MINUTES_REG
I2C_WRITE(sc, MINUTES_REG, bintobcd(dt->dt_min));
dt->dt_min = bcdtobin(I2C_READ(sc, MINUTES_REG));
minutes_reg = POWER_READ(sc, MINUTES_REG);
POWER_WRITE(sc, MINUTES_REG, bintobcd(dt->dt_min));