BMP280.h

00001 /*******************************************************************************
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00003 *
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00009 * Software is furnished to do so, subject to the following conditions:
00010 *
00011 * The above copyright notice and this permission notice shall be included
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00013 *
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00021 *
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00024 * Products, Inc. Branding Policy.
00025 *
00026 * The mere transfer of this software does not imply any licenses
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00031 *******************************************************************************/
00032 /**
00033  * Bosch BMP280 Digital Pressure Sensor
00034  *
00035  */
00036 
00037 #ifndef BMP280_H_
00038 #define BMP280_H_
00039 
00040 #include "mbed.h"
00041 
00042 /**
00043  * @brief Bosch BMP280 Digital Pressure Sensor
00044  */
00045 class BMP280 {
00046 
00047 public:
00048 
00049   typedef enum {  ///< BMP280 Register addresses
00050     
00051     BMP280_READID     = 0x58,
00052     BMP280_TEMP_XLSB  = 0xFC,
00053     BMP280_TEMP_LSB   = 0xFB,
00054     BMP280_TEMP_MSB   = 0xFA,
00055     BMP280_PRESS_XLSB = 0xF9,
00056     BMP280_PRESS_LSB  = 0xF8,
00057     BMP280_PRESS_MSB  = 0xF7,
00058     BMP280_CONFIG     = 0xF5,
00059     BMP280_CTRL_MEAS  = 0xF4,
00060     BMP280_STATUS     = 0xF3,
00061     BMP280_RESET      = 0xE0,
00062     BMP280_ID         = 0xD0,
00063     ///< calib25-calib00: 0xA1-0x88
00064     BMP280_CALIB25    = 0xA1, ///< Beginning address
00065     BMP280_CALIB00    = 0x88, ///< Ending address
00066 
00067     BMP280_REGISTER_CHIPID       = 0xD0,
00068     BMP280_REGISTER_VERSION      = 0xD1,
00069     BMP280_REGISTER_SOFTRESET    = 0xE0,
00070     BMP280_REGISTER_CAL26        = 0xE1, // R calibration stored in 0xE1-0xF0
00071     BMP280_REGISTER_CONTROL      = 0xF4,
00072     BMP280_REGISTER_CONFIG       = 0xF5,
00073     BMP280_REGISTER_PRESSUREDATA = 0xF7,
00074     BMP280_REGISTER_TEMPDATA     = 0xFA,    
00075         
00076   } BMP280_REG_map_t ;
00077     
00078 
00079   /**
00080    * @brief BMP280 constructor.
00081    * @param sda mbed pin to use for SDA line of I2C interface.
00082    * @param scl mbed pin to use for SCL line of I2C interface.
00083    * @param slaveAddress Slave Address of the device.
00084    */
00085   BMP280(PinName sda, PinName scl, int slaveAddress);
00086 
00087   /**
00088    * @brief BMP280 constructor.
00089    * @param i2c I2C object to use.
00090    * @param slaveAddress Slave Address of the device.
00091    */
00092   BMP280(I2C *i2c, int slaveAddress);
00093 
00094   char loggingEnabled;
00095   char loggingSampleRate;
00096 
00097   /**
00098   * @brief Write a device register
00099   */
00100   int writeReg(char reg, char value);
00101   /**
00102   * @brief Read a device register
00103   */
00104   int readReg(char reg, char *value);
00105   
00106   ///< @brief CONFIG_REG (0xF5)
00107   typedef union bmp280_config_reg {
00108     char all;
00109     struct {
00110       char spi3w_en : 1;
00111       char reserved : 1;
00112       char filter   : 3;
00113       char t_sb     : 3;
00114     } bit;
00115   } bmp280_config_t;
00116 
00117   ///< @brief CTRL_MEAS (0xF4)
00118   typedef union bmp280_ctrl_meas {
00119     char all;
00120     struct {
00121       char mode   : 2;
00122       char osrs_p : 3;
00123       char osrs_t : 3;
00124     } bit;
00125   } bmp280_ctrl_meas_t;
00126 
00127   ///< @brief STATUS (0xF3)
00128   typedef union bmp280_status {
00129     char all;
00130     struct {
00131       char im_update : 1;
00132       char reserved1 : 2;
00133       char measuring : 1;
00134       char reserved2 : 4;
00135     } bit;
00136   } bmp280_status_t;
00137 
00138 
00139   ///< @brief  RESET (0xE0)
00140   char bmp280_reset;
00141 
00142   ///< @brief  ID (0xD0)
00143   char bmp280_id;
00144 
00145   typedef enum {
00146     SKIPPED_P = 0,
00147     OVERSAMPLING_X1_P  = 1,
00148     OVERSAMPLING_X2_P  = 2,
00149     OVERSAMPLING_X4_P  = 3,
00150     OVERSAMPLING_X8_P  = 4,
00151     OVERSAMPLING_X16_P = 5
00152   } bmp280_osrs_P_t;
00153 
00154   typedef enum {
00155     SKIPPED_T = 0,
00156     OVERSAMPLING_X1_T  = 1,
00157     OVERSAMPLING_X2_T  = 2,
00158     OVERSAMPLING_X4_T  = 3,
00159     OVERSAMPLING_X8_T  = 4,
00160     OVERSAMPLING_X16_T = 5
00161   } bmp280_osrs_T_t;
00162 
00163   typedef enum {
00164     FILT_OFF = 1,
00165     FILT_2   = 2,
00166     FILT_3   = 4,
00167     FILT_4   = 8,
00168     FILT_5   = 16
00169   } bmp280_FILT_t;
00170 
00171   typedef enum {
00172     SLEEP_MODE  = 0,
00173     FORCED_MODE = 1,
00174     NORMAL_MODE = 3
00175   } bmp280_MODE_t;
00176 
00177   typedef enum {
00178     T_0_5  = 0,
00179     T_62_5 = 1,
00180     T_125  = 2,
00181     T_250  = 3,
00182     T_500  = 4,
00183     T_1000 = 5,
00184     T_2000 = 6,
00185     T_4000 = 7
00186   } bmp280_TSB_t;
00187 
00188   ///< @brief calib25... calib00  (0xA1...0x88)
00189   char bmp280_Calib[26];
00190 
00191   uint16_t dig_T1; ///< Unique temp coeffs. read from the chip
00192   int16_t  dig_T2;
00193   int16_t  dig_T3;
00194 
00195   uint16_t dig_P1; ///< Unique Press. coeffs. read from the chip
00196   int16_t dig_P2;
00197   int16_t dig_P3;
00198   int16_t dig_P4;
00199   int16_t dig_P5;
00200   int16_t dig_P6;
00201   int16_t dig_P7;
00202   int16_t dig_P8;
00203   int16_t dig_P9;
00204                  
00205   int32_t t_fine; ///< This is calculated int the temperature to be used by the
00206                   ///< pressure
00207 
00208   int32_t bmp280_rawPress;
00209   int32_t bmp280_rawTemp;
00210 
00211   float Temp_degC;
00212   float Press_Pa; 
00213 
00214   /**
00215    * @brief BMP280 constructor.
00216    * @param sda mbed pin to use for SDA line of I2C interface.
00217    * @param scl mbed pin to use for SCL line of I2C interface.
00218    */
00219   BMP280(PinName sda, PinName scl);
00220 
00221   /**
00222    * @brief BMP280 constructor.
00223    * @param i2c I2C object to use.
00224    */
00225   BMP280(I2C *i2c);
00226 
00227   /**
00228    * @brief BMP280 destructor.
00229    */
00230   ~BMP280(void);
00231 
00232   // Function Prototypes
00233 
00234   /**
00235   * @brief This initializes the BMP280 
00236   * @brief The BMP280 has 2 modes. FORCED mode and  NORMAL mode.  FORCED Mode gives more
00237   * @brief control to the processor as the processor sends out the Mode to initiate a conversion
00238   * @brief and a data is sent out then. NORMAL mode is initialized once and it just runs and sends
00239   * @brief out data at a programmed timed interval.  (In this example the main() will set this to Normal
00240   * @brief function)
00241   * @param Osrs_p- Pressure oversampling
00242   * @param Osrs_t-  Temperature oversampling
00243   * @param Filter-  Filter Settings
00244   * @param Mode-    Power Modes
00245   * @param T_sb-    Standby time (used with Normal mode)
00246   * @param dig_T1, dig_T2, dig_T3-  Coeffs used for temp conversion - GLOBAL variables (output)
00247   * @param dig_P1, ....  , dig_P9-  Coeffs used for press conversion - GLOBAL variables (output)
00248   * @returns  0-if no error.  A non-zero value indicates an error.
00249   */
00250   int init(bmp280_osrs_P_t Osrs_p, bmp280_osrs_T_t Osrs_t, bmp280_FILT_t Filter,
00251            bmp280_MODE_t Mode, bmp280_TSB_t T_sb);
00252 
00253   /**
00254    * @brief The BMP280 has 2 modes. FORCED mode and  NORMAL mode.  FORCED Mode
00255    * gives more
00256    * @brief control to the processor as the processor sends out the Mode to
00257    * initiate a conversion
00258    * @brief and a data is sent out then. NORMAL mode is initialized once and it
00259    * just runs and sends
00260    * @brief out data at a programmed timed interval.  (In this example the
00261    * main() will set this to Normal
00262    * @brief function)
00263    * @param *Temp_degC - Pointer to temperature (result in deg C)
00264    * @param *Press_Pa - Pointer to pressure (resul in Pascal)
00265    * @returns 0-if no error.  A non-zero value indicates an error.
00266    */
00267   int ReadCompData(float *Temp_degC, float *Press_Pa);
00268 
00269   /**
00270    *  @brief This function allows writing to a register.
00271    *  @param reg- Address of the register to write to
00272    *  @param value- Data written to the register
00273    *  @returns 0-if no error.  A non-zero value indicates an error.
00274    */
00275   int reg_write(BMP280_REG_map_t  reg, char value);
00276 
00277   /**
00278    * @brief This function allows writing to a register.
00279    * @params reg- Address of the register to read from (input)
00280    * @params *value- Pointer to the value read from the register (output)
00281    * @returns 0-if no error.  A non-zero value indicates an error.
00282    */
00283   int reg_read(BMP280_REG_map_t  reg, char *value, char number);
00284 
00285   /**
00286    * @brief Performs a soft reset on the BMP280
00287    * @param none
00288    * @returns none
00289    */
00290   void Reset(void);
00291 
00292   /**
00293    * @brief Detects if the BMP280 is present
00294    * @param none
00295    * @returns 1 for found, 0 for not found, -1 for comm error
00296    */
00297   int Detect(void);
00298 
00299   /**
00300    * @brief Performs calculations on the raw temperature data to convert to
00301    * @brief temperature in deg C, based on Bosch's algorithm
00302    * @param Raw Temp ADC value, Global dig_T1, dig_T2, dig_T3
00303    * @returns The Temperature in deg C
00304    */
00305   float compensate_T_float(int32_t adc_T); // returned value Deg C.
00306 
00307   /**
00308     * @brief Performs calculations on the raw pressure data to convert to
00309     * @brief pressure in Pascal, based on Bosch's algorithm
00310     * @param adc_P Raw Press ADC value, Global dig_P1, dig_P2,..., dig_P9
00311     * @returns The Pressure in Pascals
00312     */
00313   float compensate_P_float(int32_t adc_P); //  returned value Pascal.
00314 
00315   /**
00316    * @brief Puts the BMP280 in low power Sleep mode
00317    * @param none
00318    * @returns 0 if no errors, -1 if error.
00319    */
00320   int Sleep(void);
00321 
00322   /**
00323    * @brief This reads the raw BMP280 data
00324    * @param *bmp280_rawData- array of raw output data
00325    * @returns 0-if no error.  A non-zero value indicates an error.
00326    *
00327    */
00328   int ReadCompDataRaw(char *bmp280_rawData);
00329   /**
00330    * @brief This reads the raw BMP280 data uses the Bosch algorithm to get the
00331    * data
00332    * @brief in float, then the float gets converted to an String
00333    * @param *bmp280_rawData- array of raw output data
00334    * @returns 0-if no error.  A non-zero value indicates an error.
00335    *
00336    */
00337   int ReadCompDataRaw2(char *bmp280_rawData);
00338   /**
00339    * @brief This converts the raw BMP280 data to couble based on Bosch's
00340    * algorithm
00341    * @param *bmp280_rawData- array of raw input data
00342    * @param *Temp_degC- pointer to output, Temp value in deg C
00343    * @param *Press_Pa- pointer to output, Press value in Pascals
00344    * @returns 0-if no error.  A non-zero value indicates an error.
00345    *
00346    */
00347   void ToFloat(char *bmp280_rawData, float *Temp_degC, float *Press_Pa);
00348   /**
00349    * @brief converts to Farenhite from Centigrade
00350    * @param temperature in Centigrade
00351    * @returns temperature value in Farenhite
00352    */
00353   float ToFahrenheit(float temperature);
00354 
00355   /**
00356    * @brief Reads a unique ID from the register
00357    * @param none
00358    * @returns The correct id value which is 0x58
00359    */
00360   int ReadId(void);
00361 
00362 private:
00363   /**
00364    * @brief I2C pointer
00365    */
00366   I2C *i2c;
00367   /**
00368    * @brief Is this object the owner of the I2C object
00369    */
00370   bool isOwner;
00371   /**
00372    * @brief Device slave address
00373    */
00374   int slaveAddress;
00375 };
00376 
00377 #endif // BMP280_H_
00378