/** * Copyright (c) 2021 Bosch Sensortec GmbH. All rights reserved. * * BSD-3-Clause * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. 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. * * 3. Neither the name of the copyright holder nor the names of its * 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 THE * 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. * * @file bme68x.c * @date 2021-11-09 * @version v4.4.7 * */ #include "bme68x.h" #include /* This internal API is used to read the calibration coefficients */ static int8_t get_calib_data(struct bme68x_dev *dev); /* This internal API is used to read variant ID information register status */ static int8_t read_variant_id(struct bme68x_dev *dev); /* This internal API is used to calculate the gas wait */ static uint8_t calc_gas_wait(uint16_t dur); #ifndef BME68X_USE_FPU /* This internal API is used to calculate the temperature in integer */ static int16_t calc_temperature(uint32_t temp_adc, struct bme68x_dev *dev); /* This internal API is used to calculate the pressure in integer */ static uint32_t calc_pressure(uint32_t pres_adc, const struct bme68x_dev *dev); /* This internal API is used to calculate the humidity in integer */ static uint32_t calc_humidity(uint16_t hum_adc, const struct bme68x_dev *dev); /* This internal API is used to calculate the gas resistance high */ static uint32_t calc_gas_resistance_high(uint16_t gas_res_adc, uint8_t gas_range); /* This internal API is used to calculate the gas resistance low */ static uint32_t calc_gas_resistance_low(uint16_t gas_res_adc, uint8_t gas_range, const struct bme68x_dev *dev); /* This internal API is used to calculate the heater resistance using integer */ static uint8_t calc_res_heat(uint16_t temp, const struct bme68x_dev *dev); #else /* This internal API is used to calculate the temperature value in float */ static float calc_temperature(uint32_t temp_adc, struct bme68x_dev *dev); /* This internal API is used to calculate the pressure value in float */ static float calc_pressure(uint32_t pres_adc, const struct bme68x_dev *dev); /* This internal API is used to calculate the humidity value in float */ static float calc_humidity(uint16_t hum_adc, const struct bme68x_dev *dev); /* This internal API is used to calculate the gas resistance high value in float */ static float calc_gas_resistance_high(uint16_t gas_res_adc, uint8_t gas_range); /* This internal API is used to calculate the gas resistance low value in float */ static float calc_gas_resistance_low(uint16_t gas_res_adc, uint8_t gas_range, const struct bme68x_dev *dev); /* This internal API is used to calculate the heater resistance value using float */ static uint8_t calc_res_heat(uint16_t temp, const struct bme68x_dev *dev); #endif /* This internal API is used to read a single data of the sensor */ static int8_t read_field_data(uint8_t index, struct bme68x_data *data, struct bme68x_dev *dev); /* This internal API is used to read all data fields of the sensor */ static int8_t read_all_field_data(struct bme68x_data * const data[], struct bme68x_dev *dev); /* This internal API is used to switch between SPI memory pages */ static int8_t set_mem_page(uint8_t reg_addr, struct bme68x_dev *dev); /* This internal API is used to get the current SPI memory page */ static int8_t get_mem_page(struct bme68x_dev *dev); /* This internal API is used to check the bme68x_dev for null pointers */ static int8_t null_ptr_check(const struct bme68x_dev *dev); /* This internal API is used to set heater configurations */ static int8_t set_conf(const struct bme68x_heatr_conf *conf, uint8_t op_mode, uint8_t *nb_conv, struct bme68x_dev *dev); /* This internal API is used to limit the max value of a parameter */ static int8_t boundary_check(uint8_t *value, uint8_t max, struct bme68x_dev *dev); /* This internal API is used to calculate the register value for * shared heater duration */ static uint8_t calc_heatr_dur_shared(uint16_t dur); /* This internal API is used to swap two fields */ static void swap_fields(uint8_t index1, uint8_t index2, struct bme68x_data *field[]); /* This internal API is used sort the sensor data */ static void sort_sensor_data(uint8_t low_index, uint8_t high_index, struct bme68x_data *field[]); /* * @brief Function to analyze the sensor data * * @param[in] data Array of measurement data * @param[in] n_meas Number of measurements * * @return Result of API execution status * @retval 0 -> Success * @retval < 0 -> Fail */ static int8_t analyze_sensor_data(const struct bme68x_data *data, uint8_t n_meas); /******************************************************************************************/ /* Global API definitions */ /******************************************************************************************/ /* @brief This API reads the chip-id of the sensor which is the first step to * verify the sensor and also calibrates the sensor * As this API is the entry point, call this API before using other APIs. */ int8_t bme68x_init(struct bme68x_dev *dev) { int8_t rslt; rslt = bme68x_soft_reset(dev); if (rslt == BME68X_OK) { rslt = bme68x_get_regs(BME68X_REG_CHIP_ID, &dev->chip_id, 1, dev); printf("CHIP ID: %d\n", dev->chip_id); if (rslt == BME68X_OK) { if (dev->chip_id == BME68X_CHIP_ID) { printf("Chip ID Matched\n"); /* Read Variant ID */ rslt = read_variant_id(dev); printf("Test Afer read varient ID\n"); if (rslt == BME68X_OK) { /* Get the Calibration data */ rslt = get_calib_data(dev); printf("Test Afer Calibration data function\n"); } } else { rslt = BME68X_E_DEV_NOT_FOUND; } } } return rslt; } /* * @brief This API writes the given data to the register address of the sensor */ int8_t bme68x_set_regs(const uint8_t *reg_addr, const uint8_t *reg_data, uint32_t len, struct bme68x_dev *dev) { int8_t rslt; /* Length of the temporary buffer is 2*(length of register)*/ uint8_t tmp_buff[BME68X_LEN_INTERLEAVE_BUFF] = { 0 }; uint16_t index; /* Check for null pointer in the device structure*/ rslt = null_ptr_check(dev); if ((rslt == BME68X_OK) && reg_addr && reg_data) { if ((len > 0) && (len <= (BME68X_LEN_INTERLEAVE_BUFF / 2))) { /* Interleave the 2 arrays */ for (index = 0; index < len; index++) { if (dev->intf == BME68X_SPI_INTF) { /* Set the memory page */ rslt = set_mem_page(reg_addr[index], dev); tmp_buff[(2 * index)] = reg_addr[index] & BME68X_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 == BME68X_OK) { dev->intf_rslt = dev->write(tmp_buff[0], &tmp_buff[1], (2 * len) - 1, dev->intf_ptr); if (dev->intf_rslt != 0) { rslt = BME68X_E_COM_FAIL; } } } else { rslt = BME68X_E_INVALID_LENGTH; } } else { rslt = BME68X_E_NULL_PTR; } return rslt; } /* * @brief This API reads the data from the given register address of sensor. */ int8_t bme68x_get_regs(uint8_t reg_addr, uint8_t *reg_data, uint32_t len, struct bme68x_dev *dev) { int8_t rslt; /* Check for null pointer in the device structure*/ rslt = null_ptr_check(dev); if ((rslt == BME68X_OK) && reg_data) { if (dev->intf == BME68X_SPI_INTF) { /* Set the memory page */ rslt = set_mem_page(reg_addr, dev); if (rslt == BME68X_OK) { reg_addr = reg_addr | BME68X_SPI_RD_MSK; } } dev->intf_rslt = dev->read(reg_addr, reg_data, len, dev->intf_ptr); if (dev->intf_rslt != 0) { rslt = BME68X_E_COM_FAIL; } } else { rslt = BME68X_E_NULL_PTR; } return rslt; } /* * @brief This API soft-resets the sensor. */ int8_t bme68x_soft_reset(struct bme68x_dev *dev) { int8_t rslt; uint8_t reg_addr = BME68X_REG_SOFT_RESET; /* 0xb6 is the soft reset command */ uint8_t soft_rst_cmd = BME68X_SOFT_RESET_CMD; /* Check for null pointer in the device structure*/ rslt = null_ptr_check(dev); if (rslt == BME68X_OK) { if (dev->intf == BME68X_SPI_INTF) { rslt = get_mem_page(dev); } /* Reset the device */ if (rslt == BME68X_OK) { rslt = bme68x_set_regs(®_addr, &soft_rst_cmd, 1, dev); /* Wait for 5ms */ dev->delay_us(BME68X_PERIOD_RESET, dev->intf_ptr); if (rslt == BME68X_OK) { /* After reset get the memory page */ if (dev->intf == BME68X_SPI_INTF) { rslt = get_mem_page(dev); } } } } return rslt; } /* * @brief This API is used to set the oversampling, filter and odr configuration */ int8_t bme68x_set_conf(struct bme68x_conf *conf, struct bme68x_dev *dev) { int8_t rslt; uint8_t odr20 = 0, odr3 = 1; uint8_t current_op_mode; /* Register data starting from BME68X_REG_CTRL_GAS_1(0x71) up to BME68X_REG_CONFIG(0x75) */ uint8_t reg_array[BME68X_LEN_CONFIG] = { 0x71, 0x72, 0x73, 0x74, 0x75 }; uint8_t data_array[BME68X_LEN_CONFIG] = { 0 }; rslt = bme68x_get_op_mode(¤t_op_mode, dev); if (rslt == BME68X_OK) { /* Configure only in the sleep mode */ rslt = bme68x_set_op_mode(BME68X_SLEEP_MODE, dev); } if (conf == NULL) { rslt = BME68X_E_NULL_PTR; } else if (rslt == BME68X_OK) { /* Read the whole configuration and write it back once later */ rslt = bme68x_get_regs(reg_array[0], data_array, BME68X_LEN_CONFIG, dev); dev->info_msg = BME68X_OK; if (rslt == BME68X_OK) { rslt = boundary_check(&conf->filter, BME68X_FILTER_SIZE_127, dev); } if (rslt == BME68X_OK) { rslt = boundary_check(&conf->os_temp, BME68X_OS_16X, dev); } if (rslt == BME68X_OK) { rslt = boundary_check(&conf->os_pres, BME68X_OS_16X, dev); } if (rslt == BME68X_OK) { rslt = boundary_check(&conf->os_hum, BME68X_OS_16X, dev); } if (rslt == BME68X_OK) { rslt = boundary_check(&conf->odr, BME68X_ODR_NONE, dev); } if (rslt == BME68X_OK) { data_array[4] = BME68X_SET_BITS(data_array[4], BME68X_FILTER, conf->filter); data_array[3] = BME68X_SET_BITS(data_array[3], BME68X_OST, conf->os_temp); data_array[3] = BME68X_SET_BITS(data_array[3], BME68X_OSP, conf->os_pres); data_array[1] = BME68X_SET_BITS_POS_0(data_array[1], BME68X_OSH, conf->os_hum); if (conf->odr != BME68X_ODR_NONE) { odr20 = conf->odr; odr3 = 0; } data_array[4] = BME68X_SET_BITS(data_array[4], BME68X_ODR20, odr20); data_array[0] = BME68X_SET_BITS(data_array[0], BME68X_ODR3, odr3); } } if (rslt == BME68X_OK) { rslt = bme68x_set_regs(reg_array, data_array, BME68X_LEN_CONFIG, dev); } if ((current_op_mode != BME68X_SLEEP_MODE) && (rslt == BME68X_OK)) { rslt = bme68x_set_op_mode(current_op_mode, dev); } return rslt; } /* * @brief This API is used to get the oversampling, filter and odr */ int8_t bme68x_get_conf(struct bme68x_conf *conf, struct bme68x_dev *dev) { int8_t rslt; /* starting address of the register array for burst read*/ uint8_t reg_addr = BME68X_REG_CTRL_GAS_1; uint8_t data_array[BME68X_LEN_CONFIG]; rslt = bme68x_get_regs(reg_addr, data_array, 5, dev); if (!conf) { rslt = BME68X_E_NULL_PTR; } else if (rslt == BME68X_OK) { conf->os_hum = BME68X_GET_BITS_POS_0(data_array[1], BME68X_OSH); conf->filter = BME68X_GET_BITS(data_array[4], BME68X_FILTER); conf->os_temp = BME68X_GET_BITS(data_array[3], BME68X_OST); conf->os_pres = BME68X_GET_BITS(data_array[3], BME68X_OSP); if (BME68X_GET_BITS(data_array[0], BME68X_ODR3)) { conf->odr = BME68X_ODR_NONE; } else { conf->odr = BME68X_GET_BITS(data_array[4], BME68X_ODR20); } } return rslt; } /* * @brief This API is used to set the operation mode of the sensor */ int8_t bme68x_set_op_mode(const uint8_t op_mode, struct bme68x_dev *dev) { int8_t rslt; uint8_t tmp_pow_mode; uint8_t pow_mode = 0; uint8_t reg_addr = BME68X_REG_CTRL_MEAS; /* Call until in sleep */ do { rslt = bme68x_get_regs(BME68X_REG_CTRL_MEAS, &tmp_pow_mode, 1, dev); if (rslt == BME68X_OK) { /* Put to sleep before changing mode */ pow_mode = (tmp_pow_mode & BME68X_MODE_MSK); if (pow_mode != BME68X_SLEEP_MODE) { tmp_pow_mode &= ~BME68X_MODE_MSK; /* Set to sleep */ rslt = bme68x_set_regs(®_addr, &tmp_pow_mode, 1, dev); dev->delay_us(BME68X_PERIOD_POLL, dev->intf_ptr); } } } while ((pow_mode != BME68X_SLEEP_MODE) && (rslt == BME68X_OK)); /* Already in sleep */ if ((op_mode != BME68X_SLEEP_MODE) && (rslt == BME68X_OK)) { tmp_pow_mode = (tmp_pow_mode & ~BME68X_MODE_MSK) | (op_mode & BME68X_MODE_MSK); rslt = bme68x_set_regs(®_addr, &tmp_pow_mode, 1, dev); } return rslt; } /* * @brief This API is used to get the operation mode of the sensor. */ int8_t bme68x_get_op_mode(uint8_t *op_mode, struct bme68x_dev *dev) { int8_t rslt; uint8_t mode; if (op_mode) { rslt = bme68x_get_regs(BME68X_REG_CTRL_MEAS, &mode, 1, dev); /* Masking the other register bit info*/ *op_mode = mode & BME68X_MODE_MSK; } else { rslt = BME68X_E_NULL_PTR; } return rslt; } /* * @brief This API is used to get the remaining duration that can be used for heating. */ uint32_t bme68x_get_meas_dur(const uint8_t op_mode, struct bme68x_conf *conf, struct bme68x_dev *dev) { int8_t rslt; uint32_t meas_dur = 0; /* Calculate in us */ uint32_t meas_cycles; uint8_t os_to_meas_cycles[6] = { 0, 1, 2, 4, 8, 16 }; if (conf != NULL) { /* Boundary check for temperature oversampling */ rslt = boundary_check(&conf->os_temp, BME68X_OS_16X, dev); if (rslt == BME68X_OK) { /* Boundary check for pressure oversampling */ rslt = boundary_check(&conf->os_pres, BME68X_OS_16X, dev); } if (rslt == BME68X_OK) { /* Boundary check for humidity oversampling */ rslt = boundary_check(&conf->os_hum, BME68X_OS_16X, dev); } if (rslt == BME68X_OK) { meas_cycles = os_to_meas_cycles[conf->os_temp]; meas_cycles += os_to_meas_cycles[conf->os_pres]; meas_cycles += os_to_meas_cycles[conf->os_hum]; /* TPH measurement duration */ meas_dur = meas_cycles * UINT32_C(1963); meas_dur += UINT32_C(477 * 4); /* TPH switching duration */ meas_dur += UINT32_C(477 * 5); /* Gas measurement duration */ if (op_mode != BME68X_PARALLEL_MODE) { meas_dur += UINT32_C(1000); /* Wake up duration of 1ms */ } } } return meas_dur; } /* * @brief This API reads the pressure, temperature and humidity and gas data * from the sensor, compensates the data and store it in the bme68x_data * structure instance passed by the user. */ int8_t bme68x_get_data(uint8_t op_mode, struct bme68x_data *data, uint8_t *n_data, struct bme68x_dev *dev) { int8_t rslt; uint8_t i = 0, j = 0, new_fields = 0; struct bme68x_data *field_ptr[3] = { 0 }; struct bme68x_data field_data[3] = { { 0 } }; field_ptr[0] = &field_data[0]; field_ptr[1] = &field_data[1]; field_ptr[2] = &field_data[2]; rslt = null_ptr_check(dev); if ((rslt == BME68X_OK) && (data != NULL)) { /* Reading the sensor data in forced mode only */ if (op_mode == BME68X_FORCED_MODE) { rslt = read_field_data(0, data, dev); if (rslt == BME68X_OK) { if (data->status & BME68X_NEW_DATA_MSK) { new_fields = 1; } else { new_fields = 0; rslt = BME68X_W_NO_NEW_DATA; } } } else if ((op_mode == BME68X_PARALLEL_MODE) || (op_mode == BME68X_SEQUENTIAL_MODE)) { /* Read the 3 fields and count the number of new data fields */ rslt = read_all_field_data(field_ptr, dev); new_fields = 0; for (i = 0; (i < 3) && (rslt == BME68X_OK); i++) { if (field_ptr[i]->status & BME68X_NEW_DATA_MSK) { new_fields++; } } /* Sort the sensor data in parallel & sequential modes*/ for (i = 0; (i < 2) && (rslt == BME68X_OK); i++) { for (j = i + 1; j < 3; j++) { sort_sensor_data(i, j, field_ptr); } } /* Copy the sorted data */ for (i = 0; ((i < 3) && (rslt == BME68X_OK)); i++) { data[i] = *field_ptr[i]; } if (new_fields == 0) { rslt = BME68X_W_NO_NEW_DATA; } } else { rslt = BME68X_W_DEFINE_OP_MODE; } if (n_data == NULL) { rslt = BME68X_E_NULL_PTR; } else { *n_data = new_fields; } } else { rslt = BME68X_E_NULL_PTR; } return rslt; } /* * @brief This API is used to set the gas configuration of the sensor. */ int8_t bme68x_set_heatr_conf(uint8_t op_mode, const struct bme68x_heatr_conf *conf, struct bme68x_dev *dev) { int8_t rslt; uint8_t nb_conv = 0; uint8_t hctrl, run_gas = 0; uint8_t ctrl_gas_data[2]; uint8_t ctrl_gas_addr[2] = { BME68X_REG_CTRL_GAS_0, BME68X_REG_CTRL_GAS_1 }; if (conf != NULL) { rslt = bme68x_set_op_mode(BME68X_SLEEP_MODE, dev); if (rslt == BME68X_OK) { rslt = set_conf(conf, op_mode, &nb_conv, dev); } if (rslt == BME68X_OK) { rslt = bme68x_get_regs(BME68X_REG_CTRL_GAS_0, ctrl_gas_data, 2, dev); if (rslt == BME68X_OK) { if (conf->enable == BME68X_ENABLE) { hctrl = BME68X_ENABLE_HEATER; if (dev->variant_id == BME68X_VARIANT_GAS_HIGH) { run_gas = BME68X_ENABLE_GAS_MEAS_H; } else { run_gas = BME68X_ENABLE_GAS_MEAS_L; } } else { hctrl = BME68X_DISABLE_HEATER; run_gas = BME68X_DISABLE_GAS_MEAS; } ctrl_gas_data[0] = BME68X_SET_BITS(ctrl_gas_data[0], BME68X_HCTRL, hctrl); ctrl_gas_data[1] = BME68X_SET_BITS_POS_0(ctrl_gas_data[1], BME68X_NBCONV, nb_conv); ctrl_gas_data[1] = BME68X_SET_BITS(ctrl_gas_data[1], BME68X_RUN_GAS, run_gas); rslt = bme68x_set_regs(ctrl_gas_addr, ctrl_gas_data, 2, dev); } } } else { rslt = BME68X_E_NULL_PTR; } return rslt; } /* * @brief This API is used to get the gas configuration of the sensor. */ int8_t bme68x_get_heatr_conf(const struct bme68x_heatr_conf *conf, struct bme68x_dev *dev) { int8_t rslt; uint8_t data_array[10] = { 0 }; uint8_t i; /* FIXME: Add conversion to deg C and ms and add the other parameters */ rslt = bme68x_get_regs(BME68X_REG_RES_HEAT0, data_array, 10, dev); if (rslt == BME68X_OK) { if (conf && conf->heatr_dur_prof && conf->heatr_temp_prof) { for (i = 0; i < 10; i++) { conf->heatr_temp_prof[i] = data_array[i]; } rslt = bme68x_get_regs(BME68X_REG_GAS_WAIT0, data_array, 10, dev); if (rslt == BME68X_OK) { for (i = 0; i < 10; i++) { conf->heatr_dur_prof[i] = data_array[i]; } } } else { rslt = BME68X_E_NULL_PTR; } } return rslt; } /* * @brief This API performs Self-test of low and high gas variants of BME68X */ int8_t bme68x_selftest_check(const struct bme68x_dev *dev) { int8_t rslt; uint8_t n_fields; uint8_t i = 0; struct bme68x_data data[BME68X_N_MEAS] = { { 0 } }; struct bme68x_dev t_dev; struct bme68x_conf conf; struct bme68x_heatr_conf heatr_conf; /* Copy required parameters from reference bme68x_dev struct */ t_dev.amb_temp = 25; t_dev.read = dev->read; t_dev.write = dev->write; t_dev.intf = dev->intf; t_dev.delay_us = dev->delay_us; t_dev.intf_ptr = dev->intf_ptr; rslt = bme68x_init(&t_dev); if (rslt == BME68X_OK) { /* Set the temperature, pressure and humidity & filter settings */ conf.os_hum = BME68X_OS_1X; conf.os_pres = BME68X_OS_16X; conf.os_temp = BME68X_OS_2X; /* Set the remaining gas sensor settings and link the heating profile */ heatr_conf.enable = BME68X_ENABLE; heatr_conf.heatr_dur = BME68X_HEATR_DUR1; heatr_conf.heatr_temp = BME68X_HIGH_TEMP; rslt = bme68x_set_heatr_conf(BME68X_FORCED_MODE, &heatr_conf, &t_dev); if (rslt == BME68X_OK) { rslt = bme68x_set_conf(&conf, &t_dev); if (rslt == BME68X_OK) { rslt = bme68x_set_op_mode(BME68X_FORCED_MODE, &t_dev); /* Trigger a measurement */ if (rslt == BME68X_OK) { /* Wait for the measurement to complete */ t_dev.delay_us(BME68X_HEATR_DUR1_DELAY, t_dev.intf_ptr); rslt = bme68x_get_data(BME68X_FORCED_MODE, &data[0], &n_fields, &t_dev); if (rslt == BME68X_OK) { if ((data[0].idac != 0x00) && (data[0].idac != 0xFF) && (data[0].status & BME68X_GASM_VALID_MSK)) { rslt = BME68X_OK; } else { rslt = BME68X_E_SELF_TEST; } } } } } heatr_conf.heatr_dur = BME68X_HEATR_DUR2; while ((rslt == BME68X_OK) && (i < BME68X_N_MEAS)) { if (i % 2 == 0) { heatr_conf.heatr_temp = BME68X_HIGH_TEMP; /* Higher temperature */ } else { heatr_conf.heatr_temp = BME68X_LOW_TEMP; /* Lower temperature */ } rslt = bme68x_set_heatr_conf(BME68X_FORCED_MODE, &heatr_conf, &t_dev); if (rslt == BME68X_OK) { rslt = bme68x_set_conf(&conf, &t_dev); if (rslt == BME68X_OK) { rslt = bme68x_set_op_mode(BME68X_FORCED_MODE, &t_dev); /* Trigger a measurement */ if (rslt == BME68X_OK) { /* Wait for the measurement to complete */ t_dev.delay_us(BME68X_HEATR_DUR2_DELAY, t_dev.intf_ptr); rslt = bme68x_get_data(BME68X_FORCED_MODE, &data[i], &n_fields, &t_dev); } } } i++; } if (rslt == BME68X_OK) { rslt = analyze_sensor_data(data, BME68X_N_MEAS); } } return rslt; } /*****************************INTERNAL APIs***********************************************/ #ifndef BME68X_USE_FPU /* @brief This internal API is used to calculate the temperature value. */ static int16_t calc_temperature(uint32_t temp_adc, struct bme68x_dev *dev) { int64_t var1; int64_t var2; int64_t var3; int16_t calc_temp; /*lint -save -e701 -e702 -e704 */ 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); /*lint -restore */ 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 bme68x_dev *dev) { int32_t var1; int32_t var2; int32_t var3; int32_t pressure_comp; /* This value is used to check precedence to multiplication or division * in the pressure compensation equation to achieve least loss of precision and * avoiding overflows. * i.e Comparing value, pres_ovf_check = (1 << 31) >> 1 */ const int32_t pres_ovf_check = INT32_C(0x40000000); /*lint -save -e701 -e702 -e713 */ 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 >= pres_ovf_check) { 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); /*lint -restore */ return (uint32_t)pressure_comp; } /* This internal API is used to calculate the humidity in integer */ static uint32_t calc_humidity(uint16_t hum_adc, const struct bme68x_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; /*lint -save -e702 -e704 */ 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; } /*lint -restore */ return (uint32_t)calc_hum; } /* This internal API is used to calculate the gas resistance low */ static uint32_t calc_gas_resistance_low(uint16_t gas_res_adc, uint8_t gas_range, const struct bme68x_dev *dev) { int64_t var1; uint64_t var2; int64_t var3; uint32_t calc_gas_res; uint32_t lookup_table1[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) }; uint32_t lookup_table2[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) }; /*lint -save -e704 */ var1 = (int64_t)((1340 + (5 * (int64_t)dev->calib.range_sw_err)) * ((int64_t)lookup_table1[gas_range])) >> 16; var2 = (((int64_t)((int64_t)gas_res_adc << 15) - (int64_t)(16777216)) + var1); var3 = (((int64_t)lookup_table2[gas_range] * (int64_t)var1) >> 9); calc_gas_res = (uint32_t)((var3 + ((int64_t)var2 >> 1)) / (int64_t)var2); /*lint -restore */ return calc_gas_res; } /* This internal API is used to calculate the gas resistance */ static uint32_t calc_gas_resistance_high(uint16_t gas_res_adc, uint8_t gas_range) { uint32_t calc_gas_res; uint32_t var1 = UINT32_C(262144) >> gas_range; int32_t var2 = (int32_t)gas_res_adc - INT32_C(512); var2 *= INT32_C(3); var2 = INT32_C(4096) + var2; /* multiplying 10000 then dividing then multiplying by 100 instead of multiplying by 1000000 to prevent overflow */ calc_gas_res = (UINT32_C(10000) * var1) / (uint32_t)var2; calc_gas_res = calc_gas_res * 100; return calc_gas_res; } /* This internal API is used to calculate the heater resistance value using float */ static uint8_t calc_res_heat(uint16_t temp, const struct bme68x_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. */ static float calc_temperature(uint32_t temp_adc, struct bme68x_dev *dev) { float var1; float var2; float calc_temp; /* 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. */ static float calc_pressure(uint32_t pres_adc, const struct bme68x_dev *dev) { float var1; float var2; float var3; float calc_pres; 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; } /* This internal API is used to calculate the humidity in integer */ static float calc_humidity(uint16_t hum_adc, const struct bme68x_dev *dev) { float calc_hum; float var1; float var2; float var3; float var4; 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; } /* This internal API is used to calculate the gas resistance low value in float */ static float calc_gas_resistance_low(uint16_t gas_res_adc, uint8_t gas_range, const struct bme68x_dev *dev) { float calc_gas_res; float var1; float var2; float var3; float gas_res_f = gas_res_adc; float gas_range_f = (1U << gas_range); /*lint !e790 / Suspicious truncation, integral to float */ const float lookup_k1_range[16] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, -0.8f, 0.0f, 0.0f, -0.2f, -0.5f, 0.0f, -1.0f, 0.0f, 0.0f }; const float lookup_k2_range[16] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.1f, 0.7f, 0.0f, -0.8f, -0.1f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f }; 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) * gas_range_f * (((gas_res_f - 512.0f) / var2) + 1.0f)); return calc_gas_res; } /* This internal API is used to calculate the gas resistance value in float */ static float calc_gas_resistance_high(uint16_t gas_res_adc, uint8_t gas_range) { float calc_gas_res; uint32_t var1 = UINT32_C(262144) >> gas_range; int32_t var2 = (int32_t)gas_res_adc - INT32_C(512); var2 *= INT32_C(3); var2 = INT32_C(4096) + var2; calc_gas_res = 1000000.0f * (float)var1 / (float)var2; return calc_gas_res; } /* This internal API is used to calculate the heater resistance value */ static uint8_t calc_res_heat(uint16_t temp, const struct bme68x_dev *dev) { float var1; float var2; float var3; float var4; float var5; uint8_t res_heat; 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 /* This internal API is used to calculate the gas wait */ static uint8_t calc_gas_wait(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; } /* This internal API is used to read a single data of the sensor */ static int8_t read_field_data(uint8_t index, struct bme68x_data *data, struct bme68x_dev *dev) { int8_t rslt = BME68X_OK; uint8_t buff[BME68X_LEN_FIELD] = { 0 }; uint8_t gas_range_l, gas_range_h; uint32_t adc_temp; uint32_t adc_pres; uint16_t adc_hum; uint16_t adc_gas_res_low, adc_gas_res_high; uint8_t tries = 5; while ((tries) && (rslt == BME68X_OK)) { rslt = bme68x_get_regs(((uint8_t)(BME68X_REG_FIELD0 + (index * BME68X_LEN_FIELD_OFFSET))), buff, (uint16_t)BME68X_LEN_FIELD, dev); if (!data) { rslt = BME68X_E_NULL_PTR; break; } data->status = buff[0] & BME68X_NEW_DATA_MSK; data->gas_index = buff[0] & BME68X_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_low = (uint16_t)((uint32_t)buff[13] * 4 | (((uint32_t)buff[14]) / 64)); adc_gas_res_high = (uint16_t)((uint32_t)buff[15] * 4 | (((uint32_t)buff[16]) / 64)); gas_range_l = buff[14] & BME68X_GAS_RANGE_MSK; gas_range_h = buff[16] & BME68X_GAS_RANGE_MSK; if (dev->variant_id == BME68X_VARIANT_GAS_HIGH) { data->status |= buff[16] & BME68X_GASM_VALID_MSK; data->status |= buff[16] & BME68X_HEAT_STAB_MSK; } else { data->status |= buff[14] & BME68X_GASM_VALID_MSK; data->status |= buff[14] & BME68X_HEAT_STAB_MSK; } if ((data->status & BME68X_NEW_DATA_MSK) && (rslt == BME68X_OK)) { rslt = bme68x_get_regs(BME68X_REG_RES_HEAT0 + data->gas_index, &data->res_heat, 1, dev); if (rslt == BME68X_OK) { rslt = bme68x_get_regs(BME68X_REG_IDAC_HEAT0 + data->gas_index, &data->idac, 1, dev); } if (rslt == BME68X_OK) { rslt = bme68x_get_regs(BME68X_REG_GAS_WAIT0 + data->gas_index, &data->gas_wait, 1, dev); } if (rslt == BME68X_OK) { data->temperature = calc_temperature(adc_temp, dev); data->pressure = calc_pressure(adc_pres, dev); data->humidity = calc_humidity(adc_hum, dev); if (dev->variant_id == BME68X_VARIANT_GAS_HIGH) { data->gas_resistance = calc_gas_resistance_high(adc_gas_res_high, gas_range_h); } else { data->gas_resistance = calc_gas_resistance_low(adc_gas_res_low, gas_range_l, dev); } break; } } if (rslt == BME68X_OK) { dev->delay_us(BME68X_PERIOD_POLL, dev->intf_ptr); } tries--; } return rslt; } /* This internal API is used to read all data fields of the sensor */ static int8_t read_all_field_data(struct bme68x_data * const data[], struct bme68x_dev *dev) { int8_t rslt = BME68X_OK; uint8_t buff[BME68X_LEN_FIELD * 3] = { 0 }; uint8_t gas_range_l, gas_range_h; uint32_t adc_temp; uint32_t adc_pres; uint16_t adc_hum; uint16_t adc_gas_res_low, adc_gas_res_high; uint8_t off; uint8_t set_val[30] = { 0 }; /* idac, res_heat, gas_wait */ uint8_t i; if (!data[0] && !data[1] && !data[2]) { rslt = BME68X_E_NULL_PTR; } if (rslt == BME68X_OK) { rslt = bme68x_get_regs(BME68X_REG_FIELD0, buff, (uint32_t) BME68X_LEN_FIELD * 3, dev); } if (rslt == BME68X_OK) { rslt = bme68x_get_regs(BME68X_REG_IDAC_HEAT0, set_val, 30, dev); } for (i = 0; ((i < 3) && (rslt == BME68X_OK)); i++) { off = (uint8_t)(i * BME68X_LEN_FIELD); data[i]->status = buff[off] & BME68X_NEW_DATA_MSK; data[i]->gas_index = buff[off] & BME68X_GAS_INDEX_MSK; data[i]->meas_index = buff[off + 1]; /* read the raw data from the sensor */ adc_pres = (uint32_t) (((uint32_t) buff[off + 2] * 4096) | ((uint32_t) buff[off + 3] * 16) | ((uint32_t) buff[off + 4] / 16)); adc_temp = (uint32_t) (((uint32_t) buff[off + 5] * 4096) | ((uint32_t) buff[off + 6] * 16) | ((uint32_t) buff[off + 7] / 16)); adc_hum = (uint16_t) (((uint32_t) buff[off + 8] * 256) | (uint32_t) buff[off + 9]); adc_gas_res_low = (uint16_t) ((uint32_t) buff[off + 13] * 4 | (((uint32_t) buff[off + 14]) / 64)); adc_gas_res_high = (uint16_t) ((uint32_t) buff[off + 15] * 4 | (((uint32_t) buff[off + 16]) / 64)); gas_range_l = buff[off + 14] & BME68X_GAS_RANGE_MSK; gas_range_h = buff[off + 16] & BME68X_GAS_RANGE_MSK; if (dev->variant_id == BME68X_VARIANT_GAS_HIGH) { data[i]->status |= buff[off + 16] & BME68X_GASM_VALID_MSK; data[i]->status |= buff[off + 16] & BME68X_HEAT_STAB_MSK; } else { data[i]->status |= buff[off + 14] & BME68X_GASM_VALID_MSK; data[i]->status |= buff[off + 14] & BME68X_HEAT_STAB_MSK; } data[i]->idac = set_val[data[i]->gas_index]; data[i]->res_heat = set_val[10 + data[i]->gas_index]; data[i]->gas_wait = set_val[20 + data[i]->gas_index]; data[i]->temperature = calc_temperature(adc_temp, dev); data[i]->pressure = calc_pressure(adc_pres, dev); data[i]->humidity = calc_humidity(adc_hum, dev); if (dev->variant_id == BME68X_VARIANT_GAS_HIGH) { data[i]->gas_resistance = calc_gas_resistance_high(adc_gas_res_high, gas_range_h); } else { data[i]->gas_resistance = calc_gas_resistance_low(adc_gas_res_low, gas_range_l, dev); } } return rslt; } /* This internal API is used to switch between SPI memory pages */ static int8_t set_mem_page(uint8_t reg_addr, struct bme68x_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 == BME68X_OK) { if (reg_addr > 0x7f) { mem_page = BME68X_MEM_PAGE1; } else { mem_page = BME68X_MEM_PAGE0; } if (mem_page != dev->mem_page) { dev->mem_page = mem_page; dev->intf_rslt = dev->read(BME68X_REG_MEM_PAGE | BME68X_SPI_RD_MSK, ®, 1, dev->intf_ptr); if (dev->intf_rslt != 0) { rslt = BME68X_E_COM_FAIL; } if (rslt == BME68X_OK) { reg = reg & (~BME68X_MEM_PAGE_MSK); reg = reg | (dev->mem_page & BME68X_MEM_PAGE_MSK); dev->intf_rslt = dev->write(BME68X_REG_MEM_PAGE & BME68X_SPI_WR_MSK, ®, 1, dev->intf_ptr); if (dev->intf_rslt != 0) { rslt = BME68X_E_COM_FAIL; } } } } return rslt; } /* This internal API is used to get the current SPI memory page */ static int8_t get_mem_page(struct bme68x_dev *dev) { int8_t rslt; uint8_t reg; /* Check for null pointer in the device structure*/ rslt = null_ptr_check(dev); if (rslt == BME68X_OK) { dev->intf_rslt = dev->read(BME68X_REG_MEM_PAGE | BME68X_SPI_RD_MSK, ®, 1, dev->intf_ptr); if (dev->intf_rslt != 0) { rslt = BME68X_E_COM_FAIL; } else { dev->mem_page = reg & BME68X_MEM_PAGE_MSK; } } return rslt; } /* This internal API is used to limit the max value of a parameter */ static int8_t boundary_check(uint8_t *value, uint8_t max, struct bme68x_dev *dev) { int8_t rslt; rslt = null_ptr_check(dev); if ((value != NULL) && (rslt == BME68X_OK)) { /* Check if value is above maximum value */ if (*value > max) { /* Auto correct the invalid value to maximum value */ *value = max; dev->info_msg |= BME68X_I_PARAM_CORR; } } else { rslt = BME68X_E_NULL_PTR; } return rslt; } /* This internal API is used to check the bme68x_dev for null pointers */ static int8_t null_ptr_check(const struct bme68x_dev *dev) { int8_t rslt = BME68X_OK; if ((dev == NULL) || (dev->read == NULL) || (dev->write == NULL) || (dev->delay_us == NULL)) { /* Device structure pointer is not valid */ rslt = BME68X_E_NULL_PTR; } return rslt; } /* This internal API is used to set heater configurations */ static int8_t set_conf(const struct bme68x_heatr_conf *conf, uint8_t op_mode, uint8_t *nb_conv, struct bme68x_dev *dev) { int8_t rslt = BME68X_OK; uint8_t i; uint8_t shared_dur; uint8_t write_len = 0; uint8_t heater_dur_shared_addr = BME68X_REG_SHD_HEATR_DUR; uint8_t rh_reg_addr[10] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; uint8_t rh_reg_data[10] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; uint8_t gw_reg_addr[10] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; uint8_t gw_reg_data[10] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; switch (op_mode) { case BME68X_FORCED_MODE: rh_reg_addr[0] = BME68X_REG_RES_HEAT0; rh_reg_data[0] = calc_res_heat(conf->heatr_temp, dev); gw_reg_addr[0] = BME68X_REG_GAS_WAIT0; gw_reg_data[0] = calc_gas_wait(conf->heatr_dur); (*nb_conv) = 0; write_len = 1; break; case BME68X_SEQUENTIAL_MODE: if ((!conf->heatr_dur_prof) || (!conf->heatr_temp_prof)) { rslt = BME68X_E_NULL_PTR; break; } for (i = 0; i < conf->profile_len; i++) { rh_reg_addr[i] = BME68X_REG_RES_HEAT0 + i; rh_reg_data[i] = calc_res_heat(conf->heatr_temp_prof[i], dev); gw_reg_addr[i] = BME68X_REG_GAS_WAIT0 + i; gw_reg_data[i] = calc_gas_wait(conf->heatr_dur_prof[i]); } (*nb_conv) = conf->profile_len; write_len = conf->profile_len; break; case BME68X_PARALLEL_MODE: if ((!conf->heatr_dur_prof) || (!conf->heatr_temp_prof)) { rslt = BME68X_E_NULL_PTR; break; } if (conf->shared_heatr_dur == 0) { rslt = BME68X_W_DEFINE_SHD_HEATR_DUR; } for (i = 0; i < conf->profile_len; i++) { rh_reg_addr[i] = BME68X_REG_RES_HEAT0 + i; rh_reg_data[i] = calc_res_heat(conf->heatr_temp_prof[i], dev); gw_reg_addr[i] = BME68X_REG_GAS_WAIT0 + i; gw_reg_data[i] = (uint8_t) conf->heatr_dur_prof[i]; } (*nb_conv) = conf->profile_len; write_len = conf->profile_len; shared_dur = calc_heatr_dur_shared(conf->shared_heatr_dur); if (rslt == BME68X_OK) { rslt = bme68x_set_regs(&heater_dur_shared_addr, &shared_dur, 1, dev); } break; default: rslt = BME68X_W_DEFINE_OP_MODE; } if (rslt == BME68X_OK) { rslt = bme68x_set_regs(rh_reg_addr, rh_reg_data, write_len, dev); } if (rslt == BME68X_OK) { rslt = bme68x_set_regs(gw_reg_addr, gw_reg_data, write_len, dev); } return rslt; } /* This internal API is used to calculate the register value for * shared heater duration */ static uint8_t calc_heatr_dur_shared(uint16_t dur) { uint8_t factor = 0; uint8_t heatdurval; if (dur >= 0x783) { heatdurval = 0xff; /* Max duration */ } else { /* Step size of 0.477ms */ dur = (uint16_t)(((uint32_t)dur * 1000) / 477); while (dur > 0x3F) { dur = dur >> 2; factor += 1; } heatdurval = (uint8_t)(dur + (factor * 64)); } return heatdurval; } /* This internal API is used sort the sensor data */ static void sort_sensor_data(uint8_t low_index, uint8_t high_index, struct bme68x_data *field[]) { int16_t meas_index1; int16_t meas_index2; meas_index1 = (int16_t)field[low_index]->meas_index; meas_index2 = (int16_t)field[high_index]->meas_index; if ((field[low_index]->status & BME68X_NEW_DATA_MSK) && (field[high_index]->status & BME68X_NEW_DATA_MSK)) { int16_t diff = meas_index2 - meas_index1; if (((diff > -3) && (diff < 0)) || (diff > 2)) { swap_fields(low_index, high_index, field); } } else if (field[high_index]->status & BME68X_NEW_DATA_MSK) { swap_fields(low_index, high_index, field); } /* Sorting field data * * The 3 fields are filled in a fixed order with data in an incrementing * 8-bit sub-measurement index which looks like * Field index | Sub-meas index * 0 | 0 * 1 | 1 * 2 | 2 * 0 | 3 * 1 | 4 * 2 | 5 * ... * 0 | 252 * 1 | 253 * 2 | 254 * 0 | 255 * 1 | 0 * 2 | 1 * * The fields are sorted in a way so as to always deal with only a snapshot * of comparing 2 fields at a time. The order being * field0 & field1 * field0 & field2 * field1 & field2 * Here the oldest data should be in field0 while the newest is in field2. * In the following documentation, field0's position would referred to as * the lowest and field2 as the highest. * * In order to sort we have to consider the following cases, * * Case A: No fields have new data * Then do not sort, as this data has already been read. * * Case B: Higher field has new data * Then the new field get's the lowest position. * * Case C: Both fields have new data * We have to put the oldest sample in the lowest position. Since the * sub-meas index contains in essence the age of the sample, we calculate * the difference between the higher field and the lower field. * Here we have 3 sub-cases, * Case 1: Regular read without overwrite * Field index | Sub-meas index * 0 | 3 * 1 | 4 * * Field index | Sub-meas index * 0 | 3 * 2 | 5 * * The difference is always <= 2. There is no need to swap as the * oldest sample is already in the lowest position. * * Case 2: Regular read with an overflow and without an overwrite * Field index | Sub-meas index * 0 | 255 * 1 | 0 * * Field index | Sub-meas index * 0 | 254 * 2 | 0 * * The difference is always <= -3. There is no need to swap as the * oldest sample is already in the lowest position. * * Case 3: Regular read with overwrite * Field index | Sub-meas index * 0 | 6 * 1 | 4 * * Field index | Sub-meas index * 0 | 6 * 2 | 5 * * The difference is always > -3. There is a need to swap as the * oldest sample is not in the lowest position. * * Case 4: Regular read with overwrite and overflow * Field index | Sub-meas index * 0 | 0 * 1 | 254 * * Field index | Sub-meas index * 0 | 0 * 2 | 255 * * The difference is always > 2. There is a need to swap as the * oldest sample is not in the lowest position. * * To summarize, we have to swap when * - The higher field has new data and the lower field does not. * - If both fields have new data, then the difference of sub-meas index * between the higher field and the lower field creates the * following condition for swapping. * - (diff > -3) && (diff < 0), combination of cases 1, 2, and 3. * - diff > 2, case 4. * * Here the limits of -3 and 2 derive from the fact that there are 3 fields. * These values decrease or increase respectively if the number of fields increases. */ } /* This internal API is used sort the sensor data */ static void swap_fields(uint8_t index1, uint8_t index2, struct bme68x_data *field[]) { struct bme68x_data *temp; temp = field[index1]; field[index1] = field[index2]; field[index2] = temp; } /* This Function is to analyze the sensor data */ static int8_t analyze_sensor_data(const struct bme68x_data *data, uint8_t n_meas) { int8_t rslt = BME68X_OK; uint8_t self_test_failed = 0, i; uint32_t cent_res = 0; if ((data[0].temperature < BME68X_MIN_TEMPERATURE) || (data[0].temperature > BME68X_MAX_TEMPERATURE)) { self_test_failed++; } if ((data[0].pressure < BME68X_MIN_PRESSURE) || (data[0].pressure > BME68X_MAX_PRESSURE)) { self_test_failed++; } if ((data[0].humidity < BME68X_MIN_HUMIDITY) || (data[0].humidity > BME68X_MAX_HUMIDITY)) { self_test_failed++; } for (i = 0; i < n_meas; i++) /* Every gas measurement should be valid */ { if (!(data[i].status & BME68X_GASM_VALID_MSK)) { self_test_failed++; } } if (n_meas >= 6) { cent_res = (uint32_t)((5 * (data[3].gas_resistance + data[5].gas_resistance)) / (2 * data[4].gas_resistance)); } if (cent_res < 6) { self_test_failed++; } if (self_test_failed) { rslt = BME68X_E_SELF_TEST; } return rslt; } /* This internal API is used to read the calibration coefficients */ static int8_t get_calib_data(struct bme68x_dev *dev) { int8_t rslt; uint8_t coeff_array[BME68X_LEN_COEFF_ALL]; rslt = bme68x_get_regs(BME68X_REG_COEFF1, coeff_array, BME68X_LEN_COEFF1, dev); if (rslt == BME68X_OK) { rslt = bme68x_get_regs(BME68X_REG_COEFF2, &coeff_array[BME68X_LEN_COEFF1], BME68X_LEN_COEFF2, dev); } if (rslt == BME68X_OK) { rslt = bme68x_get_regs(BME68X_REG_COEFF3, &coeff_array[BME68X_LEN_COEFF1 + BME68X_LEN_COEFF2], BME68X_LEN_COEFF3, dev); } if (rslt == BME68X_OK) { /* Temperature related coefficients */ dev->calib.par_t1 = (uint16_t)(BME68X_CONCAT_BYTES(coeff_array[BME68X_IDX_T1_MSB], coeff_array[BME68X_IDX_T1_LSB])); dev->calib.par_t2 = (int16_t)(BME68X_CONCAT_BYTES(coeff_array[BME68X_IDX_T2_MSB], coeff_array[BME68X_IDX_T2_LSB])); dev->calib.par_t3 = (int8_t)(coeff_array[BME68X_IDX_T3]); /* Pressure related coefficients */ dev->calib.par_p1 = (uint16_t)(BME68X_CONCAT_BYTES(coeff_array[BME68X_IDX_P1_MSB], coeff_array[BME68X_IDX_P1_LSB])); dev->calib.par_p2 = (int16_t)(BME68X_CONCAT_BYTES(coeff_array[BME68X_IDX_P2_MSB], coeff_array[BME68X_IDX_P2_LSB])); dev->calib.par_p3 = (int8_t)coeff_array[BME68X_IDX_P3]; dev->calib.par_p4 = (int16_t)(BME68X_CONCAT_BYTES(coeff_array[BME68X_IDX_P4_MSB], coeff_array[BME68X_IDX_P4_LSB])); dev->calib.par_p5 = (int16_t)(BME68X_CONCAT_BYTES(coeff_array[BME68X_IDX_P5_MSB], coeff_array[BME68X_IDX_P5_LSB])); dev->calib.par_p6 = (int8_t)(coeff_array[BME68X_IDX_P6]); dev->calib.par_p7 = (int8_t)(coeff_array[BME68X_IDX_P7]); dev->calib.par_p8 = (int16_t)(BME68X_CONCAT_BYTES(coeff_array[BME68X_IDX_P8_MSB], coeff_array[BME68X_IDX_P8_LSB])); dev->calib.par_p9 = (int16_t)(BME68X_CONCAT_BYTES(coeff_array[BME68X_IDX_P9_MSB], coeff_array[BME68X_IDX_P9_LSB])); dev->calib.par_p10 = (uint8_t)(coeff_array[BME68X_IDX_P10]); /* Humidity related coefficients */ dev->calib.par_h1 = (uint16_t)(((uint16_t)coeff_array[BME68X_IDX_H1_MSB] << 4) | (coeff_array[BME68X_IDX_H1_LSB] & BME68X_BIT_H1_DATA_MSK)); dev->calib.par_h2 = (uint16_t)(((uint16_t)coeff_array[BME68X_IDX_H2_MSB] << 4) | ((coeff_array[BME68X_IDX_H2_LSB]) >> 4)); dev->calib.par_h3 = (int8_t)coeff_array[BME68X_IDX_H3]; dev->calib.par_h4 = (int8_t)coeff_array[BME68X_IDX_H4]; dev->calib.par_h5 = (int8_t)coeff_array[BME68X_IDX_H5]; dev->calib.par_h6 = (uint8_t)coeff_array[BME68X_IDX_H6]; dev->calib.par_h7 = (int8_t)coeff_array[BME68X_IDX_H7]; /* Gas heater related coefficients */ dev->calib.par_gh1 = (int8_t)coeff_array[BME68X_IDX_GH1]; dev->calib.par_gh2 = (int16_t)(BME68X_CONCAT_BYTES(coeff_array[BME68X_IDX_GH2_MSB], coeff_array[BME68X_IDX_GH2_LSB])); dev->calib.par_gh3 = (int8_t)coeff_array[BME68X_IDX_GH3]; /* Other coefficients */ dev->calib.res_heat_range = ((coeff_array[BME68X_IDX_RES_HEAT_RANGE] & BME68X_RHRANGE_MSK) / 16); dev->calib.res_heat_val = (int8_t)coeff_array[BME68X_IDX_RES_HEAT_VAL]; dev->calib.range_sw_err = ((int8_t)(coeff_array[BME68X_IDX_RANGE_SW_ERR] & BME68X_RSERROR_MSK)) / 16; } return rslt; } /* This internal API is used to read variant ID information from the register */ static int8_t read_variant_id(struct bme68x_dev *dev) { int8_t rslt; uint8_t reg_data = 0; /* Read variant ID information register */ rslt = bme68x_get_regs(BME68X_REG_VARIANT_ID, ®_data, 1, dev); if (rslt == BME68X_OK) { dev->variant_id = reg_data; } return rslt; }