DS1687_CONTROLA
i = (*sc->sc_mcread)(sc, DS1687_CONTROLA);
(*sc->sc_mcwrite)(sc, DS1687_CONTROLA, i);
ds1687_write(sc, DS1687_CONTROLA, DS1687_DV1 | DS1687_BANK1);
a = ds1687_read(mace0, DS1687_CONTROLA);
ds1687_write(mace0, DS1687_CONTROLA, a | DS1687_BANK1);
ds1687_write(mace0, DS1687_CONTROLA, a);