Optimized polling keybolard reading

Dependents:   design_project

Revision:
0:7082c7132e50
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Keypad3x4polling.cpp	Tue May 12 14:50:28 2015 +0000
@@ -0,0 +1,43 @@
+#include "mbed.h"
+#include "Keypad3x4polling.h"
+
+using namespace mbed;
+
+Keypad::Keypad(PinName col1,PinName col2,PinName col3,PinName row1,PinName row2,PinName row3,PinName row4):_cols(col1,col2,col3),_rows(row1,row2,row3,row4)   
+{ 
+    _cols.mode(PullUp);
+    _rows.write(0);     
+}
+char Keypad::read()
+{
+    char key = 10;
+    _rows.write(14);//1110b
+    switch(_cols)
+    {
+        case 3: key = '3'; break;//011b
+        case 5: key = '2'; break;//101b
+        case 6: key = '1'; break;//110b
+    }
+    _rows.write(13);//1101b
+    switch(_cols)
+    {
+        case 3: key = '6'; break;
+        case 5: key = '5'; break;
+        case 6: key = '4'; break;
+    }
+    _rows.write(11);//1011b
+    switch(_cols)
+    {
+        case 3: key = '9'; break;
+        case 5: key = '8'; break;
+        case 6: key = '7'; break;
+    }
+    _rows.write(7);//0111b
+    switch(_cols)
+    {
+        case 3: key = '#'; break;
+        case 5: key = '0'; break;
+        case 6: key = '*'; break;
+    }
+    return key;
+}
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