File content as of revision 0:f677e13975d0:

/*
 * This is USC RPL's ARM MBed BNO080 IMU driver, by Jamie Smith.
 *
 * It is based on SparkFun and Nathan Seidle's Arduino driver for this chip, but is substantially rewritten and adapted.
 * It also supports some extra features, such as setting the mounting orientation and
 * enabling some additional data reports.
 *
 * This driver uses no dynamic allocation, but does allocate a couple hundred bytes of class variables as buffers.
 * This should allow you to monitor its memory usage using MBed's size printout.
 *
 * The BNO080 is a very complex chip; it's capable of monitoring and controlling other sensors and making
 * intelligent decisions and calculations using its data.  Accordingly, the protocol for communicating with it
 * is quite complex, and it took me quite a while to wrap my head around it.  If you need to modify or debug
 * this driver, look at the CPP file for an overview of the chip's communication protocol.
 *
 * Note: this driver only supports I2C.  I attempted to create an SPI version, but as far as I can tell,
 * the BNO's SPI interface has a bug that causes you to be unable to wake the chip from sleep in some conditions.
 * Until this is fixed, SPI on it is virtually unusable.
 */

#ifndef HAMSTER_BNO080_H
#define HAMSTER_BNO080_H

#include <mbed.h>
#include <quaternion.h>

#include "BNO080Constants.h"

class BNO080
{
    /**
     * Serial stream to print debug info to.  Used for errors, and debugging output if debugging is enabled.
     */
    Serial * _debugPort;

    /**
     * I2C port object
     */
    I2C _i2cPort;

    /// user defined port speed
    int  _i2cPortSpeed;

    /// i2c address of IMU (7 bits)
    uint8_t _i2cAddress;

    DigitalIn _int;
    DigitalOut _rst;

    DigitalOut _scope;

    // packet storage
    //-----------------------------------------------------------------------------------------------------------------

#define SHTP_HEADER_SIZE 4
#define STORED_PACKET_SIZE 128

    /// Each packet has a header of 4 uint8_ts
    uint8_t shtpHeader[SHTP_HEADER_SIZE];

    /// Stores data contained in each packet.  Packets can contain an arbitrary amount of data, but we shouldn't need to read more than a few hundred bytes of them.
    /// The only long packets we actually care about are batched sensor data packets, and with how this driver handles batching, we *should* only have to deal
    /// with at most 9 reports at a time = ~90 bytes + a few bytes of padding
    uint8_t shtpData[STORED_PACKET_SIZE];

    /// Length of packet that was received into buffer.  Does NOT include header bytes.
    uint16_t packetLength;

    /// There are 6 com channels. Each channel has its own seqnum
    uint8_t sequenceNumber[6] = {0, 0, 0, 0, 0, 0};

    /// Commands have a seqNum as well. These are inside command packet, the header uses its own seqNum per channel
    uint8_t commandSequenceNumber = 0;

    // data storage
    //-----------------------------------------------------------------------------------------------------------------

    // 1 larger than the largest sensor report ID
#define STATUS_ARRAY_LEN 0x1A

    /// stores status of each sensor, indexed by report ID
    uint8_t reportStatus[STATUS_ARRAY_LEN] = {};

public:

    /// List of all sensor reports that the IMU supports.
    enum class Report : uint8_t
    {
        /**
         * Total acceleration of the IMU in world space.
         * See BNO datasheet section 2.1.1
         */
        TOTAL_ACCELERATION = SENSOR_REPORTID_ACCELEROMETER,

        /**
         * Acceleration of the IMU not including the acceleration of gravity.
         * See BNO datasheet section 2.1.1
         */
        LINEAR_ACCELERATION = SENSOR_REPORTID_LINEAR_ACCELERATION,

        /**
         * Acceleration of gravity felt by the IMU.
         * See BNO datasheet section 2.1.1
         */
        GRAVITY_ACCELERATION = SENSOR_REPORTID_GRAVITY,

        /**
         * (calibrated) gyroscope reading of the rotational speed of the IMU.
         * See BNO datasheet section 2.1.2
         */
        GYROSCOPE = SENSOR_REPORTID_GYROSCOPE_CALIBRATED,

        /**
         * (calibrated) reading of magnetic field levels.
         * See BNO datasheet section 2.1.3
         */
        MAG_FIELD = SENSOR_REPORTID_MAGNETIC_FIELD_CALIBRATED,

        /**
         * Fused reading of the IMU's rotation in space using all three sensors.  This is the most accurate reading
         * of absolute orientation that the IMU can provide.
         * See BNO datasheet section 2.2.4
         */
        ROTATION = SENSOR_REPORTID_ROTATION_VECTOR,

        /**
         * Fused reading of rotation from accelerometer and magnetometer readings.  This report is designed to decrease
         * power consumption (by turning off the gyroscope) in exchange for reduced responsiveness.
         */
        GEOMAGNETIC_ROTATION = SENSOR_REPORTID_GEOMAGNETIC_ROTATION_VECTOR,

        /**
         * Fused reading of the IMU's rotation in space.  Unlike the regular rotation vector, the Game Rotation Vector
         * is not referenced against the magnetic field and the "zero yaw" point is arbitrary.
         * See BNO datasheet section 2.2.2
         */
        GAME_ROTATION = SENSOR_REPORTID_GAME_ROTATION_VECTOR,

        /**
         * Detects a user tapping on the device containing the IMU.
         * See BNO datasheet section 2.4.2
         */
        TAP_DETECTOR = SENSOR_REPORTID_TAP_DETECTOR,

        /**
         * Detects whether the device is on a table, being held stably, or being moved.
         * See BNO datasheet section 2.4.1
         */
        STABILITY_CLASSIFIER = SENSOR_REPORTID_STABILITY_CLASSIFIER,

        /**
         * Detects a user taking a step with the IMU worn on their person.
         * See BNO datasheet section 2.4.3
         */
        STEP_DETECTOR = SENSOR_REPORTID_STEP_DETECTOR,

        /**
         * Detects how many steps a user has taken.
         * See BNO datasheet section 2.4.4
         */
        STEP_COUNTER = SENSOR_REPORTID_STEP_COUNTER,

        /**
         * Detects when the IMU has made a "significant" motion, defined as moving a few steps and/or accelerating significantly.
         * See BNO datasheet section 2.4.6
         */
        SIGNIFICANT_MOTION = SENSOR_REPORTID_SIGNIFICANT_MOTION,

        /**
         * Detects when the IMU is being shaken.
         * See BNO datasheet section 2.4.7
         */
        SHAKE_DETECTOR = SENSOR_REPORTID_SHAKE_DETECTOR
    };

    // data variables to read reports from
    //-----------------------------------------------------------------------------------------------------------------

    // @{
    /// Version info read from the IMU when it starts up
    uint8_t majorSoftwareVersion;
    uint8_t minorSoftwareVersion;
    uint16_t patchSoftwareVersion;
    uint32_t partNumber;
    uint32_t buildNumber;
    // @}


    /**
     * Readout from Accleration report.
     * Represents total acceleration in m/s^2 felt by the BNO's accelerometer.
     */
    TVector3 totalAcceleration;

    /**
     * Readout from Linear Acceleration report.
     * Represents acceleration felt in m/s^2 by the BNO's accelerometer not including the force of gravity.
     */
    TVector3 linearAcceleration;

    /**
     * Readout from Gravity report.
     * Represents the force of gravity in m/s^2 felt by the BNO's accelerometer.
     */
    TVector3 gravityAcceleration;

    /**
     * Readout from Calibrated Gyroscope report
     * Represents the angular velocities of the chip in rad/s in the X, Y, and Z axes
     */
    TVector3 gyroRotation;

    /**
     * Readout from the Magnetic Field Calibrated report.
     * Represents the magnetic field read by the chip in uT in the X, Y, and Z axes
     */
    TVector3 magField;

    /**
     * Readout from the Rotation Vector report.
     * Represents the rotation of the IMU (relative to magnetic north) in radians.
     */
    Quaternion rotationVector;

    /**
     * Auxillary accuracy readout from the Rotation Vector report.
     * Represents the estimated accuracy of the rotation vector in radians.
     */
    float rotationAccuracy;

    /**
     * Readout from the Game Rotation Vector report.
     * Represents the rotation of the IMU in radians.  Unlike the regular rotation vector, the Game Rotation Vector
     * is not referenced against the magnetic field and the "zero yaw" point is arbitrary.
     */
    Quaternion gameRotationVector;

    /**
     * Readout from the Geomagnetic Rotation Vector report.
     * Represents the geomagnetic rotation of the IMU (relative to magnetic north) in radians.
     */
    Quaternion geomagneticRotationVector;

    /**
     * Auxillary accuracy readout from the Geomagnetic Rotation Vector report.
     * Represents the estimated accuracy of the rotation vector in radians.
     */
    float geomagneticRotationAccuracy;

    /**
     * Tap readout from the Tap Detector report.  This flag is set to true whenever a tap is detected, and you should
     * manually clear it when you have processed the tap.
     */
    bool tapDetected;

    /**
     * Whether the last tap detected was a single or double tap.
     */
    bool doubleTap;


    // Management functions
    //-----------------------------------------------------------------------------------------------------------------

    /**
     * Construct a BNO080, providing pins and parameters.
     *
     * NOTE: while some schematics tell you to connect the BOOTN and WAKEN pins to the processor, this driver does not use or require them.
     * Just tie them both to VCC per the datasheet.
     *
     * @param debugPort Serial port to write output to.  Cannot be nullptr.
     * @param user_SDApin Hardware SPI MOSI pin
     * @param user_SCLpin Hardware SPI MISO pin
     * @param user_SCLKPin Hardware SPI SCLK pin
     * @param user_CSPin SPI CS pin.  Can be any IO pin, no restrictions.
     * @param user_INTPin Input pin connected to HINTN
     * @param user_RSTPin Output pin connected to NRST
     * @param i2cPortSpeed SPI frequency.  The BNO's max is 3Mhz, we default to 300Khz for safety.
     */
    BNO080(Serial *debugPort, PinName user_SDApin, PinName user_SCLpin, PinName user_INTPin, PinName user_RSTPin,
           uint8_t i2cAddress=0x4a, int i2cPortSpeed=400000);

    /**
     * Resets and connects to the IMU.
     *
     * If this function is failing, it would be a good idea to turn on BNO_DEBUG in the cpp file to get detailed output
     *
     * @return whether or not initialization was successful
     */
    bool begin();

    /**
     * Tells the IMU to use its current rotation vector as the "zero" rotation vector and to reorient
     * all outputs accordingly.
     *
     * @param zOnly If true, only the rotation about the Z axis (the heading) will be tared.
     */
    void tare(bool zOnly = false);

    /**
     * Tells the IMU to begin a dynamic sensor calibration.  To calibrate the IMU, call this function and move
     * the IMU according to the instructions in the "BNO080 Sensor Calibration Procedure" app note
     * (http://www.hillcrestlabs.com/download/59de9014566d0727bd002ae7).
     *
     * To tell when the calibration is complete, look at the status bits for Game Rotation Vector (for accel and gyro)
     * and Magnetic Field (for the magnetometer).
     *
     * The gyro and accelerometer should only need to be calibrated once, but the magnetometer will need to be recalibrated
     * every time the orientation of ferrous metals around the IMU changes (e.g. when it is put into a new enclosure).
     *
     * The new calibration will not be saved in flash until you call saveCalibration().
     *
     * @param calibrateAccel Whether to calibrate the accelerometer.
     * @param calibrateGyro Whether to calibrate the gyro.
     * @param calibrateMag Whether to calibrate the magnetometer.
     */
    void startCalibration(bool calibrateAccel, bool calibrateGyro, bool calibrateMag);

    /**
     * Saves the calibration started with startCalibration() and ends the calibration.
     * You will want to call this once the status bits read as "accuracy high".
     *
     * WARNING: if you paid for a factory calibrated IMU, then this WILL OVERWRITE THE FACTORY CALIBRATION in whatever sensors
     * are being calibrated.  Use with caution!
     */
    void saveCalibration();

    // Report functions
    //-----------------------------------------------------------------------------------------------------------------

    /**
     * Checks for new data packets queued on the IMU.
     * If there are packets queued, receives all of them and updates
     * the class variables with the results.
     *
     * @return true iff new data was received
     */
    bool updateData();


    /**
     * Gets the status of a report as a 2 bit number.
     * per SH-2 section 6.5.1, this is interpreted as: <br>
     * 0 - unreliable <br>
     * 1 - accuracy low <br>
     * 2 - accuracy medium <br>
     * 3 - accuracy high <br>
     * of course, these are only updated if a given report is enabled.
     * @param report
     * @return
     */
    uint8_t getReportStatus(Report report);


    /**
     * Enable a data report from the IMU.  Look at the comments above to see what the reports do.
     *
     * @param timeBetweenReports time in milliseconds between data updates.
     */
    void enableReport(Report report, uint16_t timeBetweenReports);

private:

    // internal utility functions
    //-----------------------------------------------------------------------------------------------------------------

    /**
     * Processes the packet currently stored in the buffer, and updates class variables to reflect the data it contains
     */
    void processPacket();

    /**
     * Processes the sensor data packet currently stored in the buffer.
     * Only called from processPacket()
     */
    void parseSensorDataPacket();

    /**
     * Call to wait for a packet with the given parameters to come in.
     *
     * @param channel Channel of the packet
     * @param reportID Report ID (first data byte) of the packet
     * @param timeout how long to wait for the packet
     * @return true if the packet has been received, false if it timed out
     */
    bool waitForPacket(int channel, uint8_t reportID, float timeout = .125f);

    /**
     * Given a Q value, converts fixed point floating to regular floating point number.
     * @param fixedPointValue
     * @param qPoint
     * @return
     */
    float qToFloat(int16_t fixedPointValue, uint8_t qPoint);

    /**
     * Given a floating point value and a Q point, convert to Q
     * See https://en.wikipedia.org/wiki/Q_(number_format)
     * @param qFloat
     * @param qPoint
     * @return
     */
    int16_t floatToQ(float qFloat, uint8_t qPoint);

    /**
     *  Tell the sensor to do a command.
     *  See SH-2 Reference Manual section 6.3.8 page 42, Command request
     *  The caller is expected to set shtpData 3 though 11 prior to calling
     */
    void sendCommand(uint8_t command);

    /**
     * Given a sensor's report ID, this tells the BNO080 to begin reporting the values.
     *
     * @param reportID
     * @param timeBetweenReports
     * @param specificConfig the specific config word. Useful for personal activity classifier.
     */
    void setFeatureCommand(uint8_t reportID, uint16_t timeBetweenReports, uint32_t specificConfig = 0);

    /**
     * Reads a packet from the IMU and stores it in the class variables.
     *
     * @param timeout how long to wait for there to be a packet
     *
     * @return whether a packet was recieved.
     */
    bool receivePacket(float timeout=.2f);

    /**
     * Sends the current shtpData contents to the BNO.  It's a good idea to disable interrupts before you call this.
     *
     * @param channelNumber the channel to send on
     * @param dataLength How many bits of shtpData to send
     * @return
     */
    bool sendPacket(uint8_t channelNumber, uint8_t dataLength);

    /**
     * Prints the current shtp packet stored in the buffer.
     * @param length
     */
    void printPacket();

    /**
     * Erases the current SHTP packet buffer so new data can be written
     */
     void zeroBuffer();

};


#endif //HAMSTER_BNO080_H