Module sht3x 

Sensirion SHT3x-DIS humidity and temperature sensor (SHT30, SHT31, SHT35).

The SHT3x returns fully calibrated, linearised 16-bit temperature and humidity words over I2C, each followed by a CRC-8, and converts to physical units with two fixed linear formulas. This module holds the command words, verifies the CRC, decodes a six-byte measurement frame, applies the datasheet’s conversion formulas in integer arithmetic, and decodes the status register, so a node reads degrees and percent relative humidity without carrying a floating-point library.

A caller writes a word from command most-significant byte first, waits the measurement duration for the chosen repeatability, reads six bytes, and hands them to Measurement::parse. In periodic mode the same six bytes follow command::FETCH_DATA.

Temperatures are returned in millidegrees and humidity in thousandths of a percent, rounded to nearest, which is finer than the part’s 0.01 °C and 0.01 %RH resolution.

Modules

command

The 16-bit command words, sent most-significant byte first.

Structs

Measurement

One temperature and humidity data pair, as the part returns it.

Status

The status register, read with command::READ_STATUS as one CRC-protected word.

Enums

Rate

The periodic-mode acquisition rate, in measurements per second (mps).

Repeatability

The measurement repeatability, which sets noise, duration, and energy per sample.

Constants

I2C_ADDRESS_A

I2C address A, selected with the ADDR pin at logic low; the default.

I2C_ADDRESS_B

I2C address B, selected with the ADDR pin at logic high.

MIN_COMMAND_GAP_MICROS

The shortest gap between two commands, in microseconds: the part needs 1 ms after a command before it accepts another.

Functions

celsius

Converts a raw temperature word to degrees Celsius.

crc

Computes the CRC-8 the part appends to every data word.

fahrenheit

Converts a raw temperature word to degrees Fahrenheit.

humidity_raw_from_milli_percent

Builds the raw humidity word a part reports for a relative humidity.

humidity_raw_from_relative_humidity

Builds the raw humidity word a part reports for a relative humidity in percent.

milli_celsius

Converts a raw temperature word to millidegrees Celsius.

milli_fahrenheit

Converts a raw temperature word to millidegrees Fahrenheit.

milli_percent

Converts a raw humidity word to thousandths of a percent relative humidity.

periodic

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

relative_humidity

Converts a raw humidity word to percent relative humidity.

single_shot

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

temperature_raw_from_celsius

Builds the raw temperature word a part reports for a temperature in Celsius.

temperature_raw_from_milli_celsius

Builds the raw temperature word a part reports for a temperature.

temperature_raw_from_milli_fahrenheit

Builds the raw temperature word a part reports for a temperature in Fahrenheit.

word

Decodes one CRC-protected 16-bit word as the part sends it.

word_bytes

Builds the three bytes that carry a 16-bit word with its CRC.