tlv493d

Documentation

Overview

Package tlv493d implements interfacing code to the Infineon TLV493D haff effect sensor.

Features of the device:

3-dimensional hall effect sensor, measures up to +/-130 mT magnetic flux.
temperature sensor
i2c interface
12-bit resolution
low power consumption

Features of the driver:

Implemented all options of the device
Power modes described in the documentation are defined as constants
2 precisions: high precision (12 bits), where all registers are read or low precision, which saves 50% of I2C bandwidth, but without temperature and only 8-bit resolution
Continuous reading mode

Datasheet and application notes: https://www.infineon.com/cms/en/product/sensor/magnetic-sensors/magnetic-position-sensors/3d-magnetics/tlv493d-a1b6/

Example

// Make sure periph is initialized.
if _, err := host.Init(); err != nil {
	log.Fatal(err)
}

// Open default I²C bus.
bus, err := i2creg.Open("")
if err != nil {
	log.Fatalf("failed to open I²C: %v", err)
}
defer bus.Close()

// Create a new TLV493D hall effect sensor.
tlv, err := tlv493d.New(bus, &tlv493d.DefaultOpts)
if err != nil {
	log.Fatalln(err)
}
defer tlv.Halt()

// Read a single value.
tlv.SetMode(tlv493d.LowPowerMode)
fmt.Println("Single reading")
reading, err := tlv.Read(tlv493d.HighPrecisionWithTemperature)

if err != nil {
	log.Fatalln(err)
}

fmt.Println(reading)

// Read values continuously from the sensor.
fmt.Println("Continuous reading")
c, err := tlv.ReadContinuous(100*physic.Hertz, tlv493d.LowPrecision)
if err != nil {
	log.Fatalln(err)
}

for reading := range c {
	fmt.Println(reading)
}

Index

• Constants
• Variables
• func CalibrateTemperatureOffsetCompensation(temperatureOffsetCompensation int, measuredTemperature physic.Temperature, ...) int
• type Dev
  • func New(i i2c.Bus, opts *Opts) (*Dev, error)
  • func (d *Dev) EnableInterruptions(enable bool) error
  • func (d *Dev) EnableParityTest(enable bool) error
  • func (d *Dev) EnableTemperatureMeasurement(enable bool) error
  • func (d *Dev) Halt() error
  • func (d *Dev) Read(precision Precision) (Sample, error)
  • func (d *Dev) ReadContinuous(frequency physic.Frequency, precision Precision) (<-chan Sample, error)
  • func (d *Dev) SetMode(mode Mode) error
  • func (d *Dev) StopContinousRead()
  • func (d *Dev) String() string
• type Mode
• type Opts
• type Precision
• type Sample

Examples

• Package

Constants

const I2CAddr uint16 = 0x5e

I2CAddr is the default I2C address for the TLV493D component.

const I2CAddr1 uint16 = 0x1f

I2CAddr1 is an alternative I2C address for TLV493D components.

Variables

var DefaultOpts = Opts{
	I2cAddress:                    I2CAddr,
	Reset:                         true,
	Mode:                          PowerDownMode,
	EnableTemperatureMeasurement:  true,
	InterruptPadEnabled:           false,
	ParityTestEnabled:             true,
	TemperatureOffsetCompensation: DefaultTemperatureOffsetCompensation,
}

DefaultOpts are the recommended default options.

var FastMode = Mode{
	// contains filtered or unexported fields
}

FastMode is the mode using the most energy

var LowPowerMode = Mode{
	// contains filtered or unexported fields
}

LowPowerMode uses less energy than FastMode, with lower measurement rate

var MasterControlledMode = Mode{
	// contains filtered or unexported fields
}

MasterControlledMode refer to TLV493D documentation on how to use this mode

var PowerDownMode = Mode{
	// contains filtered or unexported fields
}

PowerDownMode shuts down the sensor. It can still reply to I2C commands.

var UltraLowPowerMode = Mode{
	// contains filtered or unexported fields
}

UltraLowPowerMode saves the most energy but with very low measurement rate

Functions

func CalibrateTemperatureOffsetCompensation

func CalibrateTemperatureOffsetCompensation(temperatureOffsetCompensation int, measuredTemperature physic.Temperature, actualTemperature physic.Temperature) int

CalibrateTemperatureOffsetCompensation computes the temperature offset compensation based upon a reading from the sensor compared to the actual temperature.

The returned value must be stored and passed in Opts.TemperatureOffsetCompensation in future uses of TLV493D driver. See TLV493D user manual, "3.2 Calculation of the temperature" for more information.

Types

type Dev

type Dev struct {
	// contains filtered or unexported fields
}

Dev is an handle to a TLV493D hall effect sensor.

func New

func New(i i2c.Bus, opts *Opts) (*Dev, error)

New creates a new TLV493D driver for a 3D hall effect sensors

func (*Dev) EnableInterruptions

func (d *Dev) EnableInterruptions(enable bool) error

EnableInterruptions controls if the sensor should send interruption of new measurement

func (*Dev) EnableParityTest

func (d *Dev) EnableParityTest(enable bool) error

EnableParityTest controls if the sensor should control the parity of the data transmitted

func (*Dev) EnableTemperatureMeasurement

func (d *Dev) EnableTemperatureMeasurement(enable bool) error

EnableTemperatureMeasurement controls the temperature sensor activation

func (*Dev) Halt

func (d *Dev) Halt() error

Halt implements conn.Resource.

func (*Dev) Read

func (d *Dev) Read(precision Precision) (Sample, error)

Read returns a sample from the last measurement of the sensor

func (*Dev) ReadContinuous

func (d *Dev) ReadContinuous(frequency physic.Frequency, precision Precision) (<-chan Sample, error)

ReadContinuous returns a channel which will receive readings at regular intervals

func (*Dev) SetMode

func (d *Dev) SetMode(mode Mode) error

SetMode sets the power mode of the sensor

func (*Dev) StopContinousRead

func (d *Dev) StopContinousRead()

StopContinousRead stops a currently running continuous read

func (*Dev) String

func (d *Dev) String() string

String implements conn.Resource.

type Mode

type Mode struct {
	// contains filtered or unexported fields
}

Mode reprents the various power modes described in the documentation

type Opts

type Opts struct {
	I2cAddress                    uint16
	Reset                         bool
	Mode                          Mode
	InterruptPadEnabled           bool // If enabled, this can cause I2C failures. See documentation.
	EnableTemperatureMeasurement  bool // Disable to save power.
	ParityTestEnabled             bool
	TemperatureOffsetCompensation int
}

Opts holds the configuration options.

type Precision

type Precision int

Precision represents a request for a compromise between I2C bandwidth versus measurement precision.

const (
	// HighPrecisionWithTemperature reads the full 12-bit value for each axis
	// and the temperature
	HighPrecisionWithTemperature Precision = 0
	// LowPrecision reads only 8-bits for each axis. Temperature is not read.
	LowPrecision Precision = 1
	// DefaultTemperatureOffsetCompensation is the temperature offset compensation used by default, following the documentation advices.
	// For accurate results, please calibrate it using CalibrateTemperatureOffsetCompensation method.
	DefaultTemperatureOffsetCompensation = 340
)

type Sample

type Sample struct {
	Bx          physic.MagneticFluxDensity
	By          physic.MagneticFluxDensity
	Bz          physic.MagneticFluxDensity
	Temperature physic.Temperature
}

Sample contains the metrics measured by the sensor