topic RTC back up mode in Kinetis Microcontrollers

RTC back up mode

juanignaciotroi — Wed, 15 Apr 2015 19:45:39 GMT

Hello. I am developing a project in which I need the real time. Also when de source in turned off. Is there low consuming mode in which I can keep the time even though Vcc is off? I am looking for something similar to what we do when we have an integrated RTC (such as DS1307) in which with a battery the time can be kept.

I am developing with the FRDM KE02 (plus RTC component with the processor expert). If that mode exists, where should the battery be connected?

Thanks

Re: RTC back up mode

mjbcswitzerland — Wed, 15 Apr 2015 20:45:37 GMT

Hi Juan Ignacio

The KE02 has a simple counter (real-time counter and not real-time clock) with interrupt which doesn't allow the time to be maintained when the power is removed. For true RTC support you will need to add an external RTC or use a different Kinetis part that contains a battery backed up RTC.

It is however possible to use the KE02's RTC for true time/date operation as long as it remains powered - it can use low power modes to achieve reduced curent consumption. It is also possible to maintain the time/date across software resets; see the following links for more information of this possibility and support in the time keeper module of the uTasker KE02 project.

Regards

Mark

Kinetis: µTasker Kinetis support

KE: µTasker FRDM-KE02Z support / µTasker FRDM-KE02Z40M support / µTasker FRDM-KE06Z support

Time Management: http://www.utasker.com/docs/uTasker/uTasker_Time.pdf

For the complete "out-of-the-box" Kinetis experience and faster time to market

Re: RTC back up mode

Hui_Ma — Thu, 16 Apr 2015 08:09:06 GMT

Hi,

KE02 RTC module could not continue working if the KE02 VDD lost power.

Please check if customer could using K series product, such as K10 product, which has VBAT power pin and RTC module power source is from VBAT pin.

And the Kinetis M series product RTC module provides calendar feature and also get power from VBAT pin.

Have a great day,
Ma Hui

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