unit_ak8963_data.hpp File Reference

AK8963 setting enums and measurement data (framework independent) More...

#include <array>
#include <cstdint>
#include <cmath>

Go to the source code of this file.

Classes
struct	m5::unit::ak8963::Data
	One AK8963 sample: an 8-byte burst from ST1 (0x02) plus the device ASA trim. More...

Namespaces
namespace	m5
	Top level namespace of M5Stack.

Enumerations
enum class	m5::unit::ak8963::Mode : uint8_t {   PowerDown = 0x00 , Single = 0x01 , Cont8Hz = 0x02 , Cont100Hz = 0x06 ,   SelfTest = 0x08 , FuseRom = 0x0F }
	CNTL1 (0x0A) low-nibble operating mode. More...
enum class	m5::unit::ak8963::MeasurementMode : uint8_t { Cont8Hz = 0x02 , Cont100Hz = 0x06 }
	Continuous measurement rate, the subset of Mode this driver measures in. More...
enum class	m5::unit::ak8963::OutputBit : uint8_t { Bit14 = 0x00 , Bit16 = 0x10 }
	Output bit width (CNTL1 bit4 BIT) More...

Functions
constexpr uint32_t	m5::unit::ak8963::interval_ms (const MeasurementMode mode)
	Sampling interval (ms) for a continuous measurement rate.
constexpr uint8_t	m5::unit::ak8963::cntl1_value (const MeasurementMode mode, const OutputBit bit)
	REG_CNTL1 value entering a continuous measurement mode.

Variables
constexpr float	m5::unit::ak8963::RAW_UT_PER_LSB {4912.0f / 32760.0f}
	16bit-mode sensitivity (µT per raw LSB) = 4912/32760
constexpr float	m5::unit::ak8963::RAW_UT_PER_LSB_14BIT {4912.0f / 8190.0f}
	14bit-mode sensitivity (µT per raw LSB) = 4912/8190
constexpr float	m5::unit::ak8963::OUTPUT_LSB_PER_UT {16.0f}
	Library-wide magnetometer output scale (raw LSB per µT); see imu_convert_param_t.

Detailed Description

AK8963 setting enums and measurement data (framework independent)

Enumeration Type Documentation

MeasurementMode

enum class m5::unit::ak8963::MeasurementMode : uint8_t

strong

Continuous measurement rate, the subset of Mode this driver measures in.

Mode itself is the raw CNTL1 nibble and includes states the driver owns (FuseRom backs the ASA read, PowerDown backs every mode transition), so only the two continuous rates are offered here. The difference is almost entirely power: a measurement draws 5mA for 7.2ms, so Cont100Hz (10ms period) is on nearly all the time while Cont8Hz (125ms) has a ~6% duty cycle

Enumerator
Cont8Hz	Continuous measurement, 8Hz.
Cont100Hz	Continuous measurement, 100Hz.

Mode

enum class m5::unit::ak8963::Mode : uint8_t

strong

CNTL1 (0x0A) low-nibble operating mode.

Enumerator
PowerDown	Power-down.
Single	Single measurement.
Cont8Hz	Continuous measurement, 8Hz.
Cont100Hz	Continuous measurement, 100Hz.
SelfTest	Self test.
FuseRom	FUSE-ROM access (ASA readable only here)

OutputBit

enum class m5::unit::ak8963::OutputBit : uint8_t

strong

Output bit width (CNTL1 bit4 BIT)

Full scale is +/-4912µT either way; only the resolution changes. 14bit output is sign-extended and right-aligned, so it needs no shifting – just the coarser sensitivity below

Enumerator
Bit14	14bit (0.6µT/LSB)
Bit16	16bit (0.15µT/LSB)