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RIOT/drivers/include/sgp30.h
Francisco Molina 478624cbb6
driver/sgp30: initial import
2021-04-08 10:14:30 +02:00

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/*
* Copyright (C) 2021 Inria
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @defgroup drivers_sgp30 SGP30 Gas Sensor
* @ingroup drivers_sensors
* @brief Device driver interface for the Sensirion SGP30 Gas Sensor
*
* About
* =====
*
* This driver provides an interface for the Sensirion SGP30 Gas Sensor.
* The Datasheet can be found [here](https://www.mouser.com/pdfdocs/Sensirion_Gas_Sensors_SGP30_Datasheet_EN-1148053.pdf)
*
* After the sensor is powered up and starts measuring air quality for the
* first 15s @ref sgp30_read_measurements calls will return fixed values of
* of 400ppm CO2eq and 0ppb TVOC. Afterwards values should be read in regular
* intervals of 1s for best operation of the dynamic baseline compensation
* algorithm.
*
* The above is not done by default unless the `sgp30_strict` module is included.
* In that case, if attempting to read before the is completed, then -EAGAIN
* will be returned. After this periodic readings happen every 1s, and the last
* value read is returned when calling @ref sgp30_read_measurements. A
* timestamp is also added to @ref sgp30_data_t.
*
* The sensor features on-chip humidity compensation for the air quality
* measurements. @ref sgp30_set_absolute_humidity can be used to change the
* absolute humidity value used. See [SGP30 driver integration] (https://files.seeedstudio.com/wiki/Grove-VOC_and_eCO2_Gas_Sensor-SGP30/res/Sensirion_Gas_Sensors_SGP30_Driver-Integration-Guide_HW_I2C.pdf)
* for more on this. The baseline values for the correction algorithm can
* also be tweaked with @ref sgp30_set_baseline. More on how to implement
* dynamic baseline compensation can be seen at [SGP30 driver integration] (https://files.seeedstudio.com/wiki/Grove-VOC_and_eCO2_Gas_Sensor-SGP30/res/Sensirion_Gas_Sensors_SGP30_Driver-Integration-Guide_HW_I2C.pdf).
*
* @{
*
* @file
*
* @author Francisco Molina <francois-xavier.molina@inria.fr>
*/
#ifndef SGP30_H
#define SGP30_H
#include "periph/i2c.h"
#include "ztimer.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Set of measured values
*/
typedef struct {
uint16_t tvoc; /**< The last measurement of the IAQ-calculated Total
Volatile Organic Compounds in ppb. */
uint16_t eco2; /**< The last measurement of the IAQ-calculated
equivalent CO2 in ppm */
#ifdef MODULE_SGP30_STRICT
uint32_t timestamp; /**< Timestamp of last measured value */
#endif
} sgp30_data_t;
/**
* @brief Set of measured raw values
*/
typedef struct {
uint16_t raw_h2; /**< raw H2 signal, only for testing purposes */
uint16_t raw_ethanol; /**< raw Ethanol signal, only for testing purposes */
} sgp30_raw_data_t;
/**
* @brief Device initialization parameters
*/
typedef struct {
i2c_t i2c_dev; /**< I2C dev the sensor is connected to */
} sgp30_params_t;
/**
* @brief Device descriptor for the driver
*/
typedef struct {
sgp30_params_t params; /**< parameters of the sensor device */
#ifdef MODULE_SGP30_STRICT
bool ready; /**< if initialization phase is over*/
ztimer_t _timer; /**< timer */
sgp30_data_t _data; /**< internal current data */
#endif
} sgp30_t;
/**
* @brief Initialize the given device
*
* @param[inout] dev Device descriptor of the driver
* @param[in] params Initialization parameters
*
* @return 0 on success
*/
int sgp30_init(sgp30_t *dev, const sgp30_params_t *params);
/**
* @brief Start air quality measurements, called on @ref sgp30_init
*
* @note Must be called after every power-cycle or soft reset.
*
* @param[inout] dev Device descriptor of the driver
*
* @retval 0 Success
* @retval -PROTO Sensor did not acknowledge command
*/
int sgp30_start_air_quality(sgp30_t *dev);
/**
* @brief Initialize the given device
*
* @param[in] dev Device descriptor of the driver
* @param[out] version The future set version
*
* @retval 0 Success
* @retval -EBADMSG CRC checksum didn't match
* @retval -EPROTO Sensor did not acknowledge command
*/
int sgp30_read_future_set(sgp30_t *dev, uint16_t *version);
/**
* @brief Performs a soft reset on the device
*
* @warning Reset is performed via a "General Call". All devices on the
* same I2C bus that support the General Call mode will perform
* a reset.
*
* @param[in] dev Device descriptor of the driver
*
* @retval 0 Success
* @retval -PROTO Sensor did not acknowledge command
*/
int sgp30_reset(sgp30_t *dev);
#if defined(MODULE_SGP30_STRICT) || defined(DOXYGEN)
/**
* @brief If device is ready to start reading measurements
*
* @note Only available if sgp30_strict is used
*
* @param[in] dev Device descriptor of the driver
*
* @retval true If ready to read measurements
* @retval false If still in warm-up period of it @ref sgp30_start_air_quality
* has not been called
*/
bool sgp30_ready(sgp30_t *dev);
#endif
/**
* @brief Read the serial number from the sensor
*
* @param[in] dev Device descriptor of the driver
* @param[out] buf Pre-allocated memory for returning the serial number
* @param[in] len Length of the \p str buffer, must be 6
*
* @retval 0 Success
* @retval -EBADMSG CRC checksum didn't match
* @retval -EPROTO Sensor did not acknowledge command
*/
int sgp30_read_serial_number(sgp30_t *dev, uint8_t *buf, size_t len);
/**
* @brief Read air quality signals
*
* @note For the first 15s after the “Init_air_quality” command (called
* in the init function) the sensor is in an initialization phase during
* which a “Measure_air_quality” command returns fixed values of 400ppm
* CO2eq and 0ppb TVOC.
*
* @param[in] dev Device descriptor of the driver
* @param[out] data Air quality measurements
*
* @retval 0 Success
* @retval -EAGAIN Sensor is not yet ready
* @retval -EBADMSG CRC checksum didn't match
* @retval -EPROTO Sensor did not acknowledge command
*/
int sgp30_read_measurements(sgp30_t *dev, sgp30_data_t *data);
/**
* @brief Set absolute humidity value for on-chop humidity compensation
*
* @note This function requires absolute humidity values, most sensors
* output relative humidity, this can be calculated if temperature is also
* known:
*
* AH = 216.7 * ((RH / 100.0) * 6.112 * exp(17.62 * T / (243.12 + T))) / (273.15 + T)
*
* Where RH is in 0-100%, and T is in C.
*
* (*) Approximation formula from Sensirion SGP30 Driver Integration chapter 3.15
*
* @param[in] dev Device descriptor of the driver
* @param[in] humidity Humidity in mg/m3 units. A values of 0 disables
* humidity compensation, max value is 255999 mg/m3.
*
* @retval 0 Success
* @retval -PROTO Sensor did not acknowledge command
*/
int sgp30_set_absolute_humidity(sgp30_t *dev, uint32_t humidity);
/**
* @brief Set new baseline values
*
* @param[in] dev Device descriptor of the driver
* @param[in] data Baseline values to be set
*
* @retval 0 Success
* @retval -PROTO Sensor did not acknowledge command
*/
int sgp30_set_baseline(sgp30_t *dev, sgp30_data_t *data);
/**
* @brief Returns baseline values
*
* @param[in] dev Device descriptor of the driver
* @param[out] data Current baseline values
*
* @retval 0 Success
* @retval -EBADMSG CRC checksum didn't match
* @retval -EPROTO Sensor did not acknowledge command
*/
int sgp30_get_baseline(sgp30_t *dev, sgp30_data_t *data);
/**
* @brief Read raw signals H2 (sout_H2) and Ethanol(sout_EthOH)
*
* It returns the sensor raw sensor signals which are used as inputs for
* the on-chip calibration and baseline compensation algorithms.
*
* @param[in] dev Device descriptor of the driver
* @param[out] data Raw measurement values
*
* @retval 0 Success
* @retval -EBADMSG CRC checksum didn't match
* @retval -EPROTO Sensor did not acknowledge command
*/
int sgp30_read_raw_measurements(sgp30_t *dev, sgp30_raw_data_t *data);
#ifdef __cplusplus
}
#endif
#endif /* SGP30_H */
/** @} */
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