/*! * @file Adafruit_BME280.cpp * * @mainpage Adafruit BME280 humidity, temperature & pressure sensor * * @section intro_sec Introduction * * Driver for the BME280 humidity, temperature & pressure sensor * * These sensors use I2C or SPI to communicate, 2 or 4 pins are required * to interface. * * Designed specifically to work with the Adafruit BME280 Breakout * ----> http://www.adafruit.com/products/2652 * * Adafruit invests time and resources providing this open source code, * please support Adafruit and open-source hardware by purchasing * products from Adafruit! * * @section author Author * * Written by Kevin "KTOWN" Townsend for Adafruit Industries. * * @section license License * * BSD license, all text here must be included in any redistribution. * See the LICENSE file for details. * */ #include "Adafruit_BME280.h" #include "Arduino.h" /*! * @brief class constructor */ Adafruit_BME280::Adafruit_BME280() {} /*! * @brief class constructor if using hardware SPI * @param cspin the chip select pin to use * @param *theSPI * optional SPI object */ Adafruit_BME280::Adafruit_BME280(int8_t cspin, SPIClass *theSPI) { spi_dev = new Adafruit_SPIDevice(cspin, 1000000, SPI_BITORDER_MSBFIRST, SPI_MODE0, theSPI); } /*! * @brief class constructor if using software SPI * @param cspin the chip select pin to use * @param mosipin the MOSI pin to use * @param misopin the MISO pin to use * @param sckpin the SCK pin to use */ Adafruit_BME280::Adafruit_BME280(int8_t cspin, int8_t mosipin, int8_t misopin, int8_t sckpin) { spi_dev = new Adafruit_SPIDevice(cspin, sckpin, misopin, mosipin); } Adafruit_BME280::~Adafruit_BME280(void) { if (spi_dev) { delete spi_dev; } if (i2c_dev) { delete i2c_dev; } if (temp_sensor) { delete temp_sensor; } if (pressure_sensor) { delete pressure_sensor; } if (humidity_sensor) { delete humidity_sensor; } } /*! * @brief Initialise sensor with given parameters / settings * @param addr the I2C address the device can be found on * @param theWire the I2C object to use, defaults to &Wire * @returns true on success, false otherwise */ bool Adafruit_BME280::begin(uint8_t addr, TwoWire *theWire) { if (spi_dev == NULL) { // I2C mode if (i2c_dev) delete i2c_dev; i2c_dev = new Adafruit_I2CDevice(addr, theWire); if (!i2c_dev->begin()) return false; } else { // SPI mode if (!spi_dev->begin()) return false; } return init(); } /*! * @brief Initialise sensor with given parameters / settings * @returns true on success, false otherwise */ bool Adafruit_BME280::init() { // check if sensor, i.e. the chip ID is correct _sensorID = read8(BME280_REGISTER_CHIPID); if (_sensorID != 0x60) return false; // reset the device using soft-reset // this makes sure the IIR is off, etc. write8(BME280_REGISTER_SOFTRESET, 0xB6); // wait for chip to wake up. delay(10); // if chip is still reading calibration, delay while (isReadingCalibration()) delay(10); readCoefficients(); // read trimming parameters, see DS 4.2.2 setSampling(); // use defaults delay(100); return true; } /*! * @brief setup sensor with given parameters / settings * * This is simply a overload to the normal begin()-function, so SPI users * don't get confused about the library requiring an address. * @param mode the power mode to use for the sensor * @param tempSampling the temp samping rate to use * @param pressSampling the pressure sampling rate to use * @param humSampling the humidity sampling rate to use * @param filter the filter mode to use * @param duration the standby duration to use */ void Adafruit_BME280::setSampling(sensor_mode mode, sensor_sampling tempSampling, sensor_sampling pressSampling, sensor_sampling humSampling, sensor_filter filter, standby_duration duration) { _measReg.mode = mode; _measReg.osrs_t = tempSampling; _measReg.osrs_p = pressSampling; _humReg.osrs_h = humSampling; _configReg.filter = filter; _configReg.t_sb = duration; _configReg.spi3w_en = 0; // making sure sensor is in sleep mode before setting configuration // as it otherwise may be ignored write8(BME280_REGISTER_CONTROL, MODE_SLEEP); // you must make sure to also set REGISTER_CONTROL after setting the // CONTROLHUMID register, otherwise the values won't be applied (see // DS 5.4.3) write8(BME280_REGISTER_CONTROLHUMID, _humReg.get()); write8(BME280_REGISTER_CONFIG, _configReg.get()); write8(BME280_REGISTER_CONTROL, _measReg.get()); } /*! * @brief Writes an 8 bit value over I2C or SPI * @param reg the register address to write to * @param value the value to write to the register */ void Adafruit_BME280::write8(byte reg, byte value) { byte buffer[2]; buffer[1] = value; if (i2c_dev) { buffer[0] = reg; i2c_dev->write(buffer, 2); } else { buffer[0] = reg & ~0x80; spi_dev->write(buffer, 2); } } /*! * @brief Reads an 8 bit value over I2C or SPI * @param reg the register address to read from * @returns the data byte read from the device */ uint8_t Adafruit_BME280::read8(byte reg) { uint8_t buffer[1]; if (i2c_dev) { buffer[0] = uint8_t(reg); i2c_dev->write_then_read(buffer, 1, buffer, 1); } else { buffer[0] = uint8_t(reg | 0x80); spi_dev->write_then_read(buffer, 1, buffer, 1); } return buffer[0]; } /*! * @brief Reads a 16 bit value over I2C or SPI * @param reg the register address to read from * @returns the 16 bit data value read from the device */ uint16_t Adafruit_BME280::read16(byte reg) { uint8_t buffer[2]; if (i2c_dev) { buffer[0] = uint8_t(reg); i2c_dev->write_then_read(buffer, 1, buffer, 2); } else { buffer[0] = uint8_t(reg | 0x80); spi_dev->write_then_read(buffer, 1, buffer, 2); } return uint16_t(buffer[0]) << 8 | uint16_t(buffer[1]); } /*! * @brief Reads a signed 16 bit little endian value over I2C or SPI * @param reg the register address to read from * @returns the 16 bit data value read from the device */ uint16_t Adafruit_BME280::read16_LE(byte reg) { uint16_t temp = read16(reg); return (temp >> 8) | (temp << 8); } /*! * @brief Reads a signed 16 bit value over I2C or SPI * @param reg the register address to read from * @returns the 16 bit data value read from the device */ int16_t Adafruit_BME280::readS16(byte reg) { return (int16_t)read16(reg); } /*! * @brief Reads a signed little endian 16 bit value over I2C or SPI * @param reg the register address to read from * @returns the 16 bit data value read from the device */ int16_t Adafruit_BME280::readS16_LE(byte reg) { return (int16_t)read16_LE(reg); } /*! * @brief Reads a 24 bit value over I2C * @param reg the register address to read from * @returns the 24 bit data value read from the device */ uint32_t Adafruit_BME280::read24(byte reg) { uint8_t buffer[3]; if (i2c_dev) { buffer[0] = uint8_t(reg); i2c_dev->write_then_read(buffer, 1, buffer, 3); } else { buffer[0] = uint8_t(reg | 0x80); spi_dev->write_then_read(buffer, 1, buffer, 3); } return uint32_t(buffer[0]) << 16 | uint32_t(buffer[1]) << 8 | uint32_t(buffer[2]); } /*! * @brief Take a new measurement (only possible in forced mode) @returns true in case of success else false */ bool Adafruit_BME280::takeForcedMeasurement(void) { bool return_value = false; // If we are in forced mode, the BME sensor goes back to sleep after each // measurement and we need to set it to forced mode once at this point, so // it will take the next measurement and then return to sleep again. // In normal mode simply does new measurements periodically. if (_measReg.mode == MODE_FORCED) { return_value = true; // set to forced mode, i.e. "take next measurement" write8(BME280_REGISTER_CONTROL, _measReg.get()); // Store current time to measure the timeout uint32_t timeout_start = millis(); // wait until measurement has been completed, otherwise we would read the // the values from the last measurement or the timeout occurred after 2 sec. while (read8(BME280_REGISTER_STATUS) & 0x08) { // In case of a timeout, stop the while loop if ((millis() - timeout_start) > 2000) { return_value = false; break; } delay(1); } } return return_value; } /*! * @brief Reads the factory-set coefficients */ void Adafruit_BME280::readCoefficients(void) { _bme280_calib.dig_T1 = read16_LE(BME280_REGISTER_DIG_T1); _bme280_calib.dig_T2 = readS16_LE(BME280_REGISTER_DIG_T2); _bme280_calib.dig_T3 = readS16_LE(BME280_REGISTER_DIG_T3); _bme280_calib.dig_P1 = read16_LE(BME280_REGISTER_DIG_P1); _bme280_calib.dig_P2 = readS16_LE(BME280_REGISTER_DIG_P2); _bme280_calib.dig_P3 = readS16_LE(BME280_REGISTER_DIG_P3); _bme280_calib.dig_P4 = readS16_LE(BME280_REGISTER_DIG_P4); _bme280_calib.dig_P5 = readS16_LE(BME280_REGISTER_DIG_P5); _bme280_calib.dig_P6 = readS16_LE(BME280_REGISTER_DIG_P6); _bme280_calib.dig_P7 = readS16_LE(BME280_REGISTER_DIG_P7); _bme280_calib.dig_P8 = readS16_LE(BME280_REGISTER_DIG_P8); _bme280_calib.dig_P9 = readS16_LE(BME280_REGISTER_DIG_P9); _bme280_calib.dig_H1 = read8(BME280_REGISTER_DIG_H1); _bme280_calib.dig_H2 = readS16_LE(BME280_REGISTER_DIG_H2); _bme280_calib.dig_H3 = read8(BME280_REGISTER_DIG_H3); _bme280_calib.dig_H4 = ((int8_t)read8(BME280_REGISTER_DIG_H4) << 4) | (read8(BME280_REGISTER_DIG_H4 + 1) & 0xF); _bme280_calib.dig_H5 = ((int8_t)read8(BME280_REGISTER_DIG_H5 + 1) << 4) | (read8(BME280_REGISTER_DIG_H5) >> 4); _bme280_calib.dig_H6 = (int8_t)read8(BME280_REGISTER_DIG_H6); } /*! * @brief return true if chip is busy reading cal data * @returns true if reading calibration, false otherwise */ bool Adafruit_BME280::isReadingCalibration(void) { uint8_t const rStatus = read8(BME280_REGISTER_STATUS); return (rStatus & (1 << 0)) != 0; } /*! * @brief Returns the temperature from the sensor * @returns the temperature read from the device */ float Adafruit_BME280::readTemperature(void) { int32_t var1, var2; int32_t adc_T = read24(BME280_REGISTER_TEMPDATA); if (adc_T == 0x800000) // value in case temp measurement was disabled return NAN; adc_T >>= 4; var1 = (int32_t)((adc_T / 8) - ((int32_t)_bme280_calib.dig_T1 * 2)); var1 = (var1 * ((int32_t)_bme280_calib.dig_T2)) / 2048; var2 = (int32_t)((adc_T / 16) - ((int32_t)_bme280_calib.dig_T1)); var2 = (((var2 * var2) / 4096) * ((int32_t)_bme280_calib.dig_T3)) / 16384; t_fine = var1 + var2 + t_fine_adjust; int32_t T = (t_fine * 5 + 128) / 256; return (float)T / 100; } /*! * @brief Returns the pressure from the sensor * @returns the pressure value (in Pascal) read from the device */ float Adafruit_BME280::readPressure(void) { int64_t var1, var2, var3, var4; readTemperature(); // must be done first to get t_fine int32_t adc_P = read24(BME280_REGISTER_PRESSUREDATA); if (adc_P == 0x800000) // value in case pressure measurement was disabled return NAN; adc_P >>= 4; var1 = ((int64_t)t_fine) - 128000; var2 = var1 * var1 * (int64_t)_bme280_calib.dig_P6; var2 = var2 + ((var1 * (int64_t)_bme280_calib.dig_P5) * 131072); var2 = var2 + (((int64_t)_bme280_calib.dig_P4) * 34359738368); var1 = ((var1 * var1 * (int64_t)_bme280_calib.dig_P3) / 256) + ((var1 * ((int64_t)_bme280_calib.dig_P2) * 4096)); var3 = ((int64_t)1) * 140737488355328; var1 = (var3 + var1) * ((int64_t)_bme280_calib.dig_P1) / 8589934592; if (var1 == 0) { return 0; // avoid exception caused by division by zero } var4 = 1048576 - adc_P; var4 = (((var4 * 2147483648) - var2) * 3125) / var1; var1 = (((int64_t)_bme280_calib.dig_P9) * (var4 / 8192) * (var4 / 8192)) / 33554432; var2 = (((int64_t)_bme280_calib.dig_P8) * var4) / 524288; var4 = ((var4 + var1 + var2) / 256) + (((int64_t)_bme280_calib.dig_P7) * 16); float P = var4 / 256.0; return P; } /*! * @brief Returns the humidity from the sensor * @returns the humidity value read from the device */ float Adafruit_BME280::readHumidity(void) { int32_t var1, var2, var3, var4, var5; readTemperature(); // must be done first to get t_fine int32_t adc_H = read16(BME280_REGISTER_HUMIDDATA); if (adc_H == 0x8000) // value in case humidity measurement was disabled return NAN; var1 = t_fine - ((int32_t)76800); var2 = (int32_t)(adc_H * 16384); var3 = (int32_t)(((int32_t)_bme280_calib.dig_H4) * 1048576); var4 = ((int32_t)_bme280_calib.dig_H5) * var1; var5 = (((var2 - var3) - var4) + (int32_t)16384) / 32768; var2 = (var1 * ((int32_t)_bme280_calib.dig_H6)) / 1024; var3 = (var1 * ((int32_t)_bme280_calib.dig_H3)) / 2048; var4 = ((var2 * (var3 + (int32_t)32768)) / 1024) + (int32_t)2097152; var2 = ((var4 * ((int32_t)_bme280_calib.dig_H2)) + 8192) / 16384; var3 = var5 * var2; var4 = ((var3 / 32768) * (var3 / 32768)) / 128; var5 = var3 - ((var4 * ((int32_t)_bme280_calib.dig_H1)) / 16); var5 = (var5 < 0 ? 0 : var5); var5 = (var5 > 419430400 ? 419430400 : var5); uint32_t H = (uint32_t)(var5 / 4096); return (float)H / 1024.0; } /*! * Calculates the altitude (in meters) from the specified atmospheric * pressure (in hPa), and sea-level pressure (in hPa). * @param seaLevel Sea-level pressure in hPa * @returns the altitude value read from the device */ float Adafruit_BME280::readAltitude(float seaLevel) { // Equation taken from BMP180 datasheet (page 16): // http://www.adafruit.com/datasheets/BST-BMP180-DS000-09.pdf // Note that using the equation from wikipedia can give bad results // at high altitude. See this thread for more information: // http://forums.adafruit.com/viewtopic.php?f=22&t=58064 float atmospheric = readPressure() / 100.0F; return 44330.0 * (1.0 - pow(atmospheric / seaLevel, 0.1903)); } /*! * Calculates the pressure at sea level (in hPa) from the specified * altitude (in meters), and atmospheric pressure (in hPa). * @param altitude Altitude in meters * @param atmospheric Atmospheric pressure in hPa * @returns the pressure at sea level (in hPa) from the specified altitude */ float Adafruit_BME280::seaLevelForAltitude(float altitude, float atmospheric) { // Equation taken from BMP180 datasheet (page 17): // http://www.adafruit.com/datasheets/BST-BMP180-DS000-09.pdf // Note that using the equation from wikipedia can give bad results // at high altitude. See this thread for more information: // http://forums.adafruit.com/viewtopic.php?f=22&t=58064 return atmospheric / pow(1.0 - (altitude / 44330.0), 5.255); } /*! * Returns Sensor ID found by init() for diagnostics * @returns Sensor ID 0x60 for BME280, 0x56, 0x57, 0x58 BMP280 */ uint32_t Adafruit_BME280::sensorID(void) { return _sensorID; } /*! * Returns the current temperature compensation value in degrees Celsius * @returns the current temperature compensation value in degrees Celsius */ float Adafruit_BME280::getTemperatureCompensation(void) { return float((t_fine_adjust * 5) >> 8) / 100.0; }; /*! * Sets a value to be added to each temperature reading. This adjusted * temperature is used in pressure and humidity readings. * @param adjustment Value to be added to each temperature reading in Celsius */ void Adafruit_BME280::setTemperatureCompensation(float adjustment) { // convert the value in C into and adjustment to t_fine t_fine_adjust = ((int32_t(adjustment * 100) << 8)) / 5; }; /*! @brief Gets an Adafruit Unified Sensor object for the temp sensor component @return Adafruit_Sensor pointer to temperature sensor */ Adafruit_Sensor *Adafruit_BME280::getTemperatureSensor(void) { if (!temp_sensor) { temp_sensor = new Adafruit_BME280_Temp(this); } return temp_sensor; } /*! @brief Gets an Adafruit Unified Sensor object for the pressure sensor component @return Adafruit_Sensor pointer to pressure sensor */ Adafruit_Sensor *Adafruit_BME280::getPressureSensor(void) { if (!pressure_sensor) { pressure_sensor = new Adafruit_BME280_Pressure(this); } return pressure_sensor; } /*! @brief Gets an Adafruit Unified Sensor object for the humidity sensor component @return Adafruit_Sensor pointer to humidity sensor */ Adafruit_Sensor *Adafruit_BME280::getHumiditySensor(void) { if (!humidity_sensor) { humidity_sensor = new Adafruit_BME280_Humidity(this); } return humidity_sensor; } /**************************************************************************/ /*! @brief Gets the sensor_t data for the BME280's temperature sensor */ /**************************************************************************/ void Adafruit_BME280_Temp::getSensor(sensor_t *sensor) { /* Clear the sensor_t object */ memset(sensor, 0, sizeof(sensor_t)); /* Insert the sensor name in the fixed length char array */ strncpy(sensor->name, "BME280", sizeof(sensor->name) - 1); sensor->name[sizeof(sensor->name) - 1] = 0; sensor->version = 1; sensor->sensor_id = _sensorID; sensor->type = SENSOR_TYPE_AMBIENT_TEMPERATURE; sensor->min_delay = 0; sensor->min_value = -40.0; /* Temperature range -40 ~ +85 C */ sensor->max_value = +85.0; sensor->resolution = 0.01; /* 0.01 C */ } /**************************************************************************/ /*! @brief Gets the temperature as a standard sensor event @param event Sensor event object that will be populated @returns True */ /**************************************************************************/ bool Adafruit_BME280_Temp::getEvent(sensors_event_t *event) { /* Clear the event */ memset(event, 0, sizeof(sensors_event_t)); event->version = sizeof(sensors_event_t); event->sensor_id = _sensorID; event->type = SENSOR_TYPE_AMBIENT_TEMPERATURE; event->timestamp = millis(); event->temperature = _theBME280->readTemperature(); return true; } /**************************************************************************/ /*! @brief Gets the sensor_t data for the BME280's pressure sensor */ /**************************************************************************/ void Adafruit_BME280_Pressure::getSensor(sensor_t *sensor) { /* Clear the sensor_t object */ memset(sensor, 0, sizeof(sensor_t)); /* Insert the sensor name in the fixed length char array */ strncpy(sensor->name, "BME280", sizeof(sensor->name) - 1); sensor->name[sizeof(sensor->name) - 1] = 0; sensor->version = 1; sensor->sensor_id = _sensorID; sensor->type = SENSOR_TYPE_PRESSURE; sensor->min_delay = 0; sensor->min_value = 300.0; /* 300 ~ 1100 hPa */ sensor->max_value = 1100.0; sensor->resolution = 0.012; /* 0.12 hPa relative */ } /**************************************************************************/ /*! @brief Gets the pressure as a standard sensor event @param event Sensor event object that will be populated @returns True */ /**************************************************************************/ bool Adafruit_BME280_Pressure::getEvent(sensors_event_t *event) { /* Clear the event */ memset(event, 0, sizeof(sensors_event_t)); event->version = sizeof(sensors_event_t); event->sensor_id = _sensorID; event->type = SENSOR_TYPE_PRESSURE; event->timestamp = millis(); event->pressure = _theBME280->readPressure() / 100; // convert Pa to hPa return true; } /**************************************************************************/ /*! @brief Gets the sensor_t data for the BME280's humidity sensor */ /**************************************************************************/ void Adafruit_BME280_Humidity::getSensor(sensor_t *sensor) { /* Clear the sensor_t object */ memset(sensor, 0, sizeof(sensor_t)); /* Insert the sensor name in the fixed length char array */ strncpy(sensor->name, "BME280", sizeof(sensor->name) - 1); sensor->name[sizeof(sensor->name) - 1] = 0; sensor->version = 1; sensor->sensor_id = _sensorID; sensor->type = SENSOR_TYPE_RELATIVE_HUMIDITY; sensor->min_delay = 0; sensor->min_value = 0; sensor->max_value = 100; /* 0 - 100 % */ sensor->resolution = 3; /* 3% accuracy */ } /**************************************************************************/ /*! @brief Gets the humidity as a standard sensor event @param event Sensor event object that will be populated @returns True */ /**************************************************************************/ bool Adafruit_BME280_Humidity::getEvent(sensors_event_t *event) { /* Clear the event */ memset(event, 0, sizeof(sensors_event_t)); event->version = sizeof(sensors_event_t); event->sensor_id = _sensorID; event->type = SENSOR_TYPE_RELATIVE_HUMIDITY; event->timestamp = millis(); event->relative_humidity = _theBME280->readHumidity(); return true; }