+#define KEY_1 1
+#define KEY_2 2
+#define KEY_3 3
+#define KEY_4 4
+#define KEY_5 5
+#define KEY_6 6
+#define KEY_7 7
+#define KEY_8 8
+#define KEY_9 9
+#define KEY_0 10
+#define KEY_RESET 11
+
+extern volatile u8 last_key;
+
+/* returns true if a key has been pressed since the last call */
+bool keypad_pressed();
+void keypad_read();
+u8 keypad_getkey();
+void keypad_init();