USIE_UC_TX
xfer = sc->sc_uc_xfer[USIE_HIP_IF][USIE_UC_TX];
[USIE_UC_TX] = {
usbd_transfer_start(sc->sc_uc_xfer[ucom->sc_subunit][USIE_UC_TX]);
usbd_transfer_stop(sc->sc_uc_xfer[ucom->sc_subunit][USIE_UC_TX]);