Gert Jan Schoneveld / keypad

Fork without short circuits

Dependents:   SaveKeypad

Fork of keypad by HM Yoong

No extra hardware is needed besides the wires and switches. The columns are outputs configured with open drain. The rows are inputs configured with pull up resistors. A key press pulls down its row. With scanning the column is determined thereafter.

See SaveKeypad for an example usage.

Diff: keypad.h

Revision:
11:a45e64141ce6
Parent:
10:9a9ec143840b
Child:
13:fb6929fac0db
--- a/keypad.h	Fri Nov 02 22:42:28 2012 +0000
+++ b/keypad.h	Sat Nov 03 23:33:52 2012 +0000
@@ -85,6 +85,14 @@
      */
     void Stop(void);
 
+    /** Scan the keyboard for a debounced pressed key
+     */
+    int DebouncedScan(void);
+
+    /** Scan the keyboard for a pressed key
+     */
+    int Scan(void);
+
     /** User-defined function that to be called when a key is pressed
      *  @param fptr           A function pointer takes a uint32_t and
      *                        returns uint32_t
@@ -92,21 +100,20 @@
     void CallAfterInput(uint32_t (*fptr)(uint32_t));
 
 protected:
+    static const int row_count = 4;
+    static const int col_count = 4;
+
     InterruptIn      _row0;
     InterruptIn      _row1;
     InterruptIn      _row2;
     InterruptIn      _row3;
+    InterruptIn      *_rows[row_count];
     BusInOut         _cols;  // BusOut doesn't support mode() yet; need open drain to prevent short circuits...
     int              _debounce;
     FPointer         _input; // Called after each input
 
-    void _callback(int row, InterruptIn &therow);
-    void _cbRow0Fall(void);
-    void _cbRow1Fall(void);
-    void _cbRow2Fall(void);
-    void _cbRow3Fall(void);
+    void _callback();
     void _setupFallTrigger(void);
-    void _dummy(void) { };
 };
 
 #endif // KEYPAD_H