Can Broadcom confirm if WICED supports high accuracy RTC and Powersave simultaneously?
The issue is the powersave implementation.
When the device goes into powersave, the RTC clock frequency is changes from 1Hz to 800Hz.
During this transition from 1Hz to 800Hz, the sub second information is unaccounted causing the recalculation of RTC time to be inaccurate.
This issue may be see if a STM32F2 MCU is use.
Conclusion - If you need RTC to maintain perfect time do not opt for STM32F2 with powersave option enabled. Would suggest to opt for STM32F4.