BMP180.h

00001 /*******************************************************************************
00002  * Copyright (C) 2015 Maxim Integrated Products, Inc., All Rights Reserved.
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a
00005  * copy of this software and associated documentation files (the "Software"),
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00010  *
00011  * The above copyright notice and this permission notice shall be included
00012  * in all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
00015  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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00018  * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
00019  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
00020  * OTHER DEALINGS IN THE SOFTWARE.
00021  *
00022  * Except as contained in this notice, the name of Maxim Integrated
00023  * Products, Inc. shall not be used except as stated in the Maxim Integrated
00024  * Products, Inc. Branding Policy.
00025  *
00026  * The mere transfer of this software does not imply any licenses
00027  * of trade secrets, proprietary technology, copyrights, patents,
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00032  */
00033 
00034 #ifndef _BMP180_H_
00035 #define _BMP180_H_
00036 
00037 #include "mbed.h"
00038 
00039 /**
00040  * Bosch BMP180 Digital Pressure Sensor
00041  *
00042  * @code
00043  * #include <stdio.h>
00044  * #include "mbed.h"
00045  * #include "BMP180.h"
00046  *
00047  * I2C i2c(I2C_SDA, I2C_SCL);
00048  * BMP180 bmp180(&i2c);
00049  *
00050  * int main(void) {
00051  *
00052  *     while(1) {
00053  *         if (bmp180.init() != 0) {
00054  *             printf("Error communicating with BMP180\n");
00055  *         } else {
00056  *             printf("Initialized BMP180\n");
00057  *             break;
00058  *         }
00059  *         wait(1);
00060  *     }
00061  *
00062  *     while(1) {
00063  *         bmp180.startTemperature();
00064  *         wait_ms(5);     // Wait for conversion to complete
00065  *         float temp;
00066  *         if(bmp180.getTemperature(&temp) != 0) {
00067  *             printf("Error getting temperature\n");
00068  *             continue;
00069  *         }
00070  *
00071  *         bmp180.startPressure(BMP180::ULTRA_LOW_POWER);
00072  *         wait_ms(10);    // Wait for conversion to complete
00073  *         int pressure;
00074  *         if(bmp180.getPressure(&pressure) != 0) {
00075  *             printf("Error getting pressure\n");
00076  *             continue;
00077  *         }
00078  *
00079  *         printf("Pressure = %d Pa Temperature = %f C\n", pressure, temp);
00080  *         wait(1);
00081  *     }
00082  * }
00083  * @endcode
00084  */
00085 class BMP180
00086 {
00087 
00088 public:
00089 
00090     /**
00091      * @brief   Oversampling ratio.
00092      * @details Dictates how many pressure samples to take. Conversion time varies
00093      *          depending on the number of samples taken. Refer to data sheet
00094      *          for timing specifications.
00095      */
00096     typedef enum {
00097         ULTRA_LOW_POWER       = 0, ///< 1 pressure sample
00098         STANDARD              = 1, ///< 2 pressure samples
00099         HIGH_RESOLUTION       = 2, ///< 4 pressure samples
00100         ULTRA_HIGH_RESOLUTION = 3, ///< 8 pressure samples
00101     } oversampling_t;
00102 
00103     /**
00104      * BMP180 constructor.
00105      *
00106      * @param sda mbed pin to use for SDA line of I2C interface.
00107      * @param scl mbed pin to use for SCL line of I2C interface.
00108      */
00109     BMP180(PinName sda, PinName scl);
00110 
00111     /**
00112      * BMP180 constructor.
00113      *
00114      * @param i2c I2C object to use.
00115      */
00116     BMP180(I2C *i2c);
00117 
00118     /**
00119      * BMP180 destructor.
00120      */
00121     ~BMP180();
00122 
00123     /**
00124      * @brief   Initialize BMP180.
00125      * @details Gets the device ID and saves the calibration values.
00126      * @returns 0 if no errors, -1 if error.
00127      */
00128     int init(void);
00129 
00130     /**
00131      * @brief   Reset BMP180.
00132      * @details Performs a soft reset of the device. Same sequence as power on reset.
00133      * @returns 0 if no errors, -1 if error.
00134      */
00135     int reset(void);
00136 
00137     /**
00138      * @brief   Check ID.
00139      * @details Checks the device ID, should be 0x55 on reset.
00140      * @returns 0 if no errors, -1 if error.
00141      */
00142     int checkId(void);
00143 
00144     /**
00145      * @brief   Start pressure conversion.
00146      * @details Initiates the pressure conversion sequence. Refer to data sheet
00147      *          for timing specifications.
00148      *
00149      * @param   oss Number of samples to take.
00150      * @returns 0 if no errors, -1 if error.
00151      */
00152     int startPressure(BMP180::oversampling_t oss);
00153 
00154     /**
00155      * @brief   Get pressure reading.
00156      * @details Calculates the pressure using the data calibration data and formula.
00157      *          Pressure is reported in Pascals.
00158      * @note    This function should be called after calling startPressure().
00159      *          Refer to the data sheet for the timing requirements. Calling this
00160      *          function too soon can result in oversampling.
00161      *
00162      * @param   pressure Pointer to store pressure reading.
00163      * @returns 0 if no errors, -1 if error.
00164      */
00165     int getPressure(int *pressure);
00166 
00167     /**
00168      * @brief   Start temperature conversion.
00169      * @details Initiates the temperature conversion sequence. Refer to data
00170      *          sheet for timing specifications.
00171      * @returns 0 if no errors, -1 if error.
00172      */
00173     int startTemperature(void);
00174 
00175     /**
00176      * @brief   Get temperature reading.
00177      * @details Calculates the temperature using the data calibration data and formula.
00178      *          Temperature is reported in degrees Celcius.
00179      *
00180      * @note    This function should be called after calling startTemperature().
00181      *          Refer to the data sheet for the timing requirements. Calling this
00182      *          function too soon can result in oversampling.
00183      *
00184      * @param   tempC Pointer to store temperature reading.
00185      * @returns 0 if no errors, -1 if error.
00186      */
00187     int getTemperature(float *tempC);
00188 
00189     /**
00190      * @brief   Get temperature reading.
00191      * @details Calculates the temperature using the data calibration data and formula.
00192      *          Temperature is reported in 1/10ths degrees Celcius.
00193      *
00194      * @note    This function should be called after calling startTemperature().
00195      *          Refer to the data sheet for the timing requirements. Calling this
00196      *          function too soon can result in oversampling.
00197      *
00198      * @param   tempCx10 Pointer to store temperature reading.
00199      * @returns 0 if no errors, -1 if error.
00200      */
00201     int getTemperature(int16_t *tempCx10);
00202 
00203 private:
00204 
00205     typedef union {
00206         uint16_t value[11];
00207         struct {
00208             int16_t ac1;
00209             int16_t ac2;
00210             int16_t ac3;
00211             uint16_t ac4;
00212             uint16_t ac5;
00213             uint16_t ac6;
00214             int16_t b1;
00215             int16_t b2;
00216             int16_t mb;
00217             int16_t mc;
00218             int16_t md;
00219         };
00220     } calibration_t;
00221 
00222     I2C *i2c_;
00223     bool i2c_owner;
00224 
00225     BMP180::calibration_t calib;
00226     int32_t b5;
00227     BMP180::oversampling_t oss_;
00228 };
00229 
00230 #endif /* _BMP180_H_ */