MCP9808_REG_TEMP;
   i2c.write(MCP9808_ADDR, data_write, 1, 1); // no stop
   i2c.read(MCP9808_ADDR, data_read, 2, 0);

   if(data_read[0] & 0xE0) {
       data_read[0] = data_read[0] & 0x1F;  // clear flag bits
   }
   if((data_read[0] & 0x10) == 0x10) { // < 0 C
       data_read[0] = data_read[0] & 0x0F;
       tempval = 256 - (data_read[0] * 16) + (data_read[1] / 16.0);
       tempval = tempval * -1;
   } else { // > 0 C
       tempval = (data_read[0] * 16) + (data_read[1] / 16.0);
   }
   return tempval;
}

void MCP9808::goSleep()
{
   data_write[0] = MCP9808_REG_CONF;
   data_write[1] = 0x01;  // config msb
   data_write[2] = 0x00;  // config lsb
   int status = i2c.write(MCP9808_ADDR, data_write, 3, 0);    
}

void MCP9808::wakeUp()
{
   data_write[0] = MCP9808_REG_CONF;
   data_write[1] = 0x00;  // config msb
   data_write[2] = 0x00;  // config lsb
   int status = i2c.write(MCP9808_ADDR, data_write, 3, 0);    
}