File content as of revision 1:da3b20b5d38a:

/***************************************************************************************************************
* Razor AHRS Firmware v1.4.0
* 9 Degree of Measurement Attitude and Heading Reference System
* for Sparkfun "9DOF Razor IMU" (SEN-10125 and SEN-10736)
* and "9DOF Sensor Stick" (SEN-10183, 10321 and SEN-10724)
*
* Released under GNU GPL (General Public License) v3.0
* Copyright (C) 2011 Quality & Usability Lab, Deutsche Telekom Laboratories, TU Berlin
*
* Infos, updates, bug reports and feedback:
*     http://dev.qu.tu-berlin.de/projects/sf-razor-9dof-ahrs
*
*
* History:
*   * Original code (http://code.google.com/p/sf9domahrs/) by Doug Weibel and Jose Julio,
*     based on ArduIMU v1.5 by Jordi Munoz and William Premerlani, Jose Julio and Doug Weibel. Thank you!
*
*   * Updated code (http://groups.google.com/group/sf_9dof_ahrs_update) by David Malik (david.zsolt.malik@gmail.com)
*     for new Sparkfun 9DOF Razor hardware (SEN-10125).
*
*   * Updated and extended by Peter Bartz (peter-bartz@gmx.de):
*     * v1.3.0
*       * Cleaned up, streamlined and restructured most of the code to make it more comprehensible.
*       * Added sensor calibration (improves precision and responsiveness a lot!).
*       * Added binary yaw/pitch/roll output.
*       * Added basic serial command interface to set output modes/calibrate sensors/synch stream/etc.
*       * Added support to synch automatically when using Rovering Networks Bluetooth modules (and compatible).
*       * Wrote new easier to use test program (using Processing).
*       * Added support for new version of "9DOF Razor IMU": SEN-10736.
*       --> The output of this code is not compatible with the older versions!
*       --> A Processing sketch to test the tracker is available.
*     * v1.3.1
*       * Initializing rotation matrix based on start-up sensor readings -> orientation OK right away.
*       * Adjusted gyro low-pass filter and output rate settings.
*     * v1.3.2
*       * Adapted code to work with new Arduino 1.0 (and older versions still).
*     * v1.3.3
*       * Improved synching.
*     * v1.4.0
*       * Added support for SparkFun "9DOF Sensor Stick" (versions SEN-10183, SEN-10321 and SEN-10724).
*       * Ported (v1.4.0) to MBED.org by Luke Petre (lpetre@gmail.com)
*          http://mbed.org/users/lpetre/programs/RazorAHRS/
*
* TODOs:
*   * Allow optional use of EEPROM for storing and reading calibration values.
*   * Use self-test and temperature-compensation features of the sensors.
*   * Add binary output of unfused sensor data for all 9 axes.
***************************************************************************************************************/

/*
  "9DOF Razor IMU" hardware versions: SEN-10125 and SEN-10736

  ATMega328@3.3V, 8MHz

  ADXL345  : Accelerometer
  HMC5843  : Magnetometer on SEN-10125
  HMC5883L : Magnetometer on SEN-10736
  ITG-3200 : Gyro

  Arduino IDE : Select board "Arduino Pro or Pro Mini (3.3v, 8Mhz) w/ATmega328"
*/

/*
  "9DOF Sensor Stick" hardware versions: SEN-10183, SEN-10321 and SEN-10724

  ADXL345  : Accelerometer
  HMC5843  : Magnetometer on SEN-10183 and SEN-10321
  HMC5883L : Magnetometer on SEN-10724
  ITG-3200 : Gyro
*/

/*
  Axis definition (differs from definition printed on the board!):
    X axis pointing forward (towards the short edge with the connector holes)
    Y axis pointing to the right
    and Z axis pointing down.
    
  Positive yaw   : clockwise
  Positive roll  : right wing down
  Positive pitch : nose up
  
  Transformation order: first yaw then pitch then roll.
*/

/*
  Commands that the firmware understands:
  
  "#o<param>" - Set output parameter. The available options are:
      "#o0" - Disable continuous streaming output.
      "#o1" - Enable continuous streaming output.
      "#ob" - Output angles in binary format (yaw/pitch/roll as binary float, so one output frame
              is 3x4 = 12 bytes long).
      "#ot" - Output angles in text format (Output frames have form like "#YPR=-142.28,-5.38,33.52",
              followed by carriage return and line feed [\r\n]).
      "#os" - Output (calibrated) sensor data of all 9 axes in text format. One frame consist of
              three lines - one for each sensor.
      "#oc" - Go to calibration output mode.
      "#on" - When in calibration mode, go on to calibrate next sensor.
      "#oe0" - Disable error message output.
      "#oe1" - Enable error message output.
    
  "#f" - Request one output frame - useful when continuous output is disabled and updates are
         required in larger intervals only.
  "#s<xy>" - Request synch token - useful to find out where the frame boundaries are in a continuous
         binary stream or to see if tracker is present and answering. The tracker will send
         "#SYNCH<xy>\r\n" in response (so it's possible to read using a readLine() function).
         x and y are two mandatory but arbitrary bytes that can be used to find out which request
         the answer belongs to.
          
  ("#C" and "#D" - Reserved for communication with optional Bluetooth module.)
  
  Newline characters are not required. So you could send "#ob#o1#s", which
  would set binary output mode, enable continuous streaming output and request
  a synch token all at once.
  
  The status LED will be on if streaming output is enabled and off otherwise.
  
  Byte order of binary output is little-endian: least significant byte comes first.
*/
#include <mbed.h>
#include <MODSERIAL.h>


/*****************************************************************/
/*********** USER SETUP AREA! Set your options here! *************/
/*****************************************************************/

// HARDWARE OPTIONS
/*****************************************************************/
// Select your hardware here by uncommenting one line!
//#define HW__VERSION_CODE 10125 // SparkFun "9DOF Razor IMU" version "SEN-10125" (HMC5843 magnetometer)
//#define HW__VERSION_CODE 10736 // SparkFun "9DOF Razor IMU" version "SEN-10736" (HMC5883L magnetometer)
//#define HW__VERSION_CODE 10183 // SparkFun "9DOF Sensor Stick" version "SEN-10183" (HMC5843 magnetometer)
//#define HW__VERSION_CODE 10321 // SparkFun "9DOF Sensor Stick" version "SEN-10321" (HMC5843 magnetometer)
#define HW__VERSION_CODE 10724 // SparkFun "9DOF Sensor Stick" version "SEN-10724" (HMC5883L magnetometer)


// OUTPUT OPTIONS
/*****************************************************************/
// Set your serial port baud rate used to send out data here!
#define OUTPUT__BAUD_RATE 57600

// Sensor data output interval in milliseconds
// This may not work, if faster than 20ms (=50Hz)
// Code is tuned for 20ms, so better leave it like that
#define OUTPUT__DATA_INTERVAL 20  // in milliseconds

// Output mode
#define OUTPUT__MODE_CALIBRATE_SENSORS 0 // Outputs sensor min/max values as text for manual calibration
#define OUTPUT__MODE_ANGLES_TEXT 1 // Outputs yaw/pitch/roll in degrees as text
#define OUTPUT__MODE_ANGLES_BINARY 2 // Outputs yaw/pitch/roll in degrees as binary float
#define OUTPUT__MODE_SENSORS_TEXT 3 // Outputs (calibrated) sensor values for all 9 axes as text

// Select if serial continuous streaming output is enabled per default on startup.
#define OUTPUT__STARTUP_STREAM_ON true // true or false

// Bluetooth
// You can set this to true, if you have a Rovering Networks Bluetooth Module attached.
// The connect/disconnect message prefix of the module has to be set to "#".
// (Refer to manual, it can be set like this: SO,#)
// When using this, streaming output will only be enabled as long as we're connected. That way
// receiver and sender are synchronzed easily just by connecting/disconnecting.
// It is not necessary to set this! It just makes life easier when writing code for
// the receiving side. The Processing test sketch also works without setting this.
// NOTE: When using this, OUTPUT__STARTUP_STREAM_ON has no effect!
#define OUTPUT__HAS_RN_BLUETOOTH false  // true or false


// SENSOR CALIBRATION
/*****************************************************************/
// How to calibrate? Read the tutorial at http://dev.qu.tu-berlin.de/projects/sf-razor-9dof-ahrs
// Put MIN/MAX and OFFSET readings for your board here!
// Accelerometer
// "accel x,y,z (min/max) = X_MIN/X_MAX  Y_MIN/Y_MAX  Z_MIN/Z_MAX"
#define ACCEL_X_MIN ((float) -263)
#define ACCEL_X_MAX ((float) 263)
#define ACCEL_Y_MIN ((float) -257)
#define ACCEL_Y_MAX ((float) 277)
#define ACCEL_Z_MIN ((float) -270)
#define ACCEL_Z_MAX ((float) 251)

// Magnetometer
// "magn x,y,z (min/max) = X_MIN/X_MAX  Y_MIN/Y_MAX  Z_MIN/Z_MAX"
#define MAGN_X_MIN ((float) -600)
#define MAGN_X_MAX ((float) 600)
#define MAGN_Y_MIN ((float) -600)
#define MAGN_Y_MAX ((float) 600)
#define MAGN_Z_MIN ((float) -600)
#define MAGN_Z_MAX ((float) 600)

// Gyroscope
// "gyro x,y,z (current/average) = .../OFFSET_X  .../OFFSET_Y  .../OFFSET_Z
#define GYRO_AVERAGE_OFFSET_X ((float) 0.0)
#define GYRO_AVERAGE_OFFSET_Y ((float) 0.0)
#define GYRO_AVERAGE_OFFSET_Z ((float) 0.0)

/*
// Calibration example:
// "accel x,y,z (min/max) = -278.00/270.00  -254.00/284.00  -294.00/235.00"
#define ACCEL_X_MIN ((float) -278)
#define ACCEL_X_MAX ((float) 270)
#define ACCEL_Y_MIN ((float) -254)
#define ACCEL_Y_MAX ((float) 284)
#define ACCEL_Z_MIN ((float) -294)
#define ACCEL_Z_MAX ((float) 235)

// "magn x,y,z (min/max) = -511.00/581.00  -516.00/568.00  -489.00/486.00"
#define MAGN_X_MIN ((float) -511)
#define MAGN_X_MAX ((float) 581)
#define MAGN_Y_MIN ((float) -516)
#define MAGN_Y_MAX ((float) 568)
#define MAGN_Z_MIN ((float) -489)
#define MAGN_Z_MAX ((float) 486)

//"gyro x,y,z (current/average) = -32.00/-34.82  102.00/100.41  -16.00/-16.38"
#define GYRO_AVERAGE_OFFSET_X ((float) -34.82)
#define GYRO_AVERAGE_OFFSET_Y ((float) 100.41)
#define GYRO_AVERAGE_OFFSET_Z ((float) -16.38)
*/


// DEBUG OPTIONS
/*****************************************************************/
// When set to true, gyro drift correction will not be applied
#define DEBUG__NO_DRIFT_CORRECTION false
// Print elapsed time after each I/O loop
#define DEBUG__PRINT_LOOP_TIME false


/*****************************************************************/
/****************** END OF USER SETUP AREA!  *********************/
/*****************************************************************/


// Check if hardware version code is defined
#ifndef HW__VERSION_CODE
  // Generate compile error
  #error YOU HAVE TO SELECT THE HARDWARE YOU ARE USING! See "HARDWARE OPTIONS" in "USER SETUP AREA" at top of Razor_AHRS.pde!
#endif

//#include <Wire.h>

// Sensor calibration scale and offset values
#define ACCEL_X_OFFSET ((ACCEL_X_MIN + ACCEL_X_MAX) / 2.0f)
#define ACCEL_Y_OFFSET ((ACCEL_Y_MIN + ACCEL_Y_MAX) / 2.0f)
#define ACCEL_Z_OFFSET ((ACCEL_Z_MIN + ACCEL_Z_MAX) / 2.0f)
#define ACCEL_X_SCALE (GRAVITY / (ACCEL_X_MAX - ACCEL_X_OFFSET))
#define ACCEL_Y_SCALE (GRAVITY / (ACCEL_Y_MAX - ACCEL_Y_OFFSET))
#define ACCEL_Z_SCALE (GRAVITY / (ACCEL_Z_MAX - ACCEL_Z_OFFSET))

#define MAGN_X_OFFSET ((MAGN_X_MIN + MAGN_X_MAX) / 2.0f)
#define MAGN_Y_OFFSET ((MAGN_Y_MIN + MAGN_Y_MAX) / 2.0f)
#define MAGN_Z_OFFSET ((MAGN_Z_MIN + MAGN_Z_MAX) / 2.0f)
#define MAGN_X_SCALE (100.0f / (MAGN_X_MAX - MAGN_X_OFFSET))
#define MAGN_Y_SCALE (100.0f / (MAGN_Y_MAX - MAGN_Y_OFFSET))
#define MAGN_Z_SCALE (100.0f / (MAGN_Z_MAX - MAGN_Z_OFFSET))


// Gain for gyroscope (ITG-3200)
#define GYRO_GAIN 0.06957 // Same gain on all axes
#define GYRO_SCALED_RAD(x) (x * TO_RAD(GYRO_GAIN)) // Calculate the scaled gyro readings in radians per second

// DCM parameters
#define Kp_ROLLPITCH 0.02f
#define Ki_ROLLPITCH 0.00002f
#define Kp_YAW 1.2f
#define Ki_YAW 0.00002f

// Stuff
#define GRAVITY 256.0f // "1G reference" used for DCM filter and accelerometer calibration
#define TO_RAD(x) (x * 0.01745329252)  // *pi/180
#define TO_DEG(x) (x * 57.2957795131)  // *180/pi
#define NEW_LINE "\r\n"

/**
* Internal Measurement Unit
*
* Uses DCM algorithm to calculate Euler angle values
*
* Modified Razr_AHRS 1.4 code
*/
class IMU {
private:
    // Sensor variables
    int16_t accel[3];  // Actually stores the NEGATED acceleration (equals gravity, if board not moving).
    int16_t accel_min[3];
    int16_t accel_max[3];

    int16_t magnetom[3];
    int16_t magnetom_min[3];
    int16_t magnetom_max[3];

    int16_t gyro[3];
    double temperature;
    double gyro_average[3];
    int gyro_num_samples;
    
    // gyro slope offset values
    float foffset[3];
    float slope[3];

    // Euler angles
    float yaw;
    float pitch;
    float roll;

    // DCM variables
    float MAG_Heading;
    float Accel_Vector[3]; // Store the acceleration in a vector
    float Gyro_Vector[3];  // Store the gyros turn rate in a vector
    float Omega_Vector[3]; // Corrected Gyro_Vector data
    float Omega_P[3];//= {0, 0, 0}; // Omega Proportional correction
    float Omega_I[3];//= {0, 0, 0}; // Omega Integrator
    float Omega[3];//= {0, 0, 0};
    float errorRollPitch[3];// = {0, 0, 0};
    float errorYaw[3];// = {0, 0, 0};
    float DCM_Matrix[3][3];// = {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}};
    float Update_Matrix[3][3];// = {{0, 1, 2}, {3, 4, 5}, {6, 7, 8}};
    float Temporary_Matrix[3][3];// = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}};

    // DCM timing in the main loop
    long timestamp;
    long timestamp_old;
    float G_Dt; // Integration time for DCM algorithm

    // More output-state variables
    int output_mode;
    bool output_stream_on;
    bool output_single_on;
    int curr_calibration_sensor;
    bool reset_calibration_session_flag;
    int num_accel_errors;
    int num_magn_errors;
    int num_gyro_errors;

    // If set true, an error message will be output if we fail to read sensor data.
    // Message format: "!ERR: reading <sensor>", followed by "\r\n".
    bool output_errors;

    DigitalOut statusLed;
    MODSERIAL pc;
    I2C Wire;
    Timer timer;

public:    
    // Compass.cpp
    void Compass_Heading();
 
    // DCM.cpp
    void Normalize();
    void Drift_correction();
    void Matrix_update();
    void Euler_angles();
    
    // Output.cpp
    void output_angles();
    void output_calibration(int calibration_sensor);
    void output_sensors();
    
    // AHRS.cpp
    void read_sensors();
    void reset_sensor_fusion();
    void compensate_sensor_errors();
    void check_reset_calibration_session();
    void turn_output_stream_on();
    void turn_output_stream_off();
    char readChar();
    void readInput();
    
    IMU();
    void loop();
    
    /**
    * Loop that calculates values and places them in a array
    *
    * @param data array of length=4 to contain
    *                   data[0] = temperature (C);
    *                   data[1] = yaw (deg)
    *                   data[2] = pitch (deg)
    *                   data[3] = roll (deg)
    */
    void loop(float*);
    
    // Sensors.cpp
    void I2C_Init();
    void Accel_Init();
    void Read_Accel();
    void Magn_Init();
    void Read_Magn();
    void Gyro_Init();
    
    /**
    * Reads from the ITG3200 gyro
    *
    * Gyro xyz values in gyro[3]
    * Temperature value in temperature
    *
    * TODO: thermal drift adjustment
    */
    void Read_Gyro();
    
};

float Vector_Dot_Product(float vector1[3], float vector2[3]);
void Vector_Cross_Product(float vectorOut[3], float v1[3], float v2[3]);
void Vector_Scale(float vectorOut[3], float vectorIn[3], float scale2);
void Vector_Add(float vectorOut[3], float vectorIn1[3], float vectorIn2[3]);
void Matrix_Multiply(float a[3][3], float b[3][3],float mat[3][3]);
void init_rotation_matrix(float m[3][3], float yaw, float pitch, float roll);
float constrain(float in, float min, float max);