KeyboardMonitor.h

00001 #ifndef KEYBOARD_MONITOR_H_
00002 #define KEYBOARD_MONITOR_H_
00003 
00004 #include "kbd_mgr/KeyboardStateEventServer.h"
00005 #include "kbd_mgr/KeyboardState.h"
00006 
00007 #include "mbed.h"
00008 #include <vector>
00009 
00010 namespace kbd_mgr {
00011 
00012 /**
00013  * @brief A class that polls the state of a switch-matrix keyboard.
00014  * For efficiency reasons, this class uses contiguous bits in a GPIO ports for reading the state of the keys in a row.
00015  * Key rows are activated one by one using a set of digital outputs.
00016  * When a full keyboard scan has been done, it is provided to the registered handler.
00017  */
00018 class KeyboardMonitor : public KeyboardStateEventServer {
00019 public:
00020     typedef std::vector<PinName> OutPinsSet;
00021     
00022     /**
00023      * @param inPort        Port to be used for reading the key state.
00024      * @param numKeysPerRow Number of keys in a row (N)
00025      * @param inLowestBit   Index of the lowest bit of inPort (using inLowestBit to inLowestBit+N).
00026      * @param outPins       Pins to be used for powering each key row.
00027      */
00028     KeyboardMonitor (PortName inPort, std::size_t numKeysPerRow, std::size_t inLowestBit, 
00029             const OutPinsSet &outPins);
00030     
00031     ~KeyboardMonitor();
00032     
00033     /**
00034      * @brief Starts the polling of the keyboard state.
00035      */
00036     void start(float pollingPeriod = 0.001);
00037     
00038     /**
00039      * @brief Disables the polling of the keyboard state.
00040      */
00041     void stop();
00042     
00043 private:
00044     void timerHandler();
00045 
00046     PortIn in;
00047     int inBitShift;
00048     OutPinsSet outPins;
00049 
00050     Ticker ticker;
00051     std::size_t scanRow;            /*!< next key row to be scanned */
00052     KeyboardState currentState;     /*!< currently being built keyboard state */
00053 };
00054 
00055 } // kbd_mgr
00056 
00057 #endif // KEYBOARD_MONITOR_H_