SHT2x.h

00001 /* 
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00007     furnished to do so, subject to the following conditions:
00008  
00009     The above copyright notice and this permission notice shall be included in
00010     all copies or substantial portions of the Software.
00011  
00012     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00013     IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00014     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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00018     THE SOFTWARE.
00019 */
00020 
00021 //=============================================================================
00022 // Port of the SHT21 example code from Sensirion
00023 // port by Serge Sozonoff
00024 //=============================================================================
00025 
00026 #include "mbed.h"
00027 #include "SHT21_I2C.h"
00028 
00029 #ifndef SHT2x_H
00030 #define SHT2x_H
00031 
00032 const int POLYNOMIAL = 0x131;  //P(x)=x^8+x^5+x^4+1 = 100110001
00033 const int ACK = 1;
00034 const int NoACK = 0;
00035 
00036 // sensor command
00037 enum etSHT2xCommand {
00038     TRIG_T_MEASUREMENT_HM    = 0xE3, // command trig. temp meas. hold master
00039     TRIG_RH_MEASUREMENT_HM   = 0xE5, // command trig. humidity meas. hold master
00040     TRIG_T_MEASUREMENT_POLL  = 0xF3, // command trig. temp meas. no hold master
00041     TRIG_RH_MEASUREMENT_POLL = 0xF5, // command trig. humidity meas. no hold master
00042     USER_REG_W               = 0xE6, // command writing user register
00043     USER_REG_R               = 0xE7, // command reading user register
00044     SOFT_RESET               = 0xFE  // command soft reset
00045 };
00046 
00047 enum etSHT2xResolution {
00048     SHT2x_RES_12_14BIT       = 0x00, // RH=12bit, T=14bit
00049     SHT2x_RES_8_12BIT        = 0x01, // RH= 8bit, T=12bit
00050     SHT2x_RES_10_13BIT       = 0x80, // RH=10bit, T=13bit
00051     SHT2x_RES_11_11BIT       = 0x81, // RH=11bit, T=11bit
00052     SHT2x_RES_MASK           = 0x81  // Mask for res. bits (7,0) in user reg.
00053 };
00054 
00055 enum etSHT2xEob {
00056     SHT2x_EOB_ON             = 0x40, // end of battery
00057     SHT2x_EOB_MASK           = 0x40, // Mask for EOB bit(6) in user reg.
00058 };
00059 
00060 enum etSHT2xHeater {
00061     SHT2x_HEATER_ON          = 0x04, // heater on
00062     SHT2x_HEATER_OFF         = 0x00, // heater off
00063     SHT2x_HEATER_MASK        = 0x04, // Mask for Heater bit(2) in user reg.
00064 };
00065 // measurement signal selection
00066 
00067 enum etSHT2xMeasureType {
00068     HUMIDITY,
00069     TEMP
00070 };
00071 
00072 enum etI2cHeader {
00073     I2C_ADR_W                = 128,   // sensor I2C address + write bit
00074     I2C_ADR_R                = 129    // sensor I2C address + read bit
00075 };
00076 
00077 // Error codes
00078 enum etError {
00079     ACK_ERROR                = 0x01,
00080     TIME_OUT_ERROR           = 0x02,
00081     CHECKSUM_ERROR           = 0x04,
00082     UNIT_ERROR               = 0x08
00083 };
00084 
00085 class SHT2x : public Base {
00086 public:
00087     SHT2x (PinName p_sda, PinName p_scl);
00088 
00089     int SHT2x_CheckCrc(int data[], int nbrOfBytes, int checksum);
00090     int SHT2x_ReadUserRegister(int *pRegisterValue);
00091     int SHT2x_WriteUserRegister(int *pRegisterValue);
00092     int SHT2x_MeasurePoll(etSHT2xMeasureType eSHT2xMeasureType, int *pMeasurand);
00093     int SHT2x_MeasureHM(etSHT2xMeasureType eSHT2xMeasureType, int *pMeasurand);
00094     int SHT2x_SoftReset();
00095     float SHT2x_CalcRH(int u16sRH);
00096     float SHT2x_CalcTemperatureC(int u16sT);
00097     int SHT2x_GetSerialNumber(int u8SerialNumber[]);
00098     float SHT2x_GetDewpoint(float h, float t);    
00099 
00100 protected:
00101     SHT_I2C i2c;    
00102     int i2cWrite(int data);
00103 
00104 private:
00105 
00106 };
00107 #endif