typedef struct
{
    //---------------------------------------
    // Set a copy of the port address to use.
    void (*InitPort)(MotorData*, int*);

    //---------------------------------------
    // Set/Get the motor speed.
    void (*SetSpeed)(MotorData*, int);
    int (*GetSpeed)(MotorData*);

    //----------------------------------------
    // Set/Get the motor rotation direction.
    void (*SetDirection)(MotorData*, DIRECTION);
    DIRECTION (*GetDirection)(MotorData*);
} MOTOR;

Example 1: Initializing port address, and setting/getting speed and direction.