BMP280/BME280 temperature, pressure and humidity sensor

Device driver interface for the Bosch BMP280 and BME280 sensors. More...

Detailed Description

Device driver interface for the Bosch BMP280 and BME280 sensors.

BMP280 and BME280 measure temperature in centi °C and pressure in Pa. BME280 can also measure relative humidity in %.

For more information, see the datasheets:

• BMP280
• BME280

This driver provides [S]ensor [A]ctuator [U]ber [L]ayer capabilities.

Usage

To include this driver to your application, simply add one of the following to the application's Makefile:

# BME280 connected via SPI
USEMODULE += bme280_spi
# BME280 connected via I2C
USEMODULE += bme280_i2c
# BMP280 via SPI
USEMODULE += bmp280_spi
# BMP280 via I2C
USEMODULE += bmp280_i2c
 
# When using I2C, specify the default I2C device to use,
# and the BME280's address (see datasheet).
# The values below are the defaults:
CFLAGS += -DBMX280_PARAM_I2C_DEV=I2C_DEV\‍(0\‍)
CFLAGS += -DBMX280_PARAM_I2C_ADDR=0x77
 
# Using SPI, you can override the default configuration by specifying the
# used SPI bus and the ship select pin:
CFLAGS += -DBMX280_PARAM_SPI_DEV=SPI_DEV\‍(x\‍)
CFLAGS += -DBMX280_PARAM_CS=GPIO_PIN\‍(y,z\‍)

This way the default parameters in drivers/bmx280/include/bmx280_params.h are replaced by these new values.

Files
file	bmx280_internals.h
	Internal addresses, registers, constants for the BMX280 family sensors.
file	bmx280_params.h
	Default configuration for BMX280.
file	bmx280.h
	Device driver interface for the BMP280 and BME280 sensors.

Data Structures
struct	bmx280_calibration_t
	Calibration struct for the BMX280 sensor. More...
struct	bmx280_params_t
	Parameters for the BMX280 sensor. More...
struct	bmx280_t
	Device descriptor for the BMX280 sensor. More...

Macros
#define	BMX280_RAW_LEN   (6U)
	Select the number or raw data bytes depending on the device type.

Enumerations
enum	bmx280_t_sb_t {   BMX280_SB_0_5 = 0x00 , BMX280_SB_62_5 = 0x20 , BMX280_SB_125 = 0x40 , BMX280_SB_250 = 0x60 ,   BMX280_SB_500 = 0x80 , BMX280_SB_1000 = 0xa0 , BMX280_SB_10 = 0xc0 , BMX280_SB_20 = 0xe0 }
	Values for t_sb field of the BMX280 config register. More...
enum	bmx280_filter_t {   BMX280_FILTER_OFF = 0x00 , BMX280_FILTER_2 = 0x04 , BMX280_FILTER_4 = 0x08 , BMX280_FILTER_8 = 0x0c ,   BMX280_FILTER_16 = 0x10 }
	Values for filter field of the BMX280 config register. More...
enum	bmx280_mode_t { BMX280_MODE_SLEEP = 0x00 , BMX280_MODE_FORCED = 0x01 , BMX280_MODE_NORMAL = 0x03 }
	Values for mode field of the BMX280 ctrl_meas register. More...
enum	bmx280_osrs_t {   BMX280_OSRS_SKIPPED = 0x00 , BMX280_OSRS_X1 = 0x01 , BMX280_OSRS_X2 = 0x02 , BMX280_OSRS_X4 = 0x03 ,   BMX280_OSRS_X8 = 0x04 , BMX280_OSRS_X16 = 0x05 }
	Values for oversampling settings. More...
enum	{ BMX280_OK = 0 , BMX280_ERR_BUS = -1 , BMX280_ERR_NODEV = -2 }
	Status and error return codes. More...

Functions
int	bmx280_init (bmx280_t *dev, const bmx280_params_t *params)
	Initialize the given BMX280 device.
int16_t	bmx280_read_temperature (bmx280_t *dev)
	Read temperature value from the given BMX280 device.
uint32_t	bmx280_read_pressure (bmx280_t *dev)
	Read air pressure value from the given BMX280 device.
uint16_t	bme280_read_humidity (bmx280_t *dev)
	Read humidity value from the given BME280 device.

Variables
const saul_driver_t	bmx280_temperature_saul_driver
	Export of SAUL interface for temperature sensor.
const saul_driver_t	bmx280_pressure_saul_driver
	Export of SAUL interface for pressure sensor.

Macro Definition Documentation

BMX280_RAW_LEN

#define BMX280_RAW_LEN   (6U)

Select the number or raw data bytes depending on the device type.

Definition at line 96 of file bmx280.h.

Enumeration Type Documentation

anonymous enum

anonymous enum

Status and error return codes.

Enumerator
BMX280_OK	everything was fine
BMX280_ERR_BUS	bus error
BMX280_ERR_NODEV	did not detect BME280 or BMP280

Definition at line 221 of file bmx280.h.

bmx280_filter_t

enum bmx280_filter_t

Values for filter field of the BMX280 config register.

Definition at line 144 of file bmx280.h.

bmx280_mode_t

enum bmx280_mode_t

Values for mode field of the BMX280 ctrl_meas register.

Definition at line 155 of file bmx280.h.

bmx280_osrs_t

enum bmx280_osrs_t

Values for oversampling settings.

These values are used for:

• osrs_h field of the BME280 ctrl_hum register
• osrs_t field of the BMX280 ctrl_meas register
• osrs_p field of the BMX280 ctrl_meas register

Definition at line 169 of file bmx280.h.

bmx280_t_sb_t

enum bmx280_t_sb_t

Values for t_sb field of the BMX280 config register.

Definition at line 130 of file bmx280.h.

Function Documentation

bme280_read_humidity()

uint16_t bme280_read_humidity

(

bmx280_t *

dev

)

Read humidity value from the given BME280 device.

The humidity is returned in centi RH (x.xx% relative humidity).

This function returns the pressure data that was measured when bmx280_read_temperature() has been called last. So bmx280_read_temperature() has to be called before.

If bmx280_read_temperatue() did not succeed in acquiring a new set of sensor data, the result of this function is undefined.

Parameters

[in]

dev

device to read from

Returns

humidity in centi RH (i.e. the percentage times 100)

bmx280_init()

int bmx280_init	(	bmx280_t *	dev,
		const bmx280_params_t *	params
	)

Initialize the given BMX280 device.

Parameters

[out]	dev	device descriptor of the given BMX280 device
[in]	params	static configuration parameters

Returns

BMX280_OK on success

BMX280_ERR_BUS on bus error

BMX280_ERR_NODEV if no corresponding device was found on the bus

bmx280_read_pressure()

uint32_t bmx280_read_pressure

(

bmx280_t *

dev

)

Read air pressure value from the given BMX280 device.

The air pressure is returned in PA (Pascal).

This function returns the pressure data that was measured when bmx280_read_temperature() has been called last. So bmx280_read_temperature() has to be called before.

If bmx280_read_temperatue() did not succeed in acquiring a new set of sensor data, the result of this function is undefined.

Parameters

[in]

dev

device to read from

Returns

air pressure in PA

bmx280_read_temperature()

int16_t bmx280_read_temperature

(

bmx280_t *

dev

)

Read temperature value from the given BMX280 device.

The measured temperature is returned in centi °C (x.xx°C).

Parameters

[in]

dev

device to read from

Returns

measured temperature in centi Celsius

INT16_MIN on error