rudy wrote:A RTC chip can exist on it's own. It is designed to keep working when the rest of the system is turned off. As long as it has power, and a working crystal circuit, it should continue working until the battery power is exhausted.
If you have confirmed that the clock is working, incrementing time, then it should continue working when the ESP is reset, in a sleep state, or just powered off. None of those conditions should affect the RTC.
After two weeks of reading and searching (and imprecation) I achieved the fact that i can't use the pcf 8523 as i want. I don't know how to use the i2c comunication to set the alarm to wake up the esp8266 and i can't find no example to learn about. I thing i need to quit with this rtc and search some easly rtc to use in my project