3-axis magnetometer unit. No standalone GROVE unit exists; it is the magnetometer embedded in the MPU9250 found on early classic M5Stack Core/Fire boards, reachable at 0x0C once the MPU9250's I2C bypass is enabled (see m5::unit::imu::enableAuxBypass) More...

#include <unit_ak8963.hpp>

Inheritance diagram for m5::unit::UnitAK8963:

Classes
struct	config_t
	Settings for begin() More...

Public Member Functions
	UnitAK8963 (const uint8_t addr=DEFAULT_ADDRESS)
	Construct with the I2C address the chip will answer on.

virtual	~UnitAK8963 ()
	Destructor.

virtual bool	begin () override
	Begin the unit.

virtual void	update (const bool force=false) override
	Update the unit.

Settings
config_t	config () const
	Gets the configuration.

void	config (const config_t &cfg)
	Set the configuration.

Reset
bool	softReset ()
	Soft reset (REG_CNTL2 SRST), leaving the chip initialized but unconfigured and stopped.

Measurement setting (stop periodic measurement first)
bool	writeMeasurementMode (const ak8963::MeasurementMode mode, const ak8963::OutputBit bit)
	Write the continuous measurement rate and output bit width.

bool	readMeasurementMode (ak8963::MeasurementMode &mode, ak8963::OutputBit &bit) const
	Read the continuous measurement rate and output bit width.

Periodic measurement
bool	startPeriodicMeasurement (const ak8963::MeasurementMode mode, const ak8963::OutputBit bit)
	Start periodic measurement.

bool	startPeriodicMeasurement ()
	Start periodic measurement in the current settings.

bool	stopPeriodicMeasurement ()
	Mark periodic measurement as stopped (bookkeeping only; the chip stays in its current mode – call sleep() to power-down for actual quiescence)

Power
bool	sleep () override
	Enter power-down mode (REG_CNTL1 mode 0)

bool	wakeup () override
	Leave power-down.

IMUDataSource
virtual m5::imu::Capability	imuSpec () const override
	Capability of this unit.

virtual m5::imu::Capability	readImuRaw (m5::imu::imu_raw_data_t &out) override
	Read the latest raw IMU data.

virtual void	imuConvertParam (m5::imu::imu_convert_param_t &out) const override
	Gets the conversion parameters for raw IMU data.

Protected Member Functions
bool	start_periodic_measurement (const ak8963::MeasurementMode mode, const ak8963::OutputBit bit)

bool	start_periodic_measurement ()

bool	stop_periodic_measurement ()

bool	read_measurement (ak8963::Data &d)

bool	read_sensitivity (std::array< uint8_t, 3 > &asa)

	M5_UNIT_COMPONENT_PERIODIC_MEASUREMENT_ADAPTER_HPP_BUILDER (UnitAK8963, ak8963::Data)

Detailed Description

3-axis magnetometer unit. No standalone GROVE unit exists; it is the magnetometer embedded in the MPU9250 found on early classic M5Stack Core/Fire boards, reachable at 0x0C once the MPU9250's I2C bypass is enabled (see m5::unit::imu::enableAuxBypass)

Constructor & Destructor Documentation

◆ UnitAK8963()

m5::unit::UnitAK8963::UnitAK8963 ( const uint8_t addr = DEFAULT_ADDRESS )

explicit

Construct with the I2C address the chip will answer on.

Parameters

[in] addr I2C address (defaults to the chip's factory address)

Member Function Documentation

◆ imuConvertParam()

void m5::unit::UnitAK8963::imuConvertParam ( m5::imu::imu_convert_param_t & out ) const

overridevirtual

Gets the conversion parameters for raw IMU data.

Parameters

[out] out Destination for the scale factors this driver applies

Implements m5::imu::IMUDataSource.

◆ imuSpec()

virtual m5::imu::Capability m5::unit::UnitAK8963::imuSpec ( ) const

inlineoverridevirtual

Capability of this unit.

Returns: Mag (no temperature output on this chip)

Implements m5::imu::IMUDataSource.

◆ readImuRaw()

Capability m5::unit::UnitAK8963::readImuRaw ( m5::imu::imu_raw_data_t & out )

overridevirtual

Read the latest raw IMU data.

Parameters

[out] out Destination buffer filled with the most recent sample

Returns: Capability of the sample (which axes were populated)

Implements m5::imu::IMUDataSource.

◆ readMeasurementMode()

bool m5::unit::UnitAK8963::readMeasurementMode	(	ak8963::MeasurementMode &	mode,
		ak8963::OutputBit &	bit ) const

Read the continuous measurement rate and output bit width.

Parameters

[out]	mode	Continuous measurement rate
[out]	bit	Output bit width

Returns: True if successful

Note: Returns the setting this unit measures with, not a register read: REG_CNTL1 holds power-down whenever measurement is stopped, so the chip cannot answer this while idle

◆ sleep()

bool m5::unit::UnitAK8963::sleep ( )

overridevirtual

Enter power-down mode (REG_CNTL1 mode 0)

Returns: True if successful

Works while periodic measurement is running: it is stopped first, since a powered-down chip must not be polled. Power-down is the AK8963's only low-power state.

Reimplemented from m5::imu::IMUDataSource.

◆ softReset()

bool m5::unit::UnitAK8963::softReset ( )

Soft reset (REG_CNTL2 SRST), leaving the chip initialized but unconfigured and stopped.

Returns: True if successful

Warning: During periodic measurements, an error is returned; call stopPeriodicMeasurement() first; All settings revert to the chip defaults; call startPeriodicMeasurement() to reconfigure and resume measurement

◆ startPeriodicMeasurement() [1/2]

bool m5::unit::UnitAK8963::startPeriodicMeasurement ( )

Start periodic measurement in the current settings.

Returns: True if successful

◆ startPeriodicMeasurement() [2/2]

bool m5::unit::UnitAK8963::startPeriodicMeasurement	(	const ak8963::MeasurementMode	mode,
		const ak8963::OutputBit	bit )

Start periodic measurement.

Parameters

[in]	mode	Continuous measurement rate
[in]	bit	Output bit width

Returns: True if successful

◆ stopPeriodicMeasurement()

bool m5::unit::UnitAK8963::stopPeriodicMeasurement ( )

Mark periodic measurement as stopped (bookkeeping only; the chip stays in its current mode – call sleep() to power-down for actual quiescence)

Returns: True on success

◆ update()

void m5::unit::UnitAK8963::update ( const bool force = false )

overridevirtual

Update the unit.

Parameters

[in] force Forces an update if true, even if not time for periodic measurement

◆ wakeup()

bool m5::unit::UnitAK8963::wakeup ( )

overridevirtual

Leave power-down.

Returns: True (always)

No-op by design: on the AK8963 power-down is also the state every mode change has to pass through, so there is nothing to undo here. Call startPeriodicMeasurement() to re-enter continuous measurement.

Reimplemented from m5::imu::IMUDataSource.

◆ writeMeasurementMode()

bool m5::unit::UnitAK8963::writeMeasurementMode	(	const ak8963::MeasurementMode	mode,
		const ak8963::OutputBit	bit )

Write the continuous measurement rate and output bit width.

Parameters

[in]	mode	Continuous measurement rate
[in]	bit	Output bit width

Returns: True if successful

Applied to the chip by the next startPeriodicMeasurement(), along with the periodic measurement interval. Entering a continuous mode is measuring on this chip, so there is no way to park the setting in REG_CNTL1 while stopped – what this does write is the power-down every mode transition has to pass through

Warning: Fails while periodic measurement is running

Classes

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ UnitAK8963()

Member Function Documentation

◆ imuConvertParam()

◆ imuSpec()

◆ readImuRaw()

◆ readMeasurementMode()

◆ sleep()

◆ softReset()

◆ startPeriodicMeasurement() [1/2]

◆ startPeriodicMeasurement() [2/2]

◆ stopPeriodicMeasurement()

◆ update()

◆ wakeup()

◆ writeMeasurementMode()