BME280 sensor interface for reading temperature, humidity, and pressure. More...

Collaboration diagram for BME280:

Data Structures
struct	driver_bme280_t
	BME280 sensor driver structure. More...

Typedefs
typedef struct driver_bme280_t	driver_bme280_t
	BME280 sensor driver structure. More...

Enumerations
enum	driver_bme280_mode_t { DRIVER_BME280_MODE_SLEEP = 1, DRIVER_BME280_MODE_FORCED, DRIVER_BME280_MODE_NORMAL }
	BME280 sensor modes. More...

Functions
driver_bme280_t	driver_bme280_i2c_init (hw_i2c_t *i2c, uint8_t address)
	Initialize a BME280 sensor driver using the I2C interface. More...

void	driver_bme280_finalize (driver_bme280_t *bme280)
	Finalize and release a BME280 sensor driver. More...

static bool	driver_bme280_valid (driver_bme280_t *bme280)
	Get true if the BME280 interface is valid. More...

bool	driver_bme280_set_mode (driver_bme280_t *bme280, driver_bme280_mode_t mode)
	Set the operating mode of the BME280 sensor. More...

driver_bme280_mode_t	driver_bme280_get_mode (driver_bme280_t *bme280)
	Get the current operating mode of the BME280 sensor. More...

bool	driver_bme280_reset (driver_bme280_t *bme280)
	Reset the BME280 sensor to its default state. More...

bool	driver_bme280_read_data (driver_bme280_t bme280, float temperature, float pressure, float humidity)
	Read temperature, pressure, and humidity data from the BME280 sensor. More...

float	driver_bme280_read_temperature (driver_bme280_t *bme280)
	Read only temperature from the BME280 sensor. More...

float	driver_bme280_read_pressure (driver_bme280_t *bme280)
	Read only pressure from the BME280 sensor. More...

float	driver_bme280_read_humidity (driver_bme280_t *bme280)
	Read only humidity from the BME280 sensor. More...

float	driver_bme280_calculate_altitude (float pressure_pa, float sea_level_pa)
	Calculate altitude from pressure measurement. More...

float	driver_bme280_calculate_sea_level_pressure (float pressure_pa, float altitude_m)
	Calculate sea level pressure from current pressure and altitude. More...

Detailed Description

BME280 sensor interface for reading temperature, humidity, and pressure.

Typedef Documentation

◆ driver_bme280_t

typedef struct driver_bme280_t driver_bme280_t

BME280 sensor driver structure.

This structure contains the configuration and state information for a BME280 sensor instance. The BME280 is a combined digital humidity, pressure and temperature sensor from Bosch Sensortec.

Enumeration Type Documentation

◆ driver_bme280_mode_t

enum driver_bme280_mode_t

BME280 sensor modes.

This enumeration defines the operating modes for the BME280 sensor.

Enumerator
DRIVER_BME280_MODE_SLEEP	Sleep mode.
DRIVER_BME280_MODE_FORCED	Forced mode.
DRIVER_BME280_MODE_NORMAL	Normal mode.

Definition at line 44 of file drivers_bme280.h.

              {
   DRIVER_BME280_MODE_SLEEP = 1, 
   DRIVER_BME280_MODE_FORCED,    
   DRIVER_BME280_MODE_NORMAL     
 } driver_bme280_mode_t;

Function Documentation

◆ driver_bme280_calculate_altitude()

float driver_bme280_calculate_altitude	(	float	pressure_pa,
		float	sea_level_pa
	)

Calculate altitude from pressure measurement.

Parameters

pressure_pa	Current pressure in Pascals.
sea_level_pa	Sea level pressure in Pascals (default: 101325).

Returns: Altitude in meters.

Uses the barometric formula to estimate altitude. Accuracy depends on knowing the current sea level pressure for your location.

◆ driver_bme280_calculate_sea_level_pressure()

float driver_bme280_calculate_sea_level_pressure	(	float	pressure_pa,
		float	altitude_m
	)

Calculate sea level pressure from current pressure and altitude.

Parameters

pressure_pa	Current pressure in Pascals.
altitude_m	Known altitude in meters.

Returns: Estimated sea level pressure in Pascals.

◆ driver_bme280_finalize()

void driver_bme280_finalize ( driver_bme280_t * bme280 )

Finalize and release a BME280 sensor driver.

Parameters

bme280 Pointer to the BME280 driver structure to finalize.

This function releases resources associated with the BME280 sensor driver and puts the sensor into a low-power sleep mode. After calling this function, the BME280 driver should not be used for further operations.

The function performs cleanup operations including:

Putting the sensor into sleep mode to reduce power consumption
Releasing any allocated calibration data
Clearing the driver structure

Note: After finalization, the sensor driver should not be used.; This function does not finalize the underlying I2C interface.

◆ driver_bme280_get_mode()

driver_bme280_mode_t driver_bme280_get_mode ( driver_bme280_t * bme280 )

Get the current operating mode of the BME280 sensor.

Parameters

bme280 Pointer to the BME280 driver structure.

Returns: The current operating mode of the sensor, or 0 on error.

This function reads the sensor's control register to determine the current operating mode. The returned mode indicates how the sensor is currently configured for measurements and power management.

Note that in forced mode, the sensor automatically transitions back to sleep mode after completing a measurement cycle, so the returned mode may be DRIVER_BME280_MODE_SLEEP even if forced mode was recently set.

Note: The bme280 pointer should not be NULL and must be properly initialized.; The function returns 0 if an error occurs during communication.; In forced mode, the sensor may have already returned to sleep mode when this is called.

See also: driver_bme280_set_mode() for setting the operating mode.; driver_bme280_mode_t for available operating modes.

◆ driver_bme280_i2c_init()

driver_bme280_t driver_bme280_i2c_init	(	hw_i2c_t *	i2c,
		uint8_t	address
	)

Initialize a BME280 sensor driver using the I2C interface.

Parameters

i2c	Pointer to an initialized I2C interface for sensor communication.
address	The I2C address of the BME280 sensor (0x76 or 0x77). If set to 0, the default address (0x76) will be used.

Returns: A BME280 driver structure representing the initialized sensor.

This function initializes a BME280 sensor driver for communication over I2C. The BME280 sensor supports two I2C addresses: 0x76 (when SDO pin is connected to GND) and 0x77 (when SDO pin is connected to VDD).

The function performs initial sensor detection and configuration, including:

Verifying sensor presence at the specified address
Reading calibration coefficients from sensor EEPROM
Setting default measurement configuration

Note: The i2c pointer must be valid and the I2C interface must be properly initialized.

See also: hw_i2c_init() for I2C interface initialization.; driver_bme280_finalize() for cleanup and resource release.

◆ driver_bme280_read_data()

bool driver_bme280_read_data	(	driver_bme280_t *	bme280,
		float *	temperature,
		float *	pressure,
		float *	humidity
	)

Read temperature, pressure, and humidity data from the BME280 sensor.

Parameters

bme280	Pointer to the BME280 driver structure.
temperature	Pointer to store temperature in degrees Celsius (can be NULL if not needed).
pressure	Pointer to store pressure in Pascals (can be NULL if not needed).
humidity	Pointer to store relative humidity in % (can be NULL if not needed).

Returns: true if data was successfully read, false on error.

This function reads the current sensor values. If the sensor is in SLEEP mode, it will automatically switch to FORCED mode, take a measurement, then return to SLEEP. For NORMAL mode, it reads the most recent measurement.

◆ driver_bme280_read_humidity()

float driver_bme280_read_humidity ( driver_bme280_t * bme280 )

Read only humidity from the BME280 sensor.

Parameters

bme280 Pointer to the BME280 driver structure.

Returns: Relative humidity in %, or NaN on error.

◆ driver_bme280_read_pressure()

float driver_bme280_read_pressure ( driver_bme280_t * bme280 )

Read only pressure from the BME280 sensor.

Parameters

bme280 Pointer to the BME280 driver structure.

Returns: Pressure in Pascals, or NaN on error.

◆ driver_bme280_read_temperature()

float driver_bme280_read_temperature ( driver_bme280_t * bme280 )

Read only temperature from the BME280 sensor.

Parameters

bme280 Pointer to the BME280 driver structure.

Returns: Temperature in degrees Celsius, or NaN on error.

◆ driver_bme280_reset()

bool driver_bme280_reset ( driver_bme280_t * bme280 )

Reset the BME280 sensor to its default state.

Parameters

bme280 Pointer to the BME280 driver structure.

Returns: true if the reset was successful, false on error.

This function performs a software reset of the BME280 sensor by writing to the reset register. The reset operation restores the sensor to its power-on default state, which includes:

All configuration registers are reset to their default values
The sensor enters sleep mode (lowest power consumption)
All previous measurement settings are cleared
Internal state machines are reinitialized

After a successful reset, the sensor will be in the same state as immediately after power-on. Any previous configuration (sampling rates, filter settings, standby times) will need to be reconfigured.

◆ driver_bme280_set_mode()

bool driver_bme280_set_mode	(	driver_bme280_t *	bme280,
		driver_bme280_mode_t	mode
	)

Set the operating mode of the BME280 sensor.

Parameters

bme280	Pointer to the BME280 driver structure.
mode	The operating mode to set for the sensor.

Returns: true if the mode was successfully set, false on error.

This function configures the BME280 sensor's operating mode, which determines how the sensor performs measurements and manages power consumption:

SLEEP mode: The sensor is in standby, consuming minimal power. No measurements are performed.
FORCED mode: The sensor performs one measurement cycle of temperature, pressure, and humidity, then returns to sleep mode automatically.
NORMAL mode: The sensor continuously performs measurements at regular intervals according to the configured standby time.

The function writes to the sensor's control register to change the operating mode. In forced mode, the sensor will automatically return to sleep mode after completing the measurement cycle.

Note: Mode changes may take some time to take effect depending on the sensor state.; In forced mode, measurements should be read before the sensor returns to sleep.

See also: driver_bme280_get_mode() for reading the current operating mode.; driver_bme280_mode_t for available operating modes.

◆ driver_bme280_valid()

static bool driver_bme280_valid ( driver_bme280_t * bme280 )

inlinestatic

Get true if the BME280 interface is valid.

Returns: True if the BME280 interface is valid, false otherwise.

The result of driver_bme280_init can return an empty structure if the initialization fails. This function checks if the BME280 interface is valid.

Definition at line 107 of file drivers_bme280.h.

                                                                 {
   return bme280 && bme280->i2c && hw_i2c_valid(bme280->i2c) && bme280->address;
 }

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Data Structures

Typedefs

Enumerations

Functions

Detailed Description

Typedef Documentation

◆ driver_bme280_t

Enumeration Type Documentation

◆ driver_bme280_mode_t

Function Documentation

◆ driver_bme280_calculate_altitude()

◆ driver_bme280_calculate_sea_level_pressure()

◆ driver_bme280_finalize()

◆ driver_bme280_get_mode()

◆ driver_bme280_i2c_init()

◆ driver_bme280_read_data()

◆ driver_bme280_read_humidity()

◆ driver_bme280_read_pressure()

◆ driver_bme280_read_temperature()

◆ driver_bme280_reset()

◆ driver_bme280_set_mode()

◆ driver_bme280_valid()