i started working with a RTC BQ3287 and connected it like in the project from http://fritzing.org/projects/ibm-rtc-on-arduino/ after starting it up by sending 'i' via the Serial console and it starts counting seconds and works perfect. According to the manual, the 3287 series contains already a backup battery. if i disconnect my arduino from power source and reconnect it after some minutes, it holds the Time, but if it is disconnected for more then 2 hours, i have to reinitialize the clock and set the time again. Do I have to set anything in the Clock, or is my english so bad, that i missunderstood something in the manual?
Best Regards, Martin