Diff: Keypad.cpp

Revision:

0:4bbd88022a6f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Keypad.cpp	Tue Apr 05 17:37:55 2016 +0000
@@ -0,0 +1,59 @@
+#include "Keypad.h"
+#include "mbed.h"
+
+
+// Keypad layout:
+//                [row][col]   Col0 Col1 Col2 Col3 
+char const kpdLayout[4][4] = {{'1' ,'2' ,'3' ,'A'},  //row0
+                              {'4' ,'5' ,'6' ,'B'},  //row1
+                              {'7' ,'8' ,'9' ,'C'},  //row2
+                              {'*' ,'0' ,'#' ,'D'}}; //row3
+
+//NIBBLE LOW=0000,  HIGH= 0111 1011 1101 1110    Col  (x)
+//const char KpdInMask[4] ={0xe0,0xd0,0xb0,0x70};
+const char KpdInMask[4] ={0x0e,0x0d,0x0b,0x07};
+
+//NIBBLE HIGH=1111,  LOW= 0111 1011 1101 1110    Rows (y)
+//const char KpdOutMask[4]={0xfe,0xfd,0xfb,0xf7};  
+const char KpdOutMask[4]={0x0e,0x0d,0x0b,0x07};
+
+
+Keypad::Keypad(PinName col1, PinName col2, PinName col3, PinName col4, PinName row1, PinName row2, PinName row3, PinName row4) : _cols(col1,col2,col3,col4), _rows(row1,row2,row3,row4) {   }
+
+char Keypad::ReadKey() {
+    char KeyValue, Done=0;
+    uint16_t y, x;
+    
+    //delay_ms(ContactBounceTime);  //warning no contact bounce protection
+                                    //call read_key more than once with delay
+                                    //between if key stay constant then key is pressed
+    y = 0;
+    while((y < 4) && (!Done))
+    {
+        _cols = KpdOutMask[y];              //write mask value to the column outputs     
+        wait(0.01);  
+
+        KeyValue = _rows;                   //read mask value from the row inputs
+        
+        if(KeyValue == KpdInMask[0])
+            x = 0;
+        else if(KeyValue == KpdInMask[1])
+            x = 1;
+        else if(KeyValue == KpdInMask[2])
+            x = 2;
+        else if(KeyValue == KpdInMask[3])
+            x = 3;
+        else
+        {
+            KeyValue='\0';                  //more than one key was pressed or no key in this row.
+            x=9;          
+        }
+        if(x != 9)
+        {
+            Done = 1;                       //valid key found
+            KeyValue = kpdLayout[x][y];     //convert to a character eg. '1','2','3','#','*'
+        }
+        y++;
+    }
+    return(KeyValue);
+}
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