sht11.h

00001 /**
00002 @file sht11.h
00003 
00004 @brief Header file containing member functions and variables
00005 
00006 */
00007 
00008 #ifndef __SHT11_H__
00009 #define __SHT11_H__
00010 
00011 #include "mbed.h"
00012 
00013 /** 
00014 @brief Simple library for interfacing with Sensirion SHT11 
00015 
00016 @brief Revision 1.0
00017 
00018 @author Tim Meese
00019 @date   January 201
00020  *
00021  * Example:
00022  * @code
00023  
00024  #include "mbed.h"
00025  #include "sht11.h"
00026  
00027 //        clk, dat
00028  SHT11 sht(p7, p8);
00029  
00030  int main() {
00031     
00032    // initialise display 
00033   lcd.init();
00034   // print a string in top-left corner
00035   lcd.printString("Hello, World!",0,0);
00036   // move cursor to 4th row
00037   lcd.setXYAddress(0,3);
00038   // print character
00039   lcd.printChar('X');
00040     
00041   while(1);
00042  }
00043   
00044  * @endcode
00045  */
00046  
00047 class SHT11
00048 {
00049 
00050 private:
00051     DigitalOut* clk;
00052     DigitalInOut* data;
00053     float lastTemperature;
00054     float lastHumidity;
00055 
00056     void sendTransmissionStart();
00057     void connectionReset();
00058     void softReset();
00059     int writeByte(unsigned char writeData);
00060     int readByte(unsigned char *pReadData, bool doAck);
00061     int readStatus(unsigned char *pRetStatus);
00062     int writeStatus(unsigned char writeValue);
00063     int measureTemp(unsigned short *pRetTempRaw);
00064     int measureHumid(unsigned short *pRetHumidRaw);
00065     float convertTempCelsius(unsigned short rawTempIn);
00066     float convertTempFahrenheit(unsigned short rawTempIn);
00067     float convertHumid(unsigned short rawHumidIn, unsigned short rawTempIn);
00068 
00069 public:
00070     /** Create a SHT11 object connected to the specified pins
00071     *
00072     * @param clkPin  Pin connected to clk
00073     * @param dataPin Pin connected to data
00074     * 
00075     */
00076     SHT11(PinName clkPin, PinName dataPin);
00077     
00078     /** Initialise SHT11
00079     *
00080     */
00081     void init();
00082     int getTemperature(float * pRetTemperature);
00083     int getTempHumid(float * pRetTemperature, float * pRetHumidity);
00084 };
00085 
00086 #endif /* __SHT11_H__ */