3bf3169535
Bosch Sensortronic's BME680 is a brand new integrated environmental sensor. It integrates temperature, pressure, humidity and gas sensors with high accuracy within a single unit.
398 lines
14 KiB
C
398 lines
14 KiB
C
/*
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* Driver for Bosch Sensortec BME680 digital temperature, humity, pressure and
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* gas sensor connected to I2C or SPI
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*
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* Part of esp-open-rtos [https://github.com/SuperHouse/esp-open-rtos]
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*
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* PLEASE NOTE:
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* Due to the complexity of the sensor output value compputation based on many
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* calibration parameters, the original Bosch Sensortec BME680 driver that is
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* released as open source [https://github.com/BoschSensortec/BME680_driver]
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* and integrated for internal use. Please note the license of this part, which
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* is an extended BSD license and can be found in each of that source files.
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*
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* ---------------------------------------------------------------------------
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*
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* The BSD License (3-clause license)
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*
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* Copyright (c) 2017 Gunar Schorcht (https://github.com/gschorcht]
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef BME680_DRV_H_
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#define BME680_DRV_H_
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#include "stdint.h"
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#include "stdbool.h"
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#include "FreeRTOS.h"
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#include <task.h>
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#include "i2c/i2c.h"
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#include "esp/spi.h"
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#include "bme680/bme680.h"
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// Uncomment to enable debug output
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// #define BME680_DEBUG
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// Change this if you need more than 3 BME680 sensors
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#define BME680_MAX_SENSORS 3
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#ifdef __cplusplus
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extern "C"
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{
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#endif
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/**
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* @brief Type for actual and average sensor values (called TPHG values)
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*/
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typedef struct {
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float temperature; // temperature in degree Celcius
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float pressure; // barometric pressure in hPascal
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float humidity; // humidity in percent
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float gas; // gas resistance in Ohm
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} bme680_value_set_t;
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/**
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* @brief callback unction type to pass result of measurement to user tasks
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*/
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typedef void (*bme680_cb_function_t)(uint32_t sensor,
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bme680_value_set_t actual,
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bme680_value_set_t average);
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/**
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* @brief BME680 sensor device data structure type
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*/
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typedef struct {
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bool active;
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uint8_t bus; // I2C = 0, SPI = 1
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uint8_t addr; // I2C = slave address, SPI = 0
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uint8_t spi_cs_pin; // GPIO used as SPI CS
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uint32_t period;
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bme680_value_set_t actual;
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bme680_value_set_t average;
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bool average_computation;
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bool average_first_measurement;
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float average_weight;
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bme680_cb_function_t cb_function;
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TaskHandle_t bg_task;
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struct bme680_dev dev; // internal Bosch BME680 driver data structure
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} bme680_sensor_t;
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/**
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* @brief BME680 oversampling rate values
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*/
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typedef enum {
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none = 0, // measurement is skipped, output values are invalid
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os_1x = 1, // default oversampling rates
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os_2x = 2,
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os_4x = 3,
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os_8x = 4,
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os_16x = 5
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} bme680_oversampling_t;
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/**
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* @brief BME680 IIR filter sizes
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*/
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typedef enum {
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iir_size_0 = 0, // filter is not used
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iir_size_1 = 1,
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iir_size_3 = 2,
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iir_size_7 = 3,
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iir_size_15 = 4,
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iir_size_31 = 5,
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iir_size_63 = 6,
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iir_size_127 = 7
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} bme680_filter_size_t;
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/**
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* @brief Initialize the BME680 driver
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*
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* This function initializes all internal data structures. It must be called
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* exactly once at the beginning.
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*
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* @return true on success, false on error
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*/
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bool bme680_init_driver ();
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/**
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* @brief Create and initialize a BME680 sensor
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*
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* This function initializes the BME680 sensor and checks its availability.
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*
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* Furthermore, the starts a background task for measurements with
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* the sensor. The background task carries out the measurements periodically
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* using BME680's single shot data acquisition mode with a default period
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* of 1000 ms. This period be changed using function *set_measurment_period*.
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*
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* During each measurement the background task
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*
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* 1. determines *actual sensor values*
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* 2. computes optionally *average sensor values*
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* 3. calls back optionally a registered function of user task.
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*
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* The average value computation uses an exponential moving average
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* and can be activated (default) or deactivated with function
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* *bme680_enable_average_computation*. If the average value computation is
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* deactivated, *average sensor values* correspond to *actual sensor values*.
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* The weight (smoothing factor) used in the average value computatoin is 0.2
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* by default and can be changed with function *bme680_set_average_weight*.
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*
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* If a callback method has been registered with function
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* *bme680_set_callback_function*, it is called after each measurement
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* to pass measurement results to user tasks. Otherwise, user tasks have to
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* use function *bme680_get_values* explicitly to get the results.
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*
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* The sensor can either be connected to an I2C or SPI bus. If *addr* is
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* greater than 0, it defines a valid I2C slave address and the sensor is
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* connected to an I2C bus using this address. If *addr* is 0, the sensor
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* is connected to a SPI bus. In both cases, the *bus* parameter specifies
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* the ID of the corresponding bus. In case of SPI, parameter *cs* defines
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* the GPIO used as CS signal.
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*
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* @param bus I2C or SPI bus at which BME680 sensor is connected
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* @param addr I2C addr of the BME680 sensor or 0 for SPI
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* @param cs SPI CS GPIO, ignored for I2C
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*
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* @return ID of the sensor (0 or greater on success or -1 on error)
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*/
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uint32_t bme680_create_sensor (uint8_t bus, uint8_t addr, uint8_t cs_pin);
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/**
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* @brief Set the period of the background measurement task for the given
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* sensor
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*
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* Please note: The minimum period is 20 ms since each measurement takes
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* about 20 ms.
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*
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* @param sensor ID of the sensor
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* @param period Measurement period in ms (default 1000 ms)
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*
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* @return true on success, false on error
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*/
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bool bme680_set_measurement_period (uint32_t sensor, uint32_t period);
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/**
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* @brief Set the callback function for the background measurement task for
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* the given sensor
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*
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* If a callback method is registered, it is called after each measurement to
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* pass measurement results to user tasks. Thus, callback function is executed
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* at the same rate as the measurements.
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*
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* @param sensor ID of the sensor
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* @param function user function called after each measurement
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* (NULL to delete it for the sensor)
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*
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* @return true on success, false on error
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*/
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bool bme680_set_callback_function (uint32_t sensor,
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bme680_cb_function_t user_function);
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/**
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* @brief Deletes the BME680 sensor given by its ID
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*
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* @param sensor ID of the sensor
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*
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* @return true on success, false on error
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*/
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bool bme680_delete_sensor (uint32_t sensor);
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/**
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* @brief Get the actual and average sensor values
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*
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* This function returns the actual and average sensor values of the last
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* measurement. The parameters *actual* and *average* are pointers to data
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* structures of the type *bme680_value_set_t*, which are filled with the
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* of last measurement. Use NULL for the appropriate parameter if you are
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* not interested in specific results.
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*
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* If average value computation is deactivated, average sensor values
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* correspond to the actual sensor values.
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*
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* Please note: Calling this function is only necessary if no callback
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* function has been registered for the sensor.
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*
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* @param sensor ID of the sensor
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* @param actual Pointer to a data structure for actual sensor values
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* @param average Pointer to a data structure for average sensor values
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*
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* @return true on success, false on error
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*/
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bool bme680_get_values (uint32_t sensor,
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bme680_value_set_t *actual,
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bme680_value_set_t *average);
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/**
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* @brief Enable (default) or disable the average value computation
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*
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* In case, the average value computation is disabled, average sensor values
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* correspond to the actual sensor values.
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*
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* Please note: All average sensor values are reset if parameters for
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* measurement are changed using either function *bme680_set_average_weight*,
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* *bme680_set_oversampling_rates*, *bme680_set_heater_profile* or
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* *bme680_set_filter_size*.
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*
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* @param sensor id of the sensor
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* @param enabled true to enable or false to disable average computation
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*
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* @return true on success, false on error
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*/
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bool bme680_enable_average_computation (uint32_t sensor, bool enabled);
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/**
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* @brief Set the weight (smoothing factor) for average value computation
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*
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* At each measurement carried out by the background task, actual sensor
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* values are determined. If average value computation is enabled (default),
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* exponential moving average values are computed according to following
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* equation
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*
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* Average[k] = W * Value + (1-W) * Average [k-1]
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*
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* where coefficient W represents the degree of weighting decrease, a constant
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* smoothing factor between 0 and 1. A higher W discounts older observations
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* faster. W is 0.2 by default.
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*
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* @param sensor id of the sensor
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* @param weight coefficient W (default is 0.2)
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*
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* @return true on success, false on error
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*/
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bool bme680_set_average_weight (uint32_t sensor, float weight);
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/**
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* @brief Set the oversampling rates for measurements
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*
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* The BME680 sensor allows to define different oversampling rates for the
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* measurements of temperature, pressure and humidity, separatly. Possible
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* oversampling rates defined by enumaration type are none, 1x (default),
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* 2x, 4x, 8x, and 16x. In case of *none*, the corressponing measurement is
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* skipped and output values are invalid.
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*
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* Please note: To disable the measurement of either temperature, pressure
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* or humidity, set the corresponding oversamling rate to *none*.
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*
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* @param sensor id of the sensor
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* @param ost oversampling rate for temperature measurements
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* @param osp oversampling rate for pressure measurements
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* @param osh oversampling rate for humidity measurements
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*
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* @return true on success, false on error
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*/
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bool bme680_set_oversampling_rates (uint32_t sensor,
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bme680_oversampling_t ost,
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bme680_oversampling_t osp,
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bme680_oversampling_t osh);
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/**
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* @brief Set the heater profile for gas measurements
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*
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* For gas measurement the sensor integrates a heater. The paremeters for
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* this heater are defined by a heater profile. Such a heater profile
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* consists of a temperature setting point (the target temperature) and the
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* heating duration.
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*
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* Even though the sensor supports up to 10 different profiles, only one
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* profile is used by this driver for simplicity. The temperature setting
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* point and the heating duration of this profile can be defined by this
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* function. Default values are 320 degree Celcius as target temperature and
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* 150 ms heating duration. If heating duration is 0 ms, the gas measurement
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* is skipped and output values are invalid.
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*
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* Please note: To disable the measurement of gas, set the heating duration
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* to 0 ms.
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*
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* Please note: According to the datasheet, target temperatures of between
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* 200 and 400 degrees Celsius are typical and about 20 to 30 ms are necessary
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* for the heater to reach the desired target temperature.
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*
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* @param sensor id of the sensor
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* @param temperature heating temperature in degree Celcius
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* @param duration heating duration in milliseconds
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*
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* @return true on success, false on error
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*/
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bool bme680_set_heater_profile (uint32_t sensor,
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uint16_t temperature,
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uint16_t duration);
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/**
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* @brief Set the size of the IIR filter
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*
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* The sensor integrates an internal IIR filter (low pass filter) to
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* reduce short-term changes in sensor output values caused by external
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* disturbances. It effectively reduces the bandwidth of the sensor output
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* values.
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*
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* The filter can optionally be used for pressure and temperature data that
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* are subject to many short-term changes. Humidity and gas inside the sensor
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* does not fluctuate rapidly and does not require such a low pass filtering.
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*
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* This function sets the size of the filter. The default filter size is
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* 3 (iir_size_3).
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*
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* Please note: If the size of the filter is 0, the filter is not used.
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*
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* @param sensor id of the sensor
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* @param size IIR filter size
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*
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* @return true on success, false on error
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*/
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bool bme680_set_filter_size(uint32_t sensor, bme680_filter_size_t size);
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#ifdef __cplusplus
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}
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#endif /* End of CPP guard */
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#endif /* BME680_DRV_H_ */
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