BMM150 setting enums and measurement data (framework independent) More...

#include <array>
#include <cstdint>

Classes
struct	m5::unit::bmm150::trim_t
	Factory trim (calibration) values read from registers 0x5D-0x71, consumed by the compensation formulas in Data::comp_x()/comp_y()/comp_z() More...

struct	m5::unit::bmm150::Data
	One measurement (8 bytes burst from REG_DATA_X_LSB, register 0x42) More...

Namespaces
namespace	m5
	Top level namespace of M5Stack.

Enumerations
enum class	m5::unit::bmm150::DataRate : uint8_t { Rate10Hz = 0x00 , Rate2Hz = 0x01 , Rate6Hz = 0x02 , Rate8Hz = 0x03 , Rate15Hz = 0x04 , Rate20Hz = 0x05 , Rate25Hz = 0x06 , Rate30Hz = 0x07 }
	Output data rate (REG_OP_MODE register bits 5:3, value order is NOT monotonic in Hz) More...

enum class	m5::unit::bmm150::Preset : uint8_t { LowPower , Regular , EnhancedRegular , HighAccuracy }
	Preset accuracy/power modes, controlling the REG_REP_XY/REG_REP_Z repetition counts (see preset_rep_xy()/preset_rep_z()) More...

Functions
constexpr uint8_t	m5::unit::bmm150::preset_rep_xy (const Preset p)
	REG_REP_XY register value (0x51) for the given preset.

constexpr uint8_t	m5::unit::bmm150::preset_rep_z (const Preset p)
	REG_REP_Z register value (0x52) for the given preset.

constexpr uint16_t	m5::unit::bmm150::repetition_xy (const uint8_t rep_xy)
	Repetitions actually performed on X/Y for a REG_REP_XY register value (nXY = 1 + 2*REPXY)

constexpr uint16_t	m5::unit::bmm150::repetition_z (const uint8_t rep_z)
	Repetitions actually performed on Z for a REG_REP_Z register value (nZ = 1 + REPZ)

constexpr uint32_t	m5::unit::bmm150::measurement_time_us (const uint8_t rep_xy, const uint8_t rep_z)
	Active measurement time (us) for the given repetition register values.

constexpr uint32_t	m5::unit::bmm150::rate_interval_us (const DataRate rate)
	Output period (us) of the given data rate.

constexpr bool	m5::unit::bmm150::repetition_fits (const DataRate rate, const uint8_t rep_xy, const uint8_t rep_z)
	Can a measurement with these repetitions complete within one period of this rate?

Variables
constexpr int16_t	m5::unit::bmm150::OVERFLOW_OUTPUT {-32768}
	Sentinel returned by comp_x()/comp_y()/comp_z() on overflow or invalid input.

constexpr int16_t	m5::unit::bmm150::internal::XY_OVERFLOW_RAW {-4096}

constexpr int16_t	m5::unit::bmm150::internal::Z_OVERFLOW_RAW {-16384}

constexpr int32_t	m5::unit::bmm150::internal::Z_POSITIVE_SATURATION {32767}

constexpr int32_t	m5::unit::bmm150::internal::Z_NEGATIVE_SATURATION {-32767}

Detailed Description

BMM150 setting enums and measurement data (framework independent)

Enumeration Type Documentation

◆ DataRate

enum class m5::unit::bmm150::DataRate : uint8_t

strong

Output data rate (REG_OP_MODE register bits 5:3, value order is NOT monotonic in Hz)

Enumerator
Rate10Hz	10Hz (power-on default)
Rate2Hz	2Hz
Rate6Hz	6Hz
Rate8Hz	8Hz
Rate15Hz	15Hz
Rate20Hz	20Hz
Rate25Hz	25Hz
Rate30Hz	30Hz

◆ Preset

enum class m5::unit::bmm150::Preset : uint8_t

strong

Preset accuracy/power modes, controlling the REG_REP_XY/REG_REP_Z repetition counts (see preset_rep_xy()/preset_rep_z())

Enumerator
LowPower	Lowest power, lowest accuracy.
Regular	Balanced accuracy/power (recommended default)
EnhancedRegular	Enhanced accuracy over Regular.
HighAccuracy	Highest accuracy, highest power.

Function Documentation

◆ measurement_time_us()

uint32_t m5::unit::bmm150::measurement_time_us	(	const uint8_t	rep_xy,
		const uint8_t	rep_z )

constexpr

Active measurement time (us) for the given repetition register values.

Bosch's timing relation, which reproduces every "max ODR in forced mode" figure in the datasheet's preset table: Regular (9/15) -> 9.8ms = 102Hz, HighAccuracy (47/83) -> 49.3ms = 20Hz. A measurement that cannot finish inside one output period is simply not written to the data registers (datasheet 4.2.4), so this is what bounds the usable rate – see repetition_fits()

◆ repetition_fits()

bool m5::unit::bmm150::repetition_fits	(	const DataRate	rate,
		const uint8_t	rep_xy,
		const uint8_t	rep_z )

constexpr

Can a measurement with these repetitions complete within one period of this rate?

Note: HighAccuracy (49.3ms) does NOT fit 30Hz (33.3ms); its ceiling is 20Hz

Classes

Namespaces

Enumerations

Functions