3.2.1. `bmp280` — BMP280 temperature and pressure sensor¶

BMP280 is a temperature and pressure sensor from Bosch Sensortec.

../../../_images/MFG_BST-BMP280-DS001-12.jpg

This driver supports both I2C and SPI for device communication.

3.2.1.1. Example usage¶

This example illustrates how to initialize the driver with an I2C transport layer and then read temperature and pressure from the BMP280 device.

struct bmp280_driver_t bmp280;
struct i2c_driver_t i2c;
struct bmp280_transport_i2c_t transport;
float temperature;
float pressure;
float altitude;

/* Initialize and start a I2C driver. */
i2c_init(&i2c, &i2c_device[0], I2C_BAUDRATE_100KBPS, -1);
i2c_start(&i2c);

/* Initialize the BMP280 I2C transport layer. */
bmp280_transport_i2c_init(&transport,
                          &i2c,
                          BMP280_I2C_ADDRESS_AUTOMATIC);

/* Initialize and start the BMP280 driver with the I2C
   transport layer. */
bmp280_init(&bmp280,
            &transport.base,
            bmp280_mode_normal_t,
            bmp280_standby_time_500_us_t,
            bmp280_filter_off_t,
            bmp280_temperature_oversampling_1_t,
            bmp280_pressure_oversampling_1_t);
bmp280_start(&bmp280);

/* Read temperature and pressure from the BMP280. */
bmp280_read(&bmp280, &temperature, &pressure);

/* Calculate the altitude from read pressure. */
altitude = science_pressure_to_altitude(
    pressure,
    SCIENCE_SEA_LEVEL_STANDARD_PRESSURE);

std_printf(OSTR("Temperature: %f\r\n"
                "Pressure: %f\r\n"
                "Altitude: %f\r\n"),
           temperature,
           pressure,
           altitude);

Source code: src/drivers/sensors/bmp280.h, src/drivers/sensors/bmp280.c

Test code: tst/drivers/software/sensors/bmp280/main.c

Example code: examples/bmp280/main.c

Defines

BMP280_I2C_ADDRESS_0¶: I2C address #0.

BMP280_I2C_ADDRESS_1¶: I2C address #1.

BMP280_I2C_ADDRESS_AUTOMATIC¶: Automatic I2C address detection.

BMP280_SPI_POLARITY¶: Default SPI polarity and phase. Polarity 1 and phase 1 is also supported.

BMP280_SPI_PHASE¶

Enums

enum bmp280_mode_t¶

Mode configuration.

Values:

bmp280_mode_forced_t = 1¶

bmp280_mode_normal_t = 3¶

enum bmp280_standby_time_t¶

Standby time in normal mode configuration.

Values:

bmp280_standby_time_500_us_t = 0¶

bmp280_standby_time_62500_us_t¶

bmp280_standby_time_125_ms_t¶

bmp280_standby_time_250_ms_t¶

bmp280_standby_time_500_ms_t¶

bmp280_standby_time_1_s_t¶

bmp280_standby_time_2_s_t¶

bmp280_standby_time_4_s_t¶

enum bmp280_filter_t¶

Filter configuration.

Values:

bmp280_filter_off_t = 0¶

bmp280_filter_2_t¶

bmp280_filter_4_t¶

bmp280_filter_8_t¶

bmp280_filter_16_t¶

enum bmp280_temperature_oversampling_t¶

Temperature oversampling configuration.

Values:

bmp280_temperature_off_t = 0¶

bmp280_temperature_oversampling_1_t¶

bmp280_temperature_oversampling_2_t¶

bmp280_temperature_oversampling_4_t¶

bmp280_temperature_oversampling_8_t¶

bmp280_temperature_oversampling_16_t¶

enum bmp280_pressure_oversampling_t¶

Pressure oversampling configuration.

Values:

bmp280_pressure_off_t = 0¶

bmp280_pressure_oversampling_1_t¶

bmp280_pressure_oversampling_2_t¶

bmp280_pressure_oversampling_4_t¶

bmp280_pressure_oversampling_8_t¶

bmp280_pressure_oversampling_16_t¶

Functions

int bmp280_module_init(void)¶

Initialize the bmp280 module. This function must be called before calling any other function in this module.

The module will only be initialized once even if this function is called multiple times.

Return: zero(0) or negative error code.

int bmp280_init(struct bmp280_driver_t *self_p, struct bmp280_transport_t *transport_p, enum bmp280_mode_t mode, enum bmp280_standby_time_t standby_time, enum bmp280_filter_t filter, enum bmp280_temperature_oversampling_t temperature_oversampling, enum bmp280_pressure_oversampling_t pressure_oversampling)¶

Initialize given driver object.

Return