I face some problem. I start to use real time clock module with EEPROM 32K -> DS1307:
Battery should power clock chip in case outer power down and keep clock ticking.
But module share same power supply as main microcontroller board and other modules...when main power out battery start to akt as main power supply for all...buttery quickly discharge down to 0 (as I guess) and clock brake down (less then 24 hours).
How long 3V battery can hold clock chip running I don't know. I need more than 24 hours. Any suggestions how fix can be done???
Also I have DS3231 but do not test this module. Witch module is better DS1307 or DS3231??