text: /******************************************************************************
  SparkFunMPU9250-DMP.h - MPU-9250 Digital Motion Processor Arduino Library 
  Jim Lindblom @ SparkFun Electronics
  original creation date: November 23, 2016
  https://github.com/sparkfun/SparkFun_MPU9250_DMP_Arduino_Library
  
  This library implements motion processing functions of Invensense's MPU-9250.
  It is based on their Emedded MotionDriver 6.12 library.
  	https://www.invensense.com/developers/software-downloads/
  
  Development environment specifics:
  Arduino IDE 1.6.12
  SparkFun 9DoF Razor IMU M0
  
  Supported Platforms:
  - ATSAMD21 (Arduino Zero, SparkFun SAMD21 Breakouts)
  ******************************************************************************/
  #ifndef _SPARKFUN_MPU9250_DMP_H_
  #define _SPARKFUN_MPU9250_DMP_H_
  
  #include <Wire.h>
  #include <Arduino.h>
  
  // Optimally, these defines would be passed as compiler options, but Arduino
  // doesn't give us a great way to do that.
  #define MPU9250
  #define AK8963_SECONDARY
  #define COMPASS_ENABLED
  
  // Include the Invensense MPU9250 driver and DMP keys:
  extern "C" {
  #include "util/inv_mpu.h"
  #include "util/inv_mpu_dmp_motion_driver.h"
  }
  
  typedef int inv_error_t;
  #define INV_SUCCESS 0
  #define INV_ERROR 0x20
  
  enum t_axisOrder {
  	X_AXIS, // 0
  	Y_AXIS, // 1
  	Z_AXIS  // 2
  };
  
  // Define's passed to update(), to request a specific sensor (or multiple):
  #define UPDATE_ACCEL   (1<<1)
  #define UPDATE_GYRO    (1<<2)
  #define UPDATE_COMPASS (1<<3)
  #define UPDATE_TEMP    (1<<4)
  
  #define INT_ACTIVE_HIGH 0
  #define INT_ACTIVE_LOW  1
  #define INT_LATCHED     1
  #define INT_50US_PULSE  0
  
  #define MAX_DMP_SAMPLE_RATE 200 // Maximum sample rate for the DMP FIFO (200Hz)
  #define FIFO_BUFFER_SIZE 512 // Max FIFO buffer size
  
  const signed char defaultOrientation[9] = {
  	1, 0, 0,
  	0, 1, 0,
  	0, 0, 1
  };
  #define ORIENT_PORTRAIT          0
  #define ORIENT_LANDSCAPE         1
  #define ORIENT_REVERSE_PORTRAIT  2
  #define ORIENT_REVERSE_LANDSCAPE 3
  
  class MPU9250_DMP 
  {
  public:
  	int ax, ay, az;
  	int gx, gy, gz;
  	int mx, my, mz;
  	long qw, qx, qy, qz;
  	long temperature;
  	unsigned long time;
  	double pitch, roll, yaw;
  	float heading;
  	
  	MPU9250_DMP();
  	
  	// begin(void) -- Verifies communication with the MPU-9250 and the AK8963,
  	// and initializes them to the default state:
  	// All sensors enabled
  	// Gyro FSR: +/- 2000 dps
  	// Accel FSR: +/- 2g
  	// LPF: 42 Hz
  	// FIFO: 50 Hz, disabled
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t begin(void);
  	
  	// setSensors(unsigned char) -- Turn on or off MPU-9250 sensors. Any of the 
  	// following defines can be combined: INV_XYZ_GYRO, INV_XYZ_ACCEL, 
  	// INV_XYZ_COMPASS, INV_X_GYRO, INV_Y_GYRO, or INV_Z_GYRO
  	// Input: Combination of enabled sensors. Unless specified a sensor will be
  	//  disabled.
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t setSensors(unsigned char sensors);
  	
  	// setGyroFSR(unsigned short) -- Sets the full-scale range of the gyroscope
  	// Input: Gyro DPS - 250, 500, 1000, or 2000
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t setGyroFSR(unsigned short fsr);
  	// getGyroFSR -- Returns the current gyroscope FSR
  	// Output: Current Gyro DPS - 250, 500, 1000, or 2000
  	unsigned short getGyroFSR(void);
  	// getGyroSens -- Returns current gyroscope sensitivity. The FSR divided by
  	// the resolution of the sensor (signed 16-bit).
  	// Output: Currently set gyroscope sensitivity (e.g. 131, 65.5, 32.8, 16.4)
  	float getGyroSens(void);
  	
  	// setAccelFSR(unsigned short) -- Sets the FSR of the accelerometer
  	// 
  	// Input: Accel g range - 2, 4, 8, or 16
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t setAccelFSR(unsigned char fsr);
  	// getAccelFSR -- Returns the current accelerometer FSR
  	// Output: Current Accel g - 2, 4, 8, or 16
  	unsigned char getAccelFSR(void);
  	// getAccelSens -- Returns current accelerometer sensitivity. The FSR 
  	// divided by the resolution of the sensor (signed 16-bit).
  	// Output: Currently set accel sensitivity (e.g. 16384, 8192, 4096, 2048)
  	unsigned short getAccelSens(void);
  	
  	// getMagFSR -- Returns the current magnetometer FSR
  	// Output: Current mag uT range - +/-1450 uT
  	unsigned short getMagFSR(void);
  	// getMagSens -- Returns current magnetometer sensitivity. The FSR 
  	// divided by the resolution of the sensor (signed 16-bit).
  	// Output: Currently set mag sensitivity (e.g. 0.15)
  	float getMagSens(void);
  	
  	// setLPF -- Sets the digital low-pass filter of the accel and gyro.
  	// Can be any of the following: 188, 98, 42, 20, 10, 5 (value in Hz)
  	// Input: 188, 98, 42, 20, 10, or 5 (defaults to 5 if incorrectly set)
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t setLPF(unsigned short lpf);
  	// getLPF -- Returns the set value of the LPF.
  	//
  	// Output: 5, 10, 20, 42, 98, or 188 if set. 0 if the LPF is disabled.
  	unsigned short getLPF(void);
  	
  	// setSampleRate -- Set the gyroscope and accelerometer sample rate to a 
  	// value between 4Hz and 1000Hz (1kHz).
  	// The library will make an attempt to get as close as possible to the
  	// requested sample rate.
  	// Input: Value between 4 and 1000, indicating the desired sample rate
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t setSampleRate(unsigned short rate);
  	// getSampleRate -- Get the currently set sample rate.
  	// May differ slightly from what was set in setSampleRate.
  	// Output: set sample rate of the accel/gyro. A value between 4-1000.
  	unsigned short getSampleRate(void);
  	
  	// setCompassSampleRate -- Set the magnetometer sample rate to a value
  	// between 1Hz and 100 Hz.
  	// The library will make an attempt to get as close as possible to the
  	// requested sample rate.
  	// Input: Value between 1 and 100, indicating the desired sample rate
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t setCompassSampleRate(unsigned short rate);
  	// getCompassSampleRate -- Get the currently set magnetometer sample rate.
  	// May differ slightly from what was set in setCompassSampleRate.
  	//
  	// Output: set sample rate of the magnetometer. A value between 1-100
  	unsigned short getCompassSampleRate(void);
  	
  	// dataReady -- checks to see if new accel/gyro data is available.
  	// (New magnetometer data cannot be checked, as the library runs that sensor 
  	//  in single-conversion mode.)
  	// Output: true if new accel/gyro data is available
  	bool dataReady();
  	
  	// update -- Reads latest data from the MPU-9250's data registers.
  	// Sensors to be updated can be set using the [sensors] parameter.
  	// [sensors] can be any combination of UPDATE_ACCEL, UPDATE_GYRO,
  	// UPDATE_COMPASS, and UPDATE_TEMP.
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	// Note: after a successful update the public sensor variables 
  	// (e.g. ax, ay, az, gx, gy, gz) will be updated with new data 
  	inv_error_t update(unsigned char sensors = 
  	                   UPDATE_ACCEL | UPDATE_GYRO | UPDATE_COMPASS);
  	
  	// updateAccel, updateGyro, updateCompass, and updateTemperature are 
  	// called by the update() public method. They read from their respective
  	// sensor and update the class variable (e.g. ax, ay, az)
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t updateAccel(void);
  	inv_error_t updateGyro(void);
  	inv_error_t updateCompass(void);
  	inv_error_t updateTemperature(void);
  	
  	// configureFifo(unsigned char) -- Initialize the FIFO, set it to read from
  	// a select set of sensors.
  	// Any of the following defines can be combined for the [sensors] parameter:
  	// INV_XYZ_GYRO, INV_XYZ_ACCEL, INV_X_GYRO, INV_Y_GYRO, or INV_Z_GYRO
  	// Input: Combination of sensors to be read into FIFO
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t configureFifo(unsigned char sensors);
  	// getFifoConfig -- Returns the sensors configured to be read into the FIFO
  	// Output: combination of INV_XYZ_GYRO, INV_XYZ_ACCEL, INV_Y_GYRO,
  	//         INV_X_GYRO, or INV_Z_GYRO
  	unsigned char getFifoConfig(void);
  	// fifoAvailable -- Returns the number of bytes currently filled in the FIFO
  	// Outputs: Number of bytes filled in the FIFO (up to 512)
  	unsigned short fifoAvailable(void);
  	// updateFifo -- Reads from the top of the FIFO, and stores the new data
  	// in ax, ay, az, gx, gy, or gz (depending on how the FIFO is configured).
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t updateFifo(void);
  	// resetFifo -- Resets the FIFO's read/write pointers
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t resetFifo(void);
  	
  	// enableInterrupt -- Configure the MPU-9250's interrupt output to indicate
  	// when new data is ready.
  	// Input: 0 to disable, >=1 to enable
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t enableInterrupt(unsigned char enable = 1);
  	// setIntLevel -- Configure the MPU-9250's interrupt to be either active-
  	// high or active-low.
  	// Input: 0 for active-high, 1 for active-low
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t setIntLevel(unsigned char active_low);
  	// setIntLatched -- Configure the MPU-9250's interrupt to latch or operate
  	// as a 50us pulse.
  	// Input: 0 for 
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t setIntLatched(unsigned char enable);
  	// getIntStatus -- Reads the MPU-9250's INT_STATUS register, which can
  	// indicate what (if anything) caused an interrupt (e.g. FIFO overflow or
  	// or data read).
  	// Output: contents of the INT_STATUS register
  	short getIntStatus(void);
  	
  	// dmpBegin -- Initialize the DMP, enable one or more features, and set the FIFO's sample rate
  	// features can be any one of 
  	// DMP_FEATURE_TAP -- Tap detection
  	// DMP_FEATURE_ANDROID_ORIENT -- Orientation (portrait/landscape) detection
  	// DMP_FEATURE_LP_QUAT -- Accelerometer, low-power quaternion calculation
  	// DMP_FEATURE_PEDOMETER -- Pedometer (always enabled)
  	// DMP_FEATURE_6X_LP_QUAT -- 6-axis (accel/gyro) quaternion calculation
  	// DMP_FEATURE_GYRO_CAL -- Gyroscope calibration (0's out after 8 seconds of no motion)
  	// DMP_FEATURE_SEND_RAW_ACCEL -- Send raw accelerometer values to FIFO
  	// DMP_FEATURE_SEND_RAW_GYRO -- Send raw gyroscope values to FIFO
  	// DMP_FEATURE_SEND_CAL_GYRO -- Send calibrated gyroscop values to FIFO
  	// fifoRate can be anywhere between 4 and 200Hz.
  	// Input: OR'd list of features and requested FIFO sampling rate
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpBegin(unsigned short features = 0, unsigned short fifoRate = MAX_DMP_SAMPLE_RATE);
  	
  	// dmpLoad -- Loads the DMP with 3062-byte image memory. Must be called to begin DMP.
  	// This function is called by the dmpBegin function.
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpLoad(void);
  	
  	// dmpGetFifoRate -- Returns the sample rate of the FIFO
  	// Output: Set sample rate, in Hz, of the FIFO
  	unsigned short dmpGetFifoRate(void);
  	// dmpSetFiFoRate -- Sets the rate of the FIFO.
  	// Input: Requested sample rate in Hz (range: 4-200)
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpSetFifoRate(unsigned short rate);
  	
  	// dmpUpdateFifo -- Reads from the top of the FIFO and fills accelerometer, gyroscope,
  	// quaternion, and time public variables (depending on how the DMP is configured).
  	// Should be called whenever an MPU interrupt is detected
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpUpdateFifo(void); 
  	
  	// dmpEnableFeatures -- Enable one, or multiple DMP features.
  	// Input: An OR'd list of features (see dmpBegin)
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpEnableFeatures(unsigned short mask);
  	// dmpGetEnabledFeatures -- Returns the OR'd list of enabled DMP features
  	//
  	// Output: OR'd list of DMP feature's (see dmpBegin for list)
  	unsigned short dmpGetEnabledFeatures(void);
  	
  	// dmpSetTap -- Enable tap detection and configure threshold, tap time, and minimum tap count.
  	// Inputs: x/y/zThresh - accelerometer threshold on each axis. Range: 0 to 1600. 0 disables tap
  	//                       detection on that axis. Units are mg/ms.
  	//         taps - minimum number of taps to create a tap event (Range: 1-4)
  	//         tapTime - Minimum number of milliseconds between separate taps
  	//         tapMulti - Maximum number of milliseconds combined taps
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpSetTap(unsigned short xThresh = 250, 
  	                      unsigned short yThresh = 250, 
  	                      unsigned short zThresh = 250,
  						  unsigned char taps = 1, 
  						  unsigned short tapTime = 100,
  						  unsigned short tapMulti = 500);
  	// tapAvailable -- Returns true if a new tap is available
  	// Output: True if new tap data is available. Cleared on getTapDir or getTapCount.
  	bool tapAvailable(void);
  	// getTapDir -- Returns the tap direction.
  	// Output: One of the following: TAP_X_UP, TAP_X_DOWN, TAP_Y_UP, TAP_Y_DOWN, TAP_Z_UP,
  	//         or TAP_Z_DOWN
  	unsigned char getTapDir(void);
  	// getTapCount -- Returns the number of taps in the sensed direction
  	// Output: Value between 1-8 indicating successive number of taps sensed.
  	unsigned char getTapCount(void);
  
  	// dmpSetOrientation -- Set orientation matrix, used for orientation sensing.
  	// Use defaultOrientation matrix as an example input.
  	// Input: Gyro and accel orientation in body frame (9-byte array)
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpSetOrientation(const signed char * orientationMatrix = defaultOrientation);
  	// dmpGetOrientation -- Get the orientation, if any.
  	// Output: If an orientation is detected, one of ORIENT_LANDSCAPE, ORIENT_PORTRAIT,
  	//         ORIENT_REVERSE_LANDSCAPE, or ORIENT_REVERSE_PORTRAIT.
  	unsigned char dmpGetOrientation(void);
  	
  	// dmpEnable3Quat -- Enable 3-axis quaternion calculation
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpEnable3Quat(void);
  	
  	// dmpEnable6Quat -- Enable 6-axis quaternion calculation
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpEnable6Quat(void);
  	
  	// dmpGetPedometerSteps -- Get number of steps in pedometer register
  	// Output: Number of steps sensed
  	unsigned long dmpGetPedometerSteps(void);
  	// dmpSetPedometerSteps -- Set number of steps to a value
  	// Input: Desired number of steps to begin incrementing from
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpSetPedometerSteps(unsigned long steps);
  	// dmpGetPedometerTime -- Get number of milliseconds ellapsed over stepping
  	// Output: Number of milliseconds where steps were detected
  	unsigned long dmpGetPedometerTime(void);
  	// dmpSetPedometerTime -- Set number time to begin incrementing step time counter from
  	// Input: Desired number of milliseconds
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpSetPedometerTime(unsigned long time);
  	
  	// dmpSetInterruptMode --
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpSetInterruptMode(unsigned char mode);
  	// dmpSetGyroBias --
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpSetGyroBias(long * bias);
  	// dmpSetAccelBias -- 
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t dmpSetAccelBias(long * bias);
  
  
  	// lowPowerAccel --
  	// Output: INV_SUCCESS (0) on success, otherwise error
  	inv_error_t lowPowerAccel(unsigned short rate);
  
  	// calcAccel -- Convert 16-bit signed acceleration value to g's
  	float calcAccel(int axis);
  	// calcGyro -- Convert 16-bit signed gyroscope value to degree's per second
  	float calcGyro(int axis);
  	// calcMag -- Convert 16-bit signed magnetometer value to microtesla (uT)
  	float calcMag(int axis);
  	// calcQuat -- Convert Q30-format quaternion to a vector between +/- 1
  	float calcQuat(long axis);
  	
  	// computeEulerAngles -- Compute euler angles based on most recently read qw, qx, qy, and qz
  	// Input: boolean indicating whether angle results are presented in degrees or radians
  	// Output: class variables roll, pitch, and yaw will be updated on exit.	
  	void computeEulerAngles(bool degrees = true);
  	
  	// computeCompassHeading -- Compute heading based on most recently read mx, my, and mz values
  	// Output: class variable heading will be updated on exit
  	float computeCompassHeading(void);
  	
  	// selfTest -- Run gyro and accel self-test.
  	// Output: Returns bit mask, 1 indicates success. A 0x7 is success on all sensors.
  	//         Bit pos 0: gyro
  	//         Bit pos 1: accel
  	//         Bit pos 2: mag
  	int selfTest(unsigned char debug = 0);
    
    float qToFloat(long number, unsigned char q);
    
  private:
  	unsigned short _aSense;
  	float _gSense, _mSense;
  	
  	// Convert a QN-format number to a float
  	
  	unsigned short orientation_row_2_scale(const signed char *row);
  };
  
  #endif // _SPARKFUN_MPU9250_DMP_H_