IER_ERXTOUT
sc->sc_ier |= IER_ERXTOUT;
sc->sc_ier |= IER_EUART | IER_ERXTOUT;
sc->sc_ier |= IER_ERXTOUT;
SET(sc->sc_ier, IER_ERXTOUT);
SET(sc->sc_ier, IER_ERXTOUT);
CLR(sc->sc_ier, IER_ERXRDY|IER_ERXTOUT);
IER_ERXRDY | IER_ERXTOUT);
sc->sc_ier |= IER_EUART | IER_ERXTOUT;
sc->sc_ier |= IER_ERXTOUT;