Ahh ok. I didn’t realize this watch also had a stopwatch function. Sorry about that! In that case, all 16 LEDs are required. Quick question: why not use an RTC that requires an external clock source? I’ve been modifying your design a bit for my own personal use and found that RTCs with built in crystals can’t get better accuracy than about +-2ppm. For a watch without internet connectivity, I would think accuracy is very crucial since they can’t recalibrate themselves automatically. You can get RTCs that are controlled by external oscillators that have higher frequency accuracy, even over temperature ranges.
Ahh ok. I didn’t realize this watch also had a stopwatch function. Sorry about that! In that case, all 16 LEDs are required. Quick question: why not use an RTC that requires an external clock source? I’ve been modifying your design a bit for my own personal use and found that RTCs with built in crystals can’t get better accuracy than about +-2ppm. For a watch without internet connectivity, I would think accuracy is very crucial since they can’t recalibrate themselves automatically. You can get RTCs that are controlled by external oscillators that have higher frequency accuracy, even over temperature ranges.