/* * Copyright (C) 2016 Kees Bakker, SODAQ * 2017 Inria * 2018 Freie Universität Berlin * * 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_bmx280 BMP280/BME280 temperature, pressure and humidity sensor * @ingroup drivers_sensors * @brief Device driver interface for the Bosch BMP280 and BME280 sensors * * BMP280 and BME280 measure temperature in centi °C and pressure in Pa. BME280 * can also measure relative humidity in %. * * For more information, see the datasheets: * * [BMP280](https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BMP280-DS001.pdf) * * [BME280](https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BME280-DS002.pdf) * * This driver provides @ref drivers_saul capabilities. * * ## Usage * * To include this driver to your application, simply add one of the following * to the application's Makefile: * * ```make * # BME280 connected via SPI * USEMODULE += bme280_spi * # BME280 connected via I2C * USEMODULE += bme280_i2c * # BMP280 via SPI * USEMODULE += bmp280_spi * # BMP280 via I2C * USEMODULE += bmp280_i2c * * # When using I2C, specify the default I2C device to use, * # and the BME280's address (see datasheet). * # The values below are the defaults: * CFLAGS += -DBMX280_PARAM_I2C_DEV=I2C_DEV\(0\) * CFLAGS += -DBMX280_PARAM_I2C_ADDR=0x77 * * # Using SPI, you can override the default configuration by specifying the * # used SPI bus and the ship select pin: * CFLAGS += -DBMX280_PARAM_SPI_DEV=SPI_DEV\(x\) * CFLAGS += -DBMX280_PARAM_CS=GPIO_PIN\(y,z\) * ``` * * This way the default parameters in `drivers/bmx280/include/bmx280_params.h` * are replaced by these new values. * * @{ * @file * @brief Device driver interface for the BMP280 and BME280 sensors * * @details There are three sensor values that can be read: temperature, * pressure and humidity. The BME280 device usually measures them * all at once. It is possible to skip measuring either of the * values by changing the oversampling settings. The driver is * written in such a way that a measurement is only started from * the function that reads the temperature. In other words, you * always have to call bmx280_read_temperature, and then optionally * you can call the other two. * * @author Kees Bakker * @author Alexandre Abadie * @author Hauke Petersen */ #ifndef BMX280_H #define BMX280_H #include #include "saul.h" #if defined(MODULE_BME280_SPI) || defined(MODULE_BMP280_SPI) #define BMX280_USE_SPI #include "periph/spi.h" #else #include "periph/i2c.h" #endif #ifdef __cplusplus extern "C" { #endif /** * @brief Select the number or raw data bytes depending on the device type */ #if defined(MODULE_BME280_SPI) || defined(MODULE_BME280_I2C) #define BMX280_RAW_LEN (8U) #else #define BMX280_RAW_LEN (6U) #endif /** * @brief Calibration struct for the BMX280 sensor * * This must be read from the device at startup. */ typedef struct { uint16_t dig_T1; /**< T1 coefficient */ int16_t dig_T2; /**< T2 coefficient */ int16_t dig_T3; /**< T3 coefficient */ uint16_t dig_P1; /**< P1 coefficient */ int16_t dig_P2; /**< P2 coefficient */ int16_t dig_P3; /**< P3 coefficient */ int16_t dig_P4; /**< P4 coefficient */ int16_t dig_P5; /**< P5 coefficient */ int16_t dig_P6; /**< P6 coefficient */ int16_t dig_P7; /**< P7 coefficient */ int16_t dig_P8; /**< P8 coefficient */ int16_t dig_P9; /**< P9 coefficient */ uint8_t dig_H1; /**< H1 coefficient */ int16_t dig_H2; /**< H2 coefficient */ uint8_t dig_H3; /**< H3 coefficient */ int16_t dig_H4; /**< H4 coefficient */ int16_t dig_H5; /**< H5 coefficient */ int8_t dig_H6; /**< H6 coefficient */ } bmx280_calibration_t; /** * @brief Values for t_sb field of the BMX280 config register */ typedef enum { BMX280_SB_0_5 = 0x00, BMX280_SB_62_5 = 0x20, BMX280_SB_125 = 0x40, BMX280_SB_250 = 0x60, BMX280_SB_500 = 0x80, BMX280_SB_1000 = 0xa0, BMX280_SB_10 = 0xc0, BMX280_SB_20 = 0xe0, } bmx280_t_sb_t; /** * @brief Values for filter field of the BMX280 config register */ typedef enum { BMX280_FILTER_OFF = 0x00, BMX280_FILTER_2 = 0x04, BMX280_FILTER_4 = 0x08, BMX280_FILTER_8 = 0x0c, BMX280_FILTER_16 = 0x10, } bmx280_filter_t; /** * @brief Values for mode field of the BMX280 ctrl_meas register */ typedef enum { BMX280_MODE_SLEEP = 0x00, BMX280_MODE_FORCED = 0x01, BMX280_MODE_NORMAL = 0x03, } bmx280_mode_t; /** * @brief Values for oversampling settings * * These values are used for: * - osrs_h field of the BME280 ctrl_hum register * - osrs_t field of the BMX280 ctrl_meas register * - osrs_p field of the BMX280 ctrl_meas register */ typedef enum { BMX280_OSRS_SKIPPED = 0x00, BMX280_OSRS_X1 = 0x01, BMX280_OSRS_X2 = 0x02, BMX280_OSRS_X4 = 0x03, BMX280_OSRS_X8 = 0x04, BMX280_OSRS_X16 = 0x05, } bmx280_osrs_t; /** * @brief Parameters for the BMX280 sensor * * These parameters are needed to configure the device at startup. */ typedef struct { #ifdef BMX280_USE_SPI /* SPI configuration */ spi_t spi; /**< SPI bus */ spi_clk_t clk; /**< clock speed for the SPI bus */ gpio_t cs; /**< chip select pin */ #else /* I2C details */ i2c_t i2c_dev; /**< I2C device which is used */ uint8_t i2c_addr; /**< I2C address */ #endif /* Config Register */ bmx280_t_sb_t t_sb; /**< standby */ bmx280_filter_t filter; /**< filter coefficient */ /* ctrl_meas */ bmx280_mode_t run_mode; /**< ctrl_meas mode */ bmx280_osrs_t temp_oversample; /**< ctrl_meas osrs_t */ bmx280_osrs_t press_oversample; /**< ctrl_meas osrs_p */ /* ctrl_hum */ bmx280_osrs_t humid_oversample; /**< ctrl_hum osrs_h */ } bmx280_params_t; /** * @brief Device descriptor for the BMX280 sensor */ typedef struct { bmx280_params_t params; /**< Device Parameters */ bmx280_calibration_t calibration; /**< Calibration Data */ int32_t t_fine; /**< temperature compensation value */ uint8_t last_reading[BMX280_RAW_LEN]; /**< cache the RAW data */ } bmx280_t; /** * @brief Status and error return codes */ enum { BMX280_OK = 0, /**< everything was fine */ BMX280_ERR_BUS = -1, /**< bus error */ BMX280_ERR_NODEV = -2, /**< did not detect BME280 or BMP280 */ }; /** * @brief Export of SAUL interface for temperature sensor */ extern const saul_driver_t bmx280_temperature_saul_driver; /** * @brief Export of SAUL interface for pressure sensor */ extern const saul_driver_t bmx280_pressure_saul_driver; #if defined(MODULE_BME280_SPI) || defined(MODULE_BME280_I2C) /** * @brief Export of SAUL interface for humidity sensor */ extern const saul_driver_t bme280_relative_humidity_saul_driver; #endif /** * @brief Initialize the given BMX280 device * * @param[out] dev device descriptor of the given BMX280 device * @param[in] params static configuration parameters * * @return BMX280_OK on success * @return BMX280_ERR_BUS on bus error * @return BMX280_ERR_NODEV if no corresponding device was found on the bus */ int bmx280_init(bmx280_t* dev, const bmx280_params_t* params); /** * @brief Read temperature value from the given BMX280 device * * The measured temperature is returned in centi °C (x.xx°C). * * @param[in] dev device to read from * * @return measured temperature in centi Celsius * @return INT16_MIN on error */ int16_t bmx280_read_temperature(bmx280_t* dev); /** * @brief Read air pressure value from the given BMX280 device * * The air pressure is returned in PA (Pascal). * * This function returns the pressure data that was measured when * bmx280_read_temperature() has been called last. So bmx280_read_temperature() * has to be called before. * * If bmx280_read_temperatue() did not succeed in acquiring a new set of sensor * data, the result of this function is undefined. * * @param[in] dev device to read from * * @return air pressure in PA */ uint32_t bmx280_read_pressure(bmx280_t *dev); #if defined(MODULE_BME280_SPI) || defined(MODULE_BME280_I2C) || defined(DOXYGEN) /** * @brief Read humidity value from the given BME280 device * * The humidity is returned in centi %RH (x.xx% relative humidity). * * This function returns the pressure data that was measured when * bmx280_read_temperature() has been called last. So bmx280_read_temperature() * has to be called before. * * If bmx280_read_temperatue() did not succeed in acquiring a new set of sensor * data, the result of this function is undefined. * * @param[in] dev device to read from * * @return humidity in centi %RH (i.e. the percentage times 100) */ uint16_t bme280_read_humidity(bmx280_t *dev); #endif #ifdef __cplusplus } #endif #endif /* BMX280_H */ /** @} */