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esp/bme680-demo/managed_components/esp-idf-lib__bme680/bme680.c
Antoine 61de768d87 first commit
2026-06-24 23:13:57 +02:00

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/*
* Copyright (c) 2017 Gunar Schorcht <https://github.com/gschorcht>
* Copyright (c) 2019 Ruslan V. Uss <unclerus@gmail.com>
*
* 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 itscontributors
* 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.
*/
/**
* ESP-IDF driver for BME680 digital environmental sensor
*
* Forked from <https://github.com/gschorcht/bme680-esp-idf>
*
* Copyright (c) 2017 Gunar Schorcht <https://github.com/gschorcht>\n
* Copyright (c) 2019 Ruslan V. Uss <unclerus@gmail.com>
*
* BSD Licensed as described in the file LICENSE
*/
#include <string.h>
#include <inttypes.h>
#include <stdlib.h>
#include <esp_log.h>
#include <freertos/FreeRTOS.h>
#include <freertos/task.h>
#include <esp_idf_lib_helpers.h>
#include "bme680.h"
#define I2C_FREQ_HZ 1000000 // Up to 3.4MHz, but esp-idf only supports 1MHz
// modes: unfortunatly, only SLEEP_MODE and FORCED_MODE are documented
#define BME680_SLEEP_MODE 0x00 // low power sleeping
#define BME680_FORCED_MODE 0x01 // perform one TPHG cycle (field data 0 filled)
#define BME680_PARALLEL_MODE 0x02 // no information what it does :-(
#define BME680_SQUENTUAL_MODE 0x02 // no information what it does (field data 0+1+2 filled)
// register addresses
#define BME680_REG_RES_HEAT_VAL 0x00
#define BME680_REG_RES_HEAT_RANGE 0x02
#define BME680_REG_RANGE_SW_ERROR 0x06
#define BME680_REG_IDAC_HEAT_BASE 0x50 // 10 regsrs idac_heat_0 ... idac_heat_9
#define BME680_REG_RES_HEAT_BASE 0x5a // 10 registers res_heat_0 ... res_heat_9
#define BME680_REG_GAS_WAIT_BASE 0x64 // 10 registers gas_wait_0 ... gas_wait_9
#define BME680_REG_CTRL_GAS_0 0x70
#define BME680_REG_CTRL_GAS_1 0x71
#define BME680_REG_CTRL_HUM 0x72
#define BME680_REG_STATUS 0x73
#define BME680_REG_CTRL_MEAS 0x74
#define BME680_REG_CONFIG 0x75
#define BME680_REG_ID 0xd0
#define BME680_REG_RESET 0xe0
// field data 0 registers
#define BME680_REG_MEAS_STATUS_0 0x1d
#define BME680_REG_MEAS_INDEX_0 0x1e
#define BME680_REG_PRESS_MSB_0 0x1f
#define BME680_REG_PRESS_LSB_0 0x20
#define BME680_REG_PRESS_XLSB_0 0x21
#define BME680_REG_TEMP_MSB_0 0x22
#define BME680_REG_TEMP_LSB_0 0x23
#define BME680_REG_TEMP_XLSB_0 0x24
#define BME680_REG_HUM_MSB_0 0x25
#define BME680_REG_HUM_LSB_0 0x26
#define BME680_REG_GAS_R_MSB_0 0x2a
#define BME680_REG_GAS_R_LSB_0 0x2b
// field data 1 registers (not documented, used in SEQUENTIAL_MODE)
#define BME680_REG_MEAS_STATUS_1 0x2e
#define BME680_REG_MEAS_INDEX_1 0x2f
// field data 2 registers (not documented, used in SEQUENTIAL_MODE)
#define BME680_REG_MEAS_STATUS_2 0x3f
#define BME680_REG_MEAS_INDEX_2 0x40
// field data addresses
#define BME680_REG_RAW_DATA_0 BME680_REG_MEAS_STATUS_0 // 0x1d ... 0x2b
#define BME680_REG_RAW_DATA_1 BME680_REG_MEAS_STATUS_1 // 0x2e ... 0x3c
#define BME680_REG_RAW_DATA_2 BME680_REG_MEAS_STATUS_2 // 0x40 ... 0x4d
#define BME680_REG_RAW_DATA_LEN (BME680_REG_GAS_R_LSB_0 - BME680_REG_MEAS_STATUS_0 + 1)
// calibration data registers
#define BME680_REG_CD1_ADDR 0x89 // 25 byte calibration data
#define BME680_REG_CD1_LEN 25
#define BME680_REG_CD2_ADDR 0xe1 // 16 byte calibration data
#define BME680_REG_CD2_LEN 16
#define BME680_REG_CD3_ADDR 0x00 // 8 byte device specific calibration data
#define BME680_REG_CD3_LEN 8
// register structure definitions
#define BME680_NEW_DATA_BITS 0x80 // BME680_REG_MEAS_STATUS<7>
#define BME680_NEW_DATA_SHIFT 7 // BME680_REG_MEAS_STATUS<7>
#define BME680_GAS_MEASURING_BITS 0x40 // BME680_REG_MEAS_STATUS<6>
#define BME680_GAS_MEASURING_SHIFT 6 // BME680_REG_MEAS_STATUS<6>
#define BME680_MEASURING_BITS 0x20 // BME680_REG_MEAS_STATUS<5>
#define BME680_MEASURING_SHIFT 5 // BME680_REG_MEAS_STATUS<5>
#define BME680_GAS_MEAS_INDEX_BITS 0x0f // BME680_REG_MEAS_STATUS<3:0>
#define BME680_GAS_MEAS_INDEX_SHIFT 0 // BME680_REG_MEAS_STATUS<3:0>
#define BME680_GAS_R_LSB_BITS 0xc0 // BME680_REG_GAS_R_LSB<7:6>
#define BME680_GAS_R_LSB_SHIFT 6 // BME680_REG_GAS_R_LSB<7:6>
#define BME680_GAS_VALID_BITS 0x20 // BME680_REG_GAS_R_LSB<5>
#define BME680_GAS_VALID_SHIFT 5 // BME680_REG_GAS_R_LSB<5>
#define BME680_HEAT_STAB_R_BITS 0x10 // BME680_REG_GAS_R_LSB<4>
#define BME680_HEAT_STAB_R_SHIFT 4 // BME680_REG_GAS_R_LSB<4>
#define BME680_GAS_RANGE_R_BITS 0x0f // BME680_REG_GAS_R_LSB<3:0>
#define BME680_GAS_RANGE_R_SHIFT 0 // BME680_REG_GAS_R_LSB<3:0>
#define BME680_HEAT_OFF_BITS 0x04 // BME680_REG_CTRL_GAS_0<3>
#define BME680_HEAT_OFF_SHIFT 3 // BME680_REG_CTRL_GAS_0<3>
#define BME680_RUN_GAS_BITS 0x10 // BME680_REG_CTRL_GAS_1<4>
#define BME680_RUN_GAS_SHIFT 4 // BME680_REG_CTRL_GAS_1<4>
#define BME680_NB_CONV_BITS 0x0f // BME680_REG_CTRL_GAS_1<3:0>
#define BME680_NB_CONV_SHIFT 0 // BME680_REG_CTRL_GAS_1<3:0>
#define BME680_SPI_3W_INT_EN_BITS 0x40 // BME680_REG_CTRL_HUM<6>
#define BME680_SPI_3W_INT_EN_SHIFT 6 // BME680_REG_CTRL_HUM<6>
#define BME680_OSR_H_BITS 0x07 // BME680_REG_CTRL_HUM<2:0>
#define BME680_OSR_H_SHIFT 0 // BME680_REG_CTRL_HUM<2:0>
#define BME680_OSR_T_BITS 0xe0 // BME680_REG_CTRL_MEAS<7:5>
#define BME680_OSR_T_SHIFT 5 // BME680_REG_CTRL_MEAS<7:5>
#define BME680_OSR_P_BITS 0x1c // BME680_REG_CTRL_MEAS<4:2>
#define BME680_OSR_P_SHIFT 2 // BME680_REG_CTRL_MEAS<4:2>
#define BME680_MODE_BITS 0x03 // BME680_REG_CTRL_MEAS<1:0>
#define BME680_MODE_SHIFT 0 // BME680_REG_CTRL_MEAS<1:0>
#define BME680_FILTER_BITS 0x1c // BME680_REG_CONFIG<4:2>
#define BME680_FILTER_SHIFT 2 // BME680_REG_CONFIG<4:2>
#define BME680_SPI_3W_EN_BITS 0x01 // BME680_REG_CONFIG<0>
#define BME680_SPI_3W_EN_SHIFT 0 // BME680_REG_CONFIG<0>
#define BME680_SPI_MEM_PAGE_BITS 0x10 // BME680_REG_STATUS<4>
#define BME680_SPI_MEM_PAGE_SHIFT 4 // BME680_REG_STATUS<4>
#define BME680_GAS_WAIT_BITS 0x3f // BME680_REG_GAS_WAIT+x<5:0>
#define BME680_GAS_WAIT_SHIFT 0 // BME680_REG_GAS_WAIT+x<5:0>
#define BME680_GAS_WAIT_MULT_BITS 0xc0 // BME680_REG_GAS_WAIT+x<7:6>
#define BME680_GAS_WAIT_MULT_SHIFT 6 // BME680_REG_GAS_WAIT+x<7:6>
// commands
#define BME680_RESET_CMD 0xb6 // BME680_REG_RESET<7:0>
#define BME680_RESET_PERIOD 10 // reset time in ms
#define BME680_RHR_BITS 0x30 // BME680_REG_RES_HEAT_RANGE<5:4>
#define BME680_RHR_SHIFT 4 // BME680_REG_RES_HEAT_RANGE<5:4>
#define BME680_RSWE_BITS 0xf0 // BME680_REG_RANGE_SW_ERROR<7:4>
#define BME680_RSWE_SHIFT 4 // BME680_REG_RANGE_SW_ERROR<7:4>
// calibration data are stored in a calibration data map
#define BME680_CDM_SIZE (BME680_REG_CD1_LEN + BME680_REG_CD2_LEN + BME680_REG_CD3_LEN)
#define BME680_CDM_OFF1 0
#define BME680_CDM_OFF2 BME680_REG_CD1_LEN
#define BME680_CDM_OFF3 BME680_CDM_OFF2 + BME680_REG_CD2_LEN
// calibration parameter offsets in calibration data map
// calibration data from 0x89
#define BME680_CDM_T2 1
#define BME680_CDM_T3 3
#define BME680_CDM_P1 5
#define BME680_CDM_P2 7
#define BME680_CDM_P3 9
#define BME680_CDM_P4 11
#define BME680_CDM_P5 13
#define BME680_CDM_P7 15
#define BME680_CDM_P6 16
#define BME680_CDM_P8 19
#define BME680_CDM_P9 21
#define BME680_CDM_P10 23
// calibration data from 0e1
#define BME680_CDM_H2 25
#define BME680_CDM_H1 26
#define BME680_CDM_H3 28
#define BME680_CDM_H4 29
#define BME680_CDM_H5 30
#define BME680_CDM_H6 31
#define BME680_CDM_H7 32
#define BME680_CDM_T1 33
#define BME680_CDM_GH2 35
#define BME680_CDM_GH1 37
#define BME680_CDM_GH3 38
// device specific calibration data from 0x00
#define BME680_CDM_RHV 41 // 0x00 - res_heat_val
#define BME680_CDM_RHR 43 // 0x02 - res_heat_range
#define BME680_CDM_RSWE 45 // 0x04 - range_sw_error
static const char *TAG = "bme680";
#define CHECK(x) do { esp_err_t __; if ((__ = x) != ESP_OK) return __; } while (0)
#define CHECK_ARG(VAL) do { if (!(VAL)) return ESP_ERR_INVALID_ARG; } while (0)
#define CHECK_LOGE(x, msg, ...) do { \
esp_err_t __; \
if ((__ = x) != ESP_OK) { \
ESP_LOGE(TAG, msg, ## __VA_ARGS__); \
return __; \
} \
} while (0)
/**
* @brief Raw data (integer values) read from sensor
*/
typedef struct
{
bool gas_valid; // indicate that gas measurement results are valid
bool heater_stable; // indicate that heater temperature was stable
uint32_t temperature; // degree celsius x100
uint32_t pressure; // pressure in Pascal
uint16_t humidity; // relative humidity x1000 in %
uint16_t gas_resistance; // gas resistance data
uint8_t gas_range; // gas resistance range
uint8_t gas_index; // heater profile used (0 ... 9)
uint8_t meas_index;
} bme680_raw_data_t;
#define lsb_msb_to_type(t,b,o) (t)(((t)b[o+1] << 8) | b[o])
#define lsb_to_type(t,b,o) (t)(b[o])
#define bme_set_reg_bit(byte, bitname, bit) ( (byte & ~bitname##_BITS) | \
((bit << bitname##_SHIFT) & bitname##_BITS) )
#define bme_get_reg_bit(byte, bitname) ( (byte & bitname##_BITS) >> bitname##_SHIFT )
static inline esp_err_t read_reg_8_nolock(bme680_t *dev, uint8_t reg, uint8_t *data)
{
return i2c_dev_read_reg(&dev->i2c_dev, reg, data, 1);
}
static inline esp_err_t write_reg_8_nolock(bme680_t *dev, uint8_t reg, uint8_t data)
{
return i2c_dev_write_reg(&dev->i2c_dev, reg, &data, 1);
}
static esp_err_t read_reg_8(bme680_t *dev, uint8_t reg, uint8_t *data)
{
I2C_DEV_TAKE_MUTEX(&dev->i2c_dev);
I2C_DEV_CHECK(&dev->i2c_dev, read_reg_8_nolock(dev, reg, data));
I2C_DEV_GIVE_MUTEX(&dev->i2c_dev);
return ESP_OK;
}
static esp_err_t bme680_set_mode(bme680_t *dev, uint8_t mode)
{
uint8_t reg;
I2C_DEV_TAKE_MUTEX(&dev->i2c_dev);
I2C_DEV_CHECK(&dev->i2c_dev, read_reg_8_nolock(dev, BME680_REG_CTRL_MEAS, &reg));
reg = bme_set_reg_bit(reg, BME680_MODE, mode);
I2C_DEV_CHECK(&dev->i2c_dev, write_reg_8_nolock(dev, BME680_REG_CTRL_MEAS, reg));
I2C_DEV_GIVE_MUTEX(&dev->i2c_dev);
return ESP_OK;
}
#define msb_lsb_xlsb_to_20bit(t,b,o) (t)((t) b[o] << 12 | (t) b[o+1] << 4 | b[o+2] >> 4)
#define msb_lsb_to_type(t,b,o) (t)(((t)b[o] << 8) | b[o+1])
#define BME680_RAW_P_OFF BME680_REG_PRESS_MSB_0-BME680_REG_MEAS_STATUS_0
#define BME680_RAW_T_OFF (BME680_RAW_P_OFF + BME680_REG_TEMP_MSB_0 - BME680_REG_PRESS_MSB_0)
#define BME680_RAW_H_OFF (BME680_RAW_T_OFF + BME680_REG_HUM_MSB_0 - BME680_REG_TEMP_MSB_0)
#define BME680_RAW_G_OFF (BME680_RAW_H_OFF + BME680_REG_GAS_R_MSB_0 - BME680_REG_HUM_MSB_0)
static esp_err_t bme680_get_raw_data(bme680_t *dev, bme680_raw_data_t *raw_data)
{
if (!dev->meas_started)
{
ESP_LOGE(TAG, "Measurement was not started");
return ESP_ERR_INVALID_STATE;
}
uint8_t raw[BME680_REG_RAW_DATA_LEN] = { 0 };
if (!(dev->meas_status & BME680_NEW_DATA_BITS))
{
// read measurement status from sensor
CHECK(read_reg_8(dev, BME680_REG_MEAS_STATUS_0, &dev->meas_status));
// test whether there are new data
if (!(dev->meas_status & BME680_NEW_DATA_BITS))
{
if (dev->meas_status & BME680_MEASURING_BITS)
{
ESP_LOGW(TAG, "Measurement is still running");
return ESP_ERR_INVALID_STATE;
}
ESP_LOGW(TAG, "No new data");
return ESP_ERR_INVALID_RESPONSE;
}
}
dev->meas_started = false;
raw_data->gas_index = dev->meas_status & BME680_GAS_MEAS_INDEX_BITS;
// if there are new data, read raw data from sensor
I2C_DEV_TAKE_MUTEX(&dev->i2c_dev);
I2C_DEV_CHECK(&dev->i2c_dev, i2c_dev_read_reg(&dev->i2c_dev, BME680_REG_RAW_DATA_0, raw, BME680_REG_RAW_DATA_LEN));
I2C_DEV_GIVE_MUTEX(&dev->i2c_dev);
raw_data->gas_valid = bme_get_reg_bit(raw[BME680_RAW_G_OFF + 1], BME680_GAS_VALID);
raw_data->heater_stable = bme_get_reg_bit(raw[BME680_RAW_G_OFF + 1], BME680_HEAT_STAB_R);
raw_data->temperature = msb_lsb_xlsb_to_20bit(uint32_t, raw, BME680_RAW_T_OFF);
raw_data->pressure = msb_lsb_xlsb_to_20bit(uint32_t, raw, BME680_RAW_P_OFF);
raw_data->humidity = msb_lsb_to_type(uint16_t, raw, BME680_RAW_H_OFF);
raw_data->gas_resistance = ((uint16_t) raw[BME680_RAW_G_OFF] << 2) | raw[BME680_RAW_G_OFF + 1] >> 6;
raw_data->gas_range = raw[BME680_RAW_G_OFF + 1] & BME680_GAS_RANGE_R_BITS;
/*
* BME680_REG_MEAS_STATUS_1, BME680_REG_MEAS_STATUS_2
* These data are not documented and it is not really clear when they are filled
*/
ESP_LOGD(TAG, "Raw data: %" PRIu32 " %" PRIu32 " %d %d %d", raw_data->temperature, raw_data->pressure,
raw_data->humidity, raw_data->gas_resistance, raw_data->gas_range);
return ESP_OK;
}
/**
* @brief Calculate temperature from raw temperature value
* @ref BME280 datasheet, page 50
*/
static int16_t bme680_convert_temperature(bme680_t *dev, uint32_t raw_temperature)
{
bme680_calib_data_t *cd = &dev->calib_data;
int64_t var1;
int64_t var2;
int64_t var3;
int16_t temperature;
var1 = ((int32_t)raw_temperature >> 3) - ((int32_t)cd->par_t1 << 1);
var2 = (var1 * (int32_t)cd->par_t2) >> 11;
var3 = ((var1 >> 1) * (var1 >> 1)) >> 12;
var3 = ((var3) * ((int32_t)cd->par_t3 << 4)) >> 14;
cd->t_fine = (int32_t)(var2 + var3);
temperature = (int16_t)(((cd->t_fine * 5) + 128) >> 8);
return temperature;
}
/**
* @brief Calculate pressure from raw pressure value
* @copyright Copyright (c) 2017 - 2018 Bosch Sensortec GmbH
*
* The algorithm was extracted from the original Bosch Sensortec BME680 driver
* published as open source. Divisions and multiplications by potences of 2
* were replaced by shift operations for effeciency reasons.
*
* @ref [BME680_diver](https://github.com/BoschSensortec/BME680_driver)
* @ref BME280 datasheet, page 50
*/
static uint32_t bme680_convert_pressure(bme680_t *dev, uint32_t raw_pressure)
{
bme680_calib_data_t *cd = &dev->calib_data;
int32_t var1;
int32_t var2;
int32_t var3;
int32_t pressure_comp;
var1 = (((int32_t)cd->t_fine) >> 1) - 64000;
var2 = ((((var1 >> 2) * (var1 >> 2)) >> 11) *
(int32_t)cd->par_p6) >> 2;
var2 = var2 + ((var1 * (int32_t)cd->par_p5) << 1);
var2 = (var2 >> 2) + ((int32_t)cd->par_p4 << 16);
var1 = (((((var1 >> 2) * (var1 >> 2)) >> 13) *
((int32_t)cd->par_p3 << 5)) >> 3) +
(((int32_t)cd->par_p2 * var1) >> 1);
var1 = var1 >> 18;
var1 = ((32768 + var1) * (int32_t)cd->par_p1) >> 15;
pressure_comp = 1048576 - raw_pressure;
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)cd->par_p9 * (int32_t)(((pressure_comp >> 3) *
(pressure_comp >> 3)) >> 13)) >> 12;
var2 = ((int32_t)(pressure_comp >> 2) *
(int32_t)cd->par_p8) >> 13;
var3 = ((int32_t)(pressure_comp >> 8) * (int32_t)(pressure_comp >> 8) *
(int32_t)(pressure_comp >> 8) *
(int32_t)cd->par_p10) >> 17;
pressure_comp = (int32_t)(pressure_comp) + ((var1 + var2 + var3 +
((int32_t)cd->par_p7 << 7)) >> 4);
return (uint32_t)pressure_comp;
}
/**
* @brief Calculate humidty from raw humidity data
* @copyright Copyright (c) 2017 - 2018 Bosch Sensortec GmbH
*
* The algorithm was extracted from the original Bosch Sensortec BME680 driver
* published as open source. Divisions and multiplications by potences of 2
* were replaced by shift operations for effeciency reasons.
*
* @ref [BME680_diver](https://github.com/BoschSensortec/BME680_driver)
*/
static uint32_t bme680_convert_humidity(bme680_t *dev, uint16_t raw_humidity)
{
bme680_calib_data_t *cd = &dev->calib_data;
int32_t var1;
int32_t var2;
int32_t var3;
int32_t var4;
int32_t var5;
int32_t var6;
int32_t temp_scaled;
int32_t humidity;
temp_scaled = (((int32_t) cd->t_fine * 5) + 128) >> 8;
var1 = (int32_t) (raw_humidity - ((int32_t) ((int32_t) cd->par_h1 << 4)))
- (((temp_scaled * (int32_t) cd->par_h3) / ((int32_t) 100)) >> 1);
var2 = ((int32_t) cd->par_h2
* (((temp_scaled * (int32_t) cd->par_h4) / ((int32_t) 100))
+ (((temp_scaled * ((temp_scaled * (int32_t) cd->par_h5) / ((int32_t) 100))) >> 6) / ((int32_t) 100))
+ (int32_t) (1 << 14))) >> 10;
var3 = var1 * var2;
var4 = (int32_t) cd->par_h6 << 7;
var4 = ((var4) + ((temp_scaled * (int32_t) cd->par_h7) / ((int32_t) 100))) >> 4;
var5 = ((var3 >> 14) * (var3 >> 14)) >> 10;
var6 = (var4 * var5) >> 1;
humidity = (((var3 + var6) >> 10) * ((int32_t) 1000)) >> 12;
if (humidity > 100000) /* Cap at 100%rH */
humidity = 100000;
else if (humidity < 0)
humidity = 0;
return (uint32_t) humidity;
}
/**
* @brief Lookup table for gas resitance computation
* @ref BME680 datasheet, page 19
*/
static float lookup_table[16][2] =
{
// const1, const2 // gas_range
{ 1.0, 8000000.0 }, // 0
{ 1.0, 4000000.0 }, // 1
{ 1.0, 2000000.0 }, // 2
{ 1.0, 1000000.0 }, // 3
{ 1.0, 499500.4995 }, // 4
{ 0.99, 248262.1648 }, // 5
{ 1.0, 125000.0 }, // 6
{ 0.992, 63004.03226 }, // 7
{ 1.0, 31281.28128 }, // 8
{ 1.0, 15625.0 }, // 9
{ 0.998, 7812.5 }, // 10
{ 0.995, 3906.25 }, // 11
{ 1.0, 1953.125 }, // 12
{ 0.99, 976.5625 }, // 13
{ 1.0, 488.28125 }, // 14
{ 1.0, 244.140625 } // 15
};
/**
* @brief Calculate gas resistance from raw gas resitance value and gas range
* @ref BME680 datasheet
*/
static uint32_t bme680_convert_gas(bme680_t *dev, uint16_t gas, uint8_t gas_range)
{
bme680_calib_data_t *cd = &dev->calib_data;
float var1 = (1340.0 + 5.0 * cd->range_sw_err) * lookup_table[gas_range][0];
return var1 * lookup_table[gas_range][1] / (gas - 512.0 + var1);
}
/**
* @brief Calculate internal duration representation
*
* Durations are internally representes as one byte
*
* duration = value<5:0> * multiplier<7:6>
*
* where the multiplier is 1, 4, 16, or 64. Maximum duration is therefore
* 64*64 = 4032 ms. The function takes a real world duration value given
* in milliseconds and computes the internal representation.
*
* @ref Datasheet
*/
static uint8_t bme680_heater_duration(uint16_t duration)
{
uint8_t multiplier = 0;
while (duration > 63)
{
duration = duration / 4;
multiplier++;
}
return (uint8_t) (duration | (multiplier << 6));
}
/**
* @brief Calculate internal heater resistance value from real temperature.
*
* @ref Datasheet of BME680
*/
static uint8_t bme680_heater_resistance(const bme680_t *dev, uint16_t temp)
{
if (!dev)
return 0;
if (temp < BME680_HEATER_TEMP_MIN)
temp = BME680_HEATER_TEMP_MIN;
else if (temp > BME680_HEATER_TEMP_MAX)
temp = BME680_HEATER_TEMP_MAX;
const bme680_calib_data_t *cd = &dev->calib_data;
// from datasheet
double var1;
double var2;
double var3;
double var4;
double var5;
uint8_t res_heat_x;
var1 = ((double) cd->par_gh1 / 16.0) + 49.0;
var2 = (((double) cd->par_gh2 / 32768.0) * 0.0005) + 0.00235;
var3 = (double) cd->par_gh3 / 1024.0;
var4 = var1 * (1.0 + (var2 * (double) temp));
var5 = var4 + (var3 * (double) dev->settings.ambient_temperature);
res_heat_x = (uint8_t) (3.4
* ((var5 * (4.0 / (4.0 + (double) cd->res_heat_range)) * (1.0 / (1.0 + ((double) cd->res_heat_val * 0.002)))) - 25));
return res_heat_x;
}
///////////////////////////////////////////////////////////////////////////////
esp_err_t bme680_init_desc(bme680_t *dev, uint8_t addr, i2c_port_t port, gpio_num_t sda_gpio, gpio_num_t scl_gpio)
{
CHECK_ARG(dev);
if (addr != BME680_I2C_ADDR_0 && addr != BME680_I2C_ADDR_1)
{
ESP_LOGE(TAG, "Invalid I2C address");
return ESP_ERR_INVALID_ARG;
}
dev->i2c_dev.port = port;
dev->i2c_dev.addr = addr;
dev->i2c_dev.cfg.sda_io_num = sda_gpio;
dev->i2c_dev.cfg.scl_io_num = scl_gpio;
#if HELPER_TARGET_IS_ESP32
dev->i2c_dev.cfg.master.clk_speed = I2C_FREQ_HZ;
#endif
return i2c_dev_create_mutex(&dev->i2c_dev);
}
esp_err_t bme680_free_desc(bme680_t *dev)
{
CHECK_ARG(dev);
return i2c_dev_delete_mutex(&dev->i2c_dev);
}
esp_err_t bme680_init_sensor(bme680_t *dev)
{
CHECK_ARG(dev);
I2C_DEV_TAKE_MUTEX(&dev->i2c_dev);
dev->meas_started = false;
dev->meas_status = 0;
dev->settings.ambient_temperature = 0;
dev->settings.osr_temperature = BME680_OSR_NONE;
dev->settings.osr_pressure = BME680_OSR_NONE;
dev->settings.osr_humidity = BME680_OSR_NONE;
dev->settings.filter_size = BME680_IIR_SIZE_0;
dev->settings.heater_profile = BME680_HEATER_NOT_USED;
memset(dev->settings.heater_temperature, 0, sizeof(uint16_t) * 10);
memset(dev->settings.heater_duration, 0, sizeof(uint16_t) * 10);
// reset the sensor
I2C_DEV_CHECK(&dev->i2c_dev, write_reg_8_nolock(dev, BME680_REG_RESET, BME680_RESET_CMD));
vTaskDelay(pdMS_TO_TICKS(BME680_RESET_PERIOD));
uint8_t chip_id = 0;
I2C_DEV_CHECK(&dev->i2c_dev, read_reg_8_nolock(dev, BME680_REG_ID, &chip_id));
if (chip_id != 0x61)
{
I2C_DEV_GIVE_MUTEX(&dev->i2c_dev);
ESP_LOGE(TAG, "Chip id %02x is wrong, should be 0x61", chip_id);
return ESP_ERR_NOT_FOUND;
}
uint8_t buf[BME680_CDM_SIZE];
I2C_DEV_CHECK(&dev->i2c_dev, i2c_dev_read_reg(&dev->i2c_dev, BME680_REG_CD1_ADDR, buf + BME680_CDM_OFF1, BME680_REG_CD1_LEN));
I2C_DEV_CHECK(&dev->i2c_dev, i2c_dev_read_reg(&dev->i2c_dev, BME680_REG_CD2_ADDR, buf + BME680_CDM_OFF2, BME680_REG_CD2_LEN));
I2C_DEV_CHECK(&dev->i2c_dev, i2c_dev_read_reg(&dev->i2c_dev, BME680_REG_CD3_ADDR, buf + BME680_CDM_OFF3, BME680_REG_CD3_LEN));
dev->calib_data.par_t1 = lsb_msb_to_type(uint16_t, buf, BME680_CDM_T1);
dev->calib_data.par_t2 = lsb_msb_to_type(int16_t, buf, BME680_CDM_T2);
dev->calib_data.par_t3 = lsb_to_type(int8_t, buf, BME680_CDM_T3);
// pressure compensation parameters
dev->calib_data.par_p1 = lsb_msb_to_type(uint16_t, buf, BME680_CDM_P1);
dev->calib_data.par_p2 = lsb_msb_to_type(int16_t, buf, BME680_CDM_P2);
dev->calib_data.par_p3 = lsb_to_type(int8_t, buf, BME680_CDM_P3);
dev->calib_data.par_p4 = lsb_msb_to_type(int16_t, buf, BME680_CDM_P4);
dev->calib_data.par_p5 = lsb_msb_to_type(int16_t, buf, BME680_CDM_P5);
dev->calib_data.par_p6 = lsb_to_type(int8_t, buf, BME680_CDM_P6);
dev->calib_data.par_p7 = lsb_to_type(int8_t, buf, BME680_CDM_P7);
dev->calib_data.par_p8 = lsb_msb_to_type(int16_t, buf, BME680_CDM_P8);
dev->calib_data.par_p9 = lsb_msb_to_type(int16_t, buf, BME680_CDM_P9);
dev->calib_data.par_p10 = lsb_to_type(uint8_t, buf, BME680_CDM_P10);
// humidity compensation parameters
dev->calib_data.par_h1 = (uint16_t) (((uint16_t) buf[BME680_CDM_H1 + 1] << 4) | (buf[BME680_CDM_H1] & 0x0F));
dev->calib_data.par_h2 = (uint16_t) (((uint16_t) buf[BME680_CDM_H2] << 4) | (buf[BME680_CDM_H2 + 1] >> 4));
dev->calib_data.par_h3 = lsb_to_type(int8_t, buf, BME680_CDM_H3);
dev->calib_data.par_h4 = lsb_to_type(int8_t, buf, BME680_CDM_H4);
dev->calib_data.par_h5 = lsb_to_type(int8_t, buf, BME680_CDM_H5);
dev->calib_data.par_h6 = lsb_to_type(uint8_t, buf, BME680_CDM_H6);
dev->calib_data.par_h7 = lsb_to_type(int8_t, buf, BME680_CDM_H7);
// gas sensor compensation parameters
dev->calib_data.par_gh1 = lsb_to_type(int8_t, buf, BME680_CDM_GH1);
dev->calib_data.par_gh2 = lsb_msb_to_type(int16_t, buf, BME680_CDM_GH2);
dev->calib_data.par_gh3 = lsb_to_type(int8_t, buf, BME680_CDM_GH3);
dev->calib_data.res_heat_range = (lsb_to_type(uint8_t, buf, BME680_CDM_RHR) & BME680_RHR_BITS) >> BME680_RHR_SHIFT;
dev->calib_data.res_heat_val = (lsb_to_type(int8_t, buf, BME680_CDM_RHV));
dev->calib_data.range_sw_err = (lsb_to_type(int8_t, buf, BME680_CDM_RSWE) & BME680_RSWE_BITS) >> BME680_RSWE_SHIFT;
// Set ambient temperature of sensor to default value (25 degree C)
dev->settings.ambient_temperature = 25;
I2C_DEV_GIVE_MUTEX(&dev->i2c_dev);
CHECK(bme680_set_oversampling_rates(dev, BME680_OSR_1X, BME680_OSR_1X, BME680_OSR_1X));
CHECK(bme680_set_filter_size(dev, BME680_IIR_SIZE_3));
// Set heater default profile 0 to 320 degree Celcius for 150 ms
CHECK(bme680_set_heater_profile(dev, 0, 320, 150));
CHECK(bme680_use_heater_profile(dev, 0));
return ESP_OK;
}
esp_err_t bme680_force_measurement(bme680_t *dev)
{
CHECK_ARG(dev);
if (dev->meas_started)
{
ESP_LOGE(TAG, "Measurement is already running");
return ESP_ERR_INVALID_STATE;
}
// Set the power mode to forced mode to trigger one TPHG measurement cycle
CHECK_LOGE(bme680_set_mode(dev, BME680_FORCED_MODE),
"Could not set forced mode to start TPHG measurement cycle");
dev->meas_started = true;
dev->meas_status = 0;
ESP_LOGD(TAG, "Started measurement");
return ESP_OK;
}
/**
* @brief Estimate the measurement duration in RTOS ticks
*
* Timing formulas extracted from BME280 datasheet and test in some
* experiments. They represent the maximum measurement duration.
*/
esp_err_t bme680_get_measurement_duration(const bme680_t *dev, uint32_t *duration)
{
CHECK_ARG(dev && duration);
*duration = 0; /* Calculate in us */
// wake up duration from sleep into forced mode
*duration += 1250;
// THP cycle duration which consumes 1963 µs for each measurement at maximum
if (dev->settings.osr_temperature)
*duration += (1 << (dev->settings.osr_temperature - 1)) * 2300;
if (dev->settings.osr_pressure)
*duration += (1 << (dev->settings.osr_pressure - 1)) * 2300 + 575;
if (dev->settings.osr_humidity)
*duration += (1 << (dev->settings.osr_humidity - 1)) * 2300 + 575;
// if gas measurement is used
if (dev->settings.heater_profile != BME680_HEATER_NOT_USED && dev->settings.heater_duration[dev->settings.heater_profile]
&& dev->settings.heater_temperature[dev->settings.heater_profile])
{
// gas heating time
*duration += dev->settings.heater_duration[dev->settings.heater_profile] * 1000;
// gas measurement duration;
*duration += 2300 + 575;
}
// round up to next ms (1 us ... 1000 us => 1 ms)
*duration += 999;
*duration /= 1000;
// some ms tolerance
*duration += 5;
// ceil to next integer value that is divisible by portTICK_PERIOD_MS and
// compute RTOS ticks (1 ... portTICK_PERIOD_MS = 1 tick)
*duration = (*duration + portTICK_PERIOD_MS - 1) / portTICK_PERIOD_MS;
// Since first RTOS tick can be shorter than the half of defined tick period,
// the delay caused by vTaskDelay(duration) might be 1 or 2 ms shorter than
// computed duration in rare cases. Since the duration is computed for maximum
// and not for the typical durations and therefore tends to be too long, this
// should not be a problem. Therefore, only one additional tick used.
*duration += 1;
return ESP_OK;
}
esp_err_t bme680_is_measuring(bme680_t *dev, bool *busy)
{
CHECK_ARG(dev && busy);
// if measurement wasn't started, it is of course not measuring
if (!dev->meas_started)
{
*busy = false;
return ESP_OK;
}
CHECK(read_reg_8(dev, BME680_REG_MEAS_STATUS_0, &dev->meas_status));
*busy = dev->meas_status & BME680_MEASURING_BITS ? 1 : 0;
return ESP_OK;
}
esp_err_t bme680_get_results_fixed(bme680_t *dev, bme680_values_fixed_t *results)
{
CHECK_ARG(dev && results);
// fill data structure with invalid values
results->temperature = INT16_MIN;
results->pressure = 0;
results->humidity = 0;
results->gas_resistance = 0;
bme680_raw_data_t raw;
CHECK(bme680_get_raw_data(dev, &raw));
// use compensation algorithms to compute sensor values in fixed point format
if (dev->settings.osr_temperature)
results->temperature = bme680_convert_temperature(dev, raw.temperature);
if (dev->settings.osr_pressure)
results->pressure = bme680_convert_pressure(dev, raw.pressure);
if (dev->settings.osr_humidity)
results->humidity = bme680_convert_humidity(dev, raw.humidity);
if (dev->settings.heater_profile != BME680_HEATER_NOT_USED)
{
// convert gas only if raw data are valid and heater was stable
if (raw.gas_valid && raw.heater_stable)
results->gas_resistance = bme680_convert_gas(dev, raw.gas_resistance, raw.gas_range);
else if (!raw.gas_valid)
ESP_LOGW(TAG, "Gas data is not valid");
else
ESP_LOGW(TAG, "Heater is not stable");
}
ESP_LOGD(TAG, "Fixed point sensor values - %d/100 deg.C, %" PRIu32 "/1000 %%, %" PRIu32 " Pa, %" PRIu32 " Ohm",
results->temperature, results->humidity, results->pressure, results->gas_resistance);
return ESP_OK;
}
esp_err_t bme680_get_results_float(bme680_t *dev, bme680_values_float_t *results)
{
CHECK_ARG(dev && results);
bme680_values_fixed_t fixed;
CHECK(bme680_get_results_fixed(dev, &fixed));
results->temperature = fixed.temperature / 100.0f;
results->pressure = fixed.pressure / 100.0f;
results->humidity = fixed.humidity / 1000.0f;
results->gas_resistance = fixed.gas_resistance;
return ESP_OK;
}
esp_err_t bme680_measure_fixed(bme680_t *dev, bme680_values_fixed_t *results)
{
CHECK_ARG(dev && results);
uint32_t duration;
CHECK(bme680_get_measurement_duration(dev, &duration));
if (duration == 0)
{
ESP_LOGE(TAG, "Failed to get measurement duration");
return ESP_FAIL;
}
CHECK(bme680_force_measurement(dev));
vTaskDelay(duration);
return bme680_get_results_fixed(dev, results);
}
esp_err_t bme680_measure_float(bme680_t *dev, bme680_values_float_t *results)
{
CHECK_ARG(dev && results);
uint32_t duration;
CHECK(bme680_get_measurement_duration(dev, &duration));
if (duration == 0)
{
ESP_LOGE(TAG, "Failed to get measurement duration");
return ESP_FAIL;
}
CHECK(bme680_force_measurement(dev));
vTaskDelay(duration);
return bme680_get_results_float(dev, results);
}
esp_err_t bme680_set_oversampling_rates(bme680_t *dev, bme680_oversampling_rate_t ost,
bme680_oversampling_rate_t osp, bme680_oversampling_rate_t osh)
{
CHECK_ARG(dev);
bool ost_changed = dev->settings.osr_temperature != ost;
bool osp_changed = dev->settings.osr_pressure != osp;
bool osh_changed = dev->settings.osr_humidity != osh;
if (!ost_changed && !osp_changed && !osh_changed)
return ESP_OK;
// Set the temperature, pressure and humidity oversampling
dev->settings.osr_temperature = ost;
dev->settings.osr_pressure = osp;
dev->settings.osr_humidity = osh;
uint8_t reg;
I2C_DEV_TAKE_MUTEX(&dev->i2c_dev);
if (ost_changed || osp_changed)
{
// read the current register value
I2C_DEV_CHECK(&dev->i2c_dev, read_reg_8_nolock(dev, BME680_REG_CTRL_MEAS, &reg));
// set changed bit values
if (ost_changed)
reg = bme_set_reg_bit(reg, BME680_OSR_T, ost);
if (osp_changed)
reg = bme_set_reg_bit(reg, BME680_OSR_P, osp);
// write back the new register value
I2C_DEV_CHECK(&dev->i2c_dev, write_reg_8_nolock(dev, BME680_REG_CTRL_MEAS, reg));
}
if (osh_changed)
{
// read the current register value
I2C_DEV_CHECK(&dev->i2c_dev, read_reg_8_nolock(dev, BME680_REG_CTRL_HUM, &reg));
// set changed bit value
reg = bme_set_reg_bit(reg, BME680_OSR_H, osh);
// write back the new register value
I2C_DEV_CHECK(&dev->i2c_dev, write_reg_8_nolock(dev, BME680_REG_CTRL_HUM, reg));
}
I2C_DEV_GIVE_MUTEX(&dev->i2c_dev);
ESP_LOGD(TAG, "Setting oversampling rates done: osrt=%d osp=%d osrh=%d",
dev->settings.osr_temperature, dev->settings.osr_pressure, dev->settings.osr_humidity);
return ESP_OK;
}
esp_err_t bme680_set_filter_size(bme680_t *dev, bme680_filter_size_t size)
{
CHECK_ARG(dev);
if (dev->settings.filter_size == size)
return ESP_OK;
/* Set the temperature, pressure and humidity settings */
dev->settings.filter_size = size;
uint8_t reg;
I2C_DEV_TAKE_MUTEX(&dev->i2c_dev);
// read the current register value
I2C_DEV_CHECK(&dev->i2c_dev, read_reg_8_nolock(dev, BME680_REG_CONFIG, &reg));
// set changed bit value
reg = bme_set_reg_bit(reg, BME680_FILTER, size);
// write back the new register value
I2C_DEV_CHECK(&dev->i2c_dev, write_reg_8_nolock(dev, BME680_REG_CONFIG, reg));
I2C_DEV_GIVE_MUTEX(&dev->i2c_dev);
ESP_LOGD(TAG, "Setting filter size done: size=%d", dev->settings.filter_size);
return ESP_OK;
}
esp_err_t bme680_set_heater_profile(bme680_t *dev, uint8_t profile, uint16_t temperature, uint16_t duration)
{
CHECK_ARG(dev && profile < BME680_HEATER_PROFILES);
bool temperature_changed = dev->settings.heater_temperature[profile] != temperature;
bool duration_changed = dev->settings.heater_duration[profile] != duration;
if (!temperature_changed && !duration_changed)
return ESP_OK;
// set external gas sensor configuration
dev->settings.heater_temperature[profile] = temperature; // degree Celsius
dev->settings.heater_duration[profile] = duration; // milliseconds
// compute internal gas sensor configuration parameters
uint8_t heat_dur = bme680_heater_duration(duration); // internal duration value
uint8_t heat_res = bme680_heater_resistance(dev, temperature); // internal temperature value
I2C_DEV_TAKE_MUTEX(&dev->i2c_dev);
// set internal gas sensor configuration parameters if changed
if (temperature_changed)
I2C_DEV_CHECK(&dev->i2c_dev, write_reg_8_nolock(dev, BME680_REG_RES_HEAT_BASE + profile, heat_res));
if (duration_changed)
I2C_DEV_CHECK(&dev->i2c_dev, write_reg_8_nolock(dev, BME680_REG_GAS_WAIT_BASE + profile, heat_dur));
I2C_DEV_GIVE_MUTEX(&dev->i2c_dev);
ESP_LOGD(TAG, "Setting heater profile %d done: temperature=%d duration=%d"
" heater_resistance=%02x heater_duration=%02x", profile, dev->settings.heater_temperature[profile],
dev->settings.heater_duration[profile], heat_dur, heat_res);
return ESP_OK;
}
esp_err_t bme680_use_heater_profile(bme680_t *dev, int8_t profile)
{
CHECK_ARG(dev);
CHECK_ARG(profile >= -1 && profile < BME680_HEATER_PROFILES);
if (dev->settings.heater_profile == profile)
return ESP_OK;
dev->settings.heater_profile = profile;
uint8_t reg = 0; // set
// set active profile
reg = bme_set_reg_bit(reg, BME680_NB_CONV, profile != BME680_HEATER_NOT_USED ? profile : 0);
// enable or disable gas measurement
reg = bme_set_reg_bit(reg, BME680_RUN_GAS,
(profile != BME680_HEATER_NOT_USED && dev->settings.heater_temperature[profile] && dev->settings.heater_duration[profile]));
I2C_DEV_TAKE_MUTEX(&dev->i2c_dev);
I2C_DEV_CHECK(&dev->i2c_dev, write_reg_8_nolock(dev, BME680_REG_CTRL_GAS_1, reg));
I2C_DEV_GIVE_MUTEX(&dev->i2c_dev);
return ESP_OK;
}
esp_err_t bme680_set_ambient_temperature(bme680_t *dev, int16_t ambient)
{
CHECK_ARG(dev);
if (dev->settings.ambient_temperature == ambient)
return ESP_OK;
// set ambient temperature configuration
dev->settings.ambient_temperature = ambient; // degree Celsius
// update all valid heater profiles
uint8_t data[10];
for (int i = 0; i < BME680_HEATER_PROFILES; i++)
data[i] = dev->settings.heater_temperature[i]
? bme680_heater_resistance(dev, dev->settings.heater_temperature[i])
: 0;
I2C_DEV_TAKE_MUTEX(&dev->i2c_dev);
I2C_DEV_CHECK(&dev->i2c_dev, i2c_dev_write_reg(&dev->i2c_dev, BME680_REG_RES_HEAT_BASE, data, 10));
I2C_DEV_GIVE_MUTEX(&dev->i2c_dev);
ESP_LOGD(TAG, "Setting heater ambient temperature done: ambient=%d", dev->settings.ambient_temperature);
return ESP_OK;
}
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