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drivers/bmp180: initial implementation

pr/gpio
Alexandre Abadie 7 years ago committed by Alexandre Abadie
parent
commit
941bdbbc56
  1. 3
      drivers/Makefile.include
  2. 3
      drivers/bmp180/Makefile
  3. 247
      drivers/bmp180/bmp180.c
  4. 62
      drivers/bmp180/include/bmp180_internals.h
  5. 129
      drivers/include/bmp180.h
  6. 20
      tests/driver_bmp180/Makefile
  7. 15
      tests/driver_bmp180/Readme.md
  8. 102
      tests/driver_bmp180/main.c

3
drivers/Makefile.include

@ -58,3 +58,6 @@ endif
ifneq (,$(filter bh1750fvi,$(USEMODULE)))
USEMODULE_INCLUDES += $(RIOTBASE)/drivers/bh1750fvi/include
endif
ifneq (,$(filter bmp180,$(USEMODULE)))
USEMODULE_INCLUDES += $(RIOTBASE)/drivers/bmp180/include
endif

3
drivers/bmp180/Makefile

@ -0,0 +1,3 @@
MODULE = bmp180
include $(RIOTBASE)/Makefile.base

247
drivers/bmp180/bmp180.c

@ -0,0 +1,247 @@
/*
* Copyright (C) 2016 Inria
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup drivers_bmp180
* @{
*
* @file
* @brief Device driver implementation for the BMP180/BMP085 temperature and pressure sensor.
*
* @author Alexandre Abadie <alexandre.abadie@inria.fr>
*
* @}
*/
#include <math.h>
#include "bmp180.h"
#include "bmp180_internals.h"
#include "periph/i2c.h"
#include "xtimer.h"
#define ENABLE_DEBUG (0)
#include "debug.h"
/* Internal function prototypes */
static int _read_ut(bmp180_t *dev, int32_t *ut);
static int _read_up(bmp180_t *dev, int32_t *up);
static int _compute_b5(bmp180_t *dev, int32_t ut, int32_t *b5);
/*---------------------------------------------------------------------------*
* BMP180 Core API *
*---------------------------------------------------------------------------*/
int bmp180_init(bmp180_t *dev, i2c_t i2c, uint8_t mode)
{
dev->i2c_dev = i2c;
/* Clamp oversampling mode */
if (mode > BMP180_ULTRAHIGHRES) {
mode = BMP180_ULTRAHIGHRES;
}
/* Setting oversampling mode */
dev->oversampling = mode;
/* Initialize I2C interface */
if (i2c_init_master(dev->i2c_dev, I2C_SPEED_NORMAL)) {
DEBUG("[Error] I2C device not enabled\n");
return -1;
}
/* Acquire exclusive access */
i2c_acquire(dev->i2c_dev);
/* Check sensor ID */
char checkid;
i2c_write_byte(dev->i2c_dev, BMP180_ADDR, BMP180_REGISTER_ID);
i2c_read_reg(dev->i2c_dev, BMP180_ADDR, BMP180_REGISTER_ID, &checkid);
if (checkid != 0x55) {
DEBUG("[Error] Wrong device ID\n");
return -1;
}
char buffer[22] = {0};
/* Read calibration values, using contiguous register addresses */
i2c_write_byte(dev->i2c_dev, BMP180_ADDR, BMP180_CALIBRATION_AC1);
i2c_read_regs(dev->i2c_dev, BMP180_ADDR, BMP180_CALIBRATION_AC1, buffer, 22);
dev->calibration.ac1 = (int16_t)(buffer[0] << 8) | buffer[1];
dev->calibration.ac2 = (int16_t)(buffer[2] << 8) | buffer[3];
dev->calibration.ac3 = (int16_t)(buffer[4] << 8) | buffer[4];
dev->calibration.ac4 = (uint16_t)(buffer[6] << 8) | buffer[7];
dev->calibration.ac5 = (uint16_t)(buffer[8] << 8) | buffer[9];
dev->calibration.ac6 = (uint16_t)(buffer[10] << 8) | buffer[11];
dev->calibration.b1 = (int16_t)(buffer[12] << 8) | buffer[13];
dev->calibration.b2 = (int16_t)(buffer[14] << 8) | buffer[15];
dev->calibration.mb = (int16_t)(buffer[16] << 8) | buffer[17];
dev->calibration.mc = (int16_t)(buffer[18] << 8) | buffer[19];
dev->calibration.md = (int16_t)(buffer[20] << 8) | buffer[21];
/* Release I2C device */
i2c_release(dev->i2c_dev);
DEBUG("AC1: %i\n", (int)dev->calibration.ac1);
DEBUG("AC2: %i\n", (int)dev->calibration.ac2);
DEBUG("AC3: %i\n", (int)dev->calibration.ac3);
DEBUG("AC4: %i\n", (int)dev->calibration.ac4);
DEBUG("AC5: %i\n", (int)dev->calibration.ac5);
DEBUG("AC6: %i\n", (int)dev->calibration.ac6);
DEBUG("B1: %i\n", (int)dev->calibration.b1);
DEBUG("B2: %i\n", (int)dev->calibration.b2);
DEBUG("MB: %i\n", (int)dev->calibration.mb);
DEBUG("MC: %i\n", (int)dev->calibration.mc);
DEBUG("MD: %i\n", (int)dev->calibration.md);
return 0;
}
int bmp180_read_temperature(bmp180_t *dev, int32_t *temperature)
{
int32_t ut, b5;
/* Acquire exclusive access */
if (i2c_acquire(dev->i2c_dev)) {
return -1;
}
/* Read uncompensated value */
_read_ut(dev, &ut);
/* Compute true temperature value following datasheet formulas */
_compute_b5(dev, ut, &b5);
*temperature = (b5 + 8) >> 4;
/* Release I2C device */
i2c_release(dev->i2c_dev);
return 0;
}
int bmp180_read_pressure(bmp180_t *dev, int32_t *pressure)
{
int32_t ut, up, x1, x2, x3, b3, b5, b6, p;
uint32_t b4, b7;
/* Acquire exclusive access */
if (i2c_acquire(dev->i2c_dev)) {
return -1;
}
/* Read uncompensated values: first temperature, second pressure */
_read_ut(dev, &ut);
_read_up(dev, &up);
/* Compute true pressure value following datasheet formulas */
_compute_b5(dev, ut, &b5);
b6 = b5 - 4000;
x1 = ((int32_t)dev->calibration.b2 * ((b6 * b6) >> 12)) >> 11;
x2 = ((int32_t)dev->calibration.ac2 * b6) >> 11;
x3 = x1 + x2;
b3 = ((((int32_t)dev->calibration.ac1*4 + x3) << dev->oversampling) + 2) >> 2;
x1 = ((int32_t)dev->calibration.ac3 * b6) >> 13;
x2 = ((int32_t)dev->calibration.b1 * (b6 * b6) >> 12) >> 16;
x3 = ((x1 + x2) + 2) >> 2;
b4 = (int32_t)dev->calibration.ac4 * (uint32_t)(x3+32768) >> 15;
b7 = ((uint32_t)up - b3) * (uint32_t)(50000UL >> dev->oversampling);
if (b7 < 0x80000000) {
p = (b7 * 2) / b4;
}
else {
p = (b7 / b4) * 2;
}
x1 = (p >> 8) * (p >> 8);
x1 = (x1 * 3038) >> 16;
x2 = (-7357 * p) >> 16;
*pressure = p + ((x1 + x2 + 3791) >> 4);
/* release I2C device */
i2c_release(dev->i2c_dev);
return 0;
}
int bmp180_altitude(bmp180_t *dev, int32_t pressure_0, int32_t *altitude)
{
int32_t p;
bmp180_read_pressure(dev, &p);
*altitude = (int32_t)(44330.0 * (1.0 - pow((double)p / pressure_0, 0.1903)));
return 0;
}
int bmp180_sealevel_pressure(bmp180_t *dev, int32_t altitude, int32_t *pressure_0)
{
int32_t p;
bmp180_read_pressure(dev, &p);
*pressure_0 = (int32_t)((double)p / pow(1.0 - (altitude / 44330.0), 5.255));
return 0;
}
/*------------------------------------------------------------------------------------*/
/* Internal functions */
/*------------------------------------------------------------------------------------*/
static int _read_ut(bmp180_t *dev, int32_t *output)
{
/* Read UT (Uncompsensated Temperature value) */
char ut[2] = {0};
char control[2] = { BMP180_REGISTER_CONTROL, BMP180_TEMPERATURE_COMMAND };
i2c_write_bytes(dev->i2c_dev, BMP180_ADDR, control, 2);
xtimer_usleep(BMP180_ULTRALOWPOWER_DELAY);
i2c_read_regs(dev->i2c_dev, BMP180_ADDR, BMP180_REGISTER_DATA, ut, 2);
*output = ( ut[0] << 8 ) | ut[1];
DEBUG("UT: %i\n", (int)*output);
return 0;
}
static int _read_up(bmp180_t *dev, int32_t *output)
{
/* Read UP (Uncompsensated Pressure value) */
char up[3] = {0};
char control[2] = { BMP180_REGISTER_CONTROL, BMP180_PRESSURE_COMMAND | (dev->oversampling & 0x3) << 6 };
i2c_write_bytes(dev->i2c_dev, BMP180_ADDR, control, 2);
switch (dev->oversampling) {
case BMP180_ULTRALOWPOWER:
xtimer_usleep(BMP180_ULTRALOWPOWER_DELAY);
break;
case BMP180_STANDARD:
xtimer_usleep(BMP180_STANDARD_DELAY);
break;
case BMP180_HIGHRES:
xtimer_usleep(BMP180_HIGHRES_DELAY);
break;
case BMP180_ULTRAHIGHRES:
xtimer_usleep(BMP180_ULTRAHIGHRES_DELAY);
break;
default:
xtimer_usleep(BMP180_ULTRALOWPOWER_DELAY);
break;
}
i2c_read_regs(dev->i2c_dev, BMP180_ADDR, BMP180_REGISTER_DATA, up, 3);
*output = ((up[0] << 16) | (up[1] << 8) | up[2]) >> (8 - dev->oversampling);
DEBUG("UP: %i\n", (int)*output);
return 0;
}
static int _compute_b5(bmp180_t *dev, int32_t ut, int32_t *output)
{
int32_t x1, x2;
x1 = (ut - dev->calibration.ac6) * dev->calibration.ac5 >> 15;
x2 = (dev->calibration.mc << 11) / (x1 + dev->calibration.md);
*output = x1 + x2;
return 0;
}

62
drivers/bmp180/include/bmp180_internals.h

@ -0,0 +1,62 @@
/*
* Copyright (C) 2016 Inria
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @defgroup drivers_bmp180 BMP180
* @ingroup drivers_sensors
* @brief Internal addresses, registers, constants for the BMP180 sensor.
* @{
*
* @file
* @brief Internal addresses, registers, constants for the BMP180 sensor.
*
* @author Alexandre Abadie <alexandre.abadie@inria.fr>
*/
#ifndef BMP180_REGS_H_
#define BMP180_REGS_H_
#ifdef __cplusplus
extern "C" {
#endif
/**
* @name BMP180 I2C address
* @{
*/
#define BMP180_ADDR (0x77) /* 7 bit address */
/** @} */
/**
* @name BMP180 registers
* @{
*/
#define BMP180_REGISTER_ID (0xD0)
#define BMP180_REGISTER_CONTROL (0xF4)
#define BMP180_REGISTER_DATA (0xF6)
#define BMP180_TEMPERATURE_COMMAND (0x2E)
#define BMP180_PRESSURE_COMMAND (0x34)
#define BMP180_CALIBRATION_AC1 (0xAA)
/** @} */
/**
* @name Oversampling modes delays (micros)
* @{
*/
#define BMP180_ULTRALOWPOWER_DELAY (5000UL)
#define BMP180_STANDARD_DELAY (8000UL)
#define BMP180_HIGHRES_DELAY (14000UL)
#define BMP180_ULTRAHIGHRES_DELAY (26000UL)
/** @} */
#ifdef __cplusplus
}
#endif
#endif /* BMP180_REGS_H_ */
/** @} */

129
drivers/include/bmp180.h

@ -0,0 +1,129 @@
/*
* Copyright (C) 2016 Inria
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @defgroup drivers_bmp180 BMP180
* @ingroup drivers_sensors
* @brief Device driver interface for the BMP180 sensor
* @{
*
* @file
* @brief Device driver interface for the BMP180 sensor.
*
* @author Alexandre Abadie <alexandre.abadie@inria.fr>
*/
#ifndef BMP180_H_
#define BMP180_H_
#include "periph/i2c.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @name Oversampling modes
* @{
*/
#define BMP180_ULTRALOWPOWER (0)
#define BMP180_STANDARD (1)
#define BMP180_HIGHRES (2)
#define BMP180_ULTRAHIGHRES (3)
/** @} */
/**
* @brief Calibration struct for the BMP180 sensor
*/
typedef struct {
int16_t ac1; /**< ac1 coefficient */
int16_t ac2; /**< ac2 coefficient */
int16_t ac3; /**< ac3 coefficient */
int16_t b1; /**< b1 coefficient */
int16_t b2; /**< b2 coefficient */
int16_t mb; /**< mb coefficient */
int16_t mc; /**< mc coefficient */
int16_t md; /**< md coefficient */
uint16_t ac4; /**< ac4 coefficient */
uint16_t ac5; /**< ac5 coefficient */
uint16_t ac6; /**< ac6 coefficient */
} bmp180_calibration_t;
/**
* @brief Device descriptor for the BMP180 sensor
*/
typedef struct {
i2c_t i2c_dev; /**< I2C device which is used */
bmp180_calibration_t calibration; /**< Device calibration */
uint8_t oversampling; /**< Oversampling mode */
} bmp180_t;
/**
* @brief Initialize the given BMP180 device
*
* @param[out] dev Initialized device descriptor of BMP180 device
* @param[in] i2c I2C bus the sensor is connected to
* @param[in] mode BMP180 oversampling mode
*
* @return 0 on success
* @return -1 if given I2C is not enabled in board config
*/
int bmp180_init(bmp180_t *dev, i2c_t i2c, uint8_t mode);
/**
* @brief Read temperature value from the given BMP180 device, returned in d°C
*
* @param[in] dev Device descriptor of BMP180 device to read from
* @param[out] temperature Temperature in d°C
*
* @return 0 on success
* @return -1 if device's I2C is not enabled in board config
*/
int bmp180_read_temperature(bmp180_t *dev, int32_t *temperature);
/**
* @brief Read pressure value from the given BMP180 device, returned in Pa
*
* @param[in] dev Device descriptor of BMP180 device to read from
* @param[out] pressure Pressure in Pa
*
* @return 0 on success
* @return -1 if device's I2C is not enabled in board config
*/
int bmp180_read_pressure(bmp180_t *dev, int32_t *pressure);
/**
* @brief Compute altitude, returned in m.
*
* @param[in] dev Device descriptor of BMP180 device to read from
* @param[in] pressure_0 The pressure at sea level in Pa
* @param[out] altitude Altitude in m
*
* @return 0 on success
* @return -1 if device's I2C is not enabled in board config
*/
int bmp180_altitude(bmp180_t *dev, int32_t pressure_0, int32_t *altitude);
/**
* @brief Compute pressure at sea level, returned in Pa.
*
* @param[in] dev Device descriptor of BMP180 device to read from
* @param[in] altitude Altitude in m
* @param[out] pressure_0 Pressure at sea level in Pa
*
* @return 0 on success
* @return -1 if device's I2C is not enabled in board config
*/
int bmp180_sealevel_pressure(bmp180_t *dev, int32_t altitude, int32_t *pressure_0);
#ifdef __cplusplus
}
#endif
#endif /* BMP180_H_ */
/** @} */

20
tests/driver_bmp180/Makefile

@ -0,0 +1,20 @@
APPLICATION = driver_bmp180
include ../Makefile.tests_common
FEATURES_REQUIRED = periph_i2c
USEMODULE += bmp180
USEMODULE += xtimer
USEMODULE += printf_float
# set default device parameters in case they are undefined
TEST_I2C ?= I2C_0
TEST_MEASURE_OVERSAMPLING ?= BMP180_ULTRALOWPOWER
TEST_ALTITUDE ?= 158 # altitude in Polytechnique School campus
# export parameters
CFLAGS += -DTEST_I2C=$(TEST_I2C)
CFLAGS += -DTEST_MEASURE_OVERSAMPLING=$(TEST_MEASURE_OVERSAMPLING)
CFLAGS += -DTEST_ALTITUDE=$(TEST_ALTITUDE)
include $(RIOTBASE)/Makefile.include

15
tests/driver_bmp180/Readme.md

@ -0,0 +1,15 @@
## About
This is a test application for the BMP180 Pressure and Temperature sensor.
## Usage
The application will initialize the BMP180 sensor and display its calibration
coefficients. Please see section 3.4 of the
[datasheet](https://www.adafruit.com/datasheets/BST-BMP180-DS000-09.pdf) for
more information.
After initialization, every 2 seconds, the application:
* reads the temperature (d°C);
* reads the pressure (Pa);
* computes the pressure at sea level based on the TEST_ALTITUDE variable;
* computes the altitude based on the pressure at sea level calculated above;
* those values are then printed to STDOUT.

102
tests/driver_bmp180/main.c

@ -0,0 +1,102 @@
/*
* Copyright (C) 2016 Inria
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup tests
* @{
*
* @file
* @brief Test application for the BMP180 pressure and temperature sensor
*
* @author Alexandre Abadie <alexandre.abadie@inria.fr>
*
* @}
*/
#ifndef TEST_I2C
#error "TEST_I2C not defined"
#endif
#ifndef TEST_MEASURE_OVERSAMPLING
#error "TEST_MEASURE_OVERSAMPLING not defined"
#endif
#ifndef TEST_ALTITUDE
#error "TEST_ALTITUDE not defined"
#endif
#include <stdio.h>
#include <inttypes.h>
#include "bmp180.h"
#include "xtimer.h"
#include "board.h"
#define SLEEP_2S (2 * 1000 * 1000u) /* 2 seconds delay between printf */
int main(void)
{
bmp180_t dev;
int32_t temperature, pressure, altitude, pressure_0;
int result;
puts("BMP180 test application\n");
printf("+------------Initializing------------+\n");
result = bmp180_init(&dev, TEST_I2C, TEST_MEASURE_OVERSAMPLING);
if (result == -1) {
puts("[Error] The given i2c is not enabled");
return 1;
}
else if (result == -2) {
puts("[Error] The sensor did not answer correctly on the given address");
return 1;
}
else {
printf("Initialization successful\n\n");
}
printf("+------------Calibration------------+\n");
printf("AC1: %i\n", dev.calibration.ac1);
printf("AC2: %i\n", dev.calibration.ac2);
printf("AC3: %i\n", dev.calibration.ac3);
printf("AC4: %i\n", dev.calibration.ac4);
printf("AC5: %i\n", dev.calibration.ac5);
printf("AC6: %i\n", dev.calibration.ac6);
printf("B1: %i\n", dev.calibration.b1);
printf("B2: %i\n", dev.calibration.b2);
printf("MB: %i\n", dev.calibration.mb);
printf("MC: %i\n", dev.calibration.mc);
printf("MD: %i\n", dev.calibration.md);
printf("\n+--------Starting Measurements--------+\n");
while (1) {
/* Get temperature in deci degrees celsius */
bmp180_read_temperature(&dev, &temperature);
/* Get pressure in Pa */
bmp180_read_pressure(&dev, &pressure);
/* Get pressure at sealevel in Pa */
bmp180_sealevel_pressure(&dev, (int32_t)TEST_ALTITUDE, &pressure_0);
/* Get altitude in meters */
bmp180_altitude(&dev, pressure_0, &altitude);
printf("Temperature [°C]: %.1f\n"
"Pressure [hPa]: %.2f\n"
"Pressure at see level [hPa]: %.2f\n"
"Altitude [m]: %i\n"
"\n+-------------------------------------+\n",
(double)temperature / 10.0, (double)pressure / 100.0,
(double)pressure_0 / 100.0, (int)altitude);
xtimer_usleep(SLEEP_2S);
}
return 0;
}
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