+#define EVENT_SCREEN_VISIBLE (1<<0) // screen just became visible
+#define EVENT_SCREEN_DESTROY (1<<1) // screen is destroyed
+#define EVENT_ONE_SEC_TIMER (1<<2)
+#define EVENT_MS_TIMER (1<<3)
+#define EVENT_USER_BUTTONS (1<<4)
+#define EVENT_ACCEL_UPDATE (1<<5)
+#define EVENT_AMBIENTLIGHT_UPDATE (1<<6)
+#define EVENT_POWER_CHANGE (1<<7)
+#define EVENT_COMMS (1<<8)
+