I hooked up my new DS3231 clock module to an Arduino that was being fed with the one pulse per second input from a locked GPS, and counted the number of pulses from each. In 3170 seconds, the clock module generated 103874565 pulses, for an average pulse per second of 32768.0015773 pulses per second. That’s really good, only about 2 seconds per year. Of course this was a short term test, under relatively stable temperature conditions, but still, I’m highly impressed. I’m thinking that using this to drive my WSPR radio beacon is likely to work out very well.