fix missing display update

misc.c

@@ -157,6 +157,8 @@ volatile uint16_t     g_tail_tone_elimination_tick_10ms;
 	volatile uint16_t g_noaa_tick_10ms;
 #endif
 
+uint8_t               g_update_screen_tick_500ms;
+
 uint8_t               g_key_input_count_down;
 #ifdef ENABLE_KEYLOCK
 	uint8_t           g_key_lock_tick_500ms;