PD_DTR4
at91pio_set(sc->sc_piod, PD_DTR4);
at91pio_in(sc->sc_piod, PD_DTR4);
at91pio_per(sc->sc_piod, PD_DTR4, -1);
at91pio_clear(sc->sc_piod, PD_DTR4);
at91pio_out(sc->sc_piod, PD_DTR4);
at91pio_in(sc->sc_piod, PD_DTR4);