bmpx8x.h File Reference

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API Description

/*
 * Author: Jon Trulson <jtrulson@ics.com>
 * Copyright (c) 2017 Intel Corporation.
 *
 * The MIT License
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <unistd.h>
#include <stdio.h>
#include <signal.h>

#include "upm_utilities.h"
#include "bmpx8x.h"

bool shouldRun = true;

void sig_handler(int signo)
{
    if (signo == SIGINT)
        shouldRun = false;
}


int main(int argc, char **argv)
{
    signal(SIGINT, sig_handler);

    // Instantiate a BMPX8X instance using default i2c bus and address
    bmpx8x_context sensor = bmpx8x_init(BMPX8X_DEFAULT_I2C_BUS,
                                        BMPX8X_DEFAULT_I2C_ADDR);

    if (!sensor)
    {
        printf("bmpx8x_init() failed.\n");
        return 1;
    }

    // Print the pressure, altitude, sea level, and
    // temperature values every 0.5 seconds
    while (shouldRun)
    {
        if (bmpx8x_update(sensor))
        {
            printf("bmpx8x_update() failed\n");
            bmpx8x_close(sensor);
            return 1;
        }

        // assume sea level pressure is 101325 Pa.
        float altitude = bmpx8x_get_altitude(sensor, 101325);
        int   sealevel = bmpx8x_get_sealevel_pressure(sensor, altitude);

        printf("Pressure: %d Pa, Temperature: %f C, "
               "Altitude %f m, Sea level %d Pa\n",
               bmpx8x_get_pressure(sensor),
               bmpx8x_get_temperature(sensor),
               altitude,
               sealevel);

        upm_delay_ms(500);
    }

    printf("Exiting...\n");
    bmpx8x_close(sensor);

    return 0;
}

Go to the source code of this file.

Data Structures
struct	_bmpx8x_context

Functions
bmpx8x_context	bmpx8x_init (int bus, int addr)
void	bmpx8x_close (bmpx8x_context dev)
uint8_t	bmpx8x_get_chip_id (const bmpx8x_context dev)
upm_result_t	bmpx8x_devinit (const bmpx8x_context dev, BMPX8X_OSS_T oss)
upm_result_t	bmpx8x_reset (const bmpx8x_context dev)
upm_result_t	bmpx8x_update (const bmpx8x_context dev)
void	bmpx8x_set_oversampling (const bmpx8x_context dev, BMPX8X_OSS_T oss)
int	bmpx8x_get_pressure (const bmpx8x_context dev)
float	bmpx8x_get_temperature (const bmpx8x_context dev)
int	bmpx8x_get_sealevel_pressure (const bmpx8x_context dev, float altitude)
float	bmpx8x_get_altitude (const bmpx8x_context dev, int sealevel)
uint8_t	bmpx8x_read_reg (const bmpx8x_context dev, uint8_t reg)
int	bmpx8x_read_regs (const bmpx8x_context dev, uint8_t reg, uint8_t *buffer, int len)
upm_result_t	bmpx8x_write_reg (const bmpx8x_context dev, uint8_t reg, uint8_t val)

Typedefs
typedef struct _bmpx8x_context *	bmpx8x_context

Function Documentation

bmpx8x_context bmpx8x_init	(	int	bus,
		int	addr
	)

BMPX8X initialization.

By default, the device is initialized to it's highest accuracy (BMP085_OSS_ULTRAHIGHRES).

Parameters

bus	I2C bus number.
addr	I2C address of the device.

Returns

Device context, or NULL if an error occurred.

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void bmpx8x_close

(

bmpx8x_context

dev

)

BMPX8X close function.

Parameters

dev	Device context.

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uint8_t bmpx8x_get_chip_id

(

const bmpx8x_context

dev

)

Return the chip ID.

Parameters

dev	The device context.

Returns

The chip ID.

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upm_result_t bmpx8x_devinit	(	const bmpx8x_context	dev,
		BMPX8X_OSS_T	oss
	)

Initialize the device, read calibration data, and start operation. This function is called from bmpx8x_init() so it will not typically need to be called by a user unless the device is reset. This method will call bmpx8x_set_oversampling() with the passed parameter.

Parameters

dev	The device context.
oss	One of the BMPX8X_OSS_T values. The default set at bmpx8x_init() time is BMP085_OSS_ULTRAHIGHRES.

Returns

UPM result.

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upm_result_t bmpx8x_reset

(

const bmpx8x_context

dev

)

Perform a device reset. The device will be reset as if it was just powered on. All compensation values will be lost. You should call bmpx8x_devinit() afterward, or perform the same steps that bmpx8x_devinit() performs before attempting to use the device.

Parameters

dev	The device context.

Returns

UPM result.

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upm_result_t bmpx8x_update

(

const bmpx8x_context

dev

)

Update the internal stored values from sensor data.

Parameters

dev	The device context.

Returns

UPM result.

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void bmpx8x_set_oversampling	(	const bmpx8x_context	dev,
		BMPX8X_OSS_T	oss
	)

Set the oversampling (precision mode) of the device. Higher precision requires more time to complete.

Parameters

dev	The device context.
oss	The desired oversampling mode, one of the BMPX8X_OSS_T values.

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int bmpx8x_get_pressure

(

const bmpx8x_context

dev

)

Returns the pressure in Pascals. bmpx8x_update() must have been called prior to calling this function.

Parameters

dev	Device context.

Returns

The pressure in Pascals.

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float bmpx8x_get_temperature

(

const bmpx8x_context

dev

)

Returns the temperature in degrees Celsius. bmpx8x_update() must have been called prior to calling this function.

Parameters

dev	Device context.

Returns

The temperature in degrees Celsius.

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int bmpx8x_get_sealevel_pressure	(	const bmpx8x_context	dev,
		float	altitude
	)

With a given current altitude, calculate pressure at sea level. bmpx8x_update() must have been called prior to calling this function.

Parameters

dev	Device context.
altitude	Current altitude in Meters.

Returns

The pressure in Pascals at sea level.

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float bmpx8x_get_altitude	(	const bmpx8x_context	dev,
		int	sealevel
	)

With a given sea level, calculate altitude in meters. bmpx8x_update() must have been called prior to calling this function.

Parameters

dev	Device context.
sealevel	Sea level pressure in Pascals. If a negative number, or zero is supplied, a default sealevel of 101325 Pa will be used instead.

Returns

The current altitude in Meters.

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uint8_t bmpx8x_read_reg	(	const bmpx8x_context	dev,
		uint8_t	reg
	)

Read a register.

Parameters

dev	The device context.
reg	The register to read.

Returns

The value of the register.

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int bmpx8x_read_regs	(	const bmpx8x_context	dev,
		uint8_t	reg,
		uint8_t *	buffer,
		int	len
	)

Read contiguous registers into a buffer.

Parameters

dev	The device context.
buffer	The buffer to store the results.
len	The number of registers to read.

Returns

The number of bytes read, or -1 on error.

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upm_result_t bmpx8x_write_reg	(	const bmpx8x_context	dev,
		uint8_t	reg,
		uint8_t	val
	)

Write to a register.

Parameters

dev	The device context.
reg	The register to write to.
val	The value to write.

Returns

UPM result.

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Typedef Documentation

typedef struct _bmpx8x_context * bmpx8x_context

Device context