Hello! I am trying to make my own circuit board for an arduino wrist watch that I a want to make. Up until now I have been thinking that the only way to accurately get the time is to use a DS3231 in my PCB, which means I would need to include a small battery (increasing size).
I wanted to know if you know of a way to use a smaller component than a DS3231 and a coin battery. Are there any microcontrollers that have an integrated RTC which even if the main MC looses power, the time will not be lost? Or maybe a different chip than the DS3231 that has the battery already integrated in it? As you can see I just want to avoid the big coin battery!