Вот выдержка из текущей ерраты:
Цитата
Introduction:
The RTC is a set of counters for measuring time when system power is on, and optionally
when it is off. The RTC is clocked by a separate 32 kHz oscillator that produces a 1 Hz
internal time reference. The RTC is powered by its own power supply pin, VBAT, which
can be connected to a battery, externally tied to a 3 V supply, or left floating. The RTC can
operate over temperature range from -40 C to +85 C.
Problem:
The RTC does not work reliably within the temperature specification.
Work-around:
None.
А в каком диапазоне RTC работает стабильно? Есть у кого-то данные?
Нужно указать заказчику рабочий диапазон температур эксплуатации, а вот на этом споткнулся