nickds1 11 Posted July 30, 2014 Bit new to the MSP430 - I have the new FR5969 launchpad and was playing with RTC_B. Ideally, I'd like to protect the RTC over a main power failure, i.e. keep it ticking but stop the rest of the processor (think clock that doesn't lose track during a power outage). Is there a way to do this without an external RTC (e.g. DS3231 etc.)? Some other MSP430s have a "VBAT" pin that helps in this, but not the FR5969... Thanks Nick Quote Share this post Link to post Share on other sites
roadrunner84 466 Posted July 30, 2014 You could think in software solutions. Say you have a little circuit (two diodes) to have either an external power (from the mains) or a secondary supply (battery) on your supply pins. Then have a single input pin connected to only the external power. Whenever your circuit is running off of battery supply, the input pin will have a low voltage. You can then shut down all foreground tasks and go into low power mode (LPM3). You let RTC_B serve an interrupt for software timekeeping (counting hours/days/etc). Then whenever the external power comes back up again, you could have an interrupt trigger and start your foreground tasks again. Quote Share this post Link to post Share on other sites
