Using timer interrupts in a library

I admit I don't know a great deal about how classes work.

The class will only have one instance (due to the HW resources it's impossible to have multiple instances). I'm using a class, because it's a nice way to tie things together, and to have both private and public resources.

I think maybe I should ditch the class, and make "private" stuff static instead.

What do you suggest?

Something that might complicate matters a bit, is the fact that this library is taking advantage of another library (which uses a class).