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bme280.c
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bme280.c
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/**\mainpage
* Copyright (C) 2016 - 2017 Bosch Sensortec GmbH
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* Neither the name of the copyright holder nor the names of the
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER
* OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
* OR CONSEQUENTIAL DAMAGES(INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE
*
* The information provided is believed to be accurate and reliable.
* The copyright holder assumes no responsibility
* for the consequences of use
* of such information nor for any infringement of patents or
* other rights of third parties which may result from its use.
* No license is granted by implication or otherwise under any patent or
* patent rights of the copyright holder.
*
* File bme280.c
* Date 14 Feb 2018
* Version 3.3.4
*
*/
/*! @file bme280.c
@brief Sensor driver for BME280 sensor */
#include "bme280.h"
/**\name Internal macros */
/* To identify osr settings selected by user */
#define OVERSAMPLING_SETTINGS UINT8_C(0x07)
/* To identify filter and standby settings selected by user */
#define FILTER_STANDBY_SETTINGS UINT8_C(0x18)
/*!
* @brief This internal API puts the device to sleep mode.
*
* @param[in] dev : Structure instance of bme280_dev.
*
* @return Result of API execution status.
* @retval zero -> Success / +ve value -> Warning / -ve value -> Error
*/
static int8_t put_device_to_sleep(const struct bme280_dev *dev);
/*!
* @brief This internal API writes the power mode in the sensor.
*
* @param[in] dev : Structure instance of bme280_dev.
* @param[in] sensor_mode : Variable which contains the power mode to be set.
*
* @return Result of API execution status.
* @retval zero -> Success / +ve value -> Warning / -ve value -> Error
*/
static int8_t write_power_mode(uint8_t sensor_mode, const struct bme280_dev *dev);
/*!
* @brief This internal API is used to validate the device pointer for
* null conditions.
*
* @param[in] dev : Structure instance of bme280_dev.
*
* @return Result of API execution status
* @retval zero -> Success / +ve value -> Warning / -ve value -> Error
*/
static int8_t null_ptr_check(const struct bme280_dev *dev);
/*!
* @brief This internal API interleaves the register address between the
* register data buffer for burst write operation.
*
* @param[in] reg_addr : Contains the register address array.
* @param[out] temp_buff : Contains the temporary buffer to store the
* register data and register address.
* @param[in] reg_data : Contains the register data to be written in the
* temporary buffer.
* @param[in] len : No of bytes of data to be written for burst write.
*/
static void interleave_reg_addr(const uint8_t *reg_addr, uint8_t *temp_buff, const uint8_t *reg_data, uint8_t len);
/*!
* @brief This internal API reads the calibration data from the sensor, parse
* it and store in the device structure.
*
* @param[in] dev : Structure instance of bme280_dev.
*
* @return Result of API execution status
* @retval zero -> Success / +ve value -> Warning / -ve value -> Error
*/
static int8_t get_calib_data(struct bme280_dev *dev);
/*!
* @brief This internal API is used to parse the temperature and
* pressure calibration data and store it in the device structure.
*
* @param[out] dev : Structure instance of bme280_dev to store the calib data.
* @param[in] reg_data : Contains the calibration data to be parsed.
*/
static void parse_temp_press_calib_data(const uint8_t *reg_data, struct bme280_dev *dev);
/*!
* @brief This internal API is used to parse the humidity calibration data
* and store it in device structure.
*
* @param[out] dev : Structure instance of bme280_dev to store the calib data.
* @param[in] reg_data : Contains calibration data to be parsed.
*/
static void parse_humidity_calib_data(const uint8_t *reg_data, struct bme280_dev *dev);
#ifdef BME280_FLOAT_ENABLE
/*!
* @brief This internal API is used to compensate the raw pressure data and
* return the compensated pressure data in double data type.
*
* @param[in] uncomp_data : Contains the uncompensated pressure data.
* @param[in] calib_data : Pointer to the calibration data structure.
*
* @return Compensated pressure data.
* @retval Compensated pressure data in double.
*/
static double compensate_pressure(const struct bme280_uncomp_data *uncomp_data,
const struct bme280_calib_data *calib_data);
/*!
* @brief This internal API is used to compensate the raw humidity data and
* return the compensated humidity data in double data type.
*
* @param[in] uncomp_data : Contains the uncompensated humidity data.
* @param[in] calib_data : Pointer to the calibration data structure.
*
* @return Compensated humidity data.
* @retval Compensated humidity data in double.
*/
static double compensate_humidity(const struct bme280_uncomp_data *uncomp_data,
const struct bme280_calib_data *calib_data);
/*!
* @brief This internal API is used to compensate the raw temperature data and
* return the compensated temperature data in double data type.
*
* @param[in] uncomp_data : Contains the uncompensated temperature data.
* @param[in] calib_data : Pointer to calibration data structure.
*
* @return Compensated temperature data.
* @retval Compensated temperature data in double.
*/
static double compensate_temperature(const struct bme280_uncomp_data *uncomp_data,
struct bme280_calib_data *calib_data);
#else
/*!
* @brief This internal API is used to compensate the raw temperature data and
* return the compensated temperature data in integer data type.
*
* @param[in] uncomp_data : Contains the uncompensated temperature data.
* @param[in] calib_data : Pointer to calibration data structure.
*
* @return Compensated temperature data.
* @retval Compensated temperature data in integer.
*/
static int32_t compensate_temperature(const struct bme280_uncomp_data *uncomp_data,
struct bme280_calib_data *calib_data);
/*!
* @brief This internal API is used to compensate the raw pressure data and
* return the compensated pressure data in integer data type.
*
* @param[in] uncomp_data : Contains the uncompensated pressure data.
* @param[in] calib_data : Pointer to the calibration data structure.
*
* @return Compensated pressure data.
* @retval Compensated pressure data in integer.
*/
static uint32_t compensate_pressure(const struct bme280_uncomp_data *uncomp_data,
const struct bme280_calib_data *calib_data);
/*!
* @brief This internal API is used to compensate the raw humidity data and
* return the compensated humidity data in integer data type.
*
* @param[in] uncomp_data : Contains the uncompensated humidity data.
* @param[in] calib_data : Pointer to the calibration data structure.
*
* @return Compensated humidity data.
* @retval Compensated humidity data in integer.
*/
static uint32_t compensate_humidity(const struct bme280_uncomp_data *uncomp_data,
const struct bme280_calib_data *calib_data);
#endif
/*!
* @brief This internal API is used to identify the settings which the user
* wants to modify in the sensor.
*
* @param[in] sub_settings : Contains the settings subset to identify particular
* group of settings which the user is interested to change.
* @param[in] desired_settings : Contains the user specified settings.
*
* @return Indicates whether user is interested to modify the settings which
* are related to sub_settings.
* @retval True -> User wants to modify this group of settings
* @retval False -> User does not want to modify this group of settings
*/
static uint8_t are_settings_changed(uint8_t sub_settings, uint8_t desired_settings);
/*!
* @brief This API sets the humidity oversampling settings of the sensor.
*
* @param[in] dev : Structure instance of bme280_dev.
*
* @return Result of API execution status
* @retval zero -> Success / +ve value -> Warning / -ve value -> Error
*/
static int8_t set_osr_humidity_settings(const struct bme280_settings *settings, const struct bme280_dev *dev);
/*!
* @brief This internal API sets the oversampling settings for pressure,
* temperature and humidity in the sensor.
*
* @param[in] desired_settings : Variable used to select the settings which
* are to be set.
* @param[in] dev : Structure instance of bme280_dev.
*
* @return Result of API execution status
* @retval zero -> Success / +ve value -> Warning / -ve value -> Error
*/
static int8_t set_osr_settings(uint8_t desired_settings, const struct bme280_settings *settings,
const struct bme280_dev *dev);
/*!
* @brief This API sets the pressure and/or temperature oversampling settings
* in the sensor according to the settings selected by the user.
*
* @param[in] dev : Structure instance of bme280_dev.
* @param[in] desired_settings: variable to select the pressure and/or
* temperature oversampling settings.
*
* @return Result of API execution status
* @retval zero -> Success / +ve value -> Warning / -ve value -> Error
*/
static int8_t set_osr_press_temp_settings(uint8_t desired_settings, const struct bme280_settings *settings,
const struct bme280_dev *dev);
/*!
* @brief This internal API fills the pressure oversampling settings provided by
* the user in the data buffer so as to write in the sensor.
*
* @param[in] dev : Structure instance of bme280_dev.
* @param[out] reg_data : Variable which is filled according to the pressure
* oversampling data provided by the user.
*/
static void fill_osr_press_settings(uint8_t *reg_data, const struct bme280_settings *settings);
/*!
* @brief This internal API fills the temperature oversampling settings provided
* by the user in the data buffer so as to write in the sensor.
*
* @param[in] dev : Structure instance of bme280_dev.
* @param[out] reg_data : Variable which is filled according to the temperature
* oversampling data provided by the user.
*/
static void fill_osr_temp_settings(uint8_t *reg_data, const struct bme280_settings *settings);
/*!
* @brief This internal API sets the filter and/or standby duration settings
* in the sensor according to the settings selected by the user.
*
* @param[in] dev : Structure instance of bme280_dev.
* @param[in] desired_settings : variable to select the filter and/or
* standby duration settings.
*
* @return Result of API execution status
* @retval zero -> Success / +ve value -> Warning / -ve value -> Error
*/
static int8_t set_filter_standby_settings(uint8_t desired_settings, const struct bme280_settings *settings,
const struct bme280_dev *dev);
/*!
* @brief This internal API fills the filter settings provided by the user
* in the data buffer so as to write in the sensor.
*
* @param[in] dev : Structure instance of bme280_dev.
* @param[out] reg_data : Variable which is filled according to the filter
* settings data provided by the user.
*/
static void fill_filter_settings(uint8_t *reg_data, const struct bme280_settings *settings);
/*!
* @brief This internal API fills the standby duration settings provided by the
* user in the data buffer so as to write in the sensor.
*
* @param[in] dev : Structure instance of bme280_dev.
* @param[out] reg_data : Variable which is filled according to the standby
* settings data provided by the user.
*/
static void fill_standby_settings(uint8_t *reg_data, const struct bme280_settings *settings);
/*!
* @brief This internal API parse the oversampling(pressure, temperature
* and humidity), filter and standby duration settings and store in the
* device structure.
*
* @param[out] dev : Structure instance of bme280_dev.
* @param[in] reg_data : Register data to be parsed.
*/
static void parse_device_settings(const uint8_t *reg_data, struct bme280_settings *settings);
/*!
* @brief This internal API reloads the already existing device settings in the
* sensor after soft reset.
*
* @param[in] dev : Structure instance of bme280_dev.
* @param[in] settings : Pointer variable which contains the settings to
* be set in the sensor.
*
* @return Result of API execution status
* @retval zero -> Success / +ve value -> Warning / -ve value -> Error
*/
static int8_t reload_device_settings(const struct bme280_settings *settings, const struct bme280_dev *dev);
/****************** Global Function Definitions *******************************/
/*!
* @brief This API is the entry point.
* It reads the chip-id and calibration data from the sensor.
*/
int8_t bme280_init(struct bme280_dev *dev)
{
int8_t rslt;
/* chip id read try count */
uint8_t try_count = 5;
uint8_t chip_id = 0;
/* Check for null pointer in the device structure*/
rslt = null_ptr_check(dev);
/* Proceed if null check is fine */
if (rslt == BME280_OK) {
while (try_count) {
/* Read the chip-id of bme280 sensor */
rslt = bme280_get_regs(BME280_CHIP_ID_ADDR, &chip_id, 1, dev);
/* Check for chip id validity */
if ((rslt == BME280_OK) && (chip_id == BME280_CHIP_ID)) {
dev->chip_id = chip_id;
/* Reset the sensor */
rslt = bme280_soft_reset(dev);
if (rslt == BME280_OK) {
/* Read the calibration data */
rslt = get_calib_data(dev);
}
break;
}
/* Wait for 1 ms */
dev->delay_ms(1);
--try_count;
}
/* Chip id check failed */
if (!try_count)
rslt = BME280_E_DEV_NOT_FOUND;
}
return rslt;
}
/*!
* @brief This API reads the data from the given register address of the sensor.
*/
int8_t bme280_get_regs(uint8_t reg_addr, uint8_t *reg_data, uint16_t len, const struct bme280_dev *dev)
{
int8_t rslt;
/* Check for null pointer in the device structure*/
rslt = null_ptr_check(dev);
/* Proceed if null check is fine */
if (rslt == BME280_OK) {
/* If interface selected is SPI */
if (dev->intf != BME280_I2C_INTF)
reg_addr = reg_addr | 0x80;
/* Read the data */
rslt = dev->read(dev->dev_id, reg_addr, reg_data, len);
/* Check for communication error */
if (rslt != BME280_OK)
rslt = BME280_E_COMM_FAIL;
}
return rslt;
}
/*!
* @brief This API writes the given data to the register address
* of the sensor.
*/
int8_t bme280_set_regs(uint8_t *reg_addr, const uint8_t *reg_data, uint8_t len, const struct bme280_dev *dev)
{
int8_t rslt;
uint8_t temp_buff[20]; /* Typically not to write more than 10 registers */
if (len > 10)
len = 10;
uint16_t temp_len;
uint8_t reg_addr_cnt;
/* Check for null pointer in the device structure*/
rslt = null_ptr_check(dev);
/* Check for arguments validity */
if ((rslt == BME280_OK) && (reg_addr != NULL) && (reg_data != NULL)) {
if (len != 0) {
temp_buff[0] = reg_data[0];
/* If interface selected is SPI */
if (dev->intf != BME280_I2C_INTF) {
for (reg_addr_cnt = 0; reg_addr_cnt < len; reg_addr_cnt++)
reg_addr[reg_addr_cnt] = reg_addr[reg_addr_cnt] & 0x7F;
}
/* Burst write mode */
if (len > 1) {
/* Interleave register address w.r.t data for
burst write*/
interleave_reg_addr(reg_addr, temp_buff, reg_data, len);
temp_len = ((len * 2) - 1);
} else {
temp_len = len;
}
rslt = dev->write(dev->dev_id, reg_addr[0], temp_buff, temp_len);
/* Check for communication error */
if (rslt != BME280_OK)
rslt = BME280_E_COMM_FAIL;
} else {
rslt = BME280_E_INVALID_LEN;
}
} else {
rslt = BME280_E_NULL_PTR;
}
return rslt;
}
/*!
* @brief This API sets the oversampling, filter and standby duration
* (normal mode) settings in the sensor.
*/
int8_t bme280_set_sensor_settings(uint8_t desired_settings, const struct bme280_dev *dev)
{
int8_t rslt;
uint8_t sensor_mode;
/* Check for null pointer in the device structure*/
rslt = null_ptr_check(dev);
/* Proceed if null check is fine */
if (rslt == BME280_OK) {
rslt = bme280_get_sensor_mode(&sensor_mode, dev);
if ((rslt == BME280_OK) && (sensor_mode != BME280_SLEEP_MODE))
rslt = put_device_to_sleep(dev);
if (rslt == BME280_OK) {
/* Check if user wants to change oversampling
settings */
if (are_settings_changed(OVERSAMPLING_SETTINGS, desired_settings))
rslt = set_osr_settings(desired_settings, &dev->settings, dev);
/* Check if user wants to change filter and/or
standby settings */
if ((rslt == BME280_OK) && are_settings_changed(FILTER_STANDBY_SETTINGS, desired_settings))
rslt = set_filter_standby_settings(desired_settings, &dev->settings, dev);
}
}
return rslt;
}
/*!
* @brief This API gets the oversampling, filter and standby duration
* (normal mode) settings from the sensor.
*/
int8_t bme280_get_sensor_settings(struct bme280_dev *dev)
{
int8_t rslt;
uint8_t reg_data[4];
/* Check for null pointer in the device structure*/
rslt = null_ptr_check(dev);
/* Proceed if null check is fine */
if (rslt == BME280_OK) {
rslt = bme280_get_regs(BME280_CTRL_HUM_ADDR, reg_data, 4, dev);
if (rslt == BME280_OK)
parse_device_settings(reg_data, &dev->settings);
}
return rslt;
}
/*!
* @brief This API sets the power mode of the sensor.
*/
int8_t bme280_set_sensor_mode(uint8_t sensor_mode, const struct bme280_dev *dev)
{
int8_t rslt;
uint8_t last_set_mode;
/* Check for null pointer in the device structure*/
rslt = null_ptr_check(dev);
if (rslt == BME280_OK) {
rslt = bme280_get_sensor_mode(&last_set_mode, dev);
/* If the sensor is not in sleep mode put the device to sleep
mode */
if ((rslt == BME280_OK) && (last_set_mode != BME280_SLEEP_MODE))
rslt = put_device_to_sleep(dev);
/* Set the power mode */
if (rslt == BME280_OK)
rslt = write_power_mode(sensor_mode, dev);
}
return rslt;
}
/*!
* @brief This API gets the power mode of the sensor.
*/
int8_t bme280_get_sensor_mode(uint8_t *sensor_mode, const struct bme280_dev *dev)
{
int8_t rslt;
/* Check for null pointer in the device structure*/
rslt = null_ptr_check(dev);
if (rslt == BME280_OK) {
/* Read the power mode register */
rslt = bme280_get_regs(BME280_PWR_CTRL_ADDR, sensor_mode, 1, dev);
/* Assign the power mode in the device structure */
*sensor_mode = BME280_GET_BITS_POS_0(*sensor_mode, BME280_SENSOR_MODE);
}
return rslt;
}
/*!
* @brief This API performs the soft reset of the sensor.
*/
int8_t bme280_soft_reset(const struct bme280_dev *dev)
{
int8_t rslt;
uint8_t reg_addr = BME280_RESET_ADDR;
/* 0xB6 is the soft reset command */
uint8_t soft_rst_cmd = 0xB6;
/* Check for null pointer in the device structure*/
rslt = null_ptr_check(dev);
/* Proceed if null check is fine */
if (rslt == BME280_OK) {
/* Write the soft reset command in the sensor */
rslt = bme280_set_regs(®_addr, &soft_rst_cmd, 1, dev);
/* As per data sheet, startup time is 2 ms. */
dev->delay_ms(2);
}
return rslt;
}
/*!
* @brief This API reads the pressure, temperature and humidity data from the
* sensor, compensates the data and store it in the bme280_data structure
* instance passed by the user.
*/
int8_t bme280_get_sensor_data(uint8_t sensor_comp, struct bme280_data *comp_data, struct bme280_dev *dev)
{
int8_t rslt;
/* Array to store the pressure, temperature and humidity data read from
the sensor */
uint8_t reg_data[BME280_P_T_H_DATA_LEN] = {0};
struct bme280_uncomp_data uncomp_data = {0};
/* Check for null pointer in the device structure*/
rslt = null_ptr_check(dev);
if ((rslt == BME280_OK) && (comp_data != NULL)) {
/* Read the pressure and temperature data from the sensor */
rslt = bme280_get_regs(BME280_DATA_ADDR, reg_data, BME280_P_T_H_DATA_LEN, dev);
if (rslt == BME280_OK) {
/* Parse the read data from the sensor */
bme280_parse_sensor_data(reg_data, &uncomp_data);
/* Compensate the pressure and/or temperature and/or
humidity data from the sensor */
rslt = bme280_compensate_data(sensor_comp, &uncomp_data, comp_data, &dev->calib_data);
}
} else {
rslt = BME280_E_NULL_PTR;
}
return rslt;
}
/*!
* @brief This API is used to parse the pressure, temperature and
* humidity data and store it in the bme280_uncomp_data structure instance.
*/
void bme280_parse_sensor_data(const uint8_t *reg_data, struct bme280_uncomp_data *uncomp_data)
{
/* Variables to store the sensor data */
uint32_t data_xlsb;
uint32_t data_lsb;
uint32_t data_msb;
/* Store the parsed register values for pressure data */
data_msb = (uint32_t)reg_data[0] << 12;
data_lsb = (uint32_t)reg_data[1] << 4;
data_xlsb = (uint32_t)reg_data[2] >> 4;
uncomp_data->pressure = data_msb | data_lsb | data_xlsb;
/* Store the parsed register values for temperature data */
data_msb = (uint32_t)reg_data[3] << 12;
data_lsb = (uint32_t)reg_data[4] << 4;
data_xlsb = (uint32_t)reg_data[5] >> 4;
uncomp_data->temperature = data_msb | data_lsb | data_xlsb;
/* Store the parsed register values for temperature data */
data_lsb = (uint32_t)reg_data[6] << 8;
data_msb = (uint32_t)reg_data[7];
uncomp_data->humidity = data_msb | data_lsb;
}
/*!
* @brief This API is used to compensate the pressure and/or
* temperature and/or humidity data according to the component selected
* by the user.
*/
int8_t bme280_compensate_data(uint8_t sensor_comp, const struct bme280_uncomp_data *uncomp_data,
struct bme280_data *comp_data, struct bme280_calib_data *calib_data)
{
int8_t rslt = BME280_OK;
if ((uncomp_data != NULL) && (comp_data != NULL) && (calib_data != NULL)) {
/* Initialize to zero */
comp_data->temperature = 0;
comp_data->pressure = 0;
comp_data->humidity = 0;
/* If pressure or temperature component is selected */
if (sensor_comp & (BME280_PRESS | BME280_TEMP | BME280_HUM)) {
/* Compensate the temperature data */
comp_data->temperature = compensate_temperature(uncomp_data, calib_data);
}
if (sensor_comp & BME280_PRESS) {
/* Compensate the pressure data */
comp_data->pressure = compensate_pressure(uncomp_data, calib_data);
}
if (sensor_comp & BME280_HUM) {
/* Compensate the humidity data */
comp_data->humidity = compensate_humidity(uncomp_data, calib_data);
}
} else {
rslt = BME280_E_NULL_PTR;
}
return rslt;
}
/*!
* @brief This internal API sets the oversampling settings for pressure,
* temperature and humidity in the sensor.
*/
static int8_t set_osr_settings(uint8_t desired_settings, const struct bme280_settings *settings,
const struct bme280_dev *dev)
{
int8_t rslt = BME280_W_INVALID_OSR_MACRO;
if (desired_settings & BME280_OSR_HUM_SEL)
rslt = set_osr_humidity_settings(settings, dev);
if (desired_settings & (BME280_OSR_PRESS_SEL | BME280_OSR_TEMP_SEL))
rslt = set_osr_press_temp_settings(desired_settings, settings, dev);
return rslt;
}
/*!
* @brief This API sets the humidity oversampling settings of the sensor.
*/
static int8_t set_osr_humidity_settings(const struct bme280_settings *settings, const struct bme280_dev *dev)
{
int8_t rslt;
uint8_t ctrl_hum;
uint8_t ctrl_meas;
uint8_t reg_addr = BME280_CTRL_HUM_ADDR;
ctrl_hum = settings->osr_h & BME280_CTRL_HUM_MSK;
/* Write the humidity control value in the register */
rslt = bme280_set_regs(®_addr, &ctrl_hum, 1, dev);
/* Humidity related changes will be only effective after a
write operation to ctrl_meas register */
if (rslt == BME280_OK) {
reg_addr = BME280_CTRL_MEAS_ADDR;
rslt = bme280_get_regs(reg_addr, &ctrl_meas, 1, dev);
if (rslt == BME280_OK)
rslt = bme280_set_regs(®_addr, &ctrl_meas, 1, dev);
}
return rslt;
}
/*!
* @brief This API sets the pressure and/or temperature oversampling settings
* in the sensor according to the settings selected by the user.
*/
static int8_t set_osr_press_temp_settings(uint8_t desired_settings, const struct bme280_settings *settings,
const struct bme280_dev *dev)
{
int8_t rslt;
uint8_t reg_addr = BME280_CTRL_MEAS_ADDR;
uint8_t reg_data;
rslt = bme280_get_regs(reg_addr, ®_data, 1, dev);
if (rslt == BME280_OK) {
if (desired_settings & BME280_OSR_PRESS_SEL)
fill_osr_press_settings(®_data, settings);
if (desired_settings & BME280_OSR_TEMP_SEL)
fill_osr_temp_settings(®_data, settings);
/* Write the oversampling settings in the register */
rslt = bme280_set_regs(®_addr, ®_data, 1, dev);
}
return rslt;
}
/*!
* @brief This internal API sets the filter and/or standby duration settings
* in the sensor according to the settings selected by the user.
*/
static int8_t set_filter_standby_settings(uint8_t desired_settings, const struct bme280_settings *settings,
const struct bme280_dev *dev)
{
int8_t rslt;
uint8_t reg_addr = BME280_CONFIG_ADDR;
uint8_t reg_data;
rslt = bme280_get_regs(reg_addr, ®_data, 1, dev);
if (rslt == BME280_OK) {
if (desired_settings & BME280_FILTER_SEL)
fill_filter_settings(®_data, settings);
if (desired_settings & BME280_STANDBY_SEL)
fill_standby_settings(®_data, settings);
/* Write the oversampling settings in the register */
rslt = bme280_set_regs(®_addr, ®_data, 1, dev);
}
return rslt;
}
/*!
* @brief This internal API fills the filter settings provided by the user
* in the data buffer so as to write in the sensor.
*/
static void fill_filter_settings(uint8_t *reg_data, const struct bme280_settings *settings)
{
*reg_data = BME280_SET_BITS(*reg_data, BME280_FILTER, settings->filter);
}
/*!
* @brief This internal API fills the standby duration settings provided by
* the user in the data buffer so as to write in the sensor.
*/
static void fill_standby_settings(uint8_t *reg_data, const struct bme280_settings *settings)
{
*reg_data = BME280_SET_BITS(*reg_data, BME280_STANDBY, settings->standby_time);
}
/*!
* @brief This internal API fills the pressure oversampling settings provided by
* the user in the data buffer so as to write in the sensor.
*/
static void fill_osr_press_settings(uint8_t *reg_data, const struct bme280_settings *settings)
{
*reg_data = BME280_SET_BITS(*reg_data, BME280_CTRL_PRESS, settings->osr_p);
}
/*!
* @brief This internal API fills the temperature oversampling settings
* provided by the user in the data buffer so as to write in the sensor.
*/
static void fill_osr_temp_settings(uint8_t *reg_data, const struct bme280_settings *settings)
{
*reg_data = BME280_SET_BITS(*reg_data, BME280_CTRL_TEMP, settings->osr_t);
}
/*!
* @brief This internal API parse the oversampling(pressure, temperature
* and humidity), filter and standby duration settings and store in the
* device structure.
*/
static void parse_device_settings(const uint8_t *reg_data, struct bme280_settings *settings)
{
settings->osr_h = BME280_GET_BITS_POS_0(reg_data[0], BME280_CTRL_HUM);
settings->osr_p = BME280_GET_BITS(reg_data[2], BME280_CTRL_PRESS);
settings->osr_t = BME280_GET_BITS(reg_data[2], BME280_CTRL_TEMP);
settings->filter = BME280_GET_BITS(reg_data[3], BME280_FILTER);
settings->standby_time = BME280_GET_BITS(reg_data[3], BME280_STANDBY);
}
/*!
* @brief This internal API writes the power mode in the sensor.
*/
static int8_t write_power_mode(uint8_t sensor_mode, const struct bme280_dev *dev)
{
int8_t rslt;
uint8_t reg_addr = BME280_PWR_CTRL_ADDR;
/* Variable to store the value read from power mode register */
uint8_t sensor_mode_reg_val;
/* Read the power mode register */
rslt = bme280_get_regs(reg_addr, &sensor_mode_reg_val, 1, dev);
/* Set the power mode */
if (rslt == BME280_OK) {
sensor_mode_reg_val = BME280_SET_BITS_POS_0(sensor_mode_reg_val, BME280_SENSOR_MODE, sensor_mode);
/* Write the power mode in the register */
rslt = bme280_set_regs(®_addr, &sensor_mode_reg_val, 1, dev);
}
return rslt;
}
/*!
* @brief This internal API puts the device to sleep mode.
*/
static int8_t put_device_to_sleep(const struct bme280_dev *dev)
{
int8_t rslt;
uint8_t reg_data[4];
struct bme280_settings settings;
rslt = bme280_get_regs(BME280_CTRL_HUM_ADDR, reg_data, 4, dev);
if (rslt == BME280_OK) {
parse_device_settings(reg_data, &settings);
rslt = bme280_soft_reset(dev);
if (rslt == BME280_OK)
rslt = reload_device_settings(&settings, dev);
}
return rslt;
}
/*!
* @brief This internal API reloads the already existing device settings in
* the sensor after soft reset.
*/
static int8_t reload_device_settings(const struct bme280_settings *settings, const struct bme280_dev *dev)
{
int8_t rslt;
rslt = set_osr_settings(BME280_ALL_SETTINGS_SEL, settings, dev);
if (rslt == BME280_OK)
rslt = set_filter_standby_settings(BME280_ALL_SETTINGS_SEL, settings, dev);
return rslt;
}
#ifdef BME280_FLOAT_ENABLE
/*!
* @brief This internal API is used to compensate the raw temperature data and
* return the compensated temperature data in double data type.
*/
static double compensate_temperature(const struct bme280_uncomp_data *uncomp_data,
struct bme280_calib_data *calib_data)
{
double var1;
double var2;
double temperature;
double temperature_min = -40;
double temperature_max = 85;
var1 = ((double)uncomp_data->temperature) / 16384.0 - ((double)calib_data->dig_T1) / 1024.0;
var1 = var1 * ((double)calib_data->dig_T2);
var2 = (((double)uncomp_data->temperature) / 131072.0 - ((double)calib_data->dig_T1) / 8192.0);
var2 = (var2 * var2) * ((double)calib_data->dig_T3);
calib_data->t_fine = (int32_t)(var1 + var2);
temperature = (var1 + var2) / 5120.0;
if (temperature < temperature_min)
temperature = temperature_min;
else if (temperature > temperature_max)
temperature = temperature_max;
return temperature;
}
/*!
* @brief This internal API is used to compensate the raw pressure data and
* return the compensated pressure data in double data type.
*/
static double compensate_pressure(const struct bme280_uncomp_data *uncomp_data,
const struct bme280_calib_data *calib_data)
{
double var1;
double var2;
double var3;
double pressure;
double pressure_min = 30000.0;
double pressure_max = 110000.0;
var1 = ((double)calib_data->t_fine / 2.0) - 64000.0;
var2 = var1 * var1 * ((double)calib_data->dig_P6) / 32768.0;
var2 = var2 + var1 * ((double)calib_data->dig_P5) * 2.0;
var2 = (var2 / 4.0) + (((double)calib_data->dig_P4) * 65536.0);
var3 = ((double)calib_data->dig_P3) * var1 * var1 / 524288.0;
var1 = (var3 + ((double)calib_data->dig_P2) * var1) / 524288.0;
var1 = (1.0 + var1 / 32768.0) * ((double)calib_data->dig_P1);
/* avoid exception caused by division by zero */
if (var1) {
pressure = 1048576.0 - (double) uncomp_data->pressure;
pressure = (pressure - (var2 / 4096.0)) * 6250.0 / var1;
var1 = ((double)calib_data->dig_P9) * pressure * pressure / 2147483648.0;
var2 = pressure * ((double)calib_data->dig_P8) / 32768.0;
pressure = pressure + (var1 + var2 + ((double)calib_data->dig_P7)) / 16.0;
if (pressure < pressure_min)
pressure = pressure_min;
else if (pressure > pressure_max)
pressure = pressure_max;
} else { /* Invalid case */
pressure = pressure_min;
}
return pressure;
}
/*!
* @brief This internal API is used to compensate the raw humidity data and
* return the compensated humidity data in double data type.
*/
static double compensate_humidity(const struct bme280_uncomp_data *uncomp_data,
const struct bme280_calib_data *calib_data)
{
double humidity;
double humidity_min = 0.0;
double humidity_max = 100.0;
double var1;
double var2;
double var3;
double var4;
double var5;
double var6;
var1 = ((double)calib_data->t_fine) - 76800.0;
var2 = (((double)calib_data->dig_H4) * 64.0 + (((double)calib_data->dig_H5) / 16384.0) * var1);
var3 = uncomp_data->humidity - var2;
var4 = ((double)calib_data->dig_H2) / 65536.0;
var5 = (1.0 + (((double)calib_data->dig_H3) / 67108864.0) * var1);
var6 = 1.0 + (((double)calib_data->dig_H6) / 67108864.0) * var1 * var5;
var6 = var3 * var4 * (var5 * var6);
humidity = var6 * (1.0 - ((double)calib_data->dig_H1) * var6 / 524288.0);
if (humidity > humidity_max)
humidity = humidity_max;
else if (humidity < humidity_min)
humidity = humidity_min;
return humidity;
}
#else
/*!
* @brief This internal API is used to compensate the raw temperature data and
* return the compensated temperature data in integer data type.
*/
static int32_t compensate_temperature(const struct bme280_uncomp_data *uncomp_data,
struct bme280_calib_data *calib_data)
{
int32_t var1;
int32_t var2;
int32_t temperature;
int32_t temperature_min = -4000;
int32_t temperature_max = 8500;
var1 = (int32_t)((uncomp_data->temperature / 8) - ((int32_t)calib_data->dig_T1 * 2));
var1 = (var1 * ((int32_t)calib_data->dig_T2)) / 2048;
var2 = (int32_t)((uncomp_data->temperature / 16) - ((int32_t)calib_data->dig_T1));
var2 = (((var2 * var2) / 4096) * ((int32_t)calib_data->dig_T3)) / 16384;
calib_data->t_fine = var1 + var2;