Time keeping in powerdown mode

[shirish47]

Hi, I have this need of time keeping in my arduino. although its not necessary to have a perfect timing but if it was good enough for mins resolution it would be good. I wanted to use Time library and also lowpower library, in powerdown mode from lowpower library.. timer0 is shutdown too .and thus millis() fail and also Time library.. so I wanted to have timekeeping and thus I though time keeping with watchdog timer..in low power there is a mode to wake controller ever 1,2,4,8 secs.. I can adjust the timer library seconds at every wakeup and check if the wake up is not from Watchdog it will not update seconds .. this is good for 1 second sleep ... I hope some one can implement this in any of these libraries ..this way we can get a rude low power with time keeping library..but this should not be used for realtime things ...what do you think of this?