lis2mdl

Documentation

Overview

Package lis2mdl implements a driver for the LIS2MDL, a magnetic sensor which is included on BBC micro:bit v1.5.

Datasheet: https://www.st.com/resource/en/datasheet/lis2mdl.pdf

Index

• Constants
• type Configuration
• type Device
  • func New(bus drivers.I2C) Device
  • func (d *Device) Configure(cfg Configuration)
  • func (d *Device) Connected() bool
  • func (d *Device) ReadCompass() (h int32)
  • func (d *Device) ReadMagneticField() (x int32, y int32, z int32)

Constants

const (
	// Constants/addresses used for I2C.
	ADDRESS = 0x1E

	// magnetic sensor registers.
	OFFSET_X_REG_L = 0x45
	OFFSET_X_REG_H = 0x46
	OFFSET_Y_REG_L = 0x47
	OFFSET_Y_REG_H = 0x48
	OFFSET_Z_REG_L = 0x49
	OFFSET_Z_REG_H = 0x4A
	WHO_AM_I       = 0x4F
	CFG_REG_A      = 0x60
	CFG_REG_B      = 0x61
	CFG_REG_C      = 0x62
	INT_CRTL_REG   = 0x63
	INT_SOURCE_REG = 0x64
	INT_THS_L_REG  = 0x65
	INT_THS_H_REG  = 0x66
	STATUS_REG     = 0x67
	OUTX_L_REG     = 0x68
	OUTX_H_REG     = 0x69
	OUTY_L_REG     = 0x6A
	OUTY_H_REG     = 0x6B
	OUTZ_L_REG     = 0x6C
	OUTZ_H_REG     = 0x6D
	TEMP_OUT_L_REG = 0x6E
	TEMP_OUT_H_REG = 0x6F

	// magnetic sensor power mode.
	POWER_NORMAL = 0x00 // default
	POWER_LOW    = 0x01

	// magnetic sensor operate mode.
	SYSTEM_CONTINUOUS = 0x00 // default
	SYSTEM_SINGLE     = 0x01

	// magnetic sensor data rate
	DATARATE_10HZ  = 0x00 // default
	DATARATE_20HZ  = 0x01
	DATARATE_50HZ  = 0x02
	DATARATE_100HZ = 0x03
)

Types

type Configuration

type Configuration struct {
	PowerMode  uint8
	SystemMode uint8
	DataRate   uint8
}

Configuration for LIS2MDL device.

type Device

type Device struct {
	Address    uint8
	PowerMode  uint8
	SystemMode uint8
	DataRate   uint8
	// contains filtered or unexported fields
}

Device wraps an I2C connection to a LIS2MDL device.

func New

func New(bus drivers.I2C) Device

New creates a new LIS2MDL connection. The I2C bus must already be configured.

This function only creates the Device object, it does not touch the device.

func (*Device) Configure

func (d *Device) Configure(cfg Configuration)

Configure sets up the LIS2MDL device for communication.

func (*Device) Connected

func (d *Device) Connected() bool

Connected returns whether LIS2MDL sensor has been found.

func (*Device) ReadCompass

func (d *Device) ReadCompass() (h int32)

ReadCompass reads the current compass heading from the device and returns it in degrees. When the z axis is pointing straight to Earth and the y axis is pointing to North, the heading would be zero.

However, the heading may be off due to electronic compasses would be effected by strong magnetic fields and require constant calibration.

func (*Device) ReadMagneticField

func (d *Device) ReadMagneticField() (x int32, y int32, z int32)

ReadMagneticField reads the current magnetic field from the device and returns it in mG (milligauss). 1 mG = 0.1 µT (microtesla).