In reply to chr_sue:
Thank you, I thought that I cannot use internal signals in DUT.
But I am still a little confused because I want to check if that counter counts correct. If I would simply wait for the value of the counter in DUT, then I would not know if it gets to that value correct (e.g step may be wrong).
So, I wanted to wait for a specified period of time, and compare that value with the predicted value.
Is it a bad approach?