Description

The BMP180 is the function compatible successor of the BMP085, a new generation of high precision digital pressure sensors for consumer applications.

Here is a small library for work with BMP180.

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Supported devices:

• AVR microcontrollers;
• orangePi;
• raspberryPi;
• etc...

Initialize and usage

• BMP180_Init - Initialize and set the settings BMP180;

• BMP180_getCalibrationData - Reading calibration data from EEPROM BMP180;

• BMP180_readUncompTemp - Reading two-byte uncompensated temperature value from BMP180;

• BMP180_readUncompPressure - Reading three-byte uncompensated pressure value from BMP180;

• BMP180_getTemp - Calculating true temperature value [degrees Celsius];

• BMP180_getPressure - Calculating true pressure value [Pa];

• BMP180_getHeight - Calculating height over a sea level [m].

Hardware pressure sampling accuracy modes

You can use various mode. You can specify it in bmp180.h just change the value in:

#define OSS             YOUR_VALUE

Available modes you can see in the table below.

Mode	OSS	Conversion time pressure max [ms]
ultra low mode	0	4.5
standart	1	7.5
high resolution	2	13.5
ultra high resolution	3	25.5

Custom variable type

Library use stdint.h variable types.

#include <stdint.h>

// Signed custom variables types
typedef int8_t      s8;
typedef int16_t     s16;
typedef int32_t     s32;

// Unsigned custom variables types
typedef uint8_t     u8;
typedef uint16_t    u16;
typedef uint32_t    u32;

Data transmit/receive protocol

In bpm180.h file you can specify the path to the I2C library.

// Path to I2C library. You can specify your path.
#include "twi/i2c.h"

You also can specify you own I2C functions:

/**
 * I2C functions name. You can use your own functions.
 * init     - initializing I2C protocol.
 * start    - start condition
 * stop     - stop condition
 * send     - sends the one-byte value. Takes "unsigned char" value as param.
 * get      - receives the one-byte value. Pass "1" if it's the last byte
 */
#define I2C_init()      (i2c_init())
#define I2C_start()     (i2c_start_cond())
#define I2C_stop()      (i2c_stop_cond())
#define I2C_send(x)     (i2c_send_byte(x))
#define I2C_get(x)      (i2c_get_byte(x))