HTS221.h

00001 /* ===================================================================
00002 Copyright © 2016, AVNET Inc.  
00003 
00004 Licensed under the Apache License, Version 2.0 (the "License"); 
00005 you may not use this file except in compliance with the License.
00006 You may obtain a copy of the License at
00007 
00008    http://www.apache.org/licenses/LICENSE-2.0
00009 
00010 Unless required by applicable law or agreed to in writing, 
00011 software distributed under the License is distributed on an 
00012 "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, 
00013 either express or implied. See the License for the specific 
00014 language governing permissions and limitations under the License.
00015 
00016 ======================================================================== */
00017 
00018 #ifndef HTS221_H_
00019 #define HTS221_H_
00020 
00021 class HTS221 {
00022 public:
00023     HTS221(void);
00024     int begin(void);
00025     int activate(void);
00026     int deactivate(void);
00027 
00028     int bduActivate(void);
00029     int bduDeactivate(void);
00030 
00031     int readHumidity(void);
00032     double readTemperature(void);
00033 private:
00034     int storeCalibration(void);
00035     unsigned char _h0_rH, _h1_rH;
00036     unsigned int  _T0_degC, _T1_degC;
00037     unsigned int  _H0_T0, _H1_T0;
00038     unsigned int  _T0_OUT, _T1_OUT;
00039     double _temperature;
00040     int _humidity;
00041     unsigned char _address;
00042 
00043     unsigned char readRegister(unsigned char slaveAddress, unsigned char regToRead);
00044     int writeRegister(unsigned char slaveAddress, unsigned char regToWrite, unsigned char dataToWrite);
00045 };
00046 
00047 #define HTS221_ADDRESS     0xBF
00048 
00049 //Define a few of the registers that we will be accessing on the HTS221
00050 #define WHO_AM_I           0x0F
00051 #define WHO_AM_I_RETURN    0xBC //This read-only register contains the device identifier, set to BCh
00052 
00053 #define AVERAGE_REG        0x10 // To configure humidity/temperature average.
00054 #define AVERAGE_DEFAULT    0x1B
00055 
00056 /*
00057  * [7] PD: power down control
00058  * (0: power-down mode; 1: active mode)
00059  *
00060  * [6:3] Reserved
00061  *
00062  * [2] BDU: block data update
00063  * (0: continuous update; 1: output registers not updated until MSB and LSB reading)
00064 The BDU bit is used to inhibit the output register update between the reading of the upper
00065 and lower register parts. In default mode (BDU = ?0?), the lower and upper register parts are
00066 updated continuously. If it is not certain whether the read will be faster than output data rate,
00067 it is recommended to set the BDU bit to ?1?. In this way, after the reading of the lower (upper)
00068 register part, the content of that output register is not updated until the upper (lower) part is
00069 read also.
00070  *
00071  * [1:0] ODR1, ODR0: output data rate selection (see table 17)
00072  */
00073 #define CTRL_REG1          0x20
00074 #define POWER_UP           0x80
00075 #define BDU_SET            0x4
00076 #define ODR0_SET           0x1   // setting sensor reading period 1Hz
00077 
00078 #define CTRL_REG2          0x21
00079 #define CTRL_REG3          0x22
00080 #define REG_DEFAULT        0x00
00081 
00082 #define STATUS_REG         0x27
00083 #define TEMPERATURE_READY  0x1
00084 #define HUMIDITY_READY     0x2
00085 
00086 #define HUMIDITY_L_REG     0x28
00087 #define HUMIDITY_H_REG     0x29
00088 #define TEMP_L_REG         0x2A
00089 #define TEMP_H_REG         0x2B
00090 /*
00091  * calibration registry should be read for temperature and humidity calculation.
00092  * Before the first calculation of temperature and humidity,
00093  * the master reads out the calibration coefficients.
00094  * will do at init phase
00095  */
00096 #define CALIB_START        0x30
00097 #define CALIB_END          0x3F
00098 /*
00099 #define CALIB_T0_DEGC_X8   0x32
00100 #define CALIB_T1_DEGC_X8   0x33
00101 #define CALIB_T1_T0_MSB    0x35
00102 #define CALIB_T0_OUT_L     0x3C
00103 #define CALIB_T0_OUT_H     0x3D
00104 #define CALIB_T1_OUT_L     0x3E
00105 #define CALIB_T1_OUT_H     0x3F
00106  */
00107  
00108 #endif