Thank you forum members for your very useful suggestions.
To (Mr. Steve M. Taylor), I have had a very bad experience with 32kHz Crystals, and their tunings, etc, hence we ported our firmware (hardware+software) to DS1904. This DS1904, according to the datasheets of Dallas, does NOT require external crystal or Power supply, they have internal Lithium battery and should work for 10 years. The data sheet also says that, they will give a accuracy of +/- 2 minutes/month. But I get an inaccuracy os a much greater scale.

I have used capital letters just to highlight the point, but not for shouting...


Thanks.