scan a 3x4 keypad with softaware pulldown resistors by polling it continuously.

Fork of keypad by Dimiter K

Revision:
1:b8305e120e11
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/keypad3x4.h	Fri May 08 06:50:54 2015 +0000
@@ -0,0 +1,70 @@
+
+
+//Dimiter Kentri update
+
+
+/*	 Copyright (c) 2010 Dimiter Kentri
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+/*Simple example
+
+#include "mbed.h"
+#include "keypad.h"
+	  
+Serial pc(USBTX, USBRX); 
+Keypad telepad(p13,p14,p15,p17,p18,p19,p20);
+					
+int main(void){
+  char key;
+  pc.printf("Enter codes\n\r");
+  while(1){ 
+	key = telepad.getKey();	
+	if(key != KEY_RELEASED){
+	pc.printf("%c\n",key);
+	wait(0.6);
+	 }
+	}
+}*/
+
+#ifndef KEYPAD3x4_H
+#define KEYPAD3x4_H
+
+#include "DigitalIn.h"
+#include "BusOut.h"
+
+
+namespace mbed
+{
+	const char NO_KEY = '\0';
+	#define KEY_RELEASED NO_KEY
+	const int keys[12] = {'1','2','3','4','5','6','7','8','9','*','0','#',};                  
+	class Keypad
+	{    
+	    public:
+	        Keypad(PinName col1,PinName col2,PinName col3,PinName row1,PinName row2,PinName row3,PinName row4);
+	        char getKey();
+	    protected:
+	    	int getKeyIndex();
+	        DigitalIn _col1,_col2,_col3;    
+	        BusOut _rows;
+	};
+}
+#endif