From 11517648d32bc8213c38a987ec389f40feb5748e Mon Sep 17 00:00:00 2001 From: Daniel Friesel Date: Fri, 25 Oct 2019 11:27:34 +0200 Subject: Add BME280 driver --- src/driver/bme280.cc | 1178 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1178 insertions(+) create mode 100644 src/driver/bme280.cc (limited to 'src/driver/bme280.cc') diff --git a/src/driver/bme280.cc b/src/driver/bme280.cc new file mode 100644 index 0000000..69ef445 --- /dev/null +++ b/src/driver/bme280.cc @@ -0,0 +1,1178 @@ +/* + * /\ + * / \ + * / !! \ + * /______\ + * + * In order to use the I2C interface, CSB needs to be pulled up before turning + * on VDDIO (and after VDD). On most BME280 breakout boards sold on + * AliExpress and similar sites, VDD and VDDIO are connected and there is only + * one external VCC input, so following the power sequence outlined in the + * datasheet is not possible. Additionally, the pull-up resistor connecting + * CSB to VCC may delay logic high level on CSB long enough for the BM280 + * to start in SPI mode. + * + * In this case, you should connect (or power up, when using GPIO power) + * breakout board pins in the following order: + * * GND, SDA, SCLD + * * CSB to 3V3 + * * VDD to 3V3 + */ + +/**\mainpage + * Copyright (C) 2018 - 2019 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 26 Aug 2019 + * Version 3.3.7 + * + */ + +/*! @file bme280.c + * @brief Sensor driver for BME280 sensor + */ +#include "driver/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) + + +/****************** 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() +{ + 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(); + + /* Proceed if null check is fine */ + if (rslt == BME280_OK) + { + while (try_count) + { + /* Read the chip-id of bme280 sensor */ + rslt = get_regs(BME280_CHIP_ID_ADDR, &chip_id, 1); + + /* Check for chip id validity */ + if ((rslt == BME280_OK) && (chip_id == BME280_CHIP_ID)) + { + /* Reset the sensor */ + rslt = soft_reset(); + if (rslt == BME280_OK) + { + /* Read the calibration data */ + rslt = get_calib_data(); + } + break; + } + + /* Wait for 1 ms */ + 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) +{ + int8_t rslt; + + /* Check for null pointer in the device structure*/ + rslt = null_ptr_check(); + + /* Proceed if null check is fine */ + if (rslt == BME280_OK) + { + /* If interface selected is SPI */ + if (intf != BME280_I2C_INTF) + { + reg_addr = reg_addr | 0x80; + } + + /* Read the data */ + rslt = read(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) +{ + 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(); + + /* 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 (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 = write(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) +{ + int8_t rslt; + uint8_t sensor_mode; + + /* Check for null pointer in the device structure*/ + rslt = null_ptr_check(); + + /* Proceed if null check is fine */ + if (rslt == BME280_OK) + { + rslt = get_sensor_mode(&sensor_mode); + if ((rslt == BME280_OK) && (sensor_mode != BME280_SLEEP_MODE)) + { + rslt = put_device_to_sleep(); + } + 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, &settings); + } + + /* 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, &settings); + } + } + } + + return rslt; +} + +/*! + * @brief This API gets the oversampling, filter and standby duration + * (normal mode) settings from the sensor. + */ +int8_t BME280::get_sensor_settings() +{ + int8_t rslt; + uint8_t reg_data[4]; + + /* Check for null pointer in the device structure*/ + rslt = null_ptr_check(); + + /* Proceed if null check is fine */ + if (rslt == BME280_OK) + { + rslt = get_regs(BME280_CTRL_HUM_ADDR, reg_data, 4); + if (rslt == BME280_OK) + { + parse_device_settings(reg_data, &settings); + } + } + + return rslt; +} + +/*! + * @brief This API sets the power mode of the sensor. + */ +int8_t BME280::set_sensor_mode(uint8_t sensor_mode) +{ + int8_t rslt; + uint8_t last_set_mode; + + /* Check for null pointer in the device structure*/ + rslt = null_ptr_check(); + if (rslt == BME280_OK) + { + rslt = get_sensor_mode(&last_set_mode); + + /* 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(); + } + + /* Set the power mode */ + if (rslt == BME280_OK) + { + rslt = write_power_mode(sensor_mode); + } + } + + return rslt; +} + +/*! + * @brief This API gets the power mode of the sensor. + */ +int8_t BME280::get_sensor_mode(uint8_t *sensor_mode) +{ + int8_t rslt; + + /* Check for null pointer in the device structure*/ + rslt = null_ptr_check(); + if (rslt == BME280_OK) + { + /* Read the power mode register */ + rslt = get_regs(BME280_PWR_CTRL_ADDR, sensor_mode, 1); + + /* 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() +{ + int8_t rslt; + uint8_t reg_addr = BME280_RESET_ADDR; + uint8_t status_reg = 0; + uint8_t try_run = 5; + + /* 0xB6 is the soft reset command */ + uint8_t soft_rst_cmd = BME280_SOFT_RESET_COMMAND; + + /* Check for null pointer in the device structure*/ + rslt = null_ptr_check(); + + /* Proceed if null check is fine */ + if (rslt == BME280_OK) + { + /* Write the soft reset command in the sensor */ + rslt = set_regs(®_addr, &soft_rst_cmd, 1); + + if (rslt == BME280_OK) + { + /* If NVM not copied yet, Wait for NVM to copy */ + do + { + /* As per data sheet - Table 1, startup time is 2 ms. */ + delay_ms(2); + rslt = get_regs(BME280_STATUS_REG_ADDR, &status_reg, 1); + } while ((rslt == BME280_OK) && (try_run--) && (status_reg & BME280_STATUS_IM_UPDATE)); + + if (status_reg & BME280_STATUS_IM_UPDATE) + { + rslt = BME280_E_NVM_COPY_FAILED; + } + + } + } + + 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) +{ + 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, 0, 0 }; + + /* Check for null pointer in the device structure*/ + rslt = null_ptr_check(); + if ((rslt == BME280_OK) && (comp_data != NULL)) + { + /* Read the pressure and temperature data from the sensor */ + rslt = get_regs(BME280_DATA_ADDR, reg_data, BME280_P_T_H_DATA_LEN); + if (rslt == BME280_OK) + { + /* Parse the read data from the sensor */ + parse_sensor_data(reg_data, &uncomp_data); + + /* Compensate the pressure and/or temperature and/or + * humidity data from the sensor + */ + rslt = compensate_data(sensor_comp, &uncomp_data, comp_data, &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. + */ +int8_t BME280::set_osr_settings(uint8_t desired_settings, + const struct bme280_settings *settings) +{ + int8_t rslt = BME280_W_INVALID_OSR_MACRO; + + if (desired_settings & BME280_OSR_HUM_SEL) + { + rslt = set_osr_humidity_settings(settings); + } + if (desired_settings & (BME280_OSR_PRESS_SEL | BME280_OSR_TEMP_SEL)) + { + rslt = set_osr_press_temp_settings(desired_settings, settings); + } + + return rslt; +} + +/*! + * @brief This API sets the humidity oversampling settings of the sensor. + */ +int8_t BME280::set_osr_humidity_settings(const struct bme280_settings *settings) +{ + 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 = set_regs(®_addr, &ctrl_hum, 1); + + /* 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 = get_regs(reg_addr, &ctrl_meas, 1); + if (rslt == BME280_OK) + { + rslt = set_regs(®_addr, &ctrl_meas, 1); + } + } + + return rslt; +} + +/*! + * @brief This API sets the pressure and/or temperature oversampling settings + * in the sensor according to the settings selected by the user. + */ +int8_t BME280::set_osr_press_temp_settings(uint8_t desired_settings, + const struct bme280_settings *settings) +{ + int8_t rslt; + uint8_t reg_addr = BME280_CTRL_MEAS_ADDR; + uint8_t reg_data; + + rslt = BME280::get_regs(reg_addr, ®_data, 1); + 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); + } + + 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. + */ +int8_t BME280::set_filter_standby_settings(uint8_t desired_settings, + const struct bme280_settings *settings) +{ + int8_t rslt; + uint8_t reg_addr = BME280_CONFIG_ADDR; + uint8_t reg_data; + + rslt = get_regs(reg_addr, ®_data, 1); + 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 = set_regs(®_addr, ®_data, 1); + } + + 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. + */ +void BME280::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. + */ +void BME280::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. + */ +void BME280::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. + */ +void BME280::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. + */ +void BME280::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. + */ +int8_t BME280::write_power_mode(uint8_t sensor_mode) +{ + 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 = get_regs(reg_addr, &sensor_mode_reg_val, 1); + + /* 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 = set_regs(®_addr, &sensor_mode_reg_val, 1); + } + + return rslt; +} + +/*! + * @brief This internal API puts the device to sleep mode. + */ +int8_t BME280::put_device_to_sleep() +{ + int8_t rslt; + uint8_t reg_data[4]; + struct bme280_settings settings; + + rslt = get_regs(BME280_CTRL_HUM_ADDR, reg_data, 4); + if (rslt == BME280_OK) + { + parse_device_settings(reg_data, &settings); + rslt = soft_reset(); + if (rslt == BME280_OK) + { + rslt = reload_device_settings(&settings); + } + } + + return rslt; +} + +/*! + * @brief This internal API reloads the already existing device settings in + * the sensor after soft reset. + */ +int8_t BME280::reload_device_settings(const struct bme280_settings *settings) +{ + int8_t rslt; + + rslt = set_osr_settings(BME280_ALL_SETTINGS_SEL, settings); + if (rslt == BME280_OK) + { + rslt = set_filter_standby_settings(BME280_ALL_SETTINGS_SEL, settings); + } + + 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. + */ +double BME280::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. + */ +double BME280::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. + */ +double BME280::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. + */ +int32_t BME280::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; + temperature = (calib_data->t_fine * 5 + 128) / 256; + if (temperature < temperature_min) + { + temperature = temperature_min; + } + else if (temperature > temperature_max) + { + temperature = temperature_max; + } + + return temperature; +} +#ifdef BME280_64BIT_ENABLE + +/*! + * @brief This internal API is used to compensate the raw pressure data and + * return the compensated pressure data in integer data type with higher + * accuracy. + */ +uint32_t BME280::compensate_pressure(const struct bme280_uncomp_data *uncomp_data, + const struct bme280_calib_data *calib_data) +{ + int64_t var1; + int64_t var2; + int64_t var3; + int64_t var4; + uint32_t pressure; + uint32_t pressure_min = 3000000; + uint32_t pressure_max = 11000000; + + var1 = ((int64_t)calib_data->t_fine) - 128000; + var2 = var1 * var1 * (int64_t)calib_data->dig_P6; + var2 = var2 + ((var1 * (int64_t)calib_data->dig_P5) * 131072); + var2 = var2 + (((int64_t)calib_data->dig_P4) * 34359738368); + var1 = ((var1 * var1 * (int64_t)calib_data->dig_P3) / 256) + ((var1 * ((int64_t)calib_data->dig_P2) * 4096)); + var3 = ((int64_t)1) * 140737488355328; + var1 = (var3 + var1) * ((int64_t)calib_data->dig_P1) / 8589934592; + + /* To avoid divide by zero exception */ + if (var1 != 0) + { + var4 = 1048576 - uncomp_data->pressure; + var4 = (((var4 * INT64_C(2147483648)) - var2) * 3125) / var1; + var1 = (((int64_t)calib_data->dig_P9) * (var4 / 8192) * (var4 / 8192)) / 33554432; + var2 = (((int64_t)calib_data->dig_P8) * var4) / 524288; + var4 = ((var4 + var1 + var2) / 256) + (((int64_t)calib_data->dig_P7) * 16); + pressure = (uint32_t)(((var4 / 2) * 100) / 128); + if (pressure < pressure_min) + { + pressure = pressure_min; + } + else if (pressure > pressure_max) + { + pressure = pressure_max; + } + } + else + { + pressure = pressure_min; + } + + return pressure; +} +#else + +/*! + * @brief This internal API is used to compensate the raw pressure data and + * return the compensated pressure data in integer data type. + */ +uint32_t BME280::compensate_pressure(const struct bme280_uncomp_data *uncomp_data, + const struct bme280_calib_data *calib_data) +{ + int32_t var1; + int32_t var2; + int32_t var3; + int32_t var4; + uint32_t var5; + uint32_t pressure; + uint32_t pressure_min = 30000; + uint32_t pressure_max = 110000; + + var1 = (((int32_t)calib_data->t_fine) / 2) - (int32_t)64000; + var2 = (((var1 / 4) * (var1 / 4)) / 2048) * ((int32_t)calib_data->dig_P6); + var2 = var2 + ((var1 * ((int32_t)calib_data->dig_P5)) * 2); + var2 = (var2 / 4) + (((int32_t)calib_data->dig_P4) * 65536); + var3 = (calib_data->dig_P3 * (((var1 / 4) * (var1 / 4)) / 8192)) / 8; + var4 = (((int32_t)calib_data->dig_P2) * var1) / 2; + var1 = (var3 + var4) / 262144; + var1 = (((32768 + var1)) * ((int32_t)calib_data->dig_P1)) / 32768; + + /* avoid exception caused by division by zero */ + if (var1) + { + var5 = (uint32_t)((uint32_t)1048576) - uncomp_data->pressure; + pressure = ((uint32_t)(var5 - (uint32_t)(var2 / 4096))) * 3125; + if (pressure < 0x80000000) + { + pressure = (pressure << 1) / ((uint32_t)var1); + } + else + { + pressure = (pressure / (uint32_t)var1) * 2; + } + var1 = (((int32_t)calib_data->dig_P9) * ((int32_t)(((pressure / 8) * (pressure / 8)) / 8192))) / 4096; + var2 = (((int32_t)(pressure / 4)) * ((int32_t)calib_data->dig_P8)) / 8192; + pressure = (uint32_t)((int32_t)pressure + ((var1 + var2 + calib_data->dig_P7) / 16)); + if (pressure < pressure_min) + { + pressure = pressure_min; + } + else if (pressure > pressure_max) + { + pressure = pressure_max; + } + } + else + { + pressure = pressure_min; + } + + return pressure; +} +#endif + +/*! + * @brief This internal API is used to compensate the raw humidity data and + * return the compensated humidity data in integer data type. + */ +uint32_t BME280::compensate_humidity(const struct bme280_uncomp_data *uncomp_data, + const struct bme280_calib_data *calib_data) +{ + int32_t var1; + int32_t var2; + int32_t var3; + int32_t var4; + int32_t var5; + uint32_t humidity; + uint32_t humidity_max = 102400; + + var1 = calib_data->t_fine - ((int32_t)76800); + var2 = (int32_t)(uncomp_data->humidity * 16384); + var3 = (int32_t)(((int32_t)calib_data->dig_H4) * 1048576); + var4 = ((int32_t)calib_data->dig_H5) * var1; + var5 = (((var2 - var3) - var4) + (int32_t)16384) / 32768; + var2 = (var1 * ((int32_t)calib_data->dig_H6)) / 1024; + var3 = (var1 * ((int32_t)calib_data->dig_H3)) / 2048; + var4 = ((var2 * (var3 + (int32_t)32768)) / 1024) + (int32_t)2097152; + var2 = ((var4 * ((int32_t)calib_data->dig_H2)) + 8192) / 16384; + var3 = var5 * var2; + var4 = ((var3 / 32768) * (var3 / 32768)) / 128; + var5 = var3 - ((var4 * ((int32_t)calib_data->dig_H1)) / 16); + var5 = (var5 < 0 ? 0 : var5); + var5 = (var5 > 419430400 ? 419430400 : var5); + humidity = (uint32_t)(var5 / 4096); + if (humidity > humidity_max) + { + humidity = humidity_max; + } + + return humidity; +} +#endif + +/*! + * @brief This internal API reads the calibration data from the sensor, parse + * it and store in the device structure. + */ +int8_t BME280::get_calib_data() +{ + int8_t rslt; + uint8_t reg_addr = BME280_TEMP_PRESS_CALIB_DATA_ADDR; + + /* Array to store calibration data */ + uint8_t calib_data[BME280_TEMP_PRESS_CALIB_DATA_LEN] = { 0 }; + + /* Read the calibration data from the sensor */ + rslt = get_regs(reg_addr, calib_data, BME280_TEMP_PRESS_CALIB_DATA_LEN); + if (rslt == BME280_OK) + { + /* Parse temperature and pressure calibration data and store + * it in device structure + */ + parse_temp_press_calib_data(calib_data); + reg_addr = BME280_HUMIDITY_CALIB_DATA_ADDR; + + /* Read the humidity calibration data from the sensor */ + rslt = get_regs(reg_addr, calib_data, BME280_HUMIDITY_CALIB_DATA_LEN); + if (rslt == BME280_OK) + { + /* Parse humidity calibration data and store it in + * device structure + */ + parse_humidity_calib_data(calib_data); + } + } + + return rslt; +} + +/*! + * @brief This internal API interleaves the register address between the + * register data buffer for burst write operation. + */ +void BME280::interleave_reg_addr(const uint8_t *reg_addr, uint8_t *temp_buff, const uint8_t *reg_data, uint8_t len) +{ + uint8_t index; + + for (index = 1; index < len; index++) + { + temp_buff[(index * 2) - 1] = reg_addr[index]; + temp_buff[index * 2] = reg_data[index]; + } +} + +/*! + * @brief This internal API is used to parse the temperature and + * pressure calibration data and store it in device structure. + */ +void BME280::parse_temp_press_calib_data(const uint8_t *reg_data) +{ + calib_data.dig_T1 = BME280_CONCAT_BYTES(reg_data[1], reg_data[0]); + calib_data.dig_T2 = (int16_t)BME280_CONCAT_BYTES(reg_data[3], reg_data[2]); + calib_data.dig_T3 = (int16_t)BME280_CONCAT_BYTES(reg_data[5], reg_data[4]); + calib_data.dig_P1 = BME280_CONCAT_BYTES(reg_data[7], reg_data[6]); + calib_data.dig_P2 = (int16_t)BME280_CONCAT_BYTES(reg_data[9], reg_data[8]); + calib_data.dig_P3 = (int16_t)BME280_CONCAT_BYTES(reg_data[11], reg_data[10]); + calib_data.dig_P4 = (int16_t)BME280_CONCAT_BYTES(reg_data[13], reg_data[12]); + calib_data.dig_P5 = (int16_t)BME280_CONCAT_BYTES(reg_data[15], reg_data[14]); + calib_data.dig_P6 = (int16_t)BME280_CONCAT_BYTES(reg_data[17], reg_data[16]); + calib_data.dig_P7 = (int16_t)BME280_CONCAT_BYTES(reg_data[19], reg_data[18]); + calib_data.dig_P8 = (int16_t)BME280_CONCAT_BYTES(reg_data[21], reg_data[20]); + calib_data.dig_P9 = (int16_t)BME280_CONCAT_BYTES(reg_data[23], reg_data[22]); + calib_data.dig_H1 = reg_data[25]; +} + +/*! + * @brief This internal API is used to parse the humidity calibration data + * and store it in device structure. + */ +void BME280::parse_humidity_calib_data(const uint8_t *reg_data) +{ + int16_t dig_H4_lsb; + int16_t dig_H4_msb; + int16_t dig_H5_lsb; + int16_t dig_H5_msb; + + calib_data.dig_H2 = (int16_t)BME280_CONCAT_BYTES(reg_data[1], reg_data[0]); + calib_data.dig_H3 = reg_data[2]; + dig_H4_msb = (int16_t)(int8_t)reg_data[3] * 16; + dig_H4_lsb = (int16_t)(reg_data[4] & 0x0F); + calib_data.dig_H4 = dig_H4_msb | dig_H4_lsb; + dig_H5_msb = (int16_t)(int8_t)reg_data[5] * 16; + dig_H5_lsb = (int16_t)(reg_data[4] >> 4); + calib_data.dig_H5 = dig_H5_msb | dig_H5_lsb; + calib_data.dig_H6 = (int8_t)reg_data[6]; +} + +/*! + * @brief This internal API is used to identify the settings which the user + * wants to modify in the sensor. + */ +uint8_t BME280::are_settings_changed(uint8_t sub_settings, uint8_t desired_settings) +{ + uint8_t settings_changed = FALSE; + + if (sub_settings & desired_settings) + { + /* User wants to modify this particular settings */ + settings_changed = TRUE; + } + else + { + /* User don't want to modify this particular settings */ + settings_changed = FALSE; + } + + return settings_changed; +} + +/*! + * @brief This internal API is used to validate the device structure pointer for + * null conditions. + */ +int8_t BME280::null_ptr_check() +{ + int8_t rslt; + + if ((read == NULL) || (write == NULL) || (delay_ms == NULL)) + { + /* Device structure pointer is not valid */ + rslt = BME280_E_NULL_PTR; + } + else + { + /* Device structure is fine */ + rslt = BME280_OK; + } + + return rslt; +} + +BME280 bme280(BME280_I2C_ADDR_PRIM); -- cgit v1.2.3