263 lines
7.2 KiB
C++
263 lines
7.2 KiB
C++
#ifndef MICROBIT_COMPASS_H
|
|
#define MICROBIT_COMPASS_H
|
|
|
|
#include "mbed.h"
|
|
|
|
/**
|
|
* Relevant pin assignments
|
|
*/
|
|
#define MICROBIT_PIN_COMPASS_DATA_READY P0_29
|
|
|
|
/*
|
|
* I2C constants
|
|
*/
|
|
#define MAG3110_DEFAULT_ADDR 0x1D
|
|
|
|
/*
|
|
* MAG3110 Register map
|
|
*/
|
|
#define MAG_DR_STATUS 0x00
|
|
#define MAG_OUT_X_MSB 0x01
|
|
#define MAG_OUT_X_LSB 0x02
|
|
#define MAG_OUT_Y_MSB 0x03
|
|
#define MAG_OUT_Y_LSB 0x04
|
|
#define MAG_OUT_Z_MSB 0x05
|
|
#define MAG_OUT_Z_LSB 0x06
|
|
#define MAG_WHOAMI 0x07
|
|
#define MAG_SYSMOD 0x08
|
|
#define MAG_OFF_X_MSB 0x09
|
|
#define MAG_OFF_X_LSB 0x0A
|
|
#define MAG_OFF_Y_MSB 0x0B
|
|
#define MAG_OFF_Y_LSB 0x0C
|
|
#define MAG_OFF_Z_MSB 0x0D
|
|
#define MAG_OFF_Z_LSB 0x0E
|
|
#define MAG_DIE_TEMP 0x0F
|
|
#define MAG_CTRL_REG1 0x10
|
|
#define MAG_CTRL_REG2 0x11
|
|
|
|
/*
|
|
* Compass events
|
|
*/
|
|
#define MICROBIT_COMPASS_EVT_CAL_REQUIRED 1
|
|
#define MICROBIT_COMPASS_EVT_CAL_START 2
|
|
#define MICROBIT_COMPASS_EVT_CAL_END 3
|
|
|
|
/*
|
|
* Status Bits
|
|
*/
|
|
#define MICROBIT_COMPASS_STATUS_CALIBRATED 1
|
|
#define MICROBIT_COMPASS_STATUS_CALIBRATING 2
|
|
|
|
|
|
#define MICROBIT_COMPASS_CALIBRATE_PERIOD 10000
|
|
|
|
/*
|
|
* MAG3110 MAGIC ID value
|
|
* Returned from the MAG_WHO_AM_I register for ID purposes.
|
|
*/
|
|
#define MAG3110_WHOAMI_VAL 0xC4
|
|
|
|
struct CompassSample
|
|
{
|
|
int16_t x;
|
|
int16_t y;
|
|
int16_t z;
|
|
|
|
CompassSample()
|
|
{
|
|
this->x = 0;
|
|
this->y = 0;
|
|
this->z = 0;
|
|
}
|
|
};
|
|
|
|
/**
|
|
* Class definition for MicroBit Compass.
|
|
*
|
|
* Represents an implementation of the Freescale MAG3110 I2C Magnetmometer.
|
|
* Also includes basic caching, calibration and on demand activation.
|
|
*/
|
|
class MicroBitCompass : public MicroBitComponent
|
|
{
|
|
/**
|
|
* Unique, enumerated ID for this component.
|
|
* Used to track asynchronous events in the event bus.
|
|
*/
|
|
|
|
uint16_t address; // I2C address of the magnetmometer.
|
|
|
|
unsigned long eventStartTime; // used to store the current system clock when async calibration has started
|
|
|
|
public:
|
|
|
|
CompassSample minSample; // Calibration sample.
|
|
CompassSample maxSample; // Calibration sample.
|
|
CompassSample average; // Centre point of sample data.
|
|
CompassSample sample; // The latest sample data recorded.
|
|
DigitalIn int1; // Data ready interrupt.
|
|
|
|
/**
|
|
* Constructor.
|
|
* Create a compass representation with the given ID.
|
|
* @param id the event ID of the compass object.
|
|
* @param address the default address for the compass register
|
|
*
|
|
* Example:
|
|
* @code
|
|
* compass(MICROBIT_ID_COMPASS, MAG3110_DEFAULT_ADDR);
|
|
* @endcode
|
|
*
|
|
* Possible Events for the compass are as follows:
|
|
* @code
|
|
* MICROBIT_COMPASS_EVT_CAL_REQUIRED // triggered when no magnetometer data is available in persistent storage
|
|
* MICROBIT_COMPASS_EVT_CAL_START // triggered when calibration has begun
|
|
* MICROBIT_COMPASS_EVT_CAL_END // triggered when calibration has finished.
|
|
* @endcode
|
|
*/
|
|
MicroBitCompass(uint16_t id, uint16_t address);
|
|
|
|
/**
|
|
* Gets the current heading of the device, relative to magnetic north.
|
|
* @return the current heading, in degrees.
|
|
*
|
|
* Example:
|
|
* @code
|
|
* uBit.compass.heading();
|
|
* @endcode
|
|
*/
|
|
int heading();
|
|
|
|
/**
|
|
* Attempts to determine the 8 bit ID from the magnetometer.
|
|
* @return the id of the compass (magnetometer)
|
|
*
|
|
* Example:
|
|
* @code
|
|
* uBit.compass.whoAmI();
|
|
* @endcode
|
|
*/
|
|
int whoAmI();
|
|
|
|
/**
|
|
* Reads the X axis value of the latest update from the compass.
|
|
* @return The magnetic force measured in the X axis, in no specific units.
|
|
*
|
|
* Example:
|
|
* @code
|
|
* uBit.compass.getX();
|
|
* @endcode
|
|
*/
|
|
int getX();
|
|
|
|
/**
|
|
* Reads the Y axis value of the latest update from the compass.
|
|
* @return The magnetic force measured in the Y axis, in no specific units.
|
|
*
|
|
* Example:
|
|
* @code
|
|
* uBit.compass.getY();
|
|
* @endcode
|
|
*/
|
|
int getY();
|
|
|
|
/**
|
|
* Reads the Z axis value of the latest update from the compass.
|
|
* @return The magnetic force measured in the Z axis, in no specific units.
|
|
*
|
|
* Example:
|
|
* @code
|
|
* uBit.compass.getZ();
|
|
* @endcode
|
|
*/
|
|
int getZ();
|
|
|
|
/**
|
|
* Perform the asynchronous calibration of the compass.
|
|
* This will fire MICROBIT_COMPASS_EVT_CAL_START and MICROBIT_COMPASS_EVT_CAL_END when finished.
|
|
* @note THIS MUST BE CALLED TO GAIN RELIABLE VALUES FROM THE COMPASS
|
|
*/
|
|
void calibrateAsync();
|
|
|
|
/**
|
|
* Perform a calibration of the compass.
|
|
* This will fire MICROBIT_COMPASS_EVT_CAL_START.
|
|
* @note THIS MUST BE CALLED TO GAIN RELIABLE VALUES FROM THE COMPASS
|
|
*/
|
|
void calibrateStart();
|
|
|
|
/**
|
|
* Complete the calibration of the compass.
|
|
* This will fire MICROBIT_COMPASS_EVT_CAL_END.
|
|
* @note THIS MUST BE CALLED TO GAIN RELIABLE VALUES FROM THE COMPASS
|
|
*/
|
|
void calibrateEnd();
|
|
|
|
/**
|
|
* Periodic callback from MicroBit idle thread.
|
|
* Check if any data is ready for reading by checking the interrupt.
|
|
*/
|
|
virtual void idleTick();
|
|
|
|
/**
|
|
* Returns 0 or 1. 1 indicates that the compass is calibrated, zero means the compass requires calibration.
|
|
*/
|
|
int isCalibrated();
|
|
|
|
/**
|
|
* Returns 0 or 1. 1 indicates that the compass is calibrating, zero means the compass is not currently calibrating.
|
|
*/
|
|
int isCalibrating();
|
|
|
|
/**
|
|
* Clears the calibration held in persistent storage, and sets the calibrated flag to zero.
|
|
*/
|
|
void clearCalibration();
|
|
|
|
/**
|
|
* Returns 0 or 1. 1 indicates data is waiting to be read, zero means data is not ready to be read.
|
|
*/
|
|
virtual int isIdleCallbackNeeded();
|
|
|
|
private:
|
|
|
|
/**
|
|
* Issues a standard, 2 byte I2C command write to the magnetometer.
|
|
* Blocks the calling thread until complete.
|
|
*
|
|
* @param reg The address of the register to write to.
|
|
* @param value The value to write.
|
|
*/
|
|
void writeCommand(uint8_t reg, uint8_t value);
|
|
|
|
/**
|
|
* Issues a read command into the specified buffer.
|
|
* Blocks the calling thread until complete.
|
|
*
|
|
* @param reg The address of the register to access.
|
|
* @param buffer Memory area to read the data into.
|
|
* @param length The number of bytes to read.
|
|
*/
|
|
void readCommand(uint8_t reg, uint8_t* buffer, int length);
|
|
|
|
/**
|
|
* Issues a read of a given address, and returns the value.
|
|
* Blocks the calling thread until complete.
|
|
*
|
|
* @param reg The based address of the 16 bit register to access.
|
|
* @return The register value, interpreted as a 16 but signed value.
|
|
*/
|
|
int16_t read16(uint8_t reg);
|
|
|
|
|
|
/**
|
|
* Issues a read of a given address, and returns the value.
|
|
* Blocks the calling thread until complete.
|
|
*
|
|
* @param reg The based address of the 16 bit register to access.
|
|
* @return The register value, interpreted as a 8 bi signed value.
|
|
*/
|
|
int16_t read8(uint8_t reg);
|
|
};
|
|
|
|
#endif
|