I am having a project with an LPCXpresso54628 rev C board utilizing RTC. Therefore I wanted to use a battery on the board to keep the RTC running when the power is switched off. However, when the coin cell 3.6V battery is connected on the J10 connector pin 11 and 16 (pic below, + on pin 11) it seems like it is not running the RTC and when I power on the board the date/time I have set up previously runs from the beginning.
Is there an additional setting I have to make or is the wiring I have made wrong? It seems straightforward but maybe I am overlooking something.
Thank you for any help.