File content as of revision 1:7e60713aefc2:

#ifndef QEI_H
#define QEI_H

#include "mbed.h"

#define PREV_MASK 0x1 //Mask for the previous state in determining direction of rotation.
#define CURR_MASK 0x2 //Mask for the current state in determining direction of rotation.
#define INVALID   0x3 //XORing two states where both bits have changed.

class QEI {

public:

    typedef enum Encoding {

        X2_ENCODING,
        X4_ENCODING

    } Encoding;

    QEI(PinName channelA, PinName channelB, PinName index, int pulsesPerRev, Encoding encoding = X2_ENCODING);

    void reset(void);

    int getCurrentState(void);

    int getPulses(void);

    int getRevolutions(void);

private:

    void encode(void);

    void index(void);

    Encoding encoding_;

    InterruptIn channelA_;
    InterruptIn channelB_;
    InterruptIn index_;

    int          pulsesPerRev_;
    int          prevState_;
    int          currState_;

    volatile int pulses_;
    volatile int revolutions_;

};

#endif