SACOM_CR2
bus_space_write_4(iot, *iohp, SACOM_CR2, brd & 0xff);
bus_space_write_4(iot, ioh, SACOM_CR2, sc->sc_speed & 0xff);
bus_space_write_4(sc->sc_iot, sc->sc_ioh, SACOM_CR2, SACOMSPEED(115200));