I am running custom hardware with the VF61NS151 using the M4 core running MQX 4.1 and it does not keep time when power is removed from the core. I have verified 3.05 volts on the VBAT pin and it keeps time correctly as long as it is running. I am attempting to track this down, but I don't see the RTC registers in the Vybrid Reference Manual Rev. 7. Any help would be appreciated greatly.