DebouncedIn.h

00001 /**
00002  * DebouncedIn class version 1.0
00003  * Created by Andres Moya Bedoya, updated by Ben Faucher
00004  */
00005 
00006 #include "mbed.h"
00007 
00008 #ifndef _DEBOUNCED_IN_H_
00009 #define _DEBOUNCED_IN_H_
00010 
00011 /**
00012  * DebouncedIn object, uses software tickers to debounce mechanical inputs.
00013  */
00014 
00015     class DebouncedIn {
00016         public:      
00017              /** Create a DebouncedIn connected to the specified pin
00018               *
00019               *  @param in DigitalIn pin to connect to
00020               */
00021              DebouncedIn(PinName in);
00022              
00023              /** Same as before, with option to specify pin mode
00024               *
00025               *  @param in DigitalIn pin to connect to
00026               *  @param mode (optional) Set pull mode - PullUp, PullDown, PullNone, OpenDrain
00027               */
00028              DebouncedIn(PinName in, PinMode mode);
00029  
00030              /** Read the input state, represented as 0 or 1 (int)
00031               *
00032               *  @returns
00033               *    An integer representing the state of the input pin,
00034               *    0 for logical 0, 1 for logical 1. State changes when input 
00035               *    has been steady for at least 40ms (8 ticker cycles of 5ms).
00036               */
00037              int read (void);
00038              
00039              /** An operator shorthand for read()
00040               */
00041              operator int();
00042               
00043              /** Rising edge count (int)
00044               *
00045               *  @returns
00046               *    An integer representing the number of times the switch has
00047               *    changed from low to high. Count resets to zero when this
00048               *    function is called.
00049               */
00050              int rising(void);
00051              
00052               /** Falling edge count (int)
00053               *
00054               *  @returns
00055               *    An integer representing the number of times the switch has
00056               *    changed from high to low. Count resets to zero when this
00057               *    function is called.
00058               */
00059              int falling(void);
00060              
00061               /** Steady state tick count (int)
00062               *
00063               *  @returns
00064               *    An integer representing how many ticker cycles the input has been
00065               *    steady for. Ticker cycles every 5ms.
00066               */
00067              int steady(void);
00068               
00069         private :    
00070                // objects
00071                DigitalIn _in;    
00072                Ticker _ticker;
00073  
00074                // function to take a sample, and update flags
00075                void _sample(void);
00076  
00077                // counters and flags
00078                int _samples;
00079                int _output;
00080                int _output_last;
00081                int _rising_flag;
00082                int _falling_flag;
00083                int _state_counter;
00084  
00085     };
00086     
00087 #endif