This issue is likely caused by incorrect configuration of the RTC in 12-hour mode instead of 24-hour mode. In 12-hour mode, if the AM/PM bit is not properly handled or initialized, the hour may wrap around incorrectly and reset every 12 hours. To resolve this, ensure the RTC is configured in 24-hour mode in your FSP settings or initialization code, and verify that the R_RTC_CalendarTimeSet() and R_RTC_CalendarTimeGet() functions correctly handle the hour format and AM/PM settings if using 12-hour mode. https://calculadoradehoras.io/