PortsSHT21.h

// Port library interface to SHT21 sensors connected via "something like I2C"
// 2009-02-16 <[email protected]> http://opensource.org/licenses/mit-license.php
// $Id: PortsSHT21.h 4745 2009-12-18 00:56:36Z jcw $

class SHT21 : public Port {
    void clock(uint8_t x) const;
    void release() const;

    uint8_t writeByte(uint8_t value) const;
    uint8_t waitAck() const;
    uint8_t readByte(uint8_t ack) const;
    void start() const;

    static void crcCalc(uint8_t x);
    static void (*crcFun)(uint8_t);
    static uint8_t crc8;
public:
    static void enableCRC();

    enum { TEMP, HUMI };
    uint16_t meas[2];

    SHT21 (uint8_t num) : Port (num) { connReset(); }

    void connReset() const;
    void softReset() const;

    uint8_t readStatus() const;
    void writeStatus(uint8_t value) const;

    uint8_t measure(uint8_t type, void (*delayFun)() =0);

    void calculate(float& rh_true, float& t_C) const;

    static float dewpoint(float h, float t);
};