config.h
<font color="red">#define EP_INTERVAL_1    0x20</font>

usb_kbd_enum.c
code struct  
{ struct usb_st_configuration_descriptor  cfg;
  struct usb_st_interface_descriptor      ifc;
  struct usb_st_hid_descriptor            hid ;
<font color="red">  struct usb_st_endpoint_descriptor       ep1 ;</font>
  Uchar                                   rep[SIZE_OF_REPORT] ;
}
  usb_configuration =
  {
    { 9, CONFIGURATION, CONF_LENGTH, NB_INTERFACE, CONF_NB,
      CONF_INDEX, CONF_ATTRIBUTES, MAX_POWER},
    { 9, INTERFACE, INTERFACE_NB, ALTERNATE, NB_ENDPOINT, INTERFACE_CLASS,
      INTERFACE_SUB_CLASS, INTERFACE_PROTOCOL, INTERFACE_INDEX },
    { 9, HID, 0x1101, 8, 1, REPORT, 0x3B00 },
    { 7, ENDPOINT, ENDPOINT_NB_1, EP_ATTRIBUTES_1, EP_SIZE_1, <font color="red">EP_INTERVAL_1</font> },