Add Bosch SensorTec BME680 driver + utilities

author: Daniel Friesel <daniel.friesel@uos.de> 2019-09-23 12:53:07 +0200
committer: Daniel Friesel <daniel.friesel@uos.de> 2019-09-23 12:53:07 +0200
commit: a5c6adc46d696233bc67e25ac2146173dd6ee8b2 (patch)
tree: c10354d47bf545bfa0a8de5827088032b58f0198 /src
parent: 9fbfe1c5dcb12c47e6a408818dc815e3dd856518 (diff)
3 files changed, 1433 insertions, 0 deletions
diff --git a/src/app/i2cdetect/main.cc b/src/app/i2cdetect/main.cc
index a31dbc9..2b30b47 100644
--- a/src/app/i2cdetect/main.cc
+++ b/src/app/i2cdetect/main.cc
@@ -12,6 +12,10 @@
 #ifdef DRIVER_AM2320
 #include "driver/am2320.h"
 #endif
+#ifdef DRIVER_BME680
+#include "driver/bme680.h"
+#include "driver/bme680_util.h"
+#endif
 #ifdef DRIVER_CCS811
 #include "driver/ccs811.h"
 #endif
@@ -42,6 +46,41 @@ void loop(void)
 		kout << "AM2320 error " << dec << am2320.getStatus() << endl;
 	}
 #endif
+#ifdef DRIVER_BME680
+	struct bme680_dev gas_sensor;
+
+	gas_sensor.dev_id = BME680_I2C_ADDR_SECONDARY;
+	gas_sensor.intf = BME680_I2C_INTF;
+	gas_sensor.read = bme680_i2c_read;
+	gas_sensor.write = bme680_i2c_write;
+	gas_sensor.delay_ms = bme680_delay_ms;
+	/* amb_temp can be set to 25 prior to configuring the gas sensor 
+	* or by performing a few temperature readings without operating the gas sensor.
+	*/
+	gas_sensor.amb_temp = 25;
+
+	int8_t rslt = BME680_OK;
+	rslt = bme680_init(&gas_sensor);
+	kout << "BME680 init " << rslt << endl;
+
+	gas_sensor.power_mode = BME680_FORCED_MODE;
+	gas_sensor.tph_sett.os_hum = BME680_OS_1X;
+	gas_sensor.tph_sett.os_pres = BME680_OS_16X;
+	gas_sensor.tph_sett.os_temp = BME680_OS_2X;
+
+	gas_sensor.gas_sett.run_gas = BME680_ENABLE_GAS_MEAS;
+	gas_sensor.gas_sett.heatr_dur = 150;
+	gas_sensor.gas_sett.heatr_temp = 300;
+	bme680_set_sensor_settings(BME680_OST_SEL | BME680_OSP_SEL | BME680_OSH_SEL | BME680_GAS_SENSOR_SEL, &gas_sensor);
+	bme680_set_sensor_mode(&gas_sensor);
+	arch.delay_ms(500);
+	struct bme680_field_data data;
+	bme680_get_sensor_data(&data, &gas_sensor);
+	kout << "BME680 temperature " << (float)data.temperature / 100 << " degC" << endl;
+	kout << "BME680 humidity " << (float)data.humidity / 1000  << " %" << endl;
+	kout << "BME680 pressure " << (float)data.pressure / 100 << " hPa" << endl;
+	kout << "BME680 gas resistance " << data.gas_resistance << endl;
+#endif
 #ifdef DRIVER_CCS811
 	kout << "CCS811 status is " << ccs811.check() << endl;
 #endif
diff --git a/src/driver/bme680.cc b/src/driver/bme680.cc
new file mode 100644
index 0000000..9469c8f
--- /dev/null
+++ b/src/driver/bme680.cc
@@ -0,0 +1,1367 @@
+/**\mainpage
+ * Copyright (C) 2017 - 2018 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		bme680.c
+ * @date	19 Jun 2018
+ * @version	3.5.9
+ *
+ */
+
+/*! @file bme680.c
+ @brief Sensor driver for BME680 sensor */
+#include "driver/bme680.h"
+
+/*!
+ * @brief This internal API is used to read the calibrated data from the sensor.
+ *
+ * This function is used to retrieve the calibration
+ * data from the image registers of the sensor.
+ *
+ * @note Registers 89h  to A1h for calibration data 1 to 24
+ *        from bit 0 to 7
+ * @note Registers E1h to F0h for calibration data 25 to 40
+ *        from bit 0 to 7
+ * @param[in] dev	:Structure instance of bme680_dev.
+ *
+ * @return Result of API execution status.
+ * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
+ */
+static int8_t get_calib_data(struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to set the gas configuration of the sensor.
+ *
+ * @param[in] dev	:Structure instance of bme680_dev.
+ *
+ * @return Result of API execution status.
+ * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
+ */
+static int8_t set_gas_config(struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to get the gas configuration of the sensor.
+ * @note heatr_temp and heatr_dur values are currently register data
+ * and not the actual values set
+ *
+ * @param[in] dev	:Structure instance of bme680_dev.
+ *
+ * @return Result of API execution status.
+ * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
+ */
+static int8_t get_gas_config(struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to calculate the Heat duration value.
+ *
+ * @param[in] dur	:Value of the duration to be shared.
+ *
+ * @return uint8_t threshold duration after calculation.
+ */
+static uint8_t calc_heater_dur(uint16_t dur);
+
+#ifndef BME680_FLOAT_POINT_COMPENSATION
+
+/*!
+ * @brief This internal API is used to calculate the temperature value.
+ *
+ * @param[in] dev	:Structure instance of bme680_dev.
+ * @param[in] temp_adc	:Contains the temperature ADC value .
+ *
+ * @return uint32_t calculated temperature.
+ */
+static int16_t calc_temperature(uint32_t temp_adc, struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to calculate the pressure value.
+ *
+ * @param[in] dev	:Structure instance of bme680_dev.
+ * @param[in] pres_adc	:Contains the pressure ADC value .
+ *
+ * @return uint32_t calculated pressure.
+ */
+static uint32_t calc_pressure(uint32_t pres_adc, const struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to calculate the humidity value.
+ *
+ * @param[in] dev	:Structure instance of bme680_dev.
+ * @param[in] hum_adc	:Contains the humidity ADC value.
+ *
+ * @return uint32_t calculated humidity.
+ */
+static uint32_t calc_humidity(uint16_t hum_adc, const struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to calculate the Gas Resistance value.
+ *
+ * @param[in] dev		:Structure instance of bme680_dev.
+ * @param[in] gas_res_adc	:Contains the Gas Resistance ADC value.
+ * @param[in] gas_range		:Contains the range of gas values.
+ *
+ * @return uint32_t calculated gas resistance.
+ */
+static uint32_t calc_gas_resistance(uint16_t gas_res_adc, uint8_t gas_range, const struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to calculate the Heat Resistance value.
+ *
+ * @param[in] dev	: Structure instance of bme680_dev
+ * @param[in] temp	: Contains the target temperature value.
+ *
+ * @return uint8_t calculated heater resistance.
+ */
+static uint8_t calc_heater_res(uint16_t temp, const struct bme680_dev *dev);
+
+#else
+/*!
+ * @brief This internal API is used to calculate the
+ * temperature value value in float format
+ *
+ * @param[in] dev	:Structure instance of bme680_dev.
+ * @param[in] temp_adc	:Contains the temperature ADC value .
+ *
+ * @return Calculated temperature in float
+ */
+static float calc_temperature(uint32_t temp_adc, struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to calculate the
+ * pressure value value in float format
+ *
+ * @param[in] dev	:Structure instance of bme680_dev.
+ * @param[in] pres_adc	:Contains the pressure ADC value .
+ *
+ * @return Calculated pressure in float.
+ */
+static float calc_pressure(uint32_t pres_adc, const struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to calculate the
+ * humidity value value in float format
+ *
+ * @param[in] dev	:Structure instance of bme680_dev.
+ * @param[in] hum_adc	:Contains the humidity ADC value.
+ *
+ * @return Calculated humidity in float.
+ */
+static float calc_humidity(uint16_t hum_adc, const struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to calculate the
+ * gas resistance value value in float format
+ *
+ * @param[in] dev		:Structure instance of bme680_dev.
+ * @param[in] gas_res_adc	:Contains the Gas Resistance ADC value.
+ * @param[in] gas_range		:Contains the range of gas values.
+ *
+ * @return Calculated gas resistance in float.
+ */
+static float calc_gas_resistance(uint16_t gas_res_adc, uint8_t gas_range, const struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to calculate the
+ * heater resistance value in float format
+ *
+ * @param[in] temp	: Contains the target temperature value.
+ * @param[in] dev	: Structure instance of bme680_dev.
+ *
+ * @return Calculated heater resistance in float.
+ */
+static float calc_heater_res(uint16_t temp, const struct bme680_dev *dev);
+
+#endif
+
+/*!
+ * @brief This internal API is used to calculate the field data of sensor.
+ *
+ * @param[out] data :Structure instance to hold the data
+ * @param[in] dev	:Structure instance of bme680_dev.
+ *
+ *  @return int8_t result of the field data from sensor.
+ */
+static int8_t read_field_data(struct bme680_field_data *data, struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to set the memory page
+ * based on register address.
+ *
+ * The value of memory page
+ *  value  | Description
+ * --------|--------------
+ *   0     | BME680_PAGE0_SPI
+ *   1     | BME680_PAGE1_SPI
+ *
+ * @param[in] dev	:Structure instance of bme680_dev.
+ * @param[in] reg_addr	:Contains the register address array.
+ *
+ * @return Result of API execution status
+ * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
+ */
+static int8_t set_mem_page(uint8_t reg_addr, struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to get the memory page based
+ * on register address.
+ *
+ * The value of memory page
+ *  value  | Description
+ * --------|--------------
+ *   0     | BME680_PAGE0_SPI
+ *   1     | BME680_PAGE1_SPI
+ *
+ * @param[in] dev	:Structure instance of bme680_dev.
+ *
+ * @return Result of API execution status
+ * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
+ */
+static int8_t get_mem_page(struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to validate the device pointer for
+ * null conditions.
+ *
+ * @param[in] dev	:Structure instance of bme680_dev.
+ *
+ * @return Result of API execution status
+ * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
+ */
+static int8_t null_ptr_check(const struct bme680_dev *dev);
+
+/*!
+ * @brief This internal API is used to check the boundary
+ * conditions.
+ *
+ * @param[in] value	:pointer to the value.
+ * @param[in] min	:minimum value.
+ * @param[in] max	:maximum value.
+ * @param[in] dev	:Structure instance of bme680_dev.
+ *
+ * @return Result of API execution status
+ * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
+ */
+static int8_t boundary_check(uint8_t *value, uint8_t min, uint8_t max, struct bme680_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 bme680_init(struct bme680_dev *dev)
+{
+	int8_t rslt;
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+		/* Soft reset to restore it to default values*/
+		rslt = bme680_soft_reset(dev);
+		if (rslt == BME680_OK) {
+			rslt = bme680_get_regs(BME680_CHIP_ID_ADDR, &dev->chip_id, 1, dev);
+			if (rslt == BME680_OK) {
+				if (dev->chip_id == BME680_CHIP_ID) {
+					/* Get the Calibration data */
+					rslt = get_calib_data(dev);
+				} else {
+					rslt = BME680_E_DEV_NOT_FOUND;
+				}
+			}
+		}
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This API reads the data from the given register address of the sensor.
+ */
+int8_t bme680_get_regs(uint8_t reg_addr, uint8_t *reg_data, uint16_t len, struct bme680_dev *dev)
+{
+	int8_t rslt;
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+		if (dev->intf == BME680_SPI_INTF) {
+			/* Set the memory page */
+			rslt = set_mem_page(reg_addr, dev);
+			if (rslt == BME680_OK)
+				reg_addr = reg_addr | BME680_SPI_RD_MSK;
+		}
+		dev->com_rslt = dev->read(dev->dev_id, reg_addr, reg_data, len);
+		if (dev->com_rslt != 0)
+			rslt = BME680_E_COM_FAIL;
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This API writes the given data to the register address
+ * of the sensor.
+ */
+int8_t bme680_set_regs(const uint8_t *reg_addr, const uint8_t *reg_data, uint8_t len, struct bme680_dev *dev)
+{
+	int8_t rslt;
+	/* Length of the temporary buffer is 2*(length of register)*/
+	uint8_t tmp_buff[BME680_TMP_BUFFER_LENGTH] = { 0 };
+	uint16_t index;
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+		if ((len > 0) && (len < BME680_TMP_BUFFER_LENGTH / 2)) {
+			/* Interleave the 2 arrays */
+			for (index = 0; index < len; index++) {
+				if (dev->intf == BME680_SPI_INTF) {
+					/* Set the memory page */
+					rslt = set_mem_page(reg_addr[index], dev);
+					tmp_buff[(2 * index)] = reg_addr[index] & BME680_SPI_WR_MSK;
+				} else {
+					tmp_buff[(2 * index)] = reg_addr[index];
+				}
+				tmp_buff[(2 * index) + 1] = reg_data[index];
+			}
+			/* Write the interleaved array */
+			if (rslt == BME680_OK) {
+				dev->com_rslt = dev->write(dev->dev_id, tmp_buff[0], &tmp_buff[1], (2 * len) - 1);
+				if (dev->com_rslt != 0)
+					rslt = BME680_E_COM_FAIL;
+			}
+		} else {
+			rslt = BME680_E_INVALID_LENGTH;
+		}
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This API performs the soft reset of the sensor.
+ */
+int8_t bme680_soft_reset(struct bme680_dev *dev)
+{
+	int8_t rslt;
+	uint8_t reg_addr = BME680_SOFT_RESET_ADDR;
+	/* 0xb6 is the soft reset command */
+	uint8_t soft_rst_cmd = BME680_SOFT_RESET_CMD;
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+		if (dev->intf == BME680_SPI_INTF)
+			rslt = get_mem_page(dev);
+
+		/* Reset the device */
+		if (rslt == BME680_OK) {
+			rslt = bme680_set_regs(&reg_addr, &soft_rst_cmd, 1, dev);
+			/* Wait for 5ms */
+			dev->delay_ms(BME680_RESET_PERIOD);
+
+			if (rslt == BME680_OK) {
+				/* After reset get the memory page */
+				if (dev->intf == BME680_SPI_INTF)
+					rslt = get_mem_page(dev);
+			}
+		}
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This API is used to set the oversampling, filter and T,P,H, gas selection
+ * settings in the sensor.
+ */
+int8_t bme680_set_sensor_settings(uint16_t desired_settings, struct bme680_dev *dev)
+{
+	int8_t rslt;
+	uint8_t reg_addr;
+	uint8_t data = 0;
+	uint8_t count = 0;
+	uint8_t reg_array[BME680_REG_BUFFER_LENGTH] = { 0 };
+	uint8_t data_array[BME680_REG_BUFFER_LENGTH] = { 0 };
+	uint8_t intended_power_mode = dev->power_mode; /* Save intended power mode */
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+		if (desired_settings & BME680_GAS_MEAS_SEL)
+			rslt = set_gas_config(dev);
+
+		dev->power_mode = BME680_SLEEP_MODE;
+		if (rslt == BME680_OK)
+			rslt = bme680_set_sensor_mode(dev);
+
+		/* Selecting the filter */
+		if (desired_settings & BME680_FILTER_SEL) {
+			rslt = boundary_check(&dev->tph_sett.filter, BME680_FILTER_SIZE_0, BME680_FILTER_SIZE_127, dev);
+			reg_addr = BME680_CONF_ODR_FILT_ADDR;
+
+			if (rslt == BME680_OK)
+				rslt = bme680_get_regs(reg_addr, &data, 1, dev);
+
+			if (desired_settings & BME680_FILTER_SEL)
+				data = BME680_SET_BITS(data, BME680_FILTER, dev->tph_sett.filter);
+
+			reg_array[count] = reg_addr; /* Append configuration */
+			data_array[count] = data;
+			count++;
+		}
+
+		/* Selecting heater control for the sensor */
+		if (desired_settings & BME680_HCNTRL_SEL) {
+			rslt = boundary_check(&dev->gas_sett.heatr_ctrl, BME680_ENABLE_HEATER,
+				BME680_DISABLE_HEATER, dev);
+			reg_addr = BME680_CONF_HEAT_CTRL_ADDR;
+
+			if (rslt == BME680_OK)
+				rslt = bme680_get_regs(reg_addr, &data, 1, dev);
+			data = BME680_SET_BITS_POS_0(data, BME680_HCTRL, dev->gas_sett.heatr_ctrl);
+
+			reg_array[count] = reg_addr; /* Append configuration */
+			data_array[count] = data;
+			count++;
+		}
+
+		/* Selecting heater T,P oversampling for the sensor */
+		if (desired_settings & (BME680_OST_SEL | BME680_OSP_SEL)) {
+			rslt = boundary_check(&dev->tph_sett.os_temp, BME680_OS_NONE, BME680_OS_16X, dev);
+			reg_addr = BME680_CONF_T_P_MODE_ADDR;
+
+			if (rslt == BME680_OK)
+				rslt = bme680_get_regs(reg_addr, &data, 1, dev);
+
+			if (desired_settings & BME680_OST_SEL)
+				data = BME680_SET_BITS(data, BME680_OST, dev->tph_sett.os_temp);
+
+			if (desired_settings & BME680_OSP_SEL)
+				data = BME680_SET_BITS(data, BME680_OSP, dev->tph_sett.os_pres);
+
+			reg_array[count] = reg_addr;
+			data_array[count] = data;
+			count++;
+		}
+
+		/* Selecting humidity oversampling for the sensor */
+		if (desired_settings & BME680_OSH_SEL) {
+			rslt = boundary_check(&dev->tph_sett.os_hum, BME680_OS_NONE, BME680_OS_16X, dev);
+			reg_addr = BME680_CONF_OS_H_ADDR;
+
+			if (rslt == BME680_OK)
+				rslt = bme680_get_regs(reg_addr, &data, 1, dev);
+			data = BME680_SET_BITS_POS_0(data, BME680_OSH, dev->tph_sett.os_hum);
+
+			reg_array[count] = reg_addr; /* Append configuration */
+			data_array[count] = data;
+			count++;
+		}
+
+		/* Selecting the runGas and NB conversion settings for the sensor */
+		if (desired_settings & (BME680_RUN_GAS_SEL | BME680_NBCONV_SEL)) {
+			rslt = boundary_check(&dev->gas_sett.run_gas, BME680_RUN_GAS_DISABLE,
+				BME680_RUN_GAS_ENABLE, dev);
+			if (rslt == BME680_OK) {
+				/* Validate boundary conditions */
+				rslt = boundary_check(&dev->gas_sett.nb_conv, BME680_NBCONV_MIN,
+					BME680_NBCONV_MAX, dev);
+			}
+
+			reg_addr = BME680_CONF_ODR_RUN_GAS_NBC_ADDR;
+
+			if (rslt == BME680_OK)
+				rslt = bme680_get_regs(reg_addr, &data, 1, dev);
+
+			if (desired_settings & BME680_RUN_GAS_SEL)
+				data = BME680_SET_BITS(data, BME680_RUN_GAS, dev->gas_sett.run_gas);
+
+			if (desired_settings & BME680_NBCONV_SEL)
+				data = BME680_SET_BITS_POS_0(data, BME680_NBCONV, dev->gas_sett.nb_conv);
+
+			reg_array[count] = reg_addr; /* Append configuration */
+			data_array[count] = data;
+			count++;
+		}
+
+		if (rslt == BME680_OK)
+			rslt = bme680_set_regs(reg_array, data_array, count, dev);
+
+		/* Restore previous intended power mode */
+		dev->power_mode = intended_power_mode;
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This API is used to get the oversampling, filter and T,P,H, gas selection
+ * settings in the sensor.
+ */
+int8_t bme680_get_sensor_settings(uint16_t desired_settings, struct bme680_dev *dev)
+{
+	int8_t rslt;
+	/* starting address of the register array for burst read*/
+	uint8_t reg_addr = BME680_CONF_HEAT_CTRL_ADDR;
+	uint8_t data_array[BME680_REG_BUFFER_LENGTH] = { 0 };
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+		rslt = bme680_get_regs(reg_addr, data_array, BME680_REG_BUFFER_LENGTH, dev);
+
+		if (rslt == BME680_OK) {
+			if (desired_settings & BME680_GAS_MEAS_SEL)
+				rslt = get_gas_config(dev);
+
+			/* get the T,P,H ,Filter,ODR settings here */
+			if (desired_settings & BME680_FILTER_SEL)
+				dev->tph_sett.filter = BME680_GET_BITS(data_array[BME680_REG_FILTER_INDEX],
+					BME680_FILTER);
+
+			if (desired_settings & (BME680_OST_SEL | BME680_OSP_SEL)) {
+				dev->tph_sett.os_temp = BME680_GET_BITS(data_array[BME680_REG_TEMP_INDEX], BME680_OST);
+				dev->tph_sett.os_pres = BME680_GET_BITS(data_array[BME680_REG_PRES_INDEX], BME680_OSP);
+			}
+
+			if (desired_settings & BME680_OSH_SEL)
+				dev->tph_sett.os_hum = BME680_GET_BITS_POS_0(data_array[BME680_REG_HUM_INDEX],
+					BME680_OSH);
+
+			/* get the gas related settings */
+			if (desired_settings & BME680_HCNTRL_SEL)
+				dev->gas_sett.heatr_ctrl = BME680_GET_BITS_POS_0(data_array[BME680_REG_HCTRL_INDEX],
+					BME680_HCTRL);
+
+			if (desired_settings & (BME680_RUN_GAS_SEL | BME680_NBCONV_SEL)) {
+				dev->gas_sett.nb_conv = BME680_GET_BITS_POS_0(data_array[BME680_REG_NBCONV_INDEX],
+					BME680_NBCONV);
+				dev->gas_sett.run_gas = BME680_GET_BITS(data_array[BME680_REG_RUN_GAS_INDEX],
+					BME680_RUN_GAS);
+			}
+		}
+	} else {
+		rslt = BME680_E_NULL_PTR;
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This API is used to set the power mode of the sensor.
+ */
+int8_t bme680_set_sensor_mode(struct bme680_dev *dev)
+{
+	int8_t rslt;
+	uint8_t tmp_pow_mode;
+	uint8_t pow_mode = 0;
+	uint8_t reg_addr = BME680_CONF_T_P_MODE_ADDR;
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+		/* Call repeatedly until in sleep */
+		do {
+			rslt = bme680_get_regs(BME680_CONF_T_P_MODE_ADDR, &tmp_pow_mode, 1, dev);
+			if (rslt == BME680_OK) {
+				/* Put to sleep before changing mode */
+				pow_mode = (tmp_pow_mode & BME680_MODE_MSK);
+
+				if (pow_mode != BME680_SLEEP_MODE) {
+					tmp_pow_mode = tmp_pow_mode & (~BME680_MODE_MSK); /* Set to sleep */
+					rslt = bme680_set_regs(&reg_addr, &tmp_pow_mode, 1, dev);
+					dev->delay_ms(BME680_POLL_PERIOD_MS);
+				}
+			}
+		} while (pow_mode != BME680_SLEEP_MODE);
+
+		/* Already in sleep */
+		if (dev->power_mode != BME680_SLEEP_MODE) {
+			tmp_pow_mode = (tmp_pow_mode & ~BME680_MODE_MSK) | (dev->power_mode & BME680_MODE_MSK);
+			if (rslt == BME680_OK)
+				rslt = bme680_set_regs(&reg_addr, &tmp_pow_mode, 1, dev);
+		}
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This API is used to get the power mode of the sensor.
+ */
+int8_t bme680_get_sensor_mode(struct bme680_dev *dev)
+{
+	int8_t rslt;
+	uint8_t mode;
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+		rslt = bme680_get_regs(BME680_CONF_T_P_MODE_ADDR, &mode, 1, dev);
+		/* Masking the other register bit info*/
+		dev->power_mode = mode & BME680_MODE_MSK;
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This API is used to set the profile duration of the sensor.
+ */
+void bme680_set_profile_dur(uint16_t duration, struct bme680_dev *dev)
+{
+	uint32_t tph_dur; /* Calculate in us */
+	uint32_t meas_cycles;
+	uint8_t os_to_meas_cycles[6] = {0, 1, 2, 4, 8, 16};
+
+	meas_cycles = os_to_meas_cycles[dev->tph_sett.os_temp];
+	meas_cycles += os_to_meas_cycles[dev->tph_sett.os_pres];
+	meas_cycles += os_to_meas_cycles[dev->tph_sett.os_hum];
+
+	/* TPH measurement duration */
+	tph_dur = meas_cycles * UINT32_C(1963);
+	tph_dur += UINT32_C(477 * 4); /* TPH switching duration */
+	tph_dur += UINT32_C(477 * 5); /* Gas measurement duration */
+	tph_dur += UINT32_C(500); /* Get it to the closest whole number.*/
+	tph_dur /= UINT32_C(1000); /* Convert to ms */
+
+	tph_dur += UINT32_C(1); /* Wake up duration of 1ms */
+	/* The remaining time should be used for heating */
+	dev->gas_sett.heatr_dur = duration - (uint16_t) tph_dur;
+}
+
+/*!
+ * @brief This API is used to get the profile duration of the sensor.
+ */
+void bme680_get_profile_dur(uint16_t *duration, const struct bme680_dev *dev)
+{
+	uint32_t tph_dur; /* Calculate in us */
+	uint32_t meas_cycles;
+	uint8_t os_to_meas_cycles[6] = {0, 1, 2, 4, 8, 16};
+
+	meas_cycles = os_to_meas_cycles[dev->tph_sett.os_temp];
+	meas_cycles += os_to_meas_cycles[dev->tph_sett.os_pres];
+	meas_cycles += os_to_meas_cycles[dev->tph_sett.os_hum];
+
+	/* TPH measurement duration */
+	tph_dur = meas_cycles * UINT32_C(1963);
+	tph_dur += UINT32_C(477 * 4); /* TPH switching duration */
+	tph_dur += UINT32_C(477 * 5); /* Gas measurement duration */
+	tph_dur += UINT32_C(500); /* Get it to the closest whole number.*/
+	tph_dur /= UINT32_C(1000); /* Convert to ms */
+
+	tph_dur += UINT32_C(1); /* Wake up duration of 1ms */
+
+	*duration = (uint16_t) tph_dur;
+
+	/* Get the gas duration only when the run gas is enabled */
+	if (dev->gas_sett.run_gas) {
+		/* The remaining time should be used for heating */
+		*duration += dev->gas_sett.heatr_dur;
+	}
+}
+
+/*!
+ * @brief This API reads the pressure, temperature and humidity and gas data
+ * from the sensor, compensates the data and store it in the bme680_data
+ * structure instance passed by the user.
+ */
+int8_t bme680_get_sensor_data(struct bme680_field_data *data, struct bme680_dev *dev)
+{
+	int8_t rslt;
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+		/* Reading the sensor data in forced mode only */
+		rslt = read_field_data(data, dev);
+		if (rslt == BME680_OK) {
+			if (data->status & BME680_NEW_DATA_MSK)
+				dev->new_fields = 1;
+			else
+				dev->new_fields = 0;
+		}
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This internal API is used to read the calibrated data from the sensor.
+ */
+static int8_t get_calib_data(struct bme680_dev *dev)
+{
+	int8_t rslt;
+	uint8_t coeff_array[BME680_COEFF_SIZE] = { 0 };
+	uint8_t temp_var = 0; /* Temporary variable */
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+		rslt = bme680_get_regs(BME680_COEFF_ADDR1, coeff_array, BME680_COEFF_ADDR1_LEN, dev);
+		/* Append the second half in the same array */
+		if (rslt == BME680_OK)
+			rslt = bme680_get_regs(BME680_COEFF_ADDR2, &coeff_array[BME680_COEFF_ADDR1_LEN]
+			, BME680_COEFF_ADDR2_LEN, dev);
+
+		/* Temperature related coefficients */
+		dev->calib.par_t1 = (uint16_t) (BME680_CONCAT_BYTES(coeff_array[BME680_T1_MSB_REG],
+			coeff_array[BME680_T1_LSB_REG]));
+		dev->calib.par_t2 = (int16_t) (BME680_CONCAT_BYTES(coeff_array[BME680_T2_MSB_REG],
+			coeff_array[BME680_T2_LSB_REG]));
+		dev->calib.par_t3 = (int8_t) (coeff_array[BME680_T3_REG]);
+
+		/* Pressure related coefficients */
+		dev->calib.par_p1 = (uint16_t) (BME680_CONCAT_BYTES(coeff_array[BME680_P1_MSB_REG],
+			coeff_array[BME680_P1_LSB_REG]));
+		dev->calib.par_p2 = (int16_t) (BME680_CONCAT_BYTES(coeff_array[BME680_P2_MSB_REG],
+			coeff_array[BME680_P2_LSB_REG]));
+		dev->calib.par_p3 = (int8_t) coeff_array[BME680_P3_REG];
+		dev->calib.par_p4 = (int16_t) (BME680_CONCAT_BYTES(coeff_array[BME680_P4_MSB_REG],
+			coeff_array[BME680_P4_LSB_REG]));
+		dev->calib.par_p5 = (int16_t) (BME680_CONCAT_BYTES(coeff_array[BME680_P5_MSB_REG],
+			coeff_array[BME680_P5_LSB_REG]));
+		dev->calib.par_p6 = (int8_t) (coeff_array[BME680_P6_REG]);
+		dev->calib.par_p7 = (int8_t) (coeff_array[BME680_P7_REG]);
+		dev->calib.par_p8 = (int16_t) (BME680_CONCAT_BYTES(coeff_array[BME680_P8_MSB_REG],
+			coeff_array[BME680_P8_LSB_REG]));
+		dev->calib.par_p9 = (int16_t) (BME680_CONCAT_BYTES(coeff_array[BME680_P9_MSB_REG],
+			coeff_array[BME680_P9_LSB_REG]));
+		dev->calib.par_p10 = (uint8_t) (coeff_array[BME680_P10_REG]);
+
+		/* Humidity related coefficients */
+		dev->calib.par_h1 = (uint16_t) (((uint16_t) coeff_array[BME680_H1_MSB_REG] << BME680_HUM_REG_SHIFT_VAL)
+			| (coeff_array[BME680_H1_LSB_REG] & BME680_BIT_H1_DATA_MSK));
+		dev->calib.par_h2 = (uint16_t) (((uint16_t) coeff_array[BME680_H2_MSB_REG] << BME680_HUM_REG_SHIFT_VAL)
+			| ((coeff_array[BME680_H2_LSB_REG]) >> BME680_HUM_REG_SHIFT_VAL));
+		dev->calib.par_h3 = (int8_t) coeff_array[BME680_H3_REG];
+		dev->calib.par_h4 = (int8_t) coeff_array[BME680_H4_REG];
+		dev->calib.par_h5 = (int8_t) coeff_array[BME680_H5_REG];
+		dev->calib.par_h6 = (uint8_t) coeff_array[BME680_H6_REG];
+		dev->calib.par_h7 = (int8_t) coeff_array[BME680_H7_REG];
+
+		/* Gas heater related coefficients */
+		dev->calib.par_gh1 = (int8_t) coeff_array[BME680_GH1_REG];
+		dev->calib.par_gh2 = (int16_t) (BME680_CONCAT_BYTES(coeff_array[BME680_GH2_MSB_REG],
+			coeff_array[BME680_GH2_LSB_REG]));
+		dev->calib.par_gh3 = (int8_t) coeff_array[BME680_GH3_REG];
+
+		/* Other coefficients */
+		if (rslt == BME680_OK) {
+			rslt = bme680_get_regs(BME680_ADDR_RES_HEAT_RANGE_ADDR, &temp_var, 1, dev);
+
+			dev->calib.res_heat_range = ((temp_var & BME680_RHRANGE_MSK) / 16);
+			if (rslt == BME680_OK) {
+				rslt = bme680_get_regs(BME680_ADDR_RES_HEAT_VAL_ADDR, &temp_var, 1, dev);
+
+				dev->calib.res_heat_val = (int8_t) temp_var;
+				if (rslt == BME680_OK)
+					rslt = bme680_get_regs(BME680_ADDR_RANGE_SW_ERR_ADDR, &temp_var, 1, dev);
+			}
+		}
+		dev->calib.range_sw_err = ((int8_t) temp_var & (int8_t) BME680_RSERROR_MSK) / 16;
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This internal API is used to set the gas configuration of the sensor.
+ */
+static int8_t set_gas_config(struct bme680_dev *dev)
+{
+	int8_t rslt;
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+
+		uint8_t reg_addr[2] = {0};
+		uint8_t reg_data[2] = {0};
+
+		if (dev->power_mode == BME680_FORCED_MODE) {
+			reg_addr[0] = BME680_RES_HEAT0_ADDR;
+			reg_data[0] = calc_heater_res(dev->gas_sett.heatr_temp, dev);
+			reg_addr[1] = BME680_GAS_WAIT0_ADDR;
+			reg_data[1] = calc_heater_dur(dev->gas_sett.heatr_dur);
+			dev->gas_sett.nb_conv = 0;
+		} else {
+			rslt = BME680_W_DEFINE_PWR_MODE;
+		}
+		if (rslt == BME680_OK)
+			rslt = bme680_set_regs(reg_addr, reg_data, 2, dev);
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This internal API is used to get the gas configuration of the sensor.
+ * @note heatr_temp and heatr_dur values are currently register data
+ * and not the actual values set
+ */
+static int8_t get_gas_config(struct bme680_dev *dev)
+{
+	int8_t rslt;
+	/* starting address of the register array for burst read*/
+	uint8_t reg_addr1 = BME680_ADDR_SENS_CONF_START;
+	uint8_t reg_addr2 = BME680_ADDR_GAS_CONF_START;
+	uint8_t reg_data = 0;
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+		if (BME680_SPI_INTF == dev->intf) {
+			/* Memory page switch the SPI address*/
+			rslt = set_mem_page(reg_addr1, dev);
+		}
+
+		if (rslt == BME680_OK) {
+			rslt = bme680_get_regs(reg_addr1, &reg_data, 1, dev);
+			if (rslt == BME680_OK) {
+				dev->gas_sett.heatr_temp = reg_data;
+				rslt = bme680_get_regs(reg_addr2, &reg_data, 1, dev);
+				if (rslt == BME680_OK) {
+					/* Heating duration register value */
+					dev->gas_sett.heatr_dur = reg_data;
+				}
+			}
+		}
+	}
+
+	return rslt;
+}
+
+#ifndef BME680_FLOAT_POINT_COMPENSATION
+
+/*!
+ * @brief This internal API is used to calculate the temperature value.
+ */
+static int16_t calc_temperature(uint32_t temp_adc, struct bme680_dev *dev)
+{
+	int64_t var1;
+	int64_t var2;
+	int64_t var3;
+	int16_t calc_temp;
+
+	var1 = ((int32_t) temp_adc >> 3) - ((int32_t) dev->calib.par_t1 << 1);
+	var2 = (var1 * (int32_t) dev->calib.par_t2) >> 11;
+	var3 = ((var1 >> 1) * (var1 >> 1)) >> 12;
+	var3 = ((var3) * ((int32_t) dev->calib.par_t3 << 4)) >> 14;
+	dev->calib.t_fine = (int32_t) (var2 + var3);
+	calc_temp = (int16_t) (((dev->calib.t_fine * 5) + 128) >> 8);
+
+	return calc_temp;
+}
+
+/*!
+ * @brief This internal API is used to calculate the pressure value.
+ */
+static uint32_t calc_pressure(uint32_t pres_adc, const struct bme680_dev *dev)
+{
+	int32_t var1;
+	int32_t var2;
+	int32_t var3;
+	int32_t pressure_comp;
+
+	var1 = (((int32_t)dev->calib.t_fine) >> 1) - 64000;
+	var2 = ((((var1 >> 2) * (var1 >> 2)) >> 11) *
+		(int32_t)dev->calib.par_p6) >> 2;
+	var2 = var2 + ((var1 * (int32_t)dev->calib.par_p5) << 1);
+	var2 = (var2 >> 2) + ((int32_t)dev->calib.par_p4 << 16);
+	var1 = (((((var1 >> 2) * (var1 >> 2)) >> 13) *
+		((int32_t)dev->calib.par_p3 << 5)) >> 3) +
+		(((int32_t)dev->calib.par_p2 * var1) >> 1);
+	var1 = var1 >> 18;
+	var1 = ((32768 + var1) * (int32_t)dev->calib.par_p1) >> 15;
+	pressure_comp = 1048576 - pres_adc;
+	pressure_comp = (int32_t)((pressure_comp - (var2 >> 12)) * ((uint32_t)3125));
+	if (pressure_comp >= BME680_MAX_OVERFLOW_VAL)
+		pressure_comp = ((pressure_comp / var1) << 1);
+	else
+		pressure_comp = ((pressure_comp << 1) / var1);
+	var1 = ((int32_t)dev->calib.par_p9 * (int32_t)(((pressure_comp >> 3) *
+		(pressure_comp >> 3)) >> 13)) >> 12;
+	var2 = ((int32_t)(pressure_comp >> 2) *
+		(int32_t)dev->calib.par_p8) >> 13;
+	var3 = ((int32_t)(pressure_comp >> 8) * (int32_t)(pressure_comp >> 8) *
+		(int32_t)(pressure_comp >> 8) *
+		(int32_t)dev->calib.par_p10) >> 17;
+
+	pressure_comp = (int32_t)(pressure_comp) + ((var1 + var2 + var3 +
+		((int32_t)dev->calib.par_p7 << 7)) >> 4);
+
+	return (uint32_t)pressure_comp;
+
+}
+
+/*!
+ * @brief This internal API is used to calculate the humidity value.
+ */
+static uint32_t calc_humidity(uint16_t hum_adc, const struct bme680_dev *dev)
+{
+	int32_t var1;
+	int32_t var2;
+	int32_t var3;
+	int32_t var4;
+	int32_t var5;
+	int32_t var6;
+	int32_t temp_scaled;
+	int32_t calc_hum;
+
+	temp_scaled = (((int32_t) dev->calib.t_fine * 5) + 128) >> 8;
+	var1 = (int32_t) (hum_adc - ((int32_t) ((int32_t) dev->calib.par_h1 * 16)))
+		- (((temp_scaled * (int32_t) dev->calib.par_h3) / ((int32_t) 100)) >> 1);
+	var2 = ((int32_t) dev->calib.par_h2
+		* (((temp_scaled * (int32_t) dev->calib.par_h4) / ((int32_t) 100))
+			+ (((temp_scaled * ((temp_scaled * (int32_t) dev->calib.par_h5) / ((int32_t) 100))) >> 6)
+				/ ((int32_t) 100)) + (int32_t) (1 << 14))) >> 10;
+	var3 = var1 * var2;
+	var4 = (int32_t) dev->calib.par_h6 << 7;
+	var4 = ((var4) + ((temp_scaled * (int32_t) dev->calib.par_h7) / ((int32_t) 100))) >> 4;
+	var5 = ((var3 >> 14) * (var3 >> 14)) >> 10;
+	var6 = (var4 * var5) >> 1;
+	calc_hum = (((var3 + var6) >> 10) * ((int32_t) 1000)) >> 12;
+
+	if (calc_hum > 100000) /* Cap at 100%rH */
+		calc_hum = 100000;
+	else if (calc_hum < 0)
+		calc_hum = 0;
+
+	return (uint32_t) calc_hum;
+}
+
+/*!
+ * @brief This internal API is used to calculate the Gas Resistance value.
+ */
+static uint32_t calc_gas_resistance(uint16_t gas_res_adc, uint8_t gas_range, const struct bme680_dev *dev)
+{
+	int64_t var1;
+	uint64_t var2;
+	int64_t var3;
+	uint32_t calc_gas_res;
+	/**Look up table 1 for the possible gas range values */
+	uint32_t lookupTable1[16] = { UINT32_C(2147483647), UINT32_C(2147483647), UINT32_C(2147483647), UINT32_C(2147483647),
+		UINT32_C(2147483647), UINT32_C(2126008810), UINT32_C(2147483647), UINT32_C(2130303777),
+		UINT32_C(2147483647), UINT32_C(2147483647), UINT32_C(2143188679), UINT32_C(2136746228),
+		UINT32_C(2147483647), UINT32_C(2126008810), UINT32_C(2147483647), UINT32_C(2147483647) };
+	/**Look up table 2 for the possible gas range values */
+	uint32_t lookupTable2[16] = { UINT32_C(4096000000), UINT32_C(2048000000), UINT32_C(1024000000), UINT32_C(512000000),
+		UINT32_C(255744255), UINT32_C(127110228), UINT32_C(64000000), UINT32_C(32258064), UINT32_C(16016016),
+		UINT32_C(8000000), UINT32_C(4000000), UINT32_C(2000000), UINT32_C(1000000), UINT32_C(500000),
+		UINT32_C(250000), UINT32_C(125000) };
+
+	var1 = (int64_t) ((1340 + (5 * (int64_t) dev->calib.range_sw_err)) *
+		((int64_t) lookupTable1[gas_range])) >> 16;
+	var2 = (((int64_t) ((int64_t) gas_res_adc << 15) - (int64_t) (16777216)) + var1);
+	var3 = (((int64_t) lookupTable2[gas_range] * (int64_t) var1) >> 9);
+	calc_gas_res = (uint32_t) ((var3 + ((int64_t) var2 >> 1)) / (int64_t) var2);
+
+	return calc_gas_res;
+}
+
+/*!
+ * @brief This internal API is used to calculate the Heat Resistance value.
+ */
+static uint8_t calc_heater_res(uint16_t temp, const struct bme680_dev *dev)
+{
+	uint8_t heatr_res;
+	int32_t var1;
+	int32_t var2;
+	int32_t var3;
+	int32_t var4;
+	int32_t var5;
+	int32_t heatr_res_x100;
+
+	if (temp > 400) /* Cap temperature */
+		temp = 400;
+
+	var1 = (((int32_t) dev->amb_temp * dev->calib.par_gh3) / 1000) * 256;
+	var2 = (dev->calib.par_gh1 + 784) * (((((dev->calib.par_gh2 + 154009) * temp * 5) / 100) + 3276800) / 10);
+	var3 = var1 + (var2 / 2);
+	var4 = (var3 / (dev->calib.res_heat_range + 4));
+	var5 = (131 * dev->calib.res_heat_val) + 65536;
+	heatr_res_x100 = (int32_t) (((var4 / var5) - 250) * 34);
+	heatr_res = (uint8_t) ((heatr_res_x100 + 50) / 100);
+
+	return heatr_res;
+}
+
+#else
+
+
+/*!
+ * @brief This internal API is used to calculate the
+ * temperature value in float format
+ */
+static float calc_temperature(uint32_t temp_adc, struct bme680_dev *dev)
+{
+	float var1 = 0;
+	float var2 = 0;
+	float calc_temp = 0;
+
+	/* calculate var1 data */
+	var1  = ((((float)temp_adc / 16384.0f) - ((float)dev->calib.par_t1 / 1024.0f))
+			* ((float)dev->calib.par_t2));
+
+	/* calculate var2 data */
+	var2  = (((((float)temp_adc / 131072.0f) - ((float)dev->calib.par_t1 / 8192.0f)) *
+		(((float)temp_adc / 131072.0f) - ((float)dev->calib.par_t1 / 8192.0f))) *
+		((float)dev->calib.par_t3 * 16.0f));
+
+	/* t_fine value*/
+	dev->calib.t_fine = (var1 + var2);
+
+	/* compensated temperature data*/
+	calc_temp  = ((dev->calib.t_fine) / 5120.0f);
+
+	return calc_temp;
+}
+
+/*!
+ * @brief This internal API is used to calculate the
+ * pressure value in float format
+ */
+static float calc_pressure(uint32_t pres_adc, const struct bme680_dev *dev)
+{
+	float var1 = 0;
+	float var2 = 0;
+	float var3 = 0;
+	float calc_pres = 0;
+
+	var1 = (((float)dev->calib.t_fine / 2.0f) - 64000.0f);
+	var2 = var1 * var1 * (((float)dev->calib.par_p6) / (131072.0f));
+	var2 = var2 + (var1 * ((float)dev->calib.par_p5) * 2.0f);
+	var2 = (var2 / 4.0f) + (((float)dev->calib.par_p4) * 65536.0f);
+	var1 = (((((float)dev->calib.par_p3 * var1 * var1) / 16384.0f)
+		+ ((float)dev->calib.par_p2 * var1)) / 524288.0f);
+	var1 = ((1.0f + (var1 / 32768.0f)) * ((float)dev->calib.par_p1));
+	calc_pres = (1048576.0f - ((float)pres_adc));
+
+	/* Avoid exception caused by division by zero */
+	if ((int)var1 != 0) {
+		calc_pres = (((calc_pres - (var2 / 4096.0f)) * 6250.0f) / var1);
+		var1 = (((float)dev->calib.par_p9) * calc_pres * calc_pres) / 2147483648.0f;
+		var2 = calc_pres * (((float)dev->calib.par_p8) / 32768.0f);
+		var3 = ((calc_pres / 256.0f) * (calc_pres / 256.0f) * (calc_pres / 256.0f)
+			* (dev->calib.par_p10 / 131072.0f));
+		calc_pres = (calc_pres + (var1 + var2 + var3 + ((float)dev->calib.par_p7 * 128.0f)) / 16.0f);
+	} else {
+		calc_pres = 0;
+	}
+
+	return calc_pres;
+}
+
+/*!
+ * @brief This internal API is used to calculate the
+ * humidity value in float format
+ */
+static float calc_humidity(uint16_t hum_adc, const struct bme680_dev *dev)
+{
+	float calc_hum = 0;
+	float var1 = 0;
+	float var2 = 0;
+	float var3 = 0;
+	float var4 = 0;
+	float temp_comp;
+
+	/* compensated temperature data*/
+	temp_comp  = ((dev->calib.t_fine) / 5120.0f);
+
+	var1 = (float)((float)hum_adc) - (((float)dev->calib.par_h1 * 16.0f) + (((float)dev->calib.par_h3 / 2.0f)
+		* temp_comp));
+
+	var2 = var1 * ((float)(((float) dev->calib.par_h2 / 262144.0f) * (1.0f + (((float)dev->calib.par_h4 / 16384.0f)
+		* temp_comp) + (((float)dev->calib.par_h5 / 1048576.0f) * temp_comp * temp_comp))));
+
+	var3 = (float) dev->calib.par_h6 / 16384.0f;
+
+	var4 = (float) dev->calib.par_h7 / 2097152.0f;
+
+	calc_hum = var2 + ((var3 + (var4 * temp_comp)) * var2 * var2);
+
+	if (calc_hum > 100.0f)
+		calc_hum = 100.0f;
+	else if (calc_hum < 0.0f)
+		calc_hum = 0.0f;
+
+	return calc_hum;
+}
+
+/*!
+ * @brief This internal API is used to calculate the
+ * gas resistance value in float format
+ */
+static float calc_gas_resistance(uint16_t gas_res_adc, uint8_t gas_range, const struct bme680_dev *dev)
+{
+	float calc_gas_res;
+	float var1 = 0;
+	float var2 = 0;
+	float var3 = 0;
+
+	const float lookup_k1_range[16] = {
+	0.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, -0.8,
+	0.0, 0.0, -0.2, -0.5, 0.0, -1.0, 0.0, 0.0};
+	const float lookup_k2_range[16] = {
+	0.0, 0.0, 0.0, 0.0, 0.1, 0.7, 0.0, -0.8,
+	-0.1, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0};
+
+	var1 = (1340.0f + (5.0f * dev->calib.range_sw_err));
+	var2 = (var1) * (1.0f + lookup_k1_range[gas_range]/100.0f);
+	var3 = 1.0f + (lookup_k2_range[gas_range]/100.0f);
+
+	calc_gas_res = 1.0f / (float)(var3 * (0.000000125f) * (float)(1 << gas_range) * (((((float)gas_res_adc)
+		- 512.0f)/var2) + 1.0f));
+
+	return calc_gas_res;
+}
+
+/*!
+ * @brief This internal API is used to calculate the
+ * heater resistance value in float format
+ */
+static float calc_heater_res(uint16_t temp, const struct bme680_dev *dev)
+{
+	float var1 = 0;
+	float var2 = 0;
+	float var3 = 0;
+	float var4 = 0;
+	float var5 = 0;
+	float res_heat = 0;
+
+	if (temp > 400) /* Cap temperature */
+		temp = 400;
+
+	var1 = (((float)dev->calib.par_gh1 / (16.0f)) + 49.0f);
+	var2 = ((((float)dev->calib.par_gh2 / (32768.0f)) * (0.0005f)) + 0.00235f);
+	var3 = ((float)dev->calib.par_gh3 / (1024.0f));
+	var4 = (var1 * (1.0f + (var2 * (float)temp)));
+	var5 = (var4 + (var3 * (float)dev->amb_temp));
+	res_heat = (uint8_t)(3.4f * ((var5 * (4 / (4 + (float)dev->calib.res_heat_range)) *
+		(1/(1 + ((float) dev->calib.res_heat_val * 0.002f)))) - 25));
+
+	return res_heat;
+}
+
+#endif
+
+/*!
+ * @brief This internal API is used to calculate the Heat duration value.
+ */
+static uint8_t calc_heater_dur(uint16_t dur)
+{
+	uint8_t factor = 0;
+	uint8_t durval;
+
+	if (dur >= 0xfc0) {
+		durval = 0xff; /* Max duration*/
+	} else {
+		while (dur > 0x3F) {
+			dur = dur / 4;
+			factor += 1;
+		}
+		durval = (uint8_t) (dur + (factor * 64));
+	}
+
+	return durval;
+}
+
+/*!
+ * @brief This internal API is used to calculate the field data of sensor.
+ */
+static int8_t read_field_data(struct bme680_field_data *data, struct bme680_dev *dev)
+{
+	int8_t rslt;
+	uint8_t buff[BME680_FIELD_LENGTH] = { 0 };
+	uint8_t gas_range;
+	uint32_t adc_temp;
+	uint32_t adc_pres;
+	uint16_t adc_hum;
+	uint16_t adc_gas_res;
+	uint8_t tries = 10;
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	do {
+		if (rslt == BME680_OK) {
+			rslt = bme680_get_regs(((uint8_t) (BME680_FIELD0_ADDR)), buff, (uint16_t) BME680_FIELD_LENGTH,
+				dev);
+
+			data->status = buff[0] & BME680_NEW_DATA_MSK;
+			data->gas_index = buff[0] & BME680_GAS_INDEX_MSK;
+			data->meas_index = buff[1];
+
+			/* read the raw data from the sensor */
+			adc_pres = (uint32_t) (((uint32_t) buff[2] * 4096) | ((uint32_t) buff[3] * 16)
+				| ((uint32_t) buff[4] / 16));
+			adc_temp = (uint32_t) (((uint32_t) buff[5] * 4096) | ((uint32_t) buff[6] * 16)
+				| ((uint32_t) buff[7] / 16));
+			adc_hum = (uint16_t) (((uint32_t) buff[8] * 256) | (uint32_t) buff[9]);
+			adc_gas_res = (uint16_t) ((uint32_t) buff[13] * 4 | (((uint32_t) buff[14]) / 64));
+			gas_range = buff[14] & BME680_GAS_RANGE_MSK;
+
+			data->status |= buff[14] & BME680_GASM_VALID_MSK;
+			data->status |= buff[14] & BME680_HEAT_STAB_MSK;
+
+			if (data->status & BME680_NEW_DATA_MSK) {
+				data->temperature = calc_temperature(adc_temp, dev);
+				data->pressure = calc_pressure(adc_pres, dev);
+				data->humidity = calc_humidity(adc_hum, dev);
+				data->gas_resistance = calc_gas_resistance(adc_gas_res, gas_range, dev);
+				break;
+			}
+			/* Delay to poll the data */
+			dev->delay_ms(BME680_POLL_PERIOD_MS);
+		}
+		tries--;
+	} while (tries);
+
+	if (!tries)
+		rslt = BME680_W_NO_NEW_DATA;
+
+	return rslt;
+}
+
+/*!
+ * @brief This internal API is used to set the memory page based on register address.
+ */
+static int8_t set_mem_page(uint8_t reg_addr, struct bme680_dev *dev)
+{
+	int8_t rslt;
+	uint8_t reg;
+	uint8_t mem_page;
+
+	/* Check for null pointers in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+		if (reg_addr > 0x7f)
+			mem_page = BME680_MEM_PAGE1;
+		else
+			mem_page = BME680_MEM_PAGE0;
+
+		if (mem_page != dev->mem_page) {
+			dev->mem_page = mem_page;
+
+			dev->com_rslt = dev->read(dev->dev_id, BME680_MEM_PAGE_ADDR | BME680_SPI_RD_MSK, &reg, 1);
+			if (dev->com_rslt != 0)
+				rslt = BME680_E_COM_FAIL;
+
+			if (rslt == BME680_OK) {
+				reg = reg & (~BME680_MEM_PAGE_MSK);
+				reg = reg | (dev->mem_page & BME680_MEM_PAGE_MSK);
+
+				dev->com_rslt = dev->write(dev->dev_id, BME680_MEM_PAGE_ADDR & BME680_SPI_WR_MSK,
+					&reg, 1);
+				if (dev->com_rslt != 0)
+					rslt = BME680_E_COM_FAIL;
+			}
+		}
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This internal API is used to get the memory page based on register address.
+ */
+static int8_t get_mem_page(struct bme680_dev *dev)
+{
+	int8_t rslt;
+	uint8_t reg;
+
+	/* Check for null pointer in the device structure*/
+	rslt = null_ptr_check(dev);
+	if (rslt == BME680_OK) {
+		dev->com_rslt = dev->read(dev->dev_id, BME680_MEM_PAGE_ADDR | BME680_SPI_RD_MSK, &reg, 1);
+		if (dev->com_rslt != 0)
+			rslt = BME680_E_COM_FAIL;
+		else
+			dev->mem_page = reg & BME680_MEM_PAGE_MSK;
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This internal API is used to validate the boundary
+ * conditions.
+ */
+static int8_t boundary_check(uint8_t *value, uint8_t min, uint8_t max, struct bme680_dev *dev)
+{
+	int8_t rslt = BME680_OK;
+
+	if (value != NULL) {
+		/* Check if value is below minimum value */
+		if (*value < min) {
+			/* Auto correct the invalid value to minimum value */
+			*value = min;
+			dev->info_msg |= BME680_I_MIN_CORRECTION;
+		}
+		/* Check if value is above maximum value */
+		if (*value > max) {
+			/* Auto correct the invalid value to maximum value */
+			*value = max;
+			dev->info_msg |= BME680_I_MAX_CORRECTION;
+		}
+	} else {
+		rslt = BME680_E_NULL_PTR;
+	}
+
+	return rslt;
+}
+
+/*!
+ * @brief This internal API is used to validate the device structure pointer for
+ * null conditions.
+ */
+static int8_t null_ptr_check(const struct bme680_dev *dev)
+{
+	int8_t rslt;
+
+	if ((dev == NULL) || (dev->read == NULL) || (dev->write == NULL) || (dev->delay_ms == NULL)) {
+		/* Device structure pointer is not valid */
+		rslt = BME680_E_NULL_PTR;
+	} else {
+		/* Device structure is fine */
+		rslt = BME680_OK;
+	}
+
+	return rslt;
+}
diff --git a/src/driver/bme680_util.cc b/src/driver/bme680_util.cc
new file mode 100644
index 0000000..cb9b529
--- /dev/null
+++ b/src/driver/bme680_util.cc
@@ -0,0 +1,27 @@
+#include "arch.h"
+#include "driver/i2c.h"
+#include <stdint.h>
+
+void bme680_delay_ms(uint32_t const period)
+{
+	arch.delay_ms(period);
+}
+
+int8_t bme680_i2c_read(uint8_t dev_id, uint8_t reg_addr, uint8_t *reg_data, uint16_t len)
+{
+	int8_t ret = i2c.xmit(dev_id, 1, &reg_addr, 0, 0);
+	if (ret) {
+		return ret;
+	}
+	return i2c.xmit(dev_id, 0, 0, len, reg_data);
+}
+
+int8_t bme680_i2c_write(uint8_t dev_id, uint8_t reg_addr, uint8_t *reg_data, uint16_t len)
+{
+	unsigned char txbuf[len+1];
+	txbuf[0] = reg_addr;
+	for (uint16_t i = 0; i < len; i++) {
+		txbuf[i+1] = reg_data[i];
+	}
+	return i2c.xmit(dev_id, len + 1, txbuf, 0, 0);
+}
author	Daniel Friesel <daniel.friesel@uos.de>	2019-09-23 12:53:07 +0200
committer	Daniel Friesel <daniel.friesel@uos.de>	2019-09-23 12:53:07 +0200
commit	a5c6adc46d696233bc67e25ac2146173dd6ee8b2 (patch)
tree	c10354d47bf545bfa0a8de5827088032b58f0198 /src
parent	9fbfe1c5dcb12c47e6a408818dc815e3dd856518 (diff)