Question: Can the PSoC® 3/5LP real-time clock (RTC) run without a power supply or across resets (that is, no change even if PSoC 3/5LP is reset)?
The PSoC 3/5LP RTC block requires a constant power supply. There is no internal capacitor to hold some charge for keeping the RTC running for some time without a power supply. The RTC can run in sleep mode and alternate active mode. In this case, one pulse-per-second (OPPS) has to be the wake-up resource to update real-time for the clock. The RTC cannot run in hibernate mode.
Once PSoC 3/5LP is reset, the RTC block will also get reset and it will start from the beginning.