topic Re: How to get internal RTC time in millisecond in Kinetis Microcontrollers

How to get internal RTC time in millisecond

jyotiranjan_bal — Tue, 11 Dec 2018 06:57:38 GMT

Hi,

We are using MK60FN1M0VLQ12 controller and internal RTC with clock frequency 32.768KHz.

We found that internal RTC gives the time with 1sec resolution but we need time in milli seconds.

Can any one please tell us how to get time in milli seconds from internal RTC.

Thanks,

Jyotiranjan

BlackNight — Tue, 11 Dec 2018 15:21:45 GMT

You only get a 1 Hz resolution.

You could run your a timer (Software RTC) with a 1 kHz frequency and have it synchronized with the RTC. I do usually the following:

- at boot time, the software RTC is started and loaded with the value of the RTC

- the software RTC runs at 1 kHz so I get a 1 ms resolution

- from time to time (e.g. every day, the SW RTC gets synchronized with the HW RTC to compensate for any clock drift).

The advantage is that access to the SW RTC is faster/more efficient and I get the resolution I need.

I hope this helps,

Erich

mjbcswitzerland — Tue, 11 Dec 2018 16:47:23 GMT