Kevin Gillepsie / BMP180

Device driver for the BMP180 Digital pressure and temperature sensor.

Dependents:   BMP180_example MAXWSNENV_sensors MAXWSNENV_sensors nRF51822_BMP180 ... more

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BMP180 Class Reference
Public Types | Public Member Functions

BMP180 Class Reference

Bosch BMP180 Digital Pressure Sensor. More...

#include <BMP180.h>

Public Types

enum  oversampling_t { ULTRA_LOW_POWER = 0, STANDARD = 1, HIGH_RESOLUTION = 2, ULTRA_HIGH_RESOLUTION = 3 }
 

Oversampling ratio.

More...

Public Member Functions

 BMP180 (PinName sda, PinName scl)
 BMP180 constructor.
 BMP180 (I2C *i2c)
 BMP180 constructor.
 ~BMP180 ()
 BMP180 destructor.
int init (void)
 Initialize BMP180.
int reset (void)
 Reset BMP180.
int checkId (void)
 Check ID.
int startPressure (BMP180::oversampling_t oss)
 Start pressure conversion.
int getPressure (int *pressure)
 Get pressure reading.
int startTemperature (void)
 Start temperature conversion.
int getTemperature (float *tempC)
 Get temperature reading.
int getTemperature (int16_t *tempCx10)
 Get temperature reading.

Detailed Description

Bosch BMP180 Digital Pressure Sensor. 

 #include <stdio.h>
 #include "mbed.h"
 #include "BMP180.h"

 I2C i2c(I2C_SDA, I2C_SCL);
 BMP180 bmp180(&i2c);

 int main(void) {

     while(1) {
         if (bmp180.init() != 0) {
             printf("Error communicating with BMP180\n");
         } else {
             printf("Initialized BMP180\n");
             break;
         }
         wait(1);
     }

     while(1) {
         bmp180.startTemperature();
         wait_ms(5);     // Wait for conversion to complete
         float temp;
         if(bmp180.getTemperature(&temp) != 0) {
             printf("Error getting temperature\n");
             continue;
         }

         bmp180.startPressure(BMP180::ULTRA_LOW_POWER);
         wait_ms(10);    // Wait for conversion to complete
         int pressure;
         if(bmp180.getPressure(&pressure) != 0) {
             printf("Error getting pressure\n");
             continue;
         }

         printf("Pressure = %d Pa Temperature = %f C\n", pressure, temp);
         wait(1);
     }
 }

Definition at line 85 of file BMP180.h.

Member Enumeration Documentation

enum oversampling_t

Oversampling ratio.

Dictates how many pressure samples to take. Conversion time varies depending on the number of samples taken. Refer to data sheet for timing specifications.

Enumerator:
ULTRA_LOW_POWER 

1 pressure sample

STANDARD 

2 pressure samples

HIGH_RESOLUTION 

4 pressure samples

ULTRA_HIGH_RESOLUTION 

8 pressure samples

Definition at line 96 of file BMP180.h.

Constructor & Destructor Documentation

BMP180 ( PinName  sda,
PinName  scl 
)

BMP180 constructor.

Parameters:
sdambed pin to use for SDA line of I2C interface.
sclmbed pin to use for SCL line of I2C interface.

Definition at line 52 of file BMP180.cpp.

BMP180 ( I2C *  i2c )

BMP180 constructor.

Parameters:
i2cI2C object to use.

Definition at line 61 of file BMP180.cpp.

~BMP180 (  )

BMP180 destructor.

Definition at line 68 of file BMP180.cpp.

Member Function Documentation

int checkId ( void   )

Check ID.

Checks the device ID, should be 0x55 on reset.

Returns:
0 if no errors, -1 if error.

Definition at line 121 of file BMP180.cpp.

int getPressure ( int *  pressure )

Get pressure reading.

Calculates the pressure using the data calibration data and formula. Pressure is reported in Pascals.

Note:
This function should be called after calling startPressure(). Refer to the data sheet for the timing requirements. Calling this function too soon can result in oversampling.
Parameters:
pressurePointer to store pressure reading.
Returns:
0 if no errors, -1 if error.

Definition at line 159 of file BMP180.cpp.

int getTemperature ( int16_t *  tempCx10 )

Get temperature reading.

Calculates the temperature using the data calibration data and formula. Temperature is reported in 1/10ths degrees Celcius.

Note:
This function should be called after calling startTemperature(). Refer to the data sheet for the timing requirements. Calling this function too soon can result in oversampling.
Parameters:
tempCx10Pointer to store temperature reading.
Returns:
0 if no errors, -1 if error.

Definition at line 244 of file BMP180.cpp.

int getTemperature ( float *  tempC )

Get temperature reading.

Calculates the temperature using the data calibration data and formula. Temperature is reported in degrees Celcius.

Note:
This function should be called after calling startTemperature(). Refer to the data sheet for the timing requirements. Calling this function too soon can result in oversampling.
Parameters:
tempCPointer to store temperature reading.
Returns:
0 if no errors, -1 if error.

Definition at line 217 of file BMP180.cpp.

int init ( void   )

Initialize BMP180.

Gets the device ID and saves the calibration values.

Returns:
0 if no errors, -1 if error.

Definition at line 76 of file BMP180.cpp.

int reset ( void   )

Reset BMP180.

Performs a soft reset of the device. Same sequence as power on reset.

Returns:
0 if no errors, -1 if error.

Definition at line 103 of file BMP180.cpp.

int startPressure ( BMP180::oversampling_t  oss )

Start pressure conversion.

Initiates the pressure conversion sequence. Refer to data sheet for timing specifications.

Parameters:
ossNumber of samples to take.
Returns:
0 if no errors, -1 if error.

Definition at line 143 of file BMP180.cpp.

int startTemperature ( void   )

Start temperature conversion.

Initiates the temperature conversion sequence. Refer to data sheet for timing specifications.

Returns:
0 if no errors, -1 if error.

Definition at line 205 of file BMP180.cpp.

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