Any way of keeping timers running through a soft reboot/reset?

[arnevaama]

Hello, we've been working with the MK66FN2M0VLQ18 and we're looking for a way to keep the clocks running through a NVIC_SystemReset().

We're storing a clock/time value in the LTMR64H/LTMR64L registers using . Through some debugging we've determined that those registers are wiped upon rebooting.

Obviously a hard power cycle will clear them no matter what, but we're wondering if there is any way we can retain the values in those registers and keep the clocks/timers ticking through a soft-rebot via NVIC_SystemReset().

Has anybody had any experience with this? We've been experimenting a bit and we are thinking that it's not possible, unless we're missing something.

[victorjimenez · Accepted solution]

Hello Evan,

Your hypothesis is correct, it's not possible to keep the clocks running through a soft-reboot via NVIC_SystemReset(). May I ask why do you need to keep the clocks running? Also, it's not possible to retain the values of the registers through a system reset. 

Hope it helps!

Victor.

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[arnevaama]

We are using the timers to store epoch time and would like to keep that time through NVIC_SystemResets so we don't have to sync the time to a server on the next boot.

Thanks for your tip!

[mjbcswitzerland]

Evan

Keep a copy of all the time(r) values (if possible) in an area of SRAM that is not used by anything else (and not initialised at reset) and they will be preserved through resets (not power cycles).

See the following for an overview of the method used in the uTasker project to make a Kinets part without RTC (eg. KL02) into a Kinetis part (sort of) WITH RTC...;-)

http://www.utasker.com/kinetis/KL_RTC.html

Regards

Mark

For less questions and faster, cheaper developments: try uTasker for Kinetis