Clock stopped

It is a standard Pico running latest firmware as of a week ago.

I noticed my code had stopped from lack of activity on the LCD so hooked up right away to the IDE. I am not convinced that the clock stopped when I removed DC to the charger but it is possible.

I checked the error flags and nothing was set. Turning on the watchdog did not reboot. The Pico seemed responsive in all the normal ways apart from getTime returning the same value and hence no set interval functions being called.

I am 99.9% sure that setTime is what started it again. FYI I also use a Clock object and regularly set the Clock object time to what I get from the SIM800 module. (Can't remember if I create a new object or call setClock)

I do need to get a more accurate Pico clock running for the case where the GSM connection is down, do I need to add an external crystal to achieve that? Currently the clock runs about 10% fast.

But the most important thing is I need to detect and recover from the stopped clock as it is a 24x7 logging application and so cannot manually re power to fix.