topic Re: K66 RTC issue after power off in Kinetis Microcontrollers

K66 RTC issue after power off

anand_s — Wed, 17 Jul 2019 13:54:27 GMT

Hi all,

In our design we are using K66 controller with MQX RTOS. For RTC we are provided a crystal 32.768Khz and VBAT 3.3V. With MQX API's we are able to set time and it's working fine. even though we provided battery for RTC after power off RTC showing default time. For testing after setting the rtc we read back the register value and it is also fine. Could you please suggest anything we are missing?

Thanks in advance,

Regards.

Anand.S

Re: K66 RTC issue after power off

mjbcswitzerland — Wed, 17 Jul 2019 20:56:51 GMT

Are you sure that there is not some demo code being executed that is setting the RTC on each start?

By checking the TIF flag in RTC_SR you can see whether the time is valid and then avoid reconfiguring/reseting the RTC on each startup.

Regards

Mark

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Re: K66 RTC issue after power off

anand_s — Thu, 18 Jul 2019 06:14:54 GMT

Thank you Mark, i'll check that.