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TM4C123BE6PZ: RTC tick problem while waking up from Hibernate

Part Number: TM4C123BE6PZ

Dear All,

I am using TM4C123 with battery backup and hibenate mode enable. In my application whenever power supply goes off device goes in to hibernate and when the power supply comes back it switches back to power supply. In this total process we want RTC to work ok. Now with our current development it works fine but we have observed in some cases when it switches between hibernate and normal mode RTC ticks stops working.

Solution to this what we have found out is when we turn off power supply and take out battery connection also i.e. power restart to TM4C123 it starts working. But as per my knowledge when it wakes from hibernate also it's kind of power restart only. So what is the different in both of them which we are missing?


  • Can you tell me the value of HIBCTL register before VDD is removed? I assume you have CLK32EN and PWEN set, but RTCWEN cleared. Also, look at how the VDD and the voltage on the WAKE pin looks when it is removed and then restored. A voltage kickback when VDD is removed might generate a wakeup when VDD is restored for too short of a time to properly re-enable the hibernate mode.