RTCL1_L_REG_W
bus_space_write_2(sc->sc_iot, sc->sc_ioh, RTCL1_L_REG_W, 0);
RTCL1_L_REG_W, RTCL1_L_HZ / CLOCK_RATE);
timel = bus_space_read_2(sc->sc_iot, sc->sc_ioh, RTCL1_L_REG_W);