Diff: BMP180.h

Revision:

0:a5f38f79c701

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/BMP180.h	Sun May 10 21:46:51 2015 +0000
@@ -0,0 +1,132 @@
+/**
+@file BMP180.h
+
+@brief Header file containing member functions and variables
+
+*/
+
+#ifndef BMP180_H
+#define BMP180_H
+
+// BMP180 address (5.2 datasheet)
+#define BMP180_W_ADDRESS   0xEE
+#define BMP180_R_ADDRESS   0xEF
+// Register Descriptions (4 datasheet)
+#define ID_REG          0xD0
+#define EEPROM_REG_ADD  0xAA
+
+// uncomment line below to run in debug mode and compare to datasheet values
+//#define DEBUG
+
+// Struct to store calibration data
+typedef struct Calibration Calibration;
+struct Calibration {
+    int16_t AC1;
+    int16_t AC2;
+    int16_t AC3;
+    uint16_t AC4;
+    uint16_t AC5;
+    uint16_t AC6;
+    int16_t B1;
+    int16_t B2;
+    int16_t MB;
+    int16_t MC;
+    int16_t MD;
+};
+
+// Struct for measurement (temperature and pressure)
+typedef struct Measurement Measurement;
+struct Measurement {
+    float temperature;
+    float pressure;
+};
+
+#include "mbed.h"
+
+/**
+@brief Library for interfacing with BMP180 Barometer
+@see https://www.bosch-sensortec.com/en/homepage/products_3/environmental_sensors_1/bmp180_1/bmp180
+@see https://www.sparkfun.com/products/11824
+
+@brief Revision 1.0
+
+@author Craig A. Evans
+@date   March 2015
+ *
+ * Example:
+ * @code
+
+#include "mbed.h"
+#include "BMP180.h"
+
+BMP180 bmp180(p28,p27);   // SDA, SCL
+Serial serial(USBTX,USBRX);
+
+int main() {
+
+    // initiliase barometer
+    bmp180.init();
+
+    Measurement measurement;  // measurement structure declared in BMP180 class
+
+    while(1) {
+
+        // read values (T in Celsius and P in mb) and print over serial port
+        measurement = bmp180.readValues();
+        serial.printf("T = %.2f C P = %.2f mb\n",measurement.temperature,measurement.pressure);
+        wait(1.0);  // short delau until next reading
+
+    }
+}
+
+
+ * @endcode
+ */
+
+class BMP180
+{
+public:
+
+    /** Create a BMP180 object connected to the specified I2C pins
+    *
+    * @param sdaPin - mbed SDA pin
+    * @param sclPin - mbed SCL pin
+    *
+    */
+    BMP180(PinName sdaPin, PinName sclPin);
+
+    /** Initialise barometer - reads factory calibration data
+    *
+    */
+    void init();
+
+    /** Read current temperature and pressure values
+    *
+    * @returns Measurement structure. Memebers are temperature in C (float) and pressure in mbar (float)
+    *
+    */
+    Measurement readValues();
+
+private:
+    void error();
+    int32_t readUncompensatedTemperatureValue();
+    int32_t readUncompensatedPressureValue();
+    int32_t calcTrueTemperature(int32_t UT);
+    int32_t calcTruePressure(int32_t UP);
+    void sendByteToRegister(char byte,char reg);
+    char readByteFromRegister(char reg);
+    void readBytesFromRegister(char reg,int numberOfBytes,char bytes[]);
+    void readCalibrationData();
+
+
+private:  // private variables
+    I2C* i2c;
+    BusOut* leds;
+    Calibration calibration;  // variable to store calibration data
+    // variables for calculation
+    int32_t X1,X2,X3,B3,B5,B6;
+    uint32_t B4,B7;
+    int oss;  // oversampling setting
+};
+
+#endif