How much time without power for valid RTC registers ?

tech9 · ‎2007-10-23

Posted on October 24, 2007 at 03:55

tech9 · ‎2007-10-12

Posted on October 12, 2007 at 15:05

Hi everyone,

We are wondering how much time can the registers for the RTC clock value (RTC->CNTL and RTC->CNTH) ''survive'' without power and still hold valid data?

We have seen that in the event of an external reset, they still contain the correct time, and even when there is a power glitch that triggers a reset.

Anyone has an idea on how much time they last with an STR710 built following the demo board configuration?

Thank you,

Tech / Jp

kleshov · ‎2007-10-23

Posted on October 24, 2007 at 03:55

My understanding of how semiconductor circuits work is that as soon as supply voltage drops below a certain level, register contents are lost.

So the question is, how long can the capacitors on your PCB hold the necessary charge?