for (n = 1; n < 16; n++) {
              if (USB_EndPointMask & (1 << n)) {
                USB_DisableEP(n);
              }
              if (USB_EndPointMask & ((1 << 16) << n)) {
                USB_DisableEP(n | 0x80);
              }
            }
            USB_EndPointMask = 0x00010001;
            USB_EndPointHalt = 0x00000000;
            USB_Configure(TRUE);
            if (((USB_CONFIGURATION_DESCRIPTOR *)pD)->bmAttributes & USB_CONFIG_SELF_POWERED) {
              USB_DeviceStatus |=  USB_GETSTATUS_SELF_POWERED;
            } else {
              USB_DeviceStatus &= ~USB_GETSTATUS_SELF_POWERED;
            }
          } else {
            (BYTE *)pD += ((USB_CONFIGURATION_DESCRIPTOR *)pD)->wTotalLength;
            continue;
          }
          break;
        case USB_INTERFACE_DESCRIPTOR_TYPE:
          alt = ((USB_INTERFACE_DESCRIPTOR *)pD)->bAlternateSetting;
          break;
        case USB_ENDPOINT_DESCRIPTOR_TYPE:
          if (alt == 0) {
            n = ((USB_ENDPOINT_DESCRIPTOR *)pD)->bEndpointAddress & 0x8F;
            m = (n & 0x80) ? ((1 << 16) << (n & 0x0F)) : (1 << n);
            USB_EndPointMask |= m;
            USB_ConfigEP((USB_ENDPOINT_DESCRIPTOR *)pD);
            USB_EnableEP(n);
            USB_ResetEP(n);
          }
          break;
      }
      (BYTE *)pD += pD->bLength;
    }
  }
  else {
    USB_Configuration = 0;
    for (n = 1; n < 16; n++) {
      if (USB_EndPointMask & (1 << n)) {
        USB_DisableEP(n);
      }
      if (USB_EndPointMask & ((1 << 16) << n)) {
        USB_DisableEP(n | 0x80);
      }
    }
    USB_EndPointMask  = 0x00010001;
    USB_EndPointHalt  = 0x00000000;
    USB_Configure(FALSE);
  }

  if (USB_Configuration == SetupPacket.wValue.WB.L) {
    return (TRUE);
  } else {
    return (FALSE);
  }
}


/*
 *  Set Interface USB Request
 *    Parameters:      None (global SetupPacket)
 *    Return Value:    TRUE - Success, FALSE - Error
 */

__inline BOOL USB_SetInterface (void) {
  USB_COMMON_DESCRIPTOR *pD;
  DWORD                  ifn, alt, old, msk, n, m;
  BOOL                   set;

  if (USB_Configuration == 0) return (FALSE);

  set = FALSE;
  pD  = (USB_COMMON_DESCRIPTOR *)USB_ConfigDescriptor;
  while (pD->bLength) {
    switch (pD->bDescriptorType) {
      case USB_CONFIGURATION_DESCRIPTOR_TYPE:
        if (((USB_CONFIGURATION_DESCRIPTOR *)pD)->bConfigurationValue != USB_Configuration) {
          (BYTE *)pD += ((USB_CONFIGURATION_DESCRIPTOR *)pD)->wTotalLength;
          continue;
        }
        break;
      case USB_INTERFACE_DESCRIPTOR_TYPE:
        ifn = ((USB_INTERFACE_DESCRIPTOR *)pD)->bInterfaceNumber;
        alt = ((USB_INTERFACE_DESCRIPTOR *)pD)->bAlternateSetting;
        msk = 0;
        if ((ifn == SetupPacket.wIndex.WB.L) && (alt == SetupPacket.wValue.WB.L)) {
          set = TRUE;
          old = USB_AltSetting[ifn];
          USB_AltSetting[ifn] = (BYTE)alt;
        }
        break;
      case USB_ENDPOINT_DESCRIPTOR_TYPE:
        if (ifn == SetupPacket.wIndex.WB.L) {
          n = ((USB_ENDPOINT_DESCRIPTOR *)pD)->bEndpointAddress & 0x8F;
          m = (n & 0x80) ? ((1 << 16) << (n & 0x0F)) : (1 << n);
          if (alt == SetupPacket.wValue.WB.L) {
            USB_EndPointMask |=  m;
            USB_EndPointHalt &= ~m;
            USB_ConfigEP((USB_ENDPOINT_DESCRIPTOR *)pD);
            USB_EnableEP(n);
            USB_ResetEP(n);
            msk |= m;
          }
          else if ((alt == old) && ((msk & m) == 0)) {
            USB_EndPointMask &= ~m;
            USB_EndPointHalt &= ~m;
            USB_DisableEP(n);
          }
        }
        break;
    }
    (BYTE *)pD += pD->bLength;
  }
  return (set);
}


/*
 *  USB Endpoint 0 Event Callback
 *    Parameter:       event
 */

void USB_EndPoint0 (DWORD event) {

  switch (event) {

    case USB_EVT_SETUP:
      USB_SetupStage();
      USB_DirCtrlEP(SetupPacket.bmRequestType.BM.Dir);
      EP0Data.Count = SetupPacket.wLength;
      switch (SetupPacket.bmRequestType.BM.Type) {

        case REQUEST_STANDARD:
          switch (SetupPacket.bRequest) {

            case USB_REQUEST_GET_STATUS:
              if (!USB_GetStatus()) {
                goto stall_i;
              }
              break;

            case USB_REQUEST_CLEAR_FEATURE:
              if (!USB_SetClrFeature(0)) {
                goto stall_i;
              }
              USB_StatusInStage();
              break;

            case USB_REQUEST_SET_FEATURE:
              if (!USB_SetClrFeature(1)) {
                goto stall_i;
              }
              USB_StatusInStage();
              break;

            case USB_REQUEST_SET_ADDRESS:
              switch (SetupPacket.bmRequestType.BM.Recipient) {
                case REQUEST_TO_DEVICE:
                  USB_DeviceAddress = 0x80 | SetupPacket.wValue.WB.L;
                  USB_StatusInStage();
                  break;
                default:
                  goto stall_i;
              }
              break;

            case USB_REQUEST_GET_DESCRIPTOR:
              if (!USB_GetDescriptor()) {
                goto stall_i;
              }
              break;

            case USB_REQUEST_SET_DESCRIPTOR:
			  USB_SetStallEP(0x00);
              EP0Data.Count = 0;
              break;

            case USB_REQUEST_GET_CONFIGURATION:
              switch (SetupPacket.bmRequestType.BM.Recipient) {
                case REQUEST_TO_DEVICE:
                  EP0Data.pData = &USB_Configuration;
                  USB_DataInStage();
                  break;
                default:
                  goto stall_i;
              }
              break;

            case USB_REQUEST_SET_CONFIGURATION:
              switch (SetupPacket.bmRequestType.BM.Recipient) {
                case REQUEST_TO_DEVICE:
                  if (!USB_SetConfiguration()) {
                    goto stall_i;
                  }
                  USB_StatusInStage();
         break;
                default:
                  goto stall_i;
              }
              break;

            case USB_REQUEST_GET_INTERFACE:
              switch (SetupPacket.bmRequestType.BM.Recipient) {
                case REQUEST_TO_INTERFACE:
                  if ((USB_Configuration != 0) &&
                      (SetupPacket.wIndex.WB.L < USB_NumInterfaces)) {
                    EP0Data.pData = USB_AltSetting + SetupPacket.wIndex.WB.L;
                    USB_DataInStage();
                  } else {
                    goto stall_i;
                  }
                  break;
                default:
                  goto stall_i;
              }
              break;

            case USB_REQUEST_SET_INTERFACE:
              switch (SetupPacket.bmRequestType.BM.Recipient) {
                case REQUEST_TO_INTERFACE:
                  if (!USB_SetInterface()) {
                    goto stall_i;
                  }
                  USB_StatusInStage();
                  break;
                default:
                  goto stall_i;
              }
              break;
            default:
              goto stall_i;
          }
          break;

        case REQUEST_CLASS:
#if USB_CLASS
          switch (SetupPacket.bmRequestType.BM.Recipient) {
            case REQUEST_TO_INTERFACE:
              goto stall_i;
            default:
              goto stall_i;
          }
			break;
#else
          goto stall_i;
#endif
       case REQUEST_VENDOR:
          goto stall_i;

        default:
stall_i:  USB_SetStallEP(0x80);
          EP0Data.Count = 0;
          break;

      }
      break;

    case USB_EVT_OUT:
      if (SetupPacket.bmRequestType.BM.Dir == 0) {
        if (EP0Data.Count) {
          USB_DataOutStage();
          if (EP0Data.Count == 0) {
            switch (SetupPacket.bmRequestType.BM.Type) {
              case REQUEST_STANDARD:
                goto stall_i;
#if (USB_CLASS)
              case REQUEST_CLASS:
                switch (SetupPacket.bmRequestType.BM.Recipient) {
                  case REQUEST_TO_INTERFACE:
                    goto stall_i;
                  case REQUEST_TO_ENDPOINT:
                    goto stall_i;
                  default:
                    goto stall_i;
                }
                break;
#endif
              default:
                goto stall_i;
            }
            USB_StatusInStage();
          }
        }
      } else {
        USB_StatusOutStage();
      }
      break;

    case USB_EVT_IN:
      if (SetupPacket.bmRequestType.BM.Dir == 1) {
        USB_DataInStage();
      } else {
        if (USB_DeviceAddress & 0x80) {
          USB_DeviceAddress &= 0x7F;
          USB_SetAddress(USB_DeviceAddress);
        }
      }
      break;

    case USB_EVT_IN_STALL:
      USB_ClrStallEP(0x80);
      break;

    case USB_EVT_OUT_STALL:
      USB_ClrStallEP(0x00);
      break;
  }
}