Why does my 8x8 matrix stop displaying?

OK sorry @Robin, I see what you mean't with the interval I had set that to false initially, this was something I needed previously, but isn't required now.

So thanks to you two, i've been able to debug this, and it turned out to be a problem with L46.

That test there sometimes didn't reset i = 8 so the text was getting updated fine, but was so far scrolled away I could never see it.

Thanks a lot.