Diff: LSM9DS1.h

Revision:

0:e8167f37725c

Child:

1:87d535bf8c53

diff -r 000000000000 -r e8167f37725c LSM9DS1.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LSM9DS1.h	Mon Oct 26 14:55:43 2015 +0000
@@ -0,0 +1,530 @@
+/******************************************************************************
+SFE_LSM9DS1.h
+SFE_LSM9DS1 Library Header File
+Jim Lindblom @ SparkFun Electronics
+Original Creation Date: February 27, 2015
+https://github.com/sparkfun/LSM9DS1_Breakout
+
+This file prototypes the LSM9DS1 class, implemented in SFE_LSM9DS1.cpp. In
+addition, it defines every register in the LSM9DS1 (both the Gyro and Accel/
+Magnetometer registers).
+
+Development environment specifics:
+    IDE: Arduino 1.6.0
+    Hardware Platform: Arduino Uno
+    LSM9DS1 Breakout Version: 1.0
+
+This code is beerware; if you see me (or any other SparkFun employee) at the
+local, and you've found our code helpful, please buy us a round!
+
+Distributed as-is; no warranty is given.
+******************************************************************************/
+#ifndef __SparkFunLSM9DS1_H__
+#define __SparkFunLSM9DS1_H__
+
+//#if defined(ARDUINO) && ARDUINO >= 100
+//  #include "Arduino.h"
+//#else
+//  #include "WProgram.h"
+//  #include "pins_arduino.h"
+//#endif
+
+#include "mbed.h"
+#include <stdint.h>
+#include "LSM9DS1_Registers.h"
+#include "LSM9DS1_Types.h"
+
+#define LSM9DS1_AG_ADDR(sa0)    ((sa0) == 0 ? 0x6A : 0x6B)
+#define LSM9DS1_M_ADDR(sa1)     ((sa1) == 0 ? 0x1C : 0x1E)
+
+enum lsm9ds1_axis {
+    X_AXIS,
+    Y_AXIS,
+    Z_AXIS,
+    ALL_AXIS
+};
+
+class LSM9DS1
+{
+public:
+    IMUSettings settings;
+    
+    // We'll store the gyro, accel, and magnetometer readings in a series of
+    // public class variables. Each sensor gets three variables -- one for each
+    // axis. Call readGyro(), readAccel(), and readMag() first, before using
+    // these variables!
+    // These values are the RAW signed 16-bit readings from the sensors.
+    int16_t gx, gy, gz; // x, y, and z axis readings of the gyroscope
+    int16_t ax, ay, az; // x, y, and z axis readings of the accelerometer
+    int16_t mx, my, mz; // x, y, and z axis readings of the magnetometer
+    int16_t temperature; // Chip temperature
+    float gBias[3], aBias[3], mBias[3];
+    int16_t gBiasRaw[3], aBiasRaw[3], mBiasRaw[3];
+    
+    // LSM9DS1 -- LSM9DS1 class constructor
+    // The constructor will set up a handful of private variables, and set the
+    // communication mode as well.
+    // Input:
+    //  - interface = Either IMU_MODE_SPI or IMU_MODE_I2C, whichever you're using
+    //              to talk to the IC.
+    //  - xgAddr = If IMU_MODE_I2C, this is the I2C address of the accel/gyroscope.
+    //              If IMU_MODE_SPI, this is the chip select pin of the gyro (CS_AG)
+    //  - mAddr = If IMU_MODE_I2C, this is the I2C address of the magnetometer.
+    //              If IMU_MODE_SPI, this is the cs pin of the magnetometer (CS_M)
+    LSM9DS1(PinName sda, PinName scl, uint8_t xgAddr, uint8_t mAddr);
+    LSM9DS1(interface_mode interface, uint8_t xgAddr, uint8_t mAddr);
+    LSM9DS1();
+        
+    // begin() -- Initialize the gyro, accelerometer, and magnetometer.
+    // This will set up the scale and output rate of each sensor. The values set
+    // in the IMUSettings struct will take effect after calling this function.
+    uint16_t begin();
+    
+    void calibrate(bool autoCalc = true);
+    void calibrateMag(bool loadIn = true);
+    void magOffset(uint8_t axis, int16_t offset);
+    
+    // accelAvailable() -- Polls the accelerometer status register to check
+    // if new data is available.
+    // Output:  1 - New data available
+    //          0 - No new data available
+    uint8_t accelAvailable();
+    
+    // gyroAvailable() -- Polls the gyroscope status register to check
+    // if new data is available.
+    // Output:  1 - New data available
+    //          0 - No new data available
+    uint8_t gyroAvailable();
+    
+    // gyroAvailable() -- Polls the temperature status register to check
+    // if new data is available.
+    // Output:  1 - New data available
+    //          0 - No new data available
+    uint8_t tempAvailable();
+    
+    // magAvailable() -- Polls the accelerometer status register to check
+    // if new data is available.
+    // Input:
+    //  - axis can be either X_AXIS, Y_AXIS, Z_AXIS, to check for new data
+    //    on one specific axis. Or ALL_AXIS (default) to check for new data
+    //    on all axes.
+    // Output:  1 - New data available
+    //          0 - No new data available
+    uint8_t magAvailable(lsm9ds1_axis axis = ALL_AXIS);
+    
+    // readGyro() -- Read the gyroscope output registers.
+    // This function will read all six gyroscope output registers.
+    // The readings are stored in the class' gx, gy, and gz variables. Read
+    // those _after_ calling readGyro().
+    void readGyro();
+    
+    // int16_t readGyro(axis) -- Read a specific axis of the gyroscope.
+    // [axis] can be any of X_AXIS, Y_AXIS, or Z_AXIS.
+    // Input:
+    //  - axis: can be either X_AXIS, Y_AXIS, or Z_AXIS.
+    // Output:
+    //  A 16-bit signed integer with sensor data on requested axis.
+    int16_t readGyro(lsm9ds1_axis axis);
+    
+    // readAccel() -- Read the accelerometer output registers.
+    // This function will read all six accelerometer output registers.
+    // The readings are stored in the class' ax, ay, and az variables. Read
+    // those _after_ calling readAccel().
+    void readAccel();
+    
+    // int16_t readAccel(axis) -- Read a specific axis of the accelerometer.
+    // [axis] can be any of X_AXIS, Y_AXIS, or Z_AXIS.
+    // Input:
+    //  - axis: can be either X_AXIS, Y_AXIS, or Z_AXIS.
+    // Output:
+    //  A 16-bit signed integer with sensor data on requested axis.
+    int16_t readAccel(lsm9ds1_axis axis);
+    
+    // readMag() -- Read the magnetometer output registers.
+    // This function will read all six magnetometer output registers.
+    // The readings are stored in the class' mx, my, and mz variables. Read
+    // those _after_ calling readMag().
+    void readMag();
+    
+    // int16_t readMag(axis) -- Read a specific axis of the magnetometer.
+    // [axis] can be any of X_AXIS, Y_AXIS, or Z_AXIS.
+    // Input:
+    //  - axis: can be either X_AXIS, Y_AXIS, or Z_AXIS.
+    // Output:
+    //  A 16-bit signed integer with sensor data on requested axis.
+    int16_t readMag(lsm9ds1_axis axis);
+
+    // readTemp() -- Read the temperature output register.
+    // This function will read two temperature output registers.
+    // The combined readings are stored in the class' temperature variables. Read
+    // those _after_ calling readTemp().
+    void readTemp();
+    
+    // calcGyro() -- Convert from RAW signed 16-bit value to degrees per second
+    // This function reads in a signed 16-bit value and returns the scaled
+    // DPS. This function relies on gScale and gRes being correct.
+    // Input:
+    //  - gyro = A signed 16-bit raw reading from the gyroscope.
+    float calcGyro(int16_t gyro);
+    
+    // calcAccel() -- Convert from RAW signed 16-bit value to gravity (g's).
+    // This function reads in a signed 16-bit value and returns the scaled
+    // g's. This function relies on aScale and aRes being correct.
+    // Input:
+    //  - accel = A signed 16-bit raw reading from the accelerometer.
+    float calcAccel(int16_t accel);
+    
+    // calcMag() -- Convert from RAW signed 16-bit value to Gauss (Gs)
+    // This function reads in a signed 16-bit value and returns the scaled
+    // Gs. This function relies on mScale and mRes being correct.
+    // Input:
+    //  - mag = A signed 16-bit raw reading from the magnetometer.
+    float calcMag(int16_t mag);
+    
+    // setGyroScale() -- Set the full-scale range of the gyroscope.
+    // This function can be called to set the scale of the gyroscope to 
+    // 245, 500, or 200 degrees per second.
+    // Input:
+    //  - gScl = The desired gyroscope scale. Must be one of three possible
+    //      values from the gyro_scale.
+    void setGyroScale(uint16_t gScl);
+    
+    // setAccelScale() -- Set the full-scale range of the accelerometer.
+    // This function can be called to set the scale of the accelerometer to
+    // 2, 4, 6, 8, or 16 g's.
+    // Input:
+    //  - aScl = The desired accelerometer scale. Must be one of five possible
+    //      values from the accel_scale.
+    void setAccelScale(uint8_t aScl);
+    
+    // setMagScale() -- Set the full-scale range of the magnetometer.
+    // This function can be called to set the scale of the magnetometer to
+    // 2, 4, 8, or 12 Gs.
+    // Input:
+    //  - mScl = The desired magnetometer scale. Must be one of four possible
+    //      values from the mag_scale.
+    void setMagScale(uint8_t mScl);
+    
+    // setGyroODR() -- Set the output data rate and bandwidth of the gyroscope
+    // Input:
+    //  - gRate = The desired output rate and cutoff frequency of the gyro.
+    void setGyroODR(uint8_t gRate);
+    
+    // setAccelODR() -- Set the output data rate of the accelerometer
+    // Input:
+    //  - aRate = The desired output rate of the accel.
+    void setAccelODR(uint8_t aRate);    
+    
+    // setMagODR() -- Set the output data rate of the magnetometer
+    // Input:
+    //  - mRate = The desired output rate of the mag.
+    void setMagODR(uint8_t mRate);
+    
+    // configInactivity() -- Configure inactivity interrupt parameters
+    // Input:
+    //  - duration = Inactivity duration - actual value depends on gyro ODR
+    //  - threshold = Activity Threshold
+    //  - sleepOn = Gyroscope operating mode during inactivity.
+    //    true: gyroscope in sleep mode
+    //    false: gyroscope in power-down
+    void configInactivity(uint8_t duration, uint8_t threshold, bool sleepOn);
+    
+    // configAccelInt() -- Configure Accelerometer Interrupt Generator
+    // Input:
+    //  - generator = Interrupt axis/high-low events
+    //    Any OR'd combination of ZHIE_XL, ZLIE_XL, YHIE_XL, YLIE_XL, XHIE_XL, XLIE_XL
+    //  - andInterrupts = AND/OR combination of interrupt events
+    //    true: AND combination
+    //    false: OR combination
+    void configAccelInt(uint8_t generator, bool andInterrupts = false);
+    
+    // configAccelThs() -- Configure the threshold of an accelereomter axis
+    // Input:
+    //  - threshold = Interrupt threshold. Possible values: 0-255.
+    //    Multiply by 128 to get the actual raw accel value.
+    //  - axis = Axis to be configured. Either X_AXIS, Y_AXIS, or Z_AXIS
+    //  - duration = Duration value must be above or below threshold to trigger interrupt
+    //  - wait = Wait function on duration counter
+    //    true: Wait for duration samples before exiting interrupt
+    //    false: Wait function off
+    void configAccelThs(uint8_t threshold, lsm9ds1_axis axis, uint8_t duration = 0, bool wait = 0);
+    
+    // configGyroInt() -- Configure Gyroscope Interrupt Generator
+    // Input:
+    //  - generator = Interrupt axis/high-low events
+    //    Any OR'd combination of ZHIE_G, ZLIE_G, YHIE_G, YLIE_G, XHIE_G, XLIE_G
+    //  - aoi = AND/OR combination of interrupt events
+    //    true: AND combination
+    //    false: OR combination
+    //  - latch: latch gyroscope interrupt request.
+    void configGyroInt(uint8_t generator, bool aoi, bool latch);
+    
+    // configGyroThs() -- Configure the threshold of a gyroscope axis
+    // Input:
+    //  - threshold = Interrupt threshold. Possible values: 0-0x7FF.
+    //    Value is equivalent to raw gyroscope value.
+    //  - axis = Axis to be configured. Either X_AXIS, Y_AXIS, or Z_AXIS
+    //  - duration = Duration value must be above or below threshold to trigger interrupt
+    //  - wait = Wait function on duration counter
+    //    true: Wait for duration samples before exiting interrupt
+    //    false: Wait function off
+    void configGyroThs(int16_t threshold, lsm9ds1_axis axis, uint8_t duration, bool wait);
+    
+    // configInt() -- Configure INT1 or INT2 (Gyro and Accel Interrupts only)
+    // Input:
+    //  - interrupt = Select INT1 or INT2
+    //    Possible values: XG_INT1 or XG_INT2
+    //  - generator = Or'd combination of interrupt generators.
+    //    Possible values: INT_DRDY_XL, INT_DRDY_G, INT1_BOOT (INT1 only), INT2_DRDY_TEMP (INT2 only)
+    //    INT_FTH, INT_OVR, INT_FSS5, INT_IG_XL (INT1 only), INT1_IG_G (INT1 only), INT2_INACT (INT2 only)
+    //  - activeLow = Interrupt active configuration
+    //    Can be either INT_ACTIVE_HIGH or INT_ACTIVE_LOW
+    //  - pushPull =  Push-pull or open drain interrupt configuration
+    //    Can be either INT_PUSH_PULL or INT_OPEN_DRAIN
+    void configInt(interrupt_select interupt, uint8_t generator,
+                   h_lactive activeLow = INT_ACTIVE_LOW, pp_od pushPull = INT_PUSH_PULL);
+                   
+    // configMagInt() -- Configure Magnetometer Interrupt Generator
+    // Input:
+    //  - generator = Interrupt axis/high-low events
+    //    Any OR'd combination of ZIEN, YIEN, XIEN
+    //  - activeLow = Interrupt active configuration
+    //    Can be either INT_ACTIVE_HIGH or INT_ACTIVE_LOW
+    //  - latch: latch gyroscope interrupt request.
+    void configMagInt(uint8_t generator, h_lactive activeLow, bool latch = true);
+    
+    // configMagThs() -- Configure the threshold of a gyroscope axis
+    // Input:
+    //  - threshold = Interrupt threshold. Possible values: 0-0x7FF.
+    //    Value is equivalent to raw magnetometer value.
+    void configMagThs(uint16_t threshold);
+    
+    // getGyroIntSrc() -- Get contents of Gyroscope interrupt source register
+    uint8_t getGyroIntSrc();
+    
+    // getGyroIntSrc() -- Get contents of accelerometer interrupt source register
+    uint8_t getAccelIntSrc();
+    
+    // getGyroIntSrc() -- Get contents of magnetometer interrupt source register
+    uint8_t getMagIntSrc();
+    
+    // getGyroIntSrc() -- Get status of inactivity interrupt
+    uint8_t getInactivity();
+    
+    // sleepGyro() -- Sleep or wake the gyroscope
+    // Input:
+    //  - enable: True = sleep gyro. False = wake gyro.
+    void sleepGyro(bool enable = true);
+    
+    // enableFIFO() - Enable or disable the FIFO
+    // Input:
+    //  - enable: true = enable, false = disable.
+    void enableFIFO(bool enable = true);
+    
+    // setFIFO() - Configure FIFO mode and Threshold
+    // Input:
+    //  - fifoMode: Set FIFO mode to off, FIFO (stop when full), continuous, bypass
+    //    Possible inputs: FIFO_OFF, FIFO_THS, FIFO_CONT_TRIGGER, FIFO_OFF_TRIGGER, FIFO_CONT
+    //  - fifoThs: FIFO threshold level setting
+    //    Any value from 0-0x1F is acceptable.
+    void setFIFO(fifoMode_type fifoMode, uint8_t fifoThs);
+    
+    // getFIFOSamples() - Get number of FIFO samples
+    uint8_t getFIFOSamples();
+        
+
+protected:  
+    // x_mAddress and gAddress store the I2C address or SPI chip select pin
+    // for each sensor.
+    uint8_t _mAddress, _xgAddress;
+    
+    // gRes, aRes, and mRes store the current resolution for each sensor. 
+    // Units of these values would be DPS (or g's or Gs's) per ADC tick.
+    // This value is calculated as (sensor scale) / (2^15).
+    float gRes, aRes, mRes;
+    
+    // _autoCalc keeps track of whether we're automatically subtracting off
+    // accelerometer and gyroscope bias calculated in calibrate().
+    bool _autoCalc;
+    
+    // init() -- Sets up gyro, accel, and mag settings to default.
+    // - interface - Sets the interface mode (IMU_MODE_I2C or IMU_MODE_SPI)
+    // - xgAddr - Sets either the I2C address of the accel/gyro or SPI chip 
+    //   select pin connected to the CS_XG pin.
+    // - mAddr - Sets either the I2C address of the magnetometer or SPI chip 
+    //   select pin connected to the CS_M pin.
+    void init(interface_mode interface, uint8_t xgAddr, uint8_t mAddr);
+    
+    // initGyro() -- Sets up the gyroscope to begin reading.
+    // This function steps through all five gyroscope control registers.
+    // Upon exit, the following parameters will be set:
+    //  - CTRL_REG1_G = 0x0F: Normal operation mode, all axes enabled. 
+    //      95 Hz ODR, 12.5 Hz cutoff frequency.
+    //  - CTRL_REG2_G = 0x00: HPF set to normal mode, cutoff frequency
+    //      set to 7.2 Hz (depends on ODR).
+    //  - CTRL_REG3_G = 0x88: Interrupt enabled on INT_G (set to push-pull and
+    //      active high). Data-ready output enabled on DRDY_G.
+    //  - CTRL_REG4_G = 0x00: Continuous update mode. Data LSB stored in lower
+    //      address. Scale set to 245 DPS. SPI mode set to 4-wire.
+    //  - CTRL_REG5_G = 0x00: FIFO disabled. HPF disabled.
+    void initGyro();
+    
+    // initAccel() -- Sets up the accelerometer to begin reading.
+    // This function steps through all accelerometer related control registers.
+    // Upon exit these registers will be set as:
+    //  - CTRL_REG0_XM = 0x00: FIFO disabled. HPF bypassed. Normal mode.
+    //  - CTRL_REG1_XM = 0x57: 100 Hz data rate. Continuous update.
+    //      all axes enabled.
+    //  - CTRL_REG2_XM = 0x00:  2g scale. 773 Hz anti-alias filter BW.
+    //  - CTRL_REG3_XM = 0x04: Accel data ready signal on INT1_XM pin.
+    void initAccel();
+    
+    // initMag() -- Sets up the magnetometer to begin reading.
+    // This function steps through all magnetometer-related control registers.
+    // Upon exit these registers will be set as:
+    //  - CTRL_REG4_XM = 0x04: Mag data ready signal on INT2_XM pin.
+    //  - CTRL_REG5_XM = 0x14: 100 Hz update rate. Low resolution. Interrupt
+    //      requests don't latch. Temperature sensor disabled.
+    //  - CTRL_REG6_XM = 0x00:  2 Gs scale.
+    //  - CTRL_REG7_XM = 0x00: Continuous conversion mode. Normal HPF mode.
+    //  - INT_CTRL_REG_M = 0x09: Interrupt active-high. Enable interrupts.
+    void initMag();
+    
+    // gReadByte() -- Reads a byte from a specified gyroscope register.
+    // Input:
+    //  - subAddress = Register to be read from.
+    // Output:
+    //  - An 8-bit value read from the requested address.
+    uint8_t mReadByte(uint8_t subAddress);
+    
+    // gReadBytes() -- Reads a number of bytes -- beginning at an address
+    // and incrementing from there -- from the gyroscope.
+    // Input:
+    //  - subAddress = Register to be read from.
+    //  - * dest = A pointer to an array of uint8_t's. Values read will be
+    //      stored in here on return.
+    //  - count = The number of bytes to be read.
+    // Output: No value is returned, but the `dest` array will store
+    //  the data read upon exit.
+    void mReadBytes(uint8_t subAddress, uint8_t * dest, uint8_t count);
+    
+    // gWriteByte() -- Write a byte to a register in the gyroscope.
+    // Input:
+    //  - subAddress = Register to be written to.
+    //  - data = data to be written to the register.
+    void mWriteByte(uint8_t subAddress, uint8_t data);
+    
+    // xmReadByte() -- Read a byte from a register in the accel/mag sensor
+    // Input:
+    //  - subAddress = Register to be read from.
+    // Output:
+    //  - An 8-bit value read from the requested register.
+    uint8_t xgReadByte(uint8_t subAddress);
+    
+    // xmReadBytes() -- Reads a number of bytes -- beginning at an address
+    // and incrementing from there -- from the accelerometer/magnetometer.
+    // Input:
+    //  - subAddress = Register to be read from.
+    //  - * dest = A pointer to an array of uint8_t's. Values read will be
+    //      stored in here on return.
+    //  - count = The number of bytes to be read.
+    // Output: No value is returned, but the `dest` array will store
+    //  the data read upon exit.
+    void xgReadBytes(uint8_t subAddress, uint8_t * dest, uint8_t count);
+    
+    // xmWriteByte() -- Write a byte to a register in the accel/mag sensor.
+    // Input:
+    //  - subAddress = Register to be written to.
+    //  - data = data to be written to the register.
+    void xgWriteByte(uint8_t subAddress, uint8_t data);
+    
+    // calcgRes() -- Calculate the resolution of the gyroscope.
+    // This function will set the value of the gRes variable. gScale must
+    // be set prior to calling this function.
+    void calcgRes();
+    
+    // calcmRes() -- Calculate the resolution of the magnetometer.
+    // This function will set the value of the mRes variable. mScale must
+    // be set prior to calling this function.
+    void calcmRes();
+    
+    // calcaRes() -- Calculate the resolution of the accelerometer.
+    // This function will set the value of the aRes variable. aScale must
+    // be set prior to calling this function.
+    void calcaRes();
+    
+    //////////////////////
+    // Helper Functions //
+    //////////////////////
+    void constrainScales();
+    
+    ///////////////////
+    // SPI Functions //
+    ///////////////////
+    // initSPI() -- Initialize the SPI hardware.
+    // This function will setup all SPI pins and related hardware.
+    void initSPI();
+    
+    // SPIwriteByte() -- Write a byte out of SPI to a register in the device
+    // Input:
+    //  - csPin = The chip select pin of the slave device.
+    //  - subAddress = The register to be written to.
+    //  - data = Byte to be written to the register.
+    void SPIwriteByte(uint8_t csPin, uint8_t subAddress, uint8_t data);
+    
+    // SPIreadByte() -- Read a single byte from a register over SPI.
+    // Input:
+    //  - csPin = The chip select pin of the slave device.
+    //  - subAddress = The register to be read from.
+    // Output:
+    //  - The byte read from the requested address.
+    uint8_t SPIreadByte(uint8_t csPin, uint8_t subAddress);
+    
+    // SPIreadBytes() -- Read a series of bytes, starting at a register via SPI
+    // Input:
+    //  - csPin = The chip select pin of a slave device.
+    //  - subAddress = The register to begin reading.
+    //  - * dest = Pointer to an array where we'll store the readings.
+    //  - count = Number of registers to be read.
+    // Output: No value is returned by the function, but the registers read are
+    //      all stored in the *dest array given.
+    void SPIreadBytes(uint8_t csPin, uint8_t subAddress, 
+                            uint8_t * dest, uint8_t count);
+    
+    ///////////////////
+    // I2C Functions //
+    ///////////////////
+    // initI2C() -- Initialize the I2C hardware.
+    // This function will setup all I2C pins and related hardware.
+    void initI2C();
+    
+    // I2CwriteByte() -- Write a byte out of I2C to a register in the device
+    // Input:
+    //  - address = The 7-bit I2C address of the slave device.
+    //  - subAddress = The register to be written to.
+    //  - data = Byte to be written to the register.
+    void I2CwriteByte(uint8_t address, uint8_t subAddress, uint8_t data);
+    
+    // I2CreadByte() -- Read a single byte from a register over I2C.
+    // Input:
+    //  - address = The 7-bit I2C address of the slave device.
+    //  - subAddress = The register to be read from.
+    // Output:
+    //  - The byte read from the requested address.
+    uint8_t I2CreadByte(uint8_t address, uint8_t subAddress);
+    
+    // I2CreadBytes() -- Read a series of bytes, starting at a register via SPI
+    // Input:
+    //  - address = The 7-bit I2C address of the slave device.
+    //  - subAddress = The register to begin reading.
+    //  - * dest = Pointer to an array where we'll store the readings.
+    //  - count = Number of registers to be read.
+    // Output: No value is returned by the function, but the registers read are
+    //      all stored in the *dest array given.
+    uint8_t I2CreadBytes(uint8_t address, uint8_t subAddress, uint8_t * dest, uint8_t count);
+    
+private:
+    I2C i2c;
+};
+
+#endif // SFE_LSM9DS1_H //