encoder.h

00001 #ifndef _ENCODER_H_
00002 #define _ENCODER_H_
00003 
00004 #include "mbed.h"
00005 
00006 /** Encoder class.
00007  *  Used to read out incremental position encoder. Decodes position in X2 configuration.
00008  *
00009  *  Speed estimation is very crude and computationally intensive. Turned off by default
00010  *
00011  * Example:
00012  * @code
00013  * #include "mbed.h"
00014  * #include "Encoder.h"
00015  *
00016  *   Encoder motor1(PTD0,PTC9,true);
00017  *   Serial pc(USBTX,USBRX);
00018  *   pc.baud(115200);
00019  *   while(1) {
00020  *       wait(0.2);
00021  *       pc.printf("pos: %d, speed %f \r\n",motor1.getPosition(), motor1.getSpeed());
00022  *   }
00023  * @endcode
00024  */
00025 class Encoder
00026 {
00027     public:
00028     /** Create Encoder instance
00029     @param int_a Pin to be used as InterruptIn! Be careful, as not all pins on all platforms may be used as InterruptIn.
00030     @param int_b second encoder pin, used as DigitalIn. Can be any DigitalIn pin, not necessarily on InterruptIn location
00031     @param speed boolean value to determine whether speed calculation is done in interrupt routine. Default false (no speed calculation)
00032     */
00033 
00034     Encoder(PinName int_a, PinName int_b, bool speed=false);
00035     /** Request position
00036     @returns current position in encoder counts
00037     */
00038     int32_t getPosition()
00039     {
00040         return m_position;
00041     }
00042     /** Overwrite position
00043     @param pos position to be written
00044     */
00045     void    setPosition(int32_t pos){m_position = pos;}
00046     /** Request speed
00047     @returns current speed
00048     */
00049     float   m_speed;
00050     float   getSpeed(){return m_speed;}
00051     private:
00052     void encoderFalling(void);
00053     void encoderRising(void);
00054     bool m_speed_enabled;
00055     Timer EncoderTimer;
00056     Timeout EncoderTimeout;
00057     InterruptIn pin_a;
00058     DigitalIn pin_b;
00059     int32_t m_position;
00060     
00061     void timeouthandler(void);
00062     bool zero_speed;
00063 };
00064 
00065 
00066 #endif //_ENCODER_H_