ESP-Si7021

An ESP-IDF component for the Silicon Labs Si7021-A20 Relative Humidity and Temperature Sensor with I2C Interface.

Links

• Product Page
• Datasheet
• Adafruit Breakout Board
• SparkFun Breakout Board

Features

The following features have been implemented:

• Measure Relative Humidity
• Measure Temperature
• Read and Write Registers
• Read the Electronic Serial Number
• Read the Firmware Revision
• Perform a software reset of the sensor

Requirements

This component requires the ESP-IDF IoT Development Environment as well as the C99 Standard Library, and has no other external dependencies.

Example

TODO: provide an example

API

Data Structures

struct si7021_reading
{
    float humidity;
    float temperature;
};

Functions

esp_err_t readHumidity(const i2c_port_t i2c_num, float *humidity);

esp_err_t readTemperature(const i2c_port_t i2c_num, float *temperature);

esp_err_t readTemperatureAfterHumidity(const i2c_port_t i2c_num,
                                       float *temperature);

esp_err_t readSensors(const i2c_port_t i2c_num,
                      struct si7021_reading *sensor_data);

esp_err_t readSerialNumber(const i2c_port_t i2c_num, uint8_t *serial);

esp_err_t readFirmwareRevision(const i2c_port_t i2c_num, uint8_t *revision);

esp_err_t readRegister(const i2c_port_t i2c_num, const uint8_t command,
                       uint8_t *settings);

esp_err_t writeRegister(const i2c_port_t i2c_num, const uint8_t command,
                        const uint8_t settings);

esp_err_t softwareReset(const i2c_port_t i2c_num);

To Do

• implement all features documented in the datasheet
  • acknowledge the fact that checksums are, in fact, a thing
  • implement an easier method of manipulating the user and heater control registers
    • user register - measurement resolution
    • user register - vdd status
    • user register - heater status
    • heater control register - heater current
• properly comment header and source files
• provide example application
• write documentation