bmp.c File Reference

Bosch Digital pressure sensor common definitions.

This module defines registers, constants, data structures, and global function prototypes that are common to multiple Bosch sensor drivers, in particular those for BMP085 and BMP180 devices.

Copyright (c) 2014-2018 Microchip Technology Inc. and its subsidiaries.

#include "bmp.h"

Data Structures
struct	bmp_caldata_t
	BMP085 & BMP180 calibration coeffs. More...

Macros
#define	AC1   (caldata.ac1)
#define	AC2   (caldata.ac2)
#define	AC3   (caldata.ac3)
#define	AC4   (caldata.ac4)
#define	AC5   (caldata.ac5)
#define	AC6   (caldata.ac6)
#define	B1   (caldata.b1)
#define	B2   (caldata.b2)
#define	BMP_RESOLUTION   (24 - (8 - sensor_oss))
#define	Mb   (caldata.mb)
#define	Mc   (caldata.mc)
#define	Md   (caldata.md)

Enumerations
enum	osrs_t {   OSS_LOW_POWER = 0,   OSS_STANDARD = 1,   OSS_HIGH = 2,   OSS_ULTRA_HIGH = 3 }
	BMP "oversampling_setting" mode values. More...

Functions
bool	bmp085_init (sensor_t *sensor, int resvd)
	Bosch BMP085 barometric sensor driver initialization. More...
bool	bmp180_init (sensor_t *sensor, int resvd)
	Bosch BMP180 barometric sensor driver initialization. More...
static bool	bmp_device_id (sensor_hal_t *hal, sensor_data_t *data)
	Read sensor device ID and revision numbers. More...
static void	bmp_eoc_wait (sensor_hal_t *hal)
	Wait for completion of sensor analog-to-digital conversion. More...
static bool	bmp_get_cal_param (sensor_hal_t *hal)
	Read BMP085 / BMP180 calibration coefficients. More...
static bool	bmp_get_pressure (sensor_hal_t *hal, sensor_data_t *data)
	Get a pressure sensor sample. More...
static bool	bmp_get_temperature (sensor_hal_t *hal, sensor_data_t *data)
	Get a temperature sensor sample. More...
static int32_t	bmp_get_up (sensor_hal_t *hal)
	Get an uncompensated pressure (UP) reading. More...
static int32_t	bmp_get_ut (sensor_hal_t *hal)
	Get an uncompensated temperature (UT) reading. More...
static bool	bmp_ioctl (sensor_t *sensor, sensor_command_t cmd, void *arg)
	BMP085 / BMP180 ioctl control entry point. More...
static bool	bmp_read (sensor_t *sensor, sensor_read_t type, sensor_data_t *data)
	Read sensor data. More...
static bool	bmp_set_state (sensor_hal_t *hal, sensor_state_t state)
	Set the BMP085 / BMP180 execution mode. More...

Variables
static bmp_caldata_t	caldata
static osrs_t	sensor_oss

#define AC1   (caldata.ac1)

Referenced by bmp_get_cal_param(), and bmp_get_pressure().

#define AC2   (caldata.ac2)

Referenced by bmp_get_cal_param(), and bmp_get_pressure().

#define AC3   (caldata.ac3)

Referenced by bmp_get_cal_param(), and bmp_get_pressure().

#define AC4   (caldata.ac4)

Referenced by bmp_get_cal_param(), and bmp_get_pressure().

#define AC5   (caldata.ac5)

Referenced by bmp_get_cal_param(), bmp_get_pressure(), and bmp_get_temperature().

#define AC6   (caldata.ac6)

Referenced by bmp_get_cal_param(), bmp_get_pressure(), and bmp_get_temperature().

#define B1   (caldata.b1)

Referenced by bmp_get_cal_param(), and bmp_get_pressure().

#define B2   (caldata.b2)

Referenced by bmp_get_cal_param(), and bmp_get_pressure().

#define BMP_RESOLUTION   (24 - (8 - sensor_oss))

Referenced by bmp085_init(), bmp180_init(), and bmp_set_state().

#define Mb   (caldata.mb)

Referenced by bmp_get_cal_param().

#define Mc   (caldata.mc)

Referenced by bmp_get_cal_param(), bmp_get_pressure(), and bmp_get_temperature().

#define Md   (caldata.md)

Referenced by bmp_get_cal_param(), bmp_get_pressure(), and bmp_get_temperature().

enum osrs_t

BMP "oversampling_setting" mode values.

Enumerator
OSS_LOW_POWER	Ultra low power (1 internal samples)
OSS_STANDARD	Standard (2 internal samples)
OSS_HIGH	High resolution (4 internal samples)
OSS_ULTRA_HIGH	Ultra high resolution (8 internal samples)

bool bmp085_init	(	sensor_t *	sensor,
		int	resvd
	)

Bosch BMP085 barometric sensor driver initialization.

This is the main initialization function for the BMP085 device.

Parameters

sensor	Address of a sensor device descriptor.
resvd	Reserved value.

Returns

bool true if the sensor is ready for use, else false.

References BMP085_ID_VAL, BMP085_VER_VAL, BMP_CHIP_ID, BMP_CHIP_VERSION, bmp_get_cal_param(), bmp_ioctl(), bmp_read(), BMP_RESOLUTION, sensor_desc::drv, sensor_device_t::func, sensor_desc::hal, OSS_STANDARD, sensor_funcs_t::read, sensor_hal::resolution, sensor_bus_get, SENSOR_CAPS_AUX_TEMP, sensor_oss, SENSOR_UNITS_pascal, SENSOR_VENDOR_BOSCH, and status.

bool bmp180_init	(	sensor_t *	sensor,
		int	resvd
	)

Bosch BMP180 barometric sensor driver initialization.

This is the main initialization function for the BMP180 device.

Parameters

sensor	Address of a sensor device descriptor.
resvd	Reserved value.

Returns

bool true if the sensor is ready for use, else false.

References BMP180_ID_VAL, BMP180_VER_VAL, BMP_CHIP_ID, BMP_CHIP_VERSION, bmp_get_cal_param(), bmp_ioctl(), bmp_read(), BMP_RESOLUTION, sensor_desc::drv, sensor_device_t::func, sensor_desc::hal, OSS_STANDARD, sensor_funcs_t::read, sensor_hal::resolution, sensor_bus_get, SENSOR_CAPS_AUX_TEMP, sensor_oss, SENSOR_UNITS_pascal, SENSOR_VENDOR_BOSCH, and status.

static bool bmp_device_id ( sensor_hal_t *  hal, sensor_data_t *  data  )

static

Read sensor device ID and revision numbers.

This function reads the sensor hardware identification registers and returns these values to the addresses specified in the function parameters.

Parameters

sensor	Address of an initialized sensor device descriptor.
data	Address of sensor_data_t structure to return values.

Returns

bool true if the call succeeds, else false is returned.

References BMP_CHIP_ID, BMP_CHIP_VERSION, sensor_data_t::device, and sensor_bus_get.

Referenced by bmp_read().

static void bmp_eoc_wait ( sensor_hal_t *  hal )

inlinestatic

Wait for completion of sensor analog-to-digital conversion.

Per the Bosch BMP085 & BMP180 data sheets there will be a delay between the time when a data measurement is requested and the sensor internal A/D conversion is complete. The maximum conversion varies according to the oversampling mode.

Instead of waiting for the maximum conversion time, the end of conversion (EOC) digital sensor output, which is connected to a port on the "Atmel Sensor Board", can be tested for a completed conversion.

Parameters

hal	Address of an initialized sensor HAL descriptor.

Returns

Nothing.

Poll the End Of Conversion (EOC) input pin.

This works on the BMP085 but not on the BMP180.

while (gpio_pin_is_low (hal->mcu_sigint));

References delay_ms, and sensor_oss.

Referenced by bmp_get_up().

static bool bmp_get_cal_param ( sensor_hal_t *  hal )

static

Read BMP085 / BMP180 calibration coefficients.

Calculating temperature in degrees C or pressure in Pa requires the use of calibration data coefficients stored in the BMP EEPROM. Every sensor module has individual coefficients. Before the first calculation of temperature and pressure, the master reads this data from device EEPROM.

Parameters

hal	Address of an initialized sensor HAL descriptor.

Return values

bool	"true" if valid coefficients have been fetched
bool	"false" for errors reading the device coefficients

References AC1, AC2, AC3, AC4, AC5, AC6, B1, B2, BMP_EEPROM_ADDR, BMP_EEPROM_SIZE_BYTES, Mb, Mc, Md, and sensor_bus_read.

Referenced by bmp085_init(), and bmp180_init().

static bool bmp_get_pressure ( sensor_hal_t *  hal, sensor_data_t *  data  )

static

Get a pressure sensor sample.

If scaled data format is selected for the device, this routine gets a compensated "true pressure" sample using the sampling mode specified when the device was initialized. Otherwise a raw uncompensated pressure reading is returned in "data".

Parameters

sensor	Address of an initialized sensor device descriptor.
data	The address where pressure samples are returned.

Returns

bool true if the call succeeds, else false is returned.

References AC1, AC2, AC3, AC4, AC5, AC6, B1, B2, bmp_get_up(), bmp_get_ut(), Mc, Md, sensor_data_t::pressure, sensor_data_t::scaled, sensor_oss, and UP.

Referenced by bmp_read().

static bool bmp_get_temperature ( sensor_hal_t *  hal, sensor_data_t *  data  )

static

Get a temperature sensor sample.

If scaled data format is selected for the device, this routine gets a compensated "true temperature" sample. Otherwise, a raw uncompensated temperature reading is returned in "data".

Parameters

sensor	Address of an initialized sensor device descriptor.
data	The address where temperature samples are returned.

Returns

bool true if the call succeeds, else false is returned.

References AC5, AC6, bmp_get_ut(), Mc, Md, sensor_data_t::scaled, and sensor_data_t::temperature.

Referenced by bmp_read().

static int32_t bmp_get_up ( sensor_hal_t *  hal )

static

Get an uncompensated pressure (UP) reading.

This routine gets a raw pressure sample reading from a Bosch BMP085 or BMP180 device. In the event of a sensor or bus error, a 32-bit value of -1 (all bits set) may be returned from this routine.

Parameters

hal	Address of an initialized sensor HAL descriptor.

Returns

An uncompensated pressure reading.

References BMP_CONTROL, BMP_DATA_MSB, bmp_eoc_wait(), BMP_PRESS_READ, sensor_bus_put, sensor_bus_read, sensor_oss, and UP.

Referenced by bmp_get_pressure().

static int32_t bmp_get_ut ( sensor_hal_t *  hal )

static

Get an uncompensated temperature (UT) reading.

This routine gets a raw temperature sample reading from the a BMP085 or BMP180 device. In the event of a sensor or bus error, a 32-bit value of -1 (all bits set) may be returned from this routine.

Parameters

hal	Address of an initialized sensor HAL descriptor.

Returns

An uncompensated temperature reading.

References BMP_CONTROL, BMP_DATA_MSB, BMP_TEMP_READ, delay_ms, sensor_bus_put, and sensor_bus_read.

Referenced by bmp_get_pressure(), and bmp_get_temperature().

static bool bmp_ioctl ( sensor_t *  sensor, sensor_command_t  cmd, void *  arg  )

static

BMP085 / BMP180 ioctl control entry point.

Parameters

hal	Address of an initialized sensor device descriptor.
cmd	Command to execute
arg	Argument for command (varies)

Returns

bool true if the call succeeds, else false is returned.

References bmp_set_state(), sensor_desc::err, sensor_desc::hal, SENSOR_ERR_UNSUPPORTED, SENSOR_SET_STATE, and status.

Referenced by bmp085_init(), and bmp180_init().

static bool bmp_read ( sensor_t *  sensor, sensor_read_t  type, sensor_data_t *  data  )

static

Read sensor data.

If scaled data format is selected for the device, this routine gets a compensated "true pressure" sample using the sampling mode specified when the device was initialized. Otherwise a raw uncompensated pressure reading is returned in "data".

Parameters

sensor	Address of an initialized sensor device descriptor.
type	Type of sensor data to read.
data	The address where pressure samples are returned.

Returns

bool true if the call succeeds, else false is returned.

References bmp_device_id(), bmp_get_pressure(), bmp_get_temperature(), sensor_desc::err, sensor_desc::hal, SENSOR_ERR_FUNCTION, SENSOR_READ_ID, SENSOR_READ_PRESSURE, and SENSOR_READ_TEMPERATURE.

Referenced by bmp085_init(), and bmp180_init().

static bool bmp_set_state ( sensor_hal_t *  hal, sensor_state_t  state  )

static

Set the BMP085 / BMP180 execution mode.

This routine sets a specified BMP085 or BMP180 execution state to one of the following:

SENSOR_STATE_LOWEST_POWER or SENSOR_STATE_LOW_POWER Ultra low power mode (1 internal sample). In this mode the average current @ 1 sample/s is typically 3 microamps.

SENSOR_STATE_NORMAL Standard mode (2 internal samples). In this mode the average current @ 1 sample/s is typically 5 microamps.

SENSOR_STATE_HIGH_POWER High resolution mode (4 internal samples). In this mode the average current @ 1 sample/s is typically 7 microamps.

SENSOR_STATE_HIGHEST_POWER Ultra high resolution mode (8 internal samples). In this mode the average current @ 1 sample/s is 12 microamps.

SENSOR_STATE_RESET This function resets the device and internal registers to the power-up default settings.

Parameters

sensor	Address of an initialized sensor device descriptor.
state	A specified sensor operational state.

Returns

bool true if the call succeeds, else false is returned.

Activate, then deactivate, the master reset pin (XCLR).

This works on the BMP085 but not on the BMP180.

gpio_set_pin_low (hal->mcu_sigout); gpio_set_pin_high (hal->mcu_sigout);

References BMP_RESET_CMD, BMP_RESOLUTION, BMP_SOFT_RESET, OSS_HIGH, OSS_LOW_POWER, OSS_STANDARD, OSS_ULTRA_HIGH, sensor_hal::resolution, sensor_bus_put, sensor_oss, SENSOR_STATE_HIGH_POWER, SENSOR_STATE_HIGHEST_POWER, SENSOR_STATE_LOW_POWER, SENSOR_STATE_LOWEST_POWER, SENSOR_STATE_NORMAL, and SENSOR_STATE_RESET.

Referenced by bmp_ioctl().

bmp_caldata_t caldata

static

osrs_t sensor_oss

static

Referenced by bmp085_init(), bmp180_init(), bmp_eoc_wait(), bmp_get_pressure(), bmp_get_up(), and bmp_set_state().