BMP085.h

00001 /*
00002  * @file BMP085.h
00003  * @author Tyler Weaver
00004  * @author Kory Hill
00005  *
00006  * @section LICENSE
00007  *
00008  * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
00009  * and associated documentation files (the "Software"), to deal in the Software without restriction,
00010  * including without limitation the rights to use, copy, modify, merge, publish, distribute,
00011  * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
00012  * furnished to do so, subject to the following conditions:
00013  *
00014  * The above copyright notice and this permission notice shall be included in all copies or
00015  * substantial portions of the Software.
00016  *
00017  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
00018  * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00019  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
00020  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00021  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00022  *
00023  * @section DESCRIPTION
00024  *
00025  * BMP085 I2C Temperature/Pressure/Altitude Sensor
00026  *
00027  * Max sample rate: 128 samples/second (temperature at 1/second)
00028  *
00029  * Datasheet:
00030  *
00031  * http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Sensors/Pressure/BST-BMP085-DS000-06.pdf
00032  */
00033 
00034 #ifndef BMP085_H
00035 #define BMP085_H
00036 
00037 #include "mbed.h"
00038 
00039 class BMP085
00040 {
00041 public:
00042     /**
00043      * The I2C address that can be passed directly to i2c object (it's already shifted 1 bit left).
00044      */
00045     static const int16_t I2C_ADDRESS = 0xEE; //address of bmp085
00046 
00047     /**
00048      * Constructor.
00049      *
00050      * Calls init function
00051      *
00052      * @param sda - mbed pin to use for the SDA I2C line.
00053      * @param scl - mbed pin to use for the SCL I2C line.
00054      */
00055     BMP085(PinName sda, PinName scl);
00056 
00057     /**
00058     * Constructor that accepts external i2c interface object.
00059     *
00060     * Calls init function
00061     *
00062     * @param i2c The I2C interface object to use.
00063     */
00064     BMP085(I2C &i2c) : i2c_(i2c) {
00065         init();
00066     }
00067     
00068     ~BMP085();
00069     
00070     /**
00071     * Sets the oss rate variables
00072     * Acceptable values  = 1,2,4,8
00073     *
00074     *@param oss the number of over sampling
00075     */
00076     void set_oss(int oss);
00077 
00078     int32_t get_temperature();
00079     int32_t get_pressure();
00080     double get_altitude_m();
00081     double get_altitude_ft();
00082     
00083     /**
00084     * Initialize sensor and get calibration values
00085     */
00086     void init();
00087     
00088     void display_cal_param(Serial *pc);
00089 
00090 protected:
00091     
00092 
00093 private:
00094 
00095     I2C &i2c_;
00096 
00097     /**
00098      * The raw buffer for allocating I2C object in its own without heap memory.
00099      */
00100     char i2cRaw[sizeof(I2C)];
00101 
00102     // calculation variables
00103     int16_t AC1, AC2, AC3, B1, B2, MB, MC, MD;
00104     uint16_t  AC4, AC5, AC6;
00105     
00106     int32_t UT,UP; // uncompressed temperature and pressure value
00107     
00108     int32_t X1, X2, B5, temperature; // get_temperature variables
00109     
00110     int32_t B6, B3, X3, pressure; // get_pressure variables
00111     uint32_t B4, B7;
00112     
00113     double altitude;
00114     
00115     // setting variables
00116     char oss_bit_;
00117     char oversampling_setting_;
00118     float conversion_time_;
00119 
00120     void get_cal_param(); // get calibration parameters
00121     void get_ut(); // get uncompressed temperature
00122     void get_up(); // get uncompressed pressure
00123     void write_char(char,char);
00124     int16_t read_int16(char);
00125     uint16_t read_uint16(char);
00126     void read_multiple(char, char*, int);
00127 };
00128 
00129 #endif