Index: apps/debug_menu.c
===================================================================
--- apps/debug_menu.c	(revision 14867)
+++ apps/debug_menu.c	(working copy)
@@ -87,6 +87,7 @@
 #include "ds2411.h"
 #endif
 #include "hwcompat.h"
+#include "button.h"
 
 #if defined(HAVE_DIRCACHE) || defined(HAVE_TAGCACHE) || CONFIG_TUNER
 #define MAX_DEBUG_MESSAGES 16
@@ -2241,6 +2242,59 @@
 }
 #endif
 
+#if (defined(HAVE_SCROLLWHEEL) && (CONFIG_KEYPAD==IPOD_4G_PAD))
+extern bool wheel_is_touched;
+extern int old_wheel_value;
+extern int new_wheel_value;
+extern int wheel_delta;
+extern int accumulated_wheel_delta;
+extern long wheel_velocity;
+static bool dgb_scrollwheel(void)
+{
+    char buf[64];
+    unsigned int config = global_settings.wheel_accel_start;
+    unsigned int speed;
+    
+    lcd_setmargins(0, 0);
+    lcd_setfont(FONT_SYSFIXED);
+    
+    while (1)
+    {
+        if (action_userabort(HZ/10))
+            return false;
+            
+        lcd_clear_display();
+        
+        /* show internal variables of scrollwheel driver */
+        snprintf(buf, sizeof(buf), "wheel touched: %s", (wheel_is_touched) ? "true" : "false");
+        lcd_puts(0, 0, buf);
+        snprintf(buf, sizeof(buf), "new position: %2d", new_wheel_value);
+        lcd_puts(0, 1, buf);
+        snprintf(buf, sizeof(buf), "old position: %2d", old_wheel_value);
+        lcd_puts(0, 2, buf);
+        snprintf(buf, sizeof(buf), "wheel delta: %2d", wheel_delta);
+        lcd_puts(0, 3, buf);
+        snprintf(buf, sizeof(buf), "accumulated delta: %2d", accumulated_wheel_delta);
+        lcd_puts(0, 4, buf);
+        snprintf(buf, sizeof(buf), "velo [deg/s]: %4d", (int)wheel_velocity);
+        lcd_puts(0, 5, buf);
+        
+        /* show effective scrollspeed for 3 different acceleration configurations */
+        speed = button_apply_acceleration( (1<<31)|(1<<24)|wheel_velocity, config, 1);
+        snprintf(buf, sizeof(buf), "speed at v^2: %4d", speed);
+        lcd_puts(0, 7, buf);
+        speed = button_apply_acceleration( (1<<31)|(1<<24)|wheel_velocity, config, 2);
+        snprintf(buf, sizeof(buf), "speed at v^3: %4d", speed);
+        lcd_puts(0, 8, buf);
+        speed = button_apply_acceleration( (1<<31)|(1<<24)|wheel_velocity, config, 3);
+        snprintf(buf, sizeof(buf), "speed at v^4: %4d", speed);
+        lcd_puts(0, 9, buf);
+        
+        lcd_update();
+    }
+    return false;
+}
+#endif
 
 
 /****** The menu *********/
@@ -2313,6 +2367,9 @@
 #ifdef CPU_BOOST_LOGGING
         {"cpu_boost log",cpu_boost_log},
 #endif
+#ifdef HAVE_SCROLLWHEEL
+        {"Debug scrollwheel", dgb_scrollwheel},
+#endif
     };
 static int menu_action_callback(int btn, struct action_callback_info *info)
 {