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| # BME280 sensor API | ||
| ## Introduction | ||
| This package contains the Bosch Sensortec's BME280 pressure sensor driver (sensor API) | ||
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| CONTENTS OF THIS FILE | ||
| ======================= | ||
| * Introduction | ||
| * Version | ||
| * Integration details | ||
| * Driver files information | ||
| * Supported sensor interface | ||
| * Copyright | ||
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| INTRODUCTION | ||
| =============== | ||
| - This package contains the Bosch Sensortec MEMS humidity sensor driver(sensor API) | ||
| - The sensor driver package includes bme280.h, bme280.c and bme280_support.c files | ||
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| VERSION | ||
| ========= | ||
| - Version of bme280 sensor driver is: | ||
| * bme280.c - V2.0.5 | ||
| * bme280.h - V2.0.5 | ||
| * bme280_support.c - V1.0.6 | ||
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| INTEGRATION DETAILS | ||
| ===================== | ||
| - Integrate bme280.h and bme280.c file in to your project. | ||
| - The bme280_support.c file contains only examples for API use cases, so it is not required to integrate into project. | ||
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| DRIVER FILES INFORMATION | ||
| =========================== | ||
| bme280.h | ||
| ----------- | ||
| * This header file has the register address definition, constant definitions, data type definition and supported sensor driver calls declarations. | ||
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| bme280.c | ||
| ------------ | ||
| * This file contains the implementation for the sensor driver APIs. | ||
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| bme280_support.c | ||
| ---------------------- | ||
| * This file shall be used as an user guidance, here you can find samples of | ||
| * Initialize the sensor with I2C/SPI communication | ||
| - Add your code to the SPI and/or I2C bus read and bus write functions. | ||
| - Return value can be chosen by yourself | ||
| - API just passes that value to your application code | ||
| - Add your code to the delay function | ||
| - Change I2C address accordingly in bme280.h | ||
| * Power mode configuration of the sensor | ||
| * Get and set functions usage | ||
| * Reading the sensor read out data | ||
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| SUPPORTED SENSOR INTERFACE | ||
| ==================================== | ||
| - This humidity sensor driver supports SPI and I2C interfaces | ||
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| COPYRIGHT | ||
| =========== | ||
| - Copyright (C) 2013 - 2016 Bosch Sensortec GmbH | ||
| The sensor driver package includes bme280.c, bme280.h and bme280_defs.h files. | ||
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| ## Version | ||
| File | Version | Date | ||
| -----|---------|----- | ||
| bme280.c | 3.2.0 | 21 Mar 2017 | ||
| bme280.h | 3.2.0 | 21 Mar 2017 | ||
| bme280_defs.h | 3.2.0 | 21 Mar 2017 | ||
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| ## Integration details | ||
| * Integrate bme280.h, bme280_defs.h and bme280.c file in to the project. | ||
| * Include the bme280.h file in your code like below. | ||
| ``` c | ||
| #include "bme280.h" | ||
| ``` | ||
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| ## File information | ||
| * bme280_defs.h : This header file has the constants, macros and datatype declarations. | ||
| * bme280.h : This header file contains the declarations of the sensor driver APIs. | ||
| * bme280.c : This source file contains the definitions of the sensor driver APIs. | ||
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| ## Supported sensor interfaces | ||
| * SPI 4-wire | ||
| * I2C | ||
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| SPI 3-wire is currently not supported in the API. | ||
| ## Usage guide | ||
| ### Initializing the sensor | ||
| To initialize the sensor, user need to create a device structure. User can do this by | ||
| creating an instance of the structure bme280_dev. After creating the device strcuture, user | ||
| need to fill in the various parameters as shown below. | ||
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| #### Example for SPI 4-Wire | ||
| ``` c | ||
| struct bme280_dev dev; | ||
| int8_t rslt = BME280_OK; | ||
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| /* Sensor_0 interface over SPI with native chip select line */ | ||
| dev.id = 0; | ||
| dev.interface = BME280_SPI_INTF; | ||
| dev.read = user_spi_read; | ||
| dev.write = user_spi_write; | ||
| dev.delay_ms = user_delay_ms; | ||
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| rslt = bme280_init(&dev); | ||
| ``` | ||
| #### Example for I2C | ||
| ``` c | ||
| struct bme280_dev dev; | ||
| int8_t rslt = BME280_OK; | ||
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| dev.id = BME280_I2C_ADDR_PRIM; | ||
| dev.interface = BME280_I2C_INTF; | ||
| dev.read = user_i2c_read; | ||
| dev.write = user_i2c_write; | ||
| dev.delay_ms = user_delay_ms; | ||
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| rslt = bme280_init(&dev); | ||
| ``` | ||
| Regarding compensation functions for temperature,pressure and humidity we have two implementations. | ||
| 1) Double precision floating point version | ||
| 2) Integer version | ||
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| By default, integer version is used in the API. If user needs double version, user has to | ||
| enable FLOATING_POINT_REPRESENTATION macro in bme280_defs.h file. | ||
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| In integer compensation functions, we also have below two implementations for pressure. | ||
| 1) For 32 bit machine. | ||
| 2) For 64 bit machine. | ||
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| By default, 64 bit variant is used in the API. If user wants 32 bit variant, user can disable the | ||
| macro MACHINE_64_BIT in bme280_defs.h file. | ||
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| ### Get sensor data | ||
| #### Get sensor data in forced mode | ||
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| ``` c | ||
| int8_t get_sensor_data_forced_mode(struct bme280_dev *dev) | ||
| { | ||
| int8_t rslt; | ||
| uint8_t settings_sel; | ||
| struct bme280_data comp_data; | ||
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| /* Continuously get the sensor data */ | ||
| while (1) { | ||
| dev->settings.osr_h = BME280_OVERSAMPLING_4X; | ||
| dev->settings.osr_p = BME280_OVERSAMPLING_4X; | ||
| dev->settings.osr_t = BME280_OVERSAMPLING_4X; | ||
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| settings_sel = BME280_OSR_PRESS_SEL|BME280_OSR_TEMP_SEL|BME280_OSR_HUM_SEL; | ||
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| rslt = bme280_set_sensor_settings(settings_sel, dev); | ||
| rslt = bme280_set_sensor_mode(BME280_FORCED_MODE, dev); | ||
| /* Give some delay for the sensor to go into force mode */ | ||
| dev->delay_ms(5); | ||
| rslt = bme280_get_sensor_data(BME280_PRESS | BME280_HUM | BME280_TEMP, &comp_data, dev); | ||
| print_sensor_data(&comp_data); | ||
| } | ||
| return rslt; | ||
| } | ||
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| void print_sensor_data(struct bme280_data *comp_data) | ||
| { | ||
| #ifdef FLOATING_POINT_REPRESENTATION | ||
| printf("%0.2f\t\t%0.2f\t\t%0.2f\t\n",comp_data->temperature, comp_data->pressure, comp_data->humidity); | ||
| #else | ||
| printf("%ld\t\t%ld\t\t%ld\t\n",comp_data->temperature, comp_data->pressure, comp_data->humidity); | ||
| #endif | ||
| } | ||
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| ``` | ||
| ##### Get sensor data in normal mode | ||
| ``` c | ||
| int8_t get_sensor_data_normal_mode(struct bme280_dev *dev) | ||
| { | ||
| int8_t rslt; | ||
| uint8_t settings_sel; | ||
| struct bme280_data comp_data; | ||
| dev->settings.osr_h = BME280_OVERSAMPLING_4X; | ||
| dev->settings.osr_p = BME280_OVERSAMPLING_4X; | ||
| dev->settings.osr_t = BME280_OVERSAMPLING_4X; | ||
| settings_sel = BME280_OSR_PRESS_SEL|BME280_OSR_TEMP_SEL|BME280_OSR_HUM_SEL; | ||
| rslt = bme280_set_sensor_settings(settings_sel, dev); | ||
| rslt = bme280_set_sensor_mode(BME280_NORMAL_MODE, dev); | ||
| /* Give some delay for the sensor to go into normal mode */ | ||
| dev->delay_ms(5); | ||
| while (1) { | ||
| rslt = bme280_get_sensor_data(BME280_PRESS | BME280_HUM | BME280_TEMP, &comp_data, dev); | ||
| print_sensor_data(&comp_data); | ||
| } | ||
| return rslt; | ||
| } | ||
| void print_sensor_data(struct bme280_data *comp_data) | ||
| { | ||
| #ifdef FLOATING_POINT_REPRESENTATION | ||
| printf("%0.2f\t\t%0.2f\t\t%0.2f\t\n",comp_data->temperature, comp_data->pressure, comp_data->humidity); | ||
| #else | ||
| printf("%ld\t\t%ld\t\t%ld\t\n",comp_data->temperature, comp_data->pressure, comp_data->humidity); | ||
| #endif | ||
| } | ||
| ``` | ||
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| ## Copyright (C) 2016 - 2017 Bosch Sensortec GmbH |
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