File content as of revision 0:70465b25c44f:

// Accelerometer and Gyroscope registers
#define LSM9DS1XG_ACT_THS           0x04
#define LSM9DS1XG_ACT_DUR           0x05
#define LSM9DS1XG_INT_GEN_CFG_XL    0x06
#define LSM9DS1XG_INT_GEN_THS_X_XL  0x07
#define LSM9DS1XG_INT_GEN_THS_Y_XL  0x08
#define LSM9DS1XG_INT_GEN_THS_Z_XL  0x09
#define LSM9DS1XG_INT_GEN_DUR_XL    0x0A
#define LSM9DS1XG_REFERENCE_G       0x0B
#define LSM9DS1XG_INT1_CTRL         0x0C
#define LSM9DS1XG_INT2_CTRL         0x0D
#define LSM9DS1XG_WHO_AM_I          0x0F  // should return 0x68
#define LSM9DS1XG_CTRL_REG1_G       0x10
#define LSM9DS1XG_CTRL_REG2_G       0x11
#define LSM9DS1XG_CTRL_REG3_G       0x12
#define LSM9DS1XG_ORIENT_CFG_G      0x13
#define LSM9DS1XG_INT_GEN_SRC_G     0x14
#define LSM9DS1XG_OUT_TEMP_L        0x15
#define LSM9DS1XG_OUT_TEMP_H        0x16
#define LSM9DS1XG_STATUS_REG        0x17
#define LSM9DS1XG_OUT_X_L_G         0x18
#define LSM9DS1XG_OUT_X_H_G         0x19
#define LSM9DS1XG_OUT_Y_L_G         0x1A
#define LSM9DS1XG_OUT_Y_H_G         0x1B
#define LSM9DS1XG_OUT_Z_L_G         0x1C
#define LSM9DS1XG_OUT_Z_H_G         0x1D
#define LSM9DS1XG_CTRL_REG4         0x1E
#define LSM9DS1XG_CTRL_REG5_XL      0x1F
#define LSM9DS1XG_CTRL_REG6_XL      0x20
#define LSM9DS1XG_CTRL_REG7_XL      0x21
#define LSM9DS1XG_CTRL_REG8         0x22
#define LSM9DS1XG_CTRL_REG9         0x23
#define LSM9DS1XG_CTRL_REG10        0x24
#define LSM9DS1XG_INT_GEN_SRC_XL    0x26
//#define LSM9DS1XG_STATUS_REG        0x27 // duplicate of 0x17!
#define LSM9DS1XG_OUT_X_L_XL        0x28
#define LSM9DS1XG_OUT_X_H_XL        0x29
#define LSM9DS1XG_OUT_Y_L_XL        0x2A
#define LSM9DS1XG_OUT_Y_H_XL        0x2B
#define LSM9DS1XG_OUT_Z_L_XL        0x2C
#define LSM9DS1XG_OUT_Z_H_XL        0x2D
#define LSM9DS1XG_FIFO_CTRL         0x2E
#define LSM9DS1XG_FIFO_SRC          0x2F
#define LSM9DS1XG_INT_GEN_CFG_G     0x30
#define LSM9DS1XG_INT_GEN_THS_XH_G  0x31
#define LSM9DS1XG_INT_GEN_THS_XL_G  0x32
#define LSM9DS1XG_INT_GEN_THS_YH_G  0x33
#define LSM9DS1XG_INT_GEN_THS_YL_G  0x34
#define LSM9DS1XG_INT_GEN_THS_ZH_G  0x35
#define LSM9DS1XG_INT_GEN_THS_ZL_G  0x36
#define LSM9DS1XG_INT_GEN_DUR_G     0x37
//
// Magnetometer registers
#define LSM9DS1M_OFFSET_X_REG_L_M   0x05
#define LSM9DS1M_OFFSET_X_REG_H_M   0x06
#define LSM9DS1M_OFFSET_Y_REG_L_M   0x07
#define LSM9DS1M_OFFSET_Y_REG_H_M   0x08
#define LSM9DS1M_OFFSET_Z_REG_L_M   0x09
#define LSM9DS1M_OFFSET_Z_REG_H_M   0x0A
#define LSM9DS1M_WHO_AM_I           0x0F  
#define LSM9DS1M_CTRL_REG1_M        0x20
#define LSM9DS1M_CTRL_REG2_M        0x21
#define LSM9DS1M_CTRL_REG3_M        0x22
#define LSM9DS1M_CTRL_REG4_M        0x23
#define LSM9DS1M_CTRL_REG5_M        0x24
#define LSM9DS1M_STATUS_REG_M       0x27
#define LSM9DS1M_OUT_X_L_M          0x28
#define LSM9DS1M_OUT_X_H_M          0x29
#define LSM9DS1M_OUT_Y_L_M          0x2A
#define LSM9DS1M_OUT_Y_H_M          0x2B
#define LSM9DS1M_OUT_Z_L_M          0x2C
#define LSM9DS1M_OUT_Z_H_M          0x2D
#define LSM9DS1M_INT_CFG_M          0x30
#define LSM9DS1M_INT_SRC_M          0x31
#define LSM9DS1M_INT_THS_L_M        0x32
#define LSM9DS1M_INT_THS_H_M        0x33

// Using the LSM9DS1+MS5611 Teensy 3.1 Add-On shield, ADO is set to 1 
// Seven-bit device address of accel/gyro is 110101 for ADO = 0 and 110101 for ADO = 1

#define LSM9DS1XG_ADDRESS 0xD4  //  Device address when ADO = 1
#define LSM9DS1M_ADDRESS  0x38  //  Address of magnetometer
#define SerialDebug true  // set to true to get Serial output for debugging

// Set initial input parameters
enum Ascale
{  // set of allowable accel full scale settings
AFS_2G = 0,
  AFS_16G,
  AFS_4G,
  AFS_8G
};

enum Aodr {  // set of allowable gyro sample rates
  AODR_PowerDown = 0,
  AODR_10Hz,
  AODR_50Hz,
  AODR_119Hz,
  AODR_238Hz,
  AODR_476Hz,
  AODR_952Hz
};

enum Abw {  // set of allowable accewl bandwidths
   ABW_408Hz = 0,
   ABW_211Hz,
   ABW_105Hz,
   ABW_50Hz
};

enum Gscale {  // set of allowable gyro full scale settings
  GFS_245DPS = 0,
  GFS_500DPS,
  GFS_NoOp,
  GFS_2000DPS
};

enum Godr {  // set of allowable gyro sample rates
  GODR_PowerDown = 0,
  GODR_14_9Hz,
  GODR_59_5Hz,
  GODR_119Hz,
  GODR_238Hz,
  GODR_476Hz,
  GODR_952Hz
};

enum Gbw {   // set of allowable gyro data bandwidths
  GBW_low = 0,  // 14 Hz at Godr = 238 Hz,  33 Hz at Godr = 952 Hz
  GBW_med,      // 29 Hz at Godr = 238 Hz,  40 Hz at Godr = 952 Hz
  GBW_high,     // 63 Hz at Godr = 238 Hz,  58 Hz at Godr = 952 Hz
  GBW_highest   // 78 Hz at Godr = 238 Hz, 100 Hz at Godr = 952 Hz
};

enum Mscale {  // set of allowable mag full scale settings
  MFS_4G = 0,
  MFS_8G,
  MFS_12G,
  MFS_16G
};

enum Mmode {
  MMode_LowPower = 0, 
  MMode_MedPerformance,
  MMode_HighPerformance,
  MMode_UltraHighPerformance
};

enum Modr {  // set of allowable mag sample rates
  MODR_0_625Hz = 0,
  MODR_1_25Hz,
  MODR_2_5Hz,
  MODR_5Hz,
  MODR_10Hz,
  MODR_20Hz,
  MODR_80Hz
};

#define ADC_256  0x00 // define pressure and temperature conversion rates
#define ADC_512  0x02
#define ADC_1024 0x04
#define ADC_2048 0x06
#define ADC_4096 0x08
#define ADC_D1   0x40
#define ADC_D2   0x50
#define PI  3.141592653589793238463
#define Kp 2.0f * 5.0f // these are the free parameters in the Mahony filter and fusion scheme, Kp for proportional feedback, Ki for integral
#define Ki 0.0f