MCR_IENABLE
COM_WRITE(sc, com_mcr, MCR_IENABLE | MCR_DTR | MCR_RTS);
COM_WRITE(sc, com_mcr, MCR_IENABLE | MCR_DTR | MCR_RTS);
SET(sc->sc_mcr, MCR_DTR | MCR_RTS | MCR_IENABLE);
SET(sc->sc_mcr, MCR_IENABLE);