/*****************************************
 * Imports
 *****************************************/
#include <Wire.h>

/*****************************************
 * Precompiler Definitions
 *****************************************/
#define TMP_ADDRESS 0b1001011 // I2C address of the TMP2 Pmod
#define ARRAY_SIZE 4 // Maximum size of the buffer
#define BAUD 9600 // Rate at which the UART serial will communicate
#define REQUEST 2 //number of bytes to request at a time from I2C

/*****************************************
 * Global Variables 
 *****************************************/
short buffer[ARRAY_SIZE]; // Create a buffer to hold values passed through I2C

/*****************************************
 * Functions
 *****************************************/

/**
 * Establishes communication with the TMP2 Pmod, calculates the temperature in Celcius and then returns it as a short value
 */
short getTemp(){

  Wire.requestFrom(TMP_ADDRESS, REQUEST); // Request two bytes of data from the temperature sensor

  while(Wire.available()){ //While there is still data to be transfered
    for (int i =0; i < REQUEST; i++){ // Put the data in a buffer array
      buffer[i] = Wire.receive();
    }
  }

  short retTemp = 0; // define a short value that will be set and returned by the function

  for (int i = 0; i < REQUEST; i++){ // A loop to handle each byte contained in the buffer. This loop recombines the bytes sent over I2C into a single short
    retTemp = retTemp<<8; // shift all bits to the right 8 spaces
    retTemp |= buffer[i]; // This is equivalent to retTemp = retTemp | buffer[i]. This effectively concatenates the retrieved bytes into a single short 
  }  

  return retTemp*.0078; // Multiply by a scaling factor (found on the data sheet) to convert to Celsius

}

/*****************************************
 * Setup
 *****************************************/
void setup(){  
  Wire.begin(); // Enables I2C communication on the ChipKit board
  Serial.begin(BAUD); // Enables UART serial communication at the selected speed
}


/*****************************************
 * Main Loop
 *****************************************/
void loop(){

  Serial.println(getTemp(), DEC); // Print the temperature through the serial port

  delay(500); // delay for 500ms
}