Crate hdc302x_async

This is a platform-agnostic Rust driver for the HDC3020, HDC3021, HDC3022, HDC3020-Q1, HDC3021-Q1 and HDC3022-Q1 low-power humidity and temperature digital sensors using the embedded-hal-async traits. This is current no support for a blocking API. This driver was inspired by Diego Barrios Romero’s hdc20xx-rs driver.

This driver allows you to:

• Start and read samples in both one-shot and auto (self-timed) mode.
• Read last temperature and humidity values in auto mode.
• Read minimum and maximum temperature and humidity values in auto mode.
• Exit auto mode.
• Enable/disable the heater, including 100%, 50%, and 25% settings.
• Trigger a software reset.
• Read the manufacturer ID.
• Read the device serial number.
• Read and optionally clear the device status bits.
• async support.

This driver does not yet support the following device features:

• Alerts (read/write and non-volatile storage of setpoints).
• Offset calibration (non-volatile storage of temperature and relative humidity offsets).
• Configuration of post-reset state (default behavior after power-on and software reset).
• Blocking API support.

Supported devices: HDC3020, HDC3021, HDC3022, HDC3020-Q1, HDC3021-Q1, HDC3022-Q1

The following description is copied from the manufacturer’s datasheet:

The HDC302x-Q1 is an integrated capacitive based relative humidity (RH) and temperature sensor. The device provides high accuracy measurements over a wide supply range (1.62 V – 5.5 V), along with ultra-low power consumption in a compact 2.5-mm × 2.5-mm package. Both the temperature and humidity sensors are 100% tested and trimmed on a production setup that is NIST traceable and verified with equipment that is calibrated to ISO/IEC 17025 standards.

Offset Error Correction reduces RH sensor offset due to aging, exposure to extreme operating conditions, and contaminants to return device to within accuracy specifications. For battery IoT applications, auto measurement mode and ALERT feature enable low system power by maximizing MCU sleep time. There are four different I2C addresses that support speeds up to 1 MHz. A heating element is available to dissipate condensation and moisture.

The HDC3020-Q1 is an open cavity package without protective cover. Two device variants have a cover option to protect the open cavity RH sensor: HDC3021-Q1 and HDC3022-Q1. HDC3021-Q1 has removable protective tape to allow conformal coatings and PCB wash. HDC3022-Q1 has a permanent IP67 filter membrane to protect against dust, water and PCB wash. All three package variants have wettable flanks option.

Datasheets: HDC302x HDC302x-Q1

To use this driver, import this crate and an embedded_hal_async implementation, then instantiate the device.

Example:

use hdc302x_async::{
    Datum,
    Hdc302x,
    I2cAddr,
    LowPowerMode,
};

// Platform-specific
let i2c = /* embedded_hal_async::i2c::I2c instance */;
let delay = /* embedded_hal_async::delay::DelayNs instance */;

// Hdc302x
let mut hdc302x = Hdc302x::new(i2c, delay, I2cAddr::Addr00);

// Read and display a one-shot sample
let raw_datum = hdc302x.one_shot(LowPowerMode::lowest_noise()).await.unwrap();
println!("{:3} %RH, {:0.1} °C",
    raw_datum.humidity_percent(),
    raw_datum.centigrade());

// Use auto mode to continuously sample and track the min/max temperature
loop {
    // stop and restart auto_mode to reset min/max values
    hdc302x.auto_stop().await.unwrap();
    hdc302x.auto_start(HdcSampleRate::Auto500mHz, HdcLowPowerMode::lowest_power()).await.unwrap();

    // Platform-specific: sleep a while
    sleep_secs(60);

    // fetch the results from the hdc302x sensor
    println!("min/max temperature: {:0.1} °C / {:0.1} °C",
        hdc302x.auto_read(HdcAutoReadTarget::MinTemp).await.unwrap().centigrade().unwrap(),
        hdc302x.auto_read(HdcAutoReadTarget::MaxTemp).await.unwrap().centigrade().unwrap());
    println!("min/max relative humidity: {:0.1} % / {:0.1} %",
        hdc302x.auto_read(HdcAutoReadTarget::MinRelHumid).await.unwrap().humidity_percent().unwrap(),
        hdc302x.auto_read(HdcAutoReadTarget::MaxRelHumid).await.unwrap().humidity_percent().unwrap());
}

Structs

Hdc302x

HDC302x(-Q1) device driver

RawTempAndRelHumid

Raw (still in u16 format) temperature and relative humidity from the device

SerialNumber

Serial number of the device

StatusBits

Status bits from the device

Temp

Temp after conversion

TempAndRelHumid

Temp and relative humidity from the device after conversion

Enums

AutoReadTarget

Options for what to read from the device when in auto mode.

Datum

Temp and/or humidity from the device after conversion

Error

All possible errors in this crate

HeaterLevel

Options for the on-device heater. The datasheet claims this may be useful to drive off condensation.

I2cAddr

I2C device address options, which are selected via the ADDR1 and ADDR pins.

LowPowerMode

Low power mode options, which control the trade-off between power consumption, measurement noise, and sample latency.

ManufacturerId

Manufacturer ID of the device

RawDatum

Raw (still in u16 format) temperature and/or humidity from the device

SampleRate

Sample rate options, covering both the one-shot and auto modes.