diff --git a/usb_istr.c b/usb_istr.c
new file mode 100644
--- /dev/null
+++ b/usb_istr.c
@@ -0,0 +1,232 @@
+/**
+  ******************************************************************************
+  * @file    usb_istr.c
+  * @author  MCD Application Team
+  * @version V4.0.0
+  * @date    21-January-2013
+  * @brief   ISTR events interrupt service routines
+  ******************************************************************************
+  * @attention
+  *
+  * <h2><center>&copy; COPYRIGHT 2013 STMicroelectronics</center></h2>
+  *
+  * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
+  * You may not use this file except in compliance with the License.
+  * You may obtain a copy of the License at:
+  *
+  *        http://www.st.com/software_license_agreement_liberty_v2
+  *
+  * Unless required by applicable law or agreed to in writing, software 
+  * distributed under the License is distributed on an "AS IS" BASIS, 
+  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  * See the License for the specific language governing permissions and
+  * limitations under the License.
+  *
+  ******************************************************************************
+  */
+
+
+/* Includes ------------------------------------------------------------------*/
+#include "usb_lib.h"
+#include "usb_prop.h"
+#include "usb_pwr.h"
+#include "usb_istr.h"
+
+/* Private typedef -----------------------------------------------------------*/
+/* Private define ------------------------------------------------------------*/
+/* Private macro -------------------------------------------------------------*/
+/* Private variables ---------------------------------------------------------*/
+__IO uint16_t wIstr;  /* ISTR register last read value */
+__IO uint8_t bIntPackSOF = 0;  /* SOFs received between 2 consecutive packets */
+__IO uint32_t esof_counter =0; /* expected SOF counter */
+__IO uint32_t wCNTR=0;
+
+/* Extern variables ----------------------------------------------------------*/
+/* Private function prototypes -----------------------------------------------*/
+/* Private functions ---------------------------------------------------------*/
+/* function pointers to non-control endpoints service routines */
+void (*pEpInt_IN[7])(void) =
+  {
+    EP1_IN_Callback,
+    EP2_IN_Callback,
+    EP3_IN_Callback,
+    EP4_IN_Callback,
+    EP5_IN_Callback,
+    EP6_IN_Callback,
+    EP7_IN_Callback,
+  };
+
+void (*pEpInt_OUT[7])(void) =
+  {
+    EP1_OUT_Callback,
+    EP2_OUT_Callback,
+    EP3_OUT_Callback,
+    EP4_OUT_Callback,
+    EP5_OUT_Callback,
+    EP6_OUT_Callback,
+    EP7_OUT_Callback,
+  };
+
+/*******************************************************************************
+* Function Name  : USB_Istr
+* Description    : ISTR events interrupt service routine
+* Input          :
+* Output         :
+* Return         :
+*******************************************************************************/
+void USB_Istr(void)
+{
+    uint32_t i=0;
+ __IO uint32_t EP[8];
+  
+  wIstr = _GetISTR();
+
+#if (IMR_MSK & ISTR_SOF)
+  if (wIstr & ISTR_SOF & wInterrupt_Mask)
+  {
+    _SetISTR((uint16_t)CLR_SOF);
+    bIntPackSOF++;
+
+#ifdef SOF_CALLBACK
+    SOF_Callback();
+#endif
+  }
+#endif
+  /*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/  
+  
+#if (IMR_MSK & ISTR_CTR)
+  if (wIstr & ISTR_CTR & wInterrupt_Mask)
+  {
+    /* servicing of the endpoint correct transfer interrupt */
+    /* clear of the CTR flag into the sub */
+    CTR_LP();
+#ifdef CTR_CALLBACK
+    CTR_Callback();
+#endif
+  }
+#endif
+  /*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/  
+#if (IMR_MSK & ISTR_RESET)
+  if (wIstr & ISTR_RESET & wInterrupt_Mask)
+  {
+    _SetISTR((uint16_t)CLR_RESET);
+    Device_Property.Reset();
+#ifdef RESET_CALLBACK
+    RESET_Callback();
+#endif
+  }
+#endif
+  /*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
+#if (IMR_MSK & ISTR_DOVR)
+  if (wIstr & ISTR_DOVR & wInterrupt_Mask)
+  {
+    _SetISTR((uint16_t)CLR_DOVR);
+#ifdef DOVR_CALLBACK
+    DOVR_Callback();
+#endif
+  }
+#endif
+  /*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
+#if (IMR_MSK & ISTR_ERR)
+  if (wIstr & ISTR_ERR & wInterrupt_Mask)
+  {
+    _SetISTR((uint16_t)CLR_ERR);
+#ifdef ERR_CALLBACK
+    ERR_Callback();
+#endif
+  }
+#endif
+  /*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
+#if (IMR_MSK & ISTR_WKUP)
+  if (wIstr & ISTR_WKUP & wInterrupt_Mask)
+  {
+    _SetISTR((uint16_t)CLR_WKUP);
+    Resume(RESUME_EXTERNAL);
+#ifdef WKUP_CALLBACK
+    WKUP_Callback();
+#endif
+  }
+#endif
+  /*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
+#if (IMR_MSK & ISTR_SUSP)
+  if (wIstr & ISTR_SUSP & wInterrupt_Mask)
+  {
+
+    /* check if SUSPEND is possible */
+    if (fSuspendEnabled)
+    {
+      Suspend();
+    }
+    else
+    {
+      /* if not possible then resume after xx ms */
+      Resume(RESUME_LATER);
+    }
+    /* clear of the ISTR bit must be done after setting of CNTR_FSUSP */
+    _SetISTR((uint16_t)CLR_SUSP);
+#ifdef SUSP_CALLBACK
+    SUSP_Callback();
+#endif
+  }
+#endif
+  /*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
+
+#if (IMR_MSK & ISTR_ESOF)
+  if (wIstr & ISTR_ESOF & wInterrupt_Mask)
+  {
+    /* clear ESOF flag in ISTR */
+    _SetISTR((uint16_t)CLR_ESOF);
+    
+    if ((_GetFNR()&FNR_RXDP)!=0)
+    {
+      /* increment ESOF counter */
+      esof_counter ++;
+      
+      /* test if we enter in ESOF more than 3 times with FSUSP =0 and RXDP =1=>> possible missing SUSP flag*/
+      if ((esof_counter >3)&&((_GetCNTR()&CNTR_FSUSP)==0))
+      {           
+        /* this a sequence to apply a force RESET*/
+      
+        /*Store CNTR value */
+        wCNTR = _GetCNTR(); 
+      
+        /*Store endpoints registers status */
+        for (i=0;i<8;i++) EP[i] = _GetENDPOINT(i);
+      
+        /*apply FRES */
+        wCNTR|=CNTR_FRES;
+        _SetCNTR(wCNTR);
+ 
+        /*clear FRES*/
+        wCNTR&=~CNTR_FRES;
+        _SetCNTR(wCNTR);
+      
+        /*poll for RESET flag in ISTR*/
+        while((_GetISTR()&ISTR_RESET) == 0);
+        /* clear RESET flag in ISTR */
+        _SetISTR((uint16_t)CLR_RESET);
+   
+       /*restore Enpoints*/
+        for (i=0;i<8;i++)
+        _SetENDPOINT(i, EP[i]);
+      
+        esof_counter = 0;
+      }
+    }
+    else
+    {
+        esof_counter = 0;
+    }
+    
+    /* resume handling timing is made with ESOFs */
+    Resume(RESUME_ESOF); /* request without change of the machine state */
+
+#ifdef ESOF_CALLBACK
+    ESOF_Callback();
+#endif
+  }
+#endif
+} /* USB_Istr */
+
+
+/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/