#ifndef DFRobot_SHT20_h
#define DFRobot_SHT20_h

#if defined(ARDUINO) && ARDUINO >= 100
 #include "Arduino.h"
#else
 #include "WProgram.h"
#endif
#include <Wire.h>

#define ERROR_I2C_TIMEOUT                     998
#define ERROR_BAD_CRC                         999
#define SLAVE_ADDRESS                         0x40 
#define TRIGGER_TEMP_MEASURE_HOLD             0xE3
#define TRIGGER_HUMD_MEASURE_HOLD             0xE5
#define TRIGGER_TEMP_MEASURE_NOHOLD           0xF3
#define TRIGGER_HUMD_MEASURE_NOHOLD           0xF5
#define WRITE_USER_REG                        0xE6
#define READ_USER_REG                         0xE7
#define SOFT_RESET                            0xFE
#define USER_REGISTER_RESOLUTION_MASK         0x81
#define USER_REGISTER_RESOLUTION_RH12_TEMP14  0x00
#define USER_REGISTER_RESOLUTION_RH8_TEMP12   0x01
#define USER_REGISTER_RESOLUTION_RH10_TEMP13  0x80
#define USER_REGISTER_RESOLUTION_RH11_TEMP11  0x81
#define USER_REGISTER_END_OF_BATTERY          0x40
#define USER_REGISTER_HEATER_ENABLED          0x04
#define USER_REGISTER_DISABLE_OTP_RELOAD      0x02
#define MAX_WAIT                              100
#define DELAY_INTERVAL                        10
#define SHIFTED_DIVISOR                       0x988000
#define MAX_COUNTER                           (MAX_WAIT/DELAY_INTERVAL)

class DFRobot_SHT20 
{
public:
    void     checkSHT20(void);
    void     setResolution(byte resBits);
    void     writeUserRegister(byte val);
    void     initSHT20(TwoWire &wirePort = Wire);
    void     showReslut(const char *prefix, int val);
    float    readHumidity(void);
    float    readTemperature(void);
    byte     readUserRegister(void);

private:
    TwoWire *i2cPort;
    byte     checkCRC(uint16_t message_from_sensor, uint8_t check_value_from_sensor);
    uint16_t readValue(byte cmd);
};

#endif