Keypad.h

00001 /* Keypad Library v1.0
00002  * Copyright (c) 2016 Grant Phillips
00003  * grant.phillips@nmmu.ac.za
00004  *
00005  * This is a modified version of Riaan Ehlers' library which was written for the 
00006  * Microchip PIC18 series microcontrollers.
00007  *
00008  * Permission is hereby granted, free of charge, to any person obtaining a copy
00009  * of this software and associated documentation files (the "Software"), to deal
00010  * in the Software without restriction, including without limitation the rights
00011  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00012  * copies of the Software, and to permit persons to whom the Software is
00013  * furnished to do so, subject to the following conditions:
00014  *
00015  * The above copyright notice and this permission notice shall be included in
00016  * all copies or substantial portions of the Software.
00017  *
00018  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00019  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00020  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00021  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00022  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00023  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00024  * THE SOFTWARE.
00025  */
00026  
00027 #ifndef Keypad_H
00028 #define Keypad_H
00029  
00030 #include "mbed.h"
00031  
00032 /** Class library for a polling-based 4x4 keypad.
00033  * 
00034  * Example:
00035  * @code
00036  * #include "mbed.h"
00037  * #include "Keypad.h"
00038  *
00039  * Keypad kpad(PE_15, PE_14, PE_13, PE_12, PE_11, PE_10, PE_9, PE_8);
00040  *
00041  * int main() {
00042  *     char key;
00043  *     int released = 1;
00044  *
00045  *     while(1){
00046  *         key = kpad.ReadKey();                   //read the current key pressed
00047  *
00048  *         if(key == '\0')
00049  *             released = 1;                       //set the flag when all keys are released
00050  *            
00051  *         if((key != '\0') && (released == 1)) {  //if a key is pressed AND previous key was released
00052  *             printf("%c\n", key);            
00053  *             released = 0;                       //clear the flag to indicate that key is still pressed
00054  *         }
00055  *     }
00056  * }
00057  * @endcode
00058  */
00059  
00060 class Keypad {
00061   public:
00062     /** Create a Keypad object.
00063     * @param col1..4 DigitalOut (or BusOut) compatible pins for keypad Column data lines
00064     * @param row1..4 DigitalIn (or BusIn) compatible pins for keypad Row data lines
00065     */
00066     Keypad(PinName col1, PinName col2, PinName col3, PinName col4, PinName row1, PinName row2, PinName row3, PinName row4);
00067     
00068     /** Returns the letter of the key pressed.
00069     * @param 
00070     *     None
00071     * @return 
00072     *     The character of the key pressed.  Returns '\0' if no key is pressed.
00073     */
00074     char ReadKey();
00075     
00076  
00077   private:
00078     BusOut _cols;    
00079     BusIn _rows;
00080 };
00081  
00082 #endif