API for the BME280 Digital Humidity, Pressure, and Temperature Sensor. More...

Detailed Description

ID: bme280
Name: BME280 Digital Humidity, Pressure, and Temperature Sensor
Category: pressure humidity
Manufacturer: adafruit
Connection: i2c spi gpio
Link: https://www.adafruit.com/products/2652

The BME280 is as combined digital humidity, pressure and temperature sensor based on proven sensing principles. The sensor module is housed in an extremely compact metal-lid LGA package with a footprint of only 2.5 × 2.5 mm2 with a height of 0.93 mm. Its small dimensions and its low power consumption allow the implementation in battery driven devices such as handsets, GPS modules or watches. The BME280 is register and performance compatible to the Bosch Sensortec BMP280 digital pressure sensor

  // Instantiate a BME280 instance using default i2c bus and address
  upm::BME280 *sensor = new upm::BME280();
  // For SPI, bus 0, you would pass -1 as the address, and a valid pin for CS:
  // BME280(0, -1, 10);
  while (shouldRun)
    {
      // update our values from the sensor
      sensor->update();
      // we show both C and F for temperature
      cout << "Compensation Temperature: " << sensor->getTemperature()
           << " C / " << sensor->getTemperature(true) << " F"
           << endl;
      cout << "Pressure: " << sensor->getPressure() << " Pa" << endl;
      cout << "Computed Altitude: " << sensor->getAltitude() << " m" << endl;
      cout << "Humidity: " << sensor->getHumidity() << " %RH" << endl;
      cout << endl;
      sleep(1);
    }

Public Types
enum	BME280_REGS_T : uint8_t { REG_CALIB_DIG_H1 = 0xa1, REG_CALIB_DIG_H2_LSB = 0xe1, REG_CALIB_DIG_H2_MSB = 0xe2, REG_CALIB_DIG_H3 = 0xe3, REG_CALIB_DIG_H4_0 = 0xe4, REG_CALIB_DIG_H4_1 = 0xe5, REG_CALIB_DIG_H5_0 = 0xe5, REG_CALIB_DIG_H5_1 = 0xe6, REG_CALIB_DIG_H6 = 0xe7, REG_CTRL_HUM = 0xf2, REG_HUMIDITY_MSB = 0xfd, REG_HUMIDITY_LSB = 0xfe }

enum	CTRL_HUM_T { CTRL_HUM_OSRS_H0 = 0x01, CTRL_HUM_OSRS_H1 = 0x02, CTRL_HUM_OSRS_H2 = 0x04, _CTRL_HUM_OSRS_H_MASK = 3, _CTRL_HUM_OSRS_H_SHIFT = 0 }

enum	OSRS_H_T { OSRS_H_SKIPPED = 0, OSRS_H_OVERSAMPLING_1 = 1, OSRS_H_OVERSAMPLING_2 = 2, OSRS_H_OVERSAMPLING_4 = 3, OSRS_H_OVERSAMPLING_8 = 4, OSRS_H_OVERSAMPLING_16 = 5 }

Public Types inherited from BMP280
enum	BMP280_REGS_T : uint8_t { REG_CALIB00 = 0x88, REG_CALIB01 = 0x89, REG_CALIB02 = 0x8a, REG_CALIB03 = 0x8b, REG_CALIB04 = 0x8c, REG_CALIB05 = 0x8d, REG_CALIB06 = 0x8e, REG_CALIB07 = 0x8f, REG_CALIB08 = 0x90, REG_CALIB09 = 0x91, REG_CALIB10 = 0x92, REG_CALIB11 = 0x93, REG_CALIB12 = 0x94, REG_CALIB13 = 0x95, REG_CALIB14 = 0x96, REG_CALIB15 = 0x97, REG_CALIB16 = 0x98, REG_CALIB17 = 0x99, REG_CALIB18 = 0x9a, REG_CALIB19 = 0x9b, REG_CALIB20 = 0x9c, REG_CALIB21 = 0x9d, REG_CALIB22 = 0x9e, REG_CALIB23 = 0x9f, REG_CALIB24 = 0xa0, REG_CALIB25 = 0xa1, REG_CHIPID = 0xd0, REG_RESET = 0xe0, REG_STATUS = 0xf3, REG_CTRL_MEAS = 0xf4, REG_CONFIG = 0xf5, REG_PRESSURE_MSB = 0xf7, REG_PRESSURE_LSB = 0xf8, REG_PRESSURE_XLSB = 0xf9, REG_TEMPERATURE_MSB = 0xfa, REG_TEMPERATURE_LSB = 0xfb, REG_TEMPERATURE_XLSB = 0xfc }

enum	CONFIG_BITS_T { CONFIG_SPI3W_EN = 0x01, CONFIG_FILTER0 = 0x04, CONFIG_FILTER1 = 0x08, CONFIG_FILTER2 = 0x10, _CONFIG_FILTER_MASK = 7, _CONFIG_FILTER_SHIFT = 2, CONFIG_T_SB0 = 0x20, CONFIG_T_SB1 = 0x40, CONFIG_T_SB2 = 0x80, _CONFIG_T_SB_MASK = 7, _CONFIG_T_SB_SHIFT = 5 }

enum	FILTER_T { FILTER_OFF = 0, FILTER_2 = 1, FILTER_4 = 2, FILTER_8 = 3, FILTER_16 = 4 }

enum	T_SB_T { T_SB_0_5 = 0, T_SB_62_5 = 1, T_SB_125 = 2, T_SB_250 = 3, T_SB_500 = 4, T_SB_1000 = 5, T_SB_2000 = 6, T_SB_4000 = 7 }

enum	CTRL_MEAS_T { CTRL_MEAS_MODE0 = 0x01, CTRL_MEAS_MODE1 = 0x02, _CTRL_MEAS_MODE_MASK = 3, _CTRL_MEAS_MODE_SHIFT = 0, CTRL_MEAS_OSRS_P0 = 0x04, CTRL_MEAS_OSRS_P1 = 0x08, CTRL_MEAS_OSRS_P2 = 0x10, _CTRL_MEAS_OSRS_P_MASK = 7, _CTRL_MEAS_OSRS_P_SHIFT = 2, CTRL_MEAS_OSRS_T0 = 0x04, CTRL_MEAS_OSRS_T1 = 0x08, CTRL_MEAS_OSRS_T2 = 0x10, _CTRL_MEAS_OSRS_T_MASK = 7, _CTRL_MEAS_OSRS_T_SHIFT = 5 }

enum	MODES_T { MODE_SLEEP = 0, MODE_FORCED = 1, MODE_NORMAL = 3 }

enum	OSRS_P_T { OSRS_P_SKIPPED = 0, OSRS_P_OVERSAMPLING_1 = 1, OSRS_P_OVERSAMPLING_2 = 2, OSRS_P_OVERSAMPLING_4 = 3, OSRS_P_OVERSAMPLING_8 = 4, OSRS_P_OVERSAMPLING_16 = 5 }

enum	OSRS_T_T { OSRS_T_SKIPPED = 0, OSRS_T_OVERSAMPLING_1 = 1, OSRS_T_OVERSAMPLING_2 = 2, OSRS_T_OVERSAMPLING_4 = 3, OSRS_T_OVERSAMPLING_8 = 4, OSRS_T_OVERSAMPLING_16 = 5 }

enum	STATUS_T { STATUS_IM_UPDATE = 0x01, STATUS_MEASURING = 0x08 }

enum	USAGE_MODE_T { USAGE_MODE_HANDHELD_LOW_POWER = 0, USAGE_MODE_HANDHELD_DYNAMIC = 1, USAGE_MODE_WEATHER_MONITOR = 2, USAGE_MODE_FLOOR_CHG_DETECT = 3, USAGE_MODE_DROP_DETECT = 4, USAGE_MODE_INDOOR_NAV = 5 }

Public Member Functions
	BME280 (int bus=BME280_DEFAULT_I2C_BUS, int addr=BME280_DEFAULT_ADDR, int cs=-1, uint8_t theChipID=BME280_DEFAULT_CHIPID)

virtual	~BME280 ()

virtual void	update ()

float	getHumidity ()

virtual void	setUsageMode (USAGE_MODE_T mode)

void	setOversampleRateHumidity (OSRS_H_T rate)

const char *	getModuleName ()

int	getHumidityRelative ()

Public Member Functions inherited from BMP280
	BMP280 (int bus=BMP280_DEFAULT_I2C_BUS, int addr=BMP280_DEFAULT_ADDR, int cs=-1, uint8_t theChipID=BMP280_DEFAULT_CHIPID)

virtual	~BMP280 ()

uint8_t	getChipID ()

void	reset ()

float	getTemperature (bool fahrenheit=false)

float	getPressure ()

float	getAltitude (float seaLevelhPA=1013.25)

void	setOversampleRateTemperature (OSRS_T_T rate)

void	setOversampleRatePressure (OSRS_P_T rate)

void	setTimerStandby (T_SB_T tsb)

void	setFilter (FILTER_T filter)

void	setMeasureMode (MODES_T mode)

const char *	getModuleName ()

int	getTemperatureCelsius ()

int	getPressurePa ()

Protected Member Functions
virtual void	readCalibrationData ()

Protected Member Functions inherited from BMP280
uint8_t	getStatus ()

uint8_t	readReg (uint8_t reg)

int	readRegs (uint8_t reg, uint8_t *buffer, int len)

void	writeReg (uint8_t reg, uint8_t val)

void	clearData ()

void	csOn ()

void	csOff ()

Protected Attributes
float	m_humidity

Protected Attributes inherited from BMP280
mraa::I2c *	m_i2c

mraa::Spi *	m_spi

mraa::Gpio *	m_gpioCS

uint8_t	m_addr

float	m_temperature

float	m_pressure

int32_t	m_t_fine

MODES_T	m_mode

Additional Inherited Members
Data Fields inherited from BMP280
const uint8_t	BMP280_RESET_BYTE = 0xb6

const int	CALIBRATION_BYTES = 26

Member Enumeration Documentation

enum BME280_REGS_T : uint8_t

BMP280 registers

enum CTRL_HUM_T

REG_CTRL_HUM bits

enum OSRS_H_T

CTRL_HUM_OSRS_H values

Constructor & Destructor Documentation

BME280	(	int	bus = `BME280_DEFAULT_I2C_BUS`,
		int	addr = `BME280_DEFAULT_ADDR`,
		int	cs = `-1`,
		uint8_t	theChipID = `BME280_DEFAULT_CHIPID`
	)

BME280 constructor.

This device can support both I2C and SPI. For SPI, set the addr to -1, and specify a positive integer representing the Chip Select (CS) pin for the cs argument. If you are using a hardware CS pin, then you can connect the proper pin to the hardware CS pin on your MCU and supply -1 for cs. The default operating mode is I2C.

Parameters

bus	I2C or SPI bus to use.
address	The address for this device. -1 for SPI.
cs	The gpio pin to use for the SPI Chip Select. -1 for I2C or for SPI with a hardware controlled pin.
theChipID	The chip ID used for validation

Here is the call graph for this function:

~BME280 ( )

virtual

BME280 Destructor.

Member Function Documentation

void update ( void )

virtual

Update the internal stored values from sensor data.

Reimplemented from BMP280.

Here is the call graph for this function:

float getHumidity ( void )

Return the current measured relative humidity. update() must have been called prior to calling this method.

Returns: The relative humidity in percent..

void setUsageMode ( USAGE_MODE_T mode )

virtual

Set a general usage mode. This function can be used to configure the filters and oversampling for a particular use case. These settings are documented in the BMP280 and BME280 datasheets.

Parameters

mode	One of the USAGE_MODE_T values.

Reimplemented from BMP280.

Here is the call graph for this function:

Here is the caller graph for this function:

void setOversampleRateHumidity ( OSRS_H_T rate )

Set the humidity sensor oversampling parameter. See the data sheet for details. This value can be automatically set to a suitable value by using one of the predefined modes for setUsageMode().

Parameters