BNO080 Driver

Diff: BNO080.h

Revision:

0:f677e13975d0

Child:

1:aac28ffd63ed

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+++ b/BNO080.h	Sun Dec 23 05:23:21 2018 +0000
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+/*
+ * 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