HTU21D.h

00001 /**
00002  * @author Alan Lai & Nelson Diaz
00003  * The Georgia Institute of Technology 
00004  * ECE 4180 Embeded Systems
00005  * Professor Hamblen
00006  * 03/28/2014
00007  * 
00008  * @section LICENSE
00009  * ----------------------------------------------------------------------------
00010  * "THE BEER-WARE LICENSE" (Revision 42):
00011  * <alanhlai91@gmail.com> wrote this file. As long as you retain this notice you
00012  * can do whatever you want with this stuff. If we meet some day, and you think
00013  * this stuff is worth it, you can buy me a beer in return.
00014  * ----------------------------------------------------------------------------
00015  *
00016  *
00017  * @section DESCRIPTION
00018  *
00019  * Honeywell HTU21D Humidity and Temperature sensor.
00020  *
00021  * Datasheet, specs, and information:
00022  *
00023  * https://www.sparkfun.com/products/12064
00024  */
00025 
00026 #ifndef HTU21D_H
00027 #define HTU21D_H
00028 
00029 /**
00030  * Includes
00031  */
00032 #include "mbed.h"
00033 
00034 /**
00035  * Defines
00036  */
00037 // Acquired from Datasheet.
00038 
00039 #define HTU21D_I2C_ADDRESS  0x40 
00040 #define TRIGGER_TEMP_MEASURE  0xE3
00041 #define TRIGGER_HUMD_MEASURE  0xE5
00042 
00043 
00044 //Commands.
00045 #define HTU21D_EEPROM_WRITE 0x80
00046 #define HTU21D_EEPROM_READ  0x81
00047 
00048 
00049 /**
00050  * Honeywell HTU21D digital humidity and temperature sensor.
00051  */
00052 class HTU21D {
00053 
00054 public:
00055 
00056     /**
00057      * Constructor.
00058      *
00059      * @param sda mbed pin to use for SDA line of I2C interface.
00060      * @param scl mbed pin to use for SCL line of I2C interface.
00061      */
00062     HTU21D(PinName sda, PinName scl);
00063 
00064 
00065     //Samples the temperature, input void, outputs an int in celcius.
00066     int sample_ctemp(void);
00067     
00068        //Samples the temperature, input void, outputs an int in fahrenheit.
00069     int sample_ftemp(void);
00070     
00071        //Samples the temperature, input void, outputs an int in kelvin.
00072     int sample_ktemp(void);
00073     
00074     //Samples the humidity, input void, outputs and int.
00075     int sample_humid(void);
00076 
00077    
00078 
00079 private:
00080 
00081     I2C* i2c_;
00082 
00083     /**
00084      * Write to EEPROM or RAM on the device.
00085      *
00086      * @param EepromOrRam 0x80 -> Writing to EEPROM
00087      * @param address Address to write to.
00088      * @param data Data to write.
00089      */
00090     void write(int EepromOrRam, int address, int data);
00091 
00092     /**
00093      * Read EEPROM or RAM on the device.
00094      *
00095      * @param EepromOrRam 0x81 -> Reading from EEPROM
00096      * @param address Address to read from.
00097      * @return The contents of the memory address.
00098      */
00099     int read(int EepromOrRam, int address);
00100 
00101 };
00102 
00103 #endif /* HTU21D_H */