Actually I don't use beagleboard but beagleBONE. Ist of the same family.
The big problem with these kinds of boards is that the linux os isn't realtime, so you cannot get very accurate timings.
Fortunately the beaglebone also has some kind of mini CPU called PRUSS which runs on itself at 200mHz and can accept commands from the c code running on the beaglebone.
I cannot give a lot more information currently as I have to give credit to somebody else for the low level stuff.
A person from Holland is building a cape for beaglebone + the needed PRUSS driver.
Once that is ready this person is going to make the cape available commercially, but we are nog in betatest.
I just bought a beta board and am going to assist in the higher level code to run lasercutter. The lower level high frequency code is still his stuff.
So.. in future I will be able to tell more.
By the way, what you see on the movie is a testrun with EMC2 under linux, not yet the bone since EMC2 has such a nice testing routine that I didn't care to create it on the beaglebone just to be able to discover possible speeds and accelerations