UMB_BULK_TX
[UMB_BULK_TX] = {
config[UMB_BULK_TX].bufsize = UGETDW(np.dwNtbOutMaxSize);
sc->sc_tx_bufsz = config[UMB_BULK_TX].bufsize;
usbd_transfer_stop(sc->sc_xfer[UMB_BULK_TX]);
usbd_transfer_start(sc->sc_xfer[UMB_BULK_TX]);
usbd_transfer_drain(sc->sc_xfer[UMB_BULK_TX]);