diff --git a/include/main.h b/include/main.h
index 374c7b2..cc915af 100644
--- a/include/main.h
+++ b/include/main.h
@@ -1,4 +1,4 @@
-#ifndef _MAIN
-#define _MAIN
+#ifndef _MAIN_H
+#define _MAIN_H
 
 #endif
diff --git a/include/sound4calc.h b/include/sound4calc.h
index 5575ab8..f20b0d9 100644
--- a/include/sound4calc.h
+++ b/include/sound4calc.h
@@ -1,10 +1,6 @@
 #ifndef _SOUND4CALC_H
     #define _SOUND4CALC_H
 
-extern char* wave_signal = "-_"; // simple waveform*
-extern unsigned short freq = 440; // frequency by default : to get La3
-extern unsigned short duration = 2000; // equivalent as 2000 ms duration sound
-
 void CallSequence();
 void PutPinState(char level);
 void PlayNote();
diff --git a/src/main.c b/src/main.c
index 9754de2..4b071bb 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,5 +1,5 @@
 #include "main.h"
-#include <sound4calc.h>
+#include "sound4calc.h"
 //#include <timer.h> // add timer fonction
 #include <display.h> // add display fonction
 #include <keyboard.h>
@@ -9,6 +9,7 @@
 int main(void)
 {
     unsigned int key = 0;
+    unsigned short place = 2;
   //unsigned int i=0;
 
     InitPorts();
@@ -20,7 +21,7 @@ int main(void)
         dprint(1, 1, "%d", freq);
         dprint(1, 10, "%s", wave_signal);
         //dprint(1, 20, "%d", place);
-        dtext(1, 50, "F1 _    F2 -");
+        dtext(1, 50, "F5 _    F6 -");
 
         dupdate();
 
@@ -33,9 +34,9 @@ int main(void)
             case KEY_UP : freq+=10; break;
             case KEY_DOWN : freq-=10; break;
 
-            //case KEY_F1 : *(bincod+place++) = '_'; break;
-            //case KEY_F2 : *(bincod+place++) = '-'; break;
-            //case KEY_DEL : place=(place>0 ? place - 1 : 0); *(bincod+place) = 0; break;
+            case KEY_F5 : *(wave_signal+place++) = '_'; break;
+            case KEY_F6 : *(wave_signal+place++) = '-'; break;
+            case KEY_DEL : place=(place>0 ? place - 1 : 0); *(wave_signal+place) = 0; break;
 
             case KEY_EXE :
                 CallNote();
diff --git a/src/sound4calc.c b/src/sound4calc.c
index 12095d7..98de5cc 100644
--- a/src/sound4calc.c
+++ b/src/sound4calc.c
@@ -2,7 +2,6 @@
 #include <mpu.h> // from Gint
 #include <timer.h> //from Gint
 
-
 static struct {
    	int freq;
     int length_ms;
@@ -13,6 +12,10 @@ static struct {
       {   -1,   -1 }
   };
 
+extern char* wave_signal = "-_"; // simple waveform*
+extern  unsigned short duration = 2000; // equivalent as 2000 ms duration sound
+extern  unsigned int freq = 440;
+
 void CallSequence()
 {
     static int length_end = 0;