Class Sht3x

Namespace

Pamoja.Sensors

Assembly

Pamoja.Sensors.dll

A Sensirion SHT3x-DIS humidity and temperature sensor, and a driver for one on an I2C bus.

public sealed class Sht3x : IDisposable

Inheritance

object

Sht3x

Implements

IDisposable

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

The static members are the part's datasheet, decoded exactly as the manufacturer specifies, and Sht3x.Sim, a part that is not there.

An instance drives one part over an I2cBus, measuring on demand in single-shot mode. The part has no id register, so Init() soft-resets it and reads its status: a status word whose checksum holds is what confirms an SHT3x answers. Nothing is sent until Init() or the first Measure().

Constructors

Sht3x(I2cBus, byte, Repeatability)

Creates a driver for the part at address on bus.

public Sht3x(I2cBus bus, byte address, Sht3x.Repeatability repeatability = Repeatability.High)

Parameters

bus I2cBus

The bus the part is on.

address byte

AddressA with ADDR low, AddressB with ADDR high.

repeatability Sht3x.Repeatability

How repeatable each measurement is, against how long it takes.

Exceptions

PamojaException

The native driver could not be created.

Fields

AddressA

The address with ADDR low.

public const byte AddressA = 68

Field Value

byte

AddressB

The address with ADDR high.

public const byte AddressB = 69

Field Value

byte

Properties

LastStatus

The status register as it was last read, or null before it has been.

public PamojaSht3xStatus? LastStatus { get; }

Property Value

PamojaSht3xStatus?

Methods

Celsius(ushort)

Converts a raw SHT3x temperature word to degrees Celsius.

public static float Celsius(ushort raw)

Parameters

raw ushort

The raw.

Returns

float

The value the C ABI computes.

Crc(ReadOnlySpan<byte>)

Computes the CRC-8 an SHT3x appends to every data word.

public static byte Crc(ReadOnlySpan<byte> data)

Parameters

data ReadOnlySpan<byte>

The data.

Returns

byte

The value the C ABI computes.

Dispose()

Releases the driver and its share of the bus.

public void Dispose()

Fahrenheit(ushort)

Converts a raw SHT3x temperature word to degrees Fahrenheit.

public static float Fahrenheit(ushort raw)

Parameters

raw ushort

The raw.

Returns

float

The value the C ABI computes.

HeaterOff()

Switches the heater off, which is its state after any reset.

public void HeaterOff()

Exceptions

PamojaException

As Init().

HeaterOn()

Switches the plausibility-check heater on, initializing the part first if needed.

public void HeaterOn()

Exceptions

PamojaException

As Init().

HumidityRawFromMilliPercent(uint)

Builds the SHT3x humidity word that decodes to a relative humidity.

public static ushort HumidityRawFromMilliPercent(uint milliPercent)

Parameters

milliPercent uint

The milli percent.

Returns

ushort

The value the C ABI computes.

HumidityRawFromRelativeHumidity(float)

Builds the SHT3x humidity word that decodes to a relative humidity percentage.

public static ushort HumidityRawFromRelativeHumidity(float percent)

Parameters

percent float

The percent.

Returns

ushort

The value the C ABI computes.

Init()

Soft-resets the part and reads its status.

public void Init()

Exceptions

PamojaException

Nothing answered, or the status word failed its checksum.

IntervalMicros(byte)

Returns the gap between SHT3x periodic measurements at a rate.

public static uint IntervalMicros(byte rate)

Parameters

rate byte

The rate.

Returns

uint

The decoded value.

Exceptions

PamojaException

The device data is not valid.

MaxMeasurementMicros(byte)

Returns how long an SHT3x measurement may take at a repeatability.

public static uint MaxMeasurementMicros(byte repeatability)

Parameters

repeatability byte

The repeatability.

Returns

uint

The decoded value.

Exceptions

PamojaException

The device data is not valid.

Measure()

Runs one single-shot measurement, initializing the part first if needed.

public PamojaSht3xMeasurement Measure()

Returns

PamojaSht3xMeasurement

The checksum-checked temperature and humidity.

Exceptions

PamojaException

As Init(), and when a data word fails its checksum.

MeasurementBytes(ushort, ushort)

Builds the six bytes an SHT3x sends for a pair of raw words.

public static byte[] MeasurementBytes(ushort temperatureRaw, ushort humidityRaw)

Parameters

temperatureRaw ushort

The temperature raw.

humidityRaw ushort

The humidity raw.

Returns

byte[]

The decoded value.

Exceptions

PamojaException

The device data is not valid.

MilliCelsius(ushort)

Converts a raw SHT3x temperature word to milli-degrees Celsius.

public static int MilliCelsius(ushort raw)

Parameters

raw ushort

The raw.

Returns

int

The value the C ABI computes.

MilliFahrenheit(ushort)

Converts a raw SHT3x temperature word to milli-degrees Fahrenheit.

public static int MilliFahrenheit(ushort raw)

Parameters

raw ushort

The raw.

Returns

int

The value the C ABI computes.

MilliPercent(ushort)

Converts a raw SHT3x humidity word to milli-percent.

public static uint MilliPercent(ushort raw)

Parameters

raw ushort

The raw.

Returns

uint

The value the C ABI computes.

ParseMeasurement(ReadOnlySpan<byte>)

Parses and CRC-checks a six-byte SHT3x measurement frame.

public static PamojaSht3xMeasurement ParseMeasurement(ReadOnlySpan<byte> frame)

Parameters

frame ReadOnlySpan<byte>

The frame.

Returns

PamojaSht3xMeasurement

The decoded value.

Exceptions

PamojaException

The device data is not valid.

ParseStatus(ReadOnlySpan<byte>)

Parses and CRC-checks a three-byte SHT3x status frame.

public static PamojaSht3xStatus ParseStatus(ReadOnlySpan<byte> frame)

Parameters

frame ReadOnlySpan<byte>

The frame.

Returns

PamojaSht3xStatus

The decoded value.

Exceptions

PamojaException

The device data is not valid.

Periodic(byte, byte)

Returns the SHT3x periodic-mode command for a repeatability and rate.

public static ushort Periodic(byte repeatability, byte rate)

Parameters

repeatability byte

The repeatability.

rate byte

The rate.

Returns

ushort

The decoded value.

Exceptions

PamojaException

The device data is not valid.

ReadStatus()

Reads the status register.

public PamojaSht3xStatus ReadStatus()

Returns

PamojaSht3xStatus

The status, which LastStatus keeps as well.

Exceptions

PamojaException

The transfer failed, or the word failed its checksum.

RelativeHumidity(ushort)

Converts a raw SHT3x humidity word to a relative humidity percentage.

public static float RelativeHumidity(ushort raw)

Parameters

raw ushort

The raw.

Returns

float

The value the C ABI computes.

SingleShot(byte, bool)

Returns the SHT3x single-shot command for a repeatability and clock mode.

public static ushort SingleShot(byte repeatability, bool clockStretching)

Parameters

repeatability byte

The repeatability.

clockStretching bool

The clock stretching.

Returns

ushort

The decoded value.

Exceptions

PamojaException

The device data is not valid.

StatusBytes(ushort)

Builds the three bytes an SHT3x sends for a status word, CRC last.

public static byte[] StatusBytes(ushort bits)

Parameters

bits ushort

The bits.

Returns

byte[]

The decoded value.

Exceptions

PamojaException

The device data is not valid.

StatusFromBits(ushort)

Splits an SHT3x status word into its flags.

public static PamojaSht3xStatus StatusFromBits(ushort bits)

Parameters

bits ushort

The bits.

Returns

PamojaSht3xStatus

The decoded value.

Exceptions

PamojaException

The device data is not valid.

TemperatureRawFromCelsius(float)

Builds the SHT3x temperature word that decodes to a temperature in Celsius.

public static ushort TemperatureRawFromCelsius(float celsius)

Parameters

celsius float

The celsius.

Returns

ushort

The value the C ABI computes.

TemperatureRawFromMilliCelsius(int)

Builds the SHT3x temperature word that decodes to a temperature.

public static ushort TemperatureRawFromMilliCelsius(int milliCelsius)

Parameters

milliCelsius int

The milli celsius.

Returns

ushort

The value the C ABI computes.

TemperatureRawFromMilliFahrenheit(int)

Builds the SHT3x temperature word that decodes to a temperature in Fahrenheit.

public static ushort TemperatureRawFromMilliFahrenheit(int milliFahrenheit)

Parameters

milliFahrenheit int

The milli fahrenheit.

Returns

ushort

The value the C ABI computes.

TypicalMeasurementMicros(byte)

Returns how long an SHT3x measurement typically takes at a repeatability.

public static uint TypicalMeasurementMicros(byte repeatability)

Parameters

repeatability byte

The repeatability.

Returns

uint

The decoded value.

Exceptions

PamojaException

The device data is not valid.

Word(ReadOnlySpan<byte>)

Reads a CRC-checked three-byte SHT3x word frame.

public static ushort Word(ReadOnlySpan<byte> frame)

Parameters

frame ReadOnlySpan<byte>

The frame.

Returns

ushort

The decoded value.

Exceptions

PamojaException

The device data is not valid.

WordBytes(ushort)

Builds the three bytes an SHT3x sends for a word: the word then its CRC.

public static byte[] WordBytes(ushort value)

Parameters

value ushort

The value.

Returns

byte[]

The decoded value.

Exceptions

PamojaException

The device data is not valid.