DS1307 and a LED array, need ideas

[Melanie]

Actually, just between you, me and the rest of the forum, I hate the DS1307. It's overpriced for what it is (even when bought in large quantities), and has worse timekeeping than your average 99 cent Chinese Digital Watch (even when you perfectly match the specified 12.5pF crystal with it).

To be honest, what I'm doing nowadays is designing-out the DS1307, chosing a micropower PIC, running it from two supplies (+5v for normal operation and +3v Battery back-up) and using a background Interrupt Routine that runs 24/7. The accuracy (for Data-Logging) is no worse than a DS1307 and you save yourself a dollars worth of chip, plus crystal, plus PCB real-estate!

[Ioannis]

To be honest, what I'm doing nowadays is designing-out the DS1307, chosing a micropower PIC, running it from two supplies (+5v for normal operation and +3v Battery back-up) and using a background Interrupt Routine that runs 24/7. The accuracy (for Data-Logging) is no worse than a DS1307 and you save yourself a dollars worth of chip, plus crystal, plus PCB real-estate!

And if you trim the Xtal with a trimmer it is going to be even more accurate.

Also somewhere in this forum there was a thread for canceling out the clock error but cannot find it.

Ioannis

[wellyboot]

Are you scrolling the time on your display?



This project i built a few months ago, uses a 8x7 led matrix & DS1307 RTC

It reads the DS1307 at the end of the scroll cycle when the display is blank.