diff --git a/common/usb_hc.h b/common/usb_hc.h
index 9a2d4cd1..880149fe 100644
--- a/common/usb_hc.h
+++ b/common/usb_hc.h
@@ -56,6 +56,7 @@ struct usbh_urb {
     uint32_t timeout;
     int errorcode;
     uint32_t num_of_iso_packets;
+    uint32_t start_frame;
     usbh_complete_callback_t complete;
     void *arg;
     struct usbh_iso_frame_packet iso_packet[0];
@@ -68,6 +69,12 @@ struct usbh_urb {
  */
 int usb_hc_init(void);
 
+/**
+ * @brief Get frame number.
+ *
+ * @return frame number.
+ */
+uint16_t usbh_get_frame_number(void);
 /**
  * @brief control roothub.
  *
diff --git a/port/dwc2/usb_hc_dwc2.c b/port/dwc2/usb_hc_dwc2.c
index c12c9f57..e1591ae6 100644
--- a/port/dwc2/usb_hc_dwc2.c
+++ b/port/dwc2/usb_hc_dwc2.c
@@ -348,11 +348,6 @@ static inline uint32_t dwc2_get_glb_intstatus(void)
     return tmpreg;
 }
 
-static inline uint32_t dwc2_get_current_frame(void)
-{
-    return (USB_OTG_HOST->HFNUM & USB_OTG_HFNUM_FRNUM);
-}
-
 static int dwc2_pipe_alloc(void)
 {
     int chidx;
@@ -534,6 +529,11 @@ int usb_hc_init(void)
     return 0;
 }
 
+uint16_t usbh_get_frame_number(void)
+{
+    return (USB_OTG_HOST->HFNUM & USB_OTG_HFNUM_FRNUM);
+}
+
 int usbh_roothub_control(struct usb_setup_packet *setup, uint8_t *buf)
 {
     __IO uint32_t hprt0;