scd41.h

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/*
 * hvac.h
 *
 *  Created on: 29. 12. 2025
 *      Author: Milan
 *
 * reading from sensors SCD41
 *
 *  sensor HVAC Click, SCD41 - CO2, temperature, humidity    SCD41Datasheet.pdf
 *  https://www.mikroe.com/hvac-click
 *  https://download.mikroe.com/documents/datasheets/SCD41%20Datasheet.pdf
 *  Sensor is electrically quite demanding, therefore it is necessary to control environment reading via Start/Stop
 *
 *
 *  geminy:
 *  https://gemini.google.com/share/a96b452eacf9
 *
 *
 */
 
#ifndef INC_SCD41_H_
#define INC_SCD41_H_
 
#include "mysensors_def.h"
 
#ifdef SENSOR_SCD41
 
#include "stm32wlxx_hal.h"
 
#pragma pack(1)
/**
 * @brief Measurement data produced by the SCD41 CO2 / temperature / humidity sensor.
 *        Populated by scd41_Read(); check IsDataValid before using the values.
 */
typedef struct
{
    float Co2;          /**< CO2 concentration in ppm */
    float Temperature;  /**< Temperature in degrees Celsius */
    float Humidity;     /**< Relative humidity in percent (0–100 %) */
    int8_t IsDataValid; /**< 1 – values are valid; 0 – last read failed or data not yet available */
} scd41_t;
#pragma pack()
 
/** @brief Live measurement data from the SCD41 sensor; updated by scd41_Read(). */
extern scd41_t _scd41Data;
/** @brief Snapshot copy of the last completed measurement; used for LoRaWAN transmission. */
extern scd41_t _bck_scd41Data;
 
/**
 * @brief - check if CO2 sensor is present
 * @param tryInit - in case sensor is not yet initialized, 1 - attempt to initialize again, 0 - no
 * @retval 1 - is present, 0 - is not
 */
int8_t scd41_Is(I2C_HandleTypeDef *hi2c, int8_t tryInit);
 
/**
 * @brief initialization of sensor sdc41
 * @retval HAL_OK - sensor is present, HAL_ERROR - error
 */
HAL_StatusTypeDef scd41_Init(I2C_HandleTypeDef *hi2c);
 
/**
 * @brief start reading - turn on sensor, reading mode can be:
 * SCD41_CMD_START_PERIODIC - every 5s - this is probably most accurate
 * SCD41_CMD_START_LOW_POWER_PERIODIC - every 30s
 */
HAL_StatusTypeDef scd41_On(I2C_HandleTypeDef *hi2c);
 
/**
 * @brief stop reading
 */
HAL_StatusTypeDef scd41_Off(I2C_HandleTypeDef *hi2c);
 
/**
 * @brief check if data is available
 * @retval HAL_OK - data is available, can be read, HAL_BUSY - data not yet available, HAL_ERROR - error
 */
HAL_StatusTypeDef scd41_IsDataReady(I2C_HandleTypeDef *hi2c);
 
/**
 * @brief read value from sensor
 * @retval HAL_OK - have data, HAL_BUSY - data not yet available, HAL_ERROR - error
 */
HAL_StatusTypeDef scd41_Read(I2C_HandleTypeDef *hi2c);
 
/**
 * @brief log data to buffer
 */
void scd41_LogData(char* buf);
 
#endif
 
#endif /* INC_SCD41_H_ */