No accurate clock function by using timer example from SDK 15.3

[BelvitaSoft]

Hi guys!

I want to develop clock function and for this issue, I am using the timer from SDK 15.3 peripheral examples.

Unfortunately, the clock speeds up every iteration. As I read in this post, the Real Tick Time is not equal to 10 ms, but to 9.979 ms. It looks like a trivial problem, but it isn't. The error that I obtained from one day raised to 7 minutes and this mistake is not acceptable for the clock's accuracy...
Another very interesting discussion, that I truly recommend, was started here.

If I can ask you, please explore this problem and if you know what can affect this difficulty, then please let me know.

Kind regards,
B.S. 

[Edvin]

Hello,

What is your LFLCK source? Do you have an external crystal or do you use the RC oscillator? (There should be a define in sdk_config.h).

I see that a similar issue is described here. It is not the exact same question, but how do you increment your time? Is it dependent on the interrupts? And if so, do you use the softdevice as well?

BR,

Edvin