topic KL26Z - 32.768Khz external crystal in Kinetis Microcontrollers

KL26Z - 32.768Khz external crystal

_daniel_ — Tue, 19 Dec 2017 00:46:58 GMT

Hi, please, I don't understand: How to using the external 32.768Khz crystal in the MKL26Z chip to get counter precision in date and time with the low power mode (LLS). I don't intend uses the internal LPO1khz. Thanks.

Re: KL26Z - 32.768Khz external crystal

jingpan — Wed, 27 Dec 2017 08:20:11 GMT

Hi Daniel,

Please install MCUXpresso Config Tool and set clock tree like the picture below:

Regards

jing

Re: KL26Z - 32.768Khz external crystal

_daniel_ — Sat, 06 Jan 2018 20:47:09 GMT

Thank you.

My conclusions for my application is:
>LPO with LPTMR is not good, why the interrupt is 1,0007 seconds.
>with external crystal 32.768khz, the core and bus clock is to low.
So, I will test the external RTC input clock with internal 4Mhz clock to core and 2Mhz to bus.

At the moment, I found another alternative, as soon as possible I will try to employ an crystal of the ABRACON - ASDK series.

http://www.mouser.com/ds/2/3/ASDK-24348.pdf

Re: KL26Z - 32.768Khz external crystal

mjbcswitzerland — Sun, 07 Jan 2018 18:07:26 GMT

Hi Daniel

There is some more general info here that may help: http://www.utasker.com/kinetis/KL_RTC.html

Generally one uses an external low power oscillator.

Regards

Mark

Free Open Source solution: https://github.com/uTasker/uTasker-Kinetis
Working project in 15 minutes video: https://youtu.be/K8ScSgpgQ6M

Professional Kinetis support, one-on-one training and complete fast-track project solutions: http://www.utasker.com/support.html