diff --git a/Makefile.vusb b/Makefile.vusb
index 0ef1b115..b8e71a8e 100644
--- a/Makefile.vusb
+++ b/Makefile.vusb
@@ -2,7 +2,8 @@ OPT_DEFS += -DHOST_VUSB
 
 SRC =	usbdrv.c \
 	usbdrvasm.S \
-	oddebug.c
+	oddebug.c \
+	sendchar_usart.c
 SRC +=	$(TARGET_SRC)
 
 
diff --git a/ps2_usb/main_vusb.c b/main_vusb.c
similarity index 100%
rename from ps2_usb/main_vusb.c
rename to main_vusb.c
diff --git a/ps2_usb/ps2_usart.c b/ps2_usart.c
similarity index 100%
rename from ps2_usb/ps2_usart.c
rename to ps2_usart.c
diff --git a/ps2_usb/Makefile b/ps2_usb/Makefile
index 7b55e020..60596291 100755
--- a/ps2_usb/Makefile
+++ b/ps2_usb/Makefile
@@ -10,7 +10,7 @@ TARGET_DIR = .
 # keyboard dependent files
 TARGET_SRC =	main_pjrc.c \
 		keymap.c \
-  	        matrix.c \
+		matrix.c \
 		led.c \
 		ps2.c
 
diff --git a/ps2_usb/Makefile.vusb b/ps2_usb/Makefile.vusb
index 7b69dc27..6e49fc44 100644
--- a/ps2_usb/Makefile.vusb
+++ b/ps2_usb/Makefile.vusb
@@ -12,13 +12,13 @@ TARGET_SRC =	main_vusb.c \
 		keymap.c \
 		matrix.c \
 		led.c \
-		ps2_usart.c \
-		sendchar_dummy.c
-#		sendchar_usart.c
+		ps2_usart.c
 
 CONFIG_H = config_vusb.h
 
 
+# V-USB debug level: To use ps2_usart.c level must be 0
+# ps2_usart.c requires USART to receive PS/2 signal.
 OPT_DEFS = -DDEBUG_LEVEL=0
 
 
diff --git a/ps2_usb/sendchar_dummy.c b/ps2_usb/sendchar_dummy.c
deleted file mode 100644
index 8c9e583f..00000000
--- a/ps2_usb/sendchar_dummy.c
+++ /dev/null
@@ -1,8 +0,0 @@
-#include <stdint.h>
-#include "sendchar.h"
-
-
-int8_t sendchar(uint8_t c)
-{
-    return 1;
-}
diff --git a/ps2_usb/sendchar_usart.c b/ps2_usb/sendchar_usart.c
deleted file mode 100644
index fe18177a..00000000
--- a/ps2_usb/sendchar_usart.c
+++ /dev/null
@@ -1,58 +0,0 @@
-#include <stdint.h>
-#include "oddebug.h"
-#include "sendchar.h"
-
-
-/* from oddebug.h */
-#if defined UBRR
-#   define  ODDBG_UBRR  UBRR
-#elif defined UBRRL
-#   define  ODDBG_UBRR  UBRRL
-#elif defined UBRR0
-#   define  ODDBG_UBRR  UBRR0
-#elif defined UBRR0L
-#   define  ODDBG_UBRR  UBRR0L
-#endif
-
-#if defined UCR
-#   define  ODDBG_UCR   UCR
-#elif defined UCSRB
-#   define  ODDBG_UCR   UCSRB
-#elif defined UCSR0B
-#   define  ODDBG_UCR   UCSR0B
-#endif
-
-#if defined TXEN
-#   define  ODDBG_TXEN  TXEN
-#else
-#   define  ODDBG_TXEN  TXEN0
-#endif
-
-#if defined USR
-#   define  ODDBG_USR   USR
-#elif defined UCSRA
-#   define  ODDBG_USR   UCSRA
-#elif defined UCSR0A
-#   define  ODDBG_USR   UCSR0A
-#endif
-
-#if defined UDRE
-#   define  ODDBG_UDRE  UDRE
-#else
-#   define  ODDBG_UDRE  UDRE0
-#endif
-
-#if defined UDR
-#   define  ODDBG_UDR   UDR
-#elif defined UDR0
-#   define  ODDBG_UDR   UDR0
-#endif
-
-
-/* from oddebug.c */
-int8_t sendchar(uint8_t c)
-{
-    while(!(ODDBG_USR & (1 << ODDBG_UDRE)));    /* wait for data register empty */
-    ODDBG_UDR = c;
-    return 1;
-}
diff --git a/vusb/sendchar_usart.c b/vusb/sendchar_usart.c
new file mode 100644
index 00000000..d6f3c894
--- /dev/null
+++ b/vusb/sendchar_usart.c
@@ -0,0 +1,19 @@
+#include <stdint.h>
+#include "oddebug.h"
+#include "sendchar.h"
+
+
+#if DEBUG_LEVEL > 0
+/* from oddebug.c */
+int8_t sendchar(uint8_t c)
+{
+    while(!(ODDBG_USR & (1 << ODDBG_UDRE)));    /* wait for data register empty */
+    ODDBG_UDR = c;
+    return 1;
+}
+#else
+int8_t sendchar(uint8_t c)
+{
+    return 1;
+}
+#endif