UBT_N_TRANSFER
for (i = 0; i < UBT_N_TRANSFER; i ++)
static const struct usb_config ubt_config[UBT_N_TRANSFER] =
ng_usb_isoc_enable ? UBT_N_TRANSFER : UBT_IF_1_ISOC_DT_RD1,
usbd_transfer_unsetup(sc->sc_xfer, UBT_N_TRANSFER);
struct usb_xfer *sc_xfer[UBT_N_TRANSFER];