I2C driver for cmps03 electronic compass

cmps03.c

/*
 * cmps03.c
 *
 *  Created on: 26 Jan 2013
 *      Author: David
 */

// driver for cmps03 electronic compass


// includes


#include "lm4f120h5qr.h"
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/i2c.h"
#include "driverlib/debug.h"
#include "driverlib/gpio.h"
#include "driverlib/pin_map.h"
#include "I2C_Stellaris_API.h"
#include "utils/uartstdio.h"
#include "driverlib/sysctl.h"
#include "cmps03.h"

// FreeRtos includes

#include "priorities.h"
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
#include "semphr.h"


// variables

extern int bearing=0;
int readValues[2] = {0x00,0x00};// array storing high and low byte of word in register 3 (0-359.9 degrees)
int d1,d2,d3,d4;



int read_cmps03(void)
{
  I2CReadData(I2C3_MASTER_BASE, 0xE0, 0x02, readValues, 2); // read registers 2>high byte and 3>low byte

	bearing=((int)readValues[0] << 8) | ((int)readValues[1]);     // store result of read in d1

return bearing;
};


void init_quadrants(void)
{
  /* initialise 4 relative quadrant directions */

  I2CReadData(I2C3_MASTER_BASE, 0xE0, 0x02, readValues, 2); // read registers 2>high byte and 3>low byte
  d1=((int)readValues[0] << 8) | ((int)readValues[1]);     // store result of read in d1
  d2 = d1 + 900;
  if (d2 >= 3600) d2 = d2 - 3600;
  d3 = d2 + 900;
  if (d3 >= 3600) d3 = d3 - 3600;
  d4 = d3 + 900;
  if (d4 >= 3600) d4 = d4 - 3600;
return;
};