Using such a circuit can produce very stable frequencies and since the 32.768 kHz crystal is a power of 2, you get nice divisions out of the counter. We’ve seen the same trick done with decade ...

With some beautiful die shots, [electronupdate] walks us through the various areas of the chip – the oscillator, the 15-stage divider cascade that changes the 32.768 kHz signal to a 1 Hz pulse ...