diff --git a/nucleo-wb55-usb/Core/Src/main.c b/nucleo-wb55-usb/Core/Src/main.c
index 8bd7484..52b88ac 100644
--- a/nucleo-wb55-usb/Core/Src/main.c
+++ b/nucleo-wb55-usb/Core/Src/main.c
@@ -23,7 +23,7 @@
 
 /* Private includes ----------------------------------------------------------*/
 /* USER CODE BEGIN Includes */
-
+#include "usbd_cdc_if.h"
 /* USER CODE END Includes */
 
 /* Private typedef -----------------------------------------------------------*/
@@ -55,7 +55,9 @@ static void MX_GPIO_Init(void);
 
 /* Private user code ---------------------------------------------------------*/
 /* USER CODE BEGIN 0 */
-
+void usb_receive(uint8_t *Buf, uint32_t *Len) {
+  CDC_Transmit_FS(Buf, *Len);
+}
 /* USER CODE END 0 */
 
 /**
diff --git a/nucleo-wb55-usb/USB_Device/App/usbd_cdc_if.c b/nucleo-wb55-usb/USB_Device/App/usbd_cdc_if.c
index 65c88d9..84c869a 100644
--- a/nucleo-wb55-usb/USB_Device/App/usbd_cdc_if.c
+++ b/nucleo-wb55-usb/USB_Device/App/usbd_cdc_if.c
@@ -136,6 +136,9 @@ int Debug_write(uint8_t *ptr, uint16_t *Len) {
 	}
 	return i;
 }
+
+__weak void usb_receive(uint8_t *Buf, uint32_t *Len) {}
+
 /* USER CODE END PRIVATE_FUNCTIONS_DECLARATION */
 
 /**
@@ -276,7 +279,7 @@ static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
   /* USER CODE BEGIN 6 */
   USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);
   USBD_CDC_ReceivePacket(&hUsbDeviceFS);
-  CDC_Transmit_FS(Buf, *Len);
+  usb_receive(Buf, Len);
   Debug_write("count\n", (uint16_t)7);
   return (USBD_OK);
   /* USER CODE END 6 */
diff --git a/nucleo-wb55-usb/USB_Device/App/usbd_cdc_if.h b/nucleo-wb55-usb/USB_Device/App/usbd_cdc_if.h
index fabb17a..20f5d85 100644
--- a/nucleo-wb55-usb/USB_Device/App/usbd_cdc_if.h
+++ b/nucleo-wb55-usb/USB_Device/App/usbd_cdc_if.h
@@ -110,7 +110,7 @@ extern USBD_CDC_ItfTypeDef USBD_Interface_fops_FS;
 uint8_t CDC_Transmit_FS(uint8_t* Buf, uint16_t Len);
 
 /* USER CODE BEGIN EXPORTED_FUNCTIONS */
-
+void usb_receive(uint8_t *Buf, uint32_t *Len);
 /* USER CODE END EXPORTED_FUNCTIONS */
 
 /**