3-axis magnetometer unit. No standalone GROVE unit exists for this chip; it is found built into some boards (e.g. classic M5Stack Core/Fire, paired with MPU6886) and as the auxiliary sensor of UnitBMI270 More...

#include <unit_bmm150.hpp>

Inheritance diagram for m5::unit::UnitBMM150:

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

Public Member Functions
	UnitBMM150 (const uint8_t addr=DEFAULT_ADDRESS)
	Construct with the I2C address the chip will answer on.

virtual	~UnitBMM150 ()
	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.

Setting (applies immediately)
bool	writePreset (const bmm150::Preset preset)
	Write the accuracy/power preset (REG_REP_XY/REG_REP_Z)

bool	writeRepetition (const uint8_t rep_xy, const uint8_t rep_z)
	Write the repetition (oversampling) registers directly.

bool	readRepetition (uint8_t &rep_xy, uint8_t &rep_z)
	Read the repetition registers from the device (REG_REP_XY/REG_REP_Z)

bool	writeDataRate (const bmm150::DataRate rate)
	Write the output data rate.

bool	readDataRate (bmm150::DataRate &rate)
	Read the output data rate from the device (REG_OP_MODE bits[5:3])

Reset
bool	softReset ()
	Soft reset (REG_POWER_CONTROL soft-reset bits, keeping the power control bit on), leaving the chip initialized but unconfigured and stopped.

Periodic measurement
bool	startPeriodicMeasurement (const bmm150::DataRate rate, const bmm150::Preset preset)
	Start periodic measurement.

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

bool	stopPeriodicMeasurement ()
	Stop periodic measurement.

Power
bool	sleep () override
	Put the chip into suspend mode (REG_POWER_CONTROL power bit cleared)

bool	wakeup () override
	Bring the chip out of suspend.

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 bmm150::DataRate rate, const bmm150::Preset preset)

bool	start_periodic_measurement ()

bool	stop_periodic_measurement ()

bool	read_measurement (bmm150::Data &d)

bool	write_repetition_unchecked (const uint8_t rep_xy, const uint8_t rep_z)

bool	write_data_rate_unchecked (const bmm150::DataRate rate)

bool	write_register8_verified (const uint8_t reg, const uint8_t val)

bool	read_trim (bmm150::trim_t &trim)

	M5_UNIT_COMPONENT_PERIODIC_MEASUREMENT_ADAPTER_HPP_BUILDER (UnitBMM150, bmm150::Data)

Detailed Description

3-axis magnetometer unit. No standalone GROVE unit exists for this chip; it is found built into some boards (e.g. classic M5Stack Core/Fire, paired with MPU6886) and as the auxiliary sensor of UnitBMI270

Constructor & Destructor Documentation

◆ UnitBMM150()

m5::unit::UnitBMM150::UnitBMM150 ( 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

◆ config() [1/2]

config_t m5::unit::UnitBMM150::config ( ) const

inline

Gets the configuration.

Returns: Current configuration

◆ config() [2/2]

void m5::unit::UnitBMM150::config ( const config_t & cfg )

inline

Set the configuration.

Parameters

[in] cfg Configuration

◆ imuConvertParam()

void m5::unit::UnitBMM150::imuConvertParam ( m5::imu::imu_convert_param_t & out ) const

overridevirtual

Gets the conversion parameters for raw IMU data.

Parameters

[out] out Conversion parameters

Implements m5::imu::IMUDataSource.

◆ imuSpec()

virtual m5::imu::Capability m5::unit::UnitBMM150::imuSpec ( ) const

inlineoverridevirtual

Capability of this unit.

Returns: Mag (no temperature output on this chip)

Implements m5::imu::IMUDataSource.

◆ readDataRate()

bool m5::unit::UnitBMM150::readDataRate ( bmm150::DataRate & rate )

Read the output data rate from the device (REG_OP_MODE bits[5:3])

Parameters

[out] rate Data rate

Returns: True if successful

◆ readImuRaw()

Capability m5::unit::UnitBMM150::readImuRaw ( m5::imu::imu_raw_data_t & out )

overridevirtual

Read the latest raw IMU data.

Parameters

[out] out Raw IMU data

Returns: Capability of the data actually stored in out (None if no data available)

Implements m5::imu::IMUDataSource.

◆ readRepetition()

bool m5::unit::UnitBMM150::readRepetition	(	uint8_t &	rep_xy,
		uint8_t &	rep_z )

Read the repetition registers from the device (REG_REP_XY/REG_REP_Z)

Parameters

[out]	rep_xy	REG_REP_XY value
[out]	rep_z	REG_REP_Z value

Returns: True if successful

◆ sleep()

bool m5::unit::UnitBMM150::sleep ( )

overridevirtual

Put the chip into suspend mode (REG_POWER_CONTROL power bit cleared)

Returns: True if successful

Works while periodic measurement is running: it is stopped first, since a suspended chip must not be polled. Suspend is the BMM150's lowest power state.

Warning: Suspend resets the register map, so the measurement settings do not survive it; startPeriodicMeasurement() re-applies the preset and data rate.

Reimplemented from m5::imu::IMUDataSource.

◆ softReset()

bool m5::unit::UnitBMM150::softReset ( )

Soft reset (REG_POWER_CONTROL soft-reset bits, keeping the power control bit on), 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::UnitBMM150::startPeriodicMeasurement ( )

Start periodic measurement in the current settings.

Returns: True if successful

◆ startPeriodicMeasurement() [2/2]

bool m5::unit::UnitBMM150::startPeriodicMeasurement	(	const bmm150::DataRate	rate,
		const bmm150::Preset	preset )

Start periodic measurement.

Parameters

rate	Output data rate
preset	Accuracy/power preset (controls REG_REP_XY/REG_REP_Z)

Returns: True if successful

◆ stopPeriodicMeasurement()

bool m5::unit::UnitBMM150::stopPeriodicMeasurement ( )

Stop periodic measurement.

Returns: True if successful

◆ update()

void m5::unit::UnitBMM150::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::UnitBMM150::wakeup ( )

overridevirtual

Bring the chip out of suspend.

Returns: True if successful

Sets the power bit and waits for the chip to reach sleep mode, where its registers are writable again – measurement stays stopped. Call startPeriodicMeasurement() to reconfigure and resume sampling. Harmless without a preceding sleep().

Reimplemented from m5::imu::IMUDataSource.

◆ writeDataRate()

bool m5::unit::UnitBMM150::writeDataRate ( const bmm150::DataRate rate )

Write the output data rate.

Parameters

[in] rate Data rate

Returns: True if successful, false if the current repetitions cannot keep up with the new rate

Warning: During periodic measurement runs, an error is returned

◆ writePreset()

bool m5::unit::UnitBMM150::writePreset ( const bmm150::Preset preset )

Write the accuracy/power preset (REG_REP_XY/REG_REP_Z)

Parameters

[in] preset Preset

Returns: True if successful, false if the preset cannot keep up with the current data rate

Note: Convenience wrapper around writeRepetition() with the preset's repetition values

Warning: During periodic measurement runs, an error is returned

◆ writeRepetition()

bool m5::unit::UnitBMM150::writeRepetition	(	const uint8_t	rep_xy,
		const uint8_t	rep_z )

Write the repetition (oversampling) registers directly.

Parameters

[in]	rep_xy	REG_REP_XY value; the sensor performs 1 + 2*rep_xy repetitions on X/Y
[in]	rep_z	REG_REP_Z value; the sensor performs 1 + rep_z repetitions on Z

Returns: True if successful, false if the repetitions cannot keep up with the current data rate

The four presets are only Bosch's recommendations – both registers accept any 8bit value. More repetitions means less noise but a longer measurement, so the pair is rejected when it cannot finish inside one output period (bmm150::repetition_fits()); raise it here by slowing the rate first. Register values, not repetition counts, because nXY can only be odd

Warning: During periodic measurement runs, an error is returned

Classes

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ UnitBMM150()

Member Function Documentation

◆ config() [1/2]

◆ config() [2/2]

◆ imuConvertParam()

◆ imuSpec()

◆ readDataRate()

◆ readImuRaw()

◆ readRepetition()

◆ sleep()

◆ softReset()

◆ startPeriodicMeasurement() [1/2]

◆ startPeriodicMeasurement() [2/2]

◆ stopPeriodicMeasurement()

◆ update()

◆ wakeup()

◆ writeDataRate()

◆ writePreset()

◆ writeRepetition()