This helps alot. But think of the situation where yo want to play the tone in an ordinary Linux box using C/C++ as the programming language, from there we can start moving to smaller devices. There's a project called beep as shown here which is said to solve the problem. I however haven't had a lot of success with it. Funny enough, when I try to play sounds even using some methods as described there, I hear sounds much later and cannot see how to actually play a wav equivalent continuous sound using this.