YEARS_REG
I2C_WRITE(sc, YEARS_REG, bintobcd(dt->dt_year % 100));
dt->dt_year = 2000 + bcdtobin(I2C_READ(sc, YEARS_REG));
years_reg = POWER_READ(sc, YEARS_REG);
POWER_WRITE(sc, YEARS_REG, bintobcd(dt->dt_year % 100));