DAYS_REG
I2C_WRITE(sc, DAYS_REG, bintobcd(dt->dt_day));
dt->dt_day = bcdtobin(I2C_READ(sc, DAYS_REG));
days_reg = POWER_READ(sc, DAYS_REG);
POWER_WRITE(sc, DAYS_REG, bintobcd(dt->dt_day));