Is arduino fast enough to handle brushless motors commutation?!

You will need to enlighten me because I'm lost here.

What is Pin 17 for? I have done both the sensing EMF from all 3 phases with a 10k resistor and also using the 4'th connector on the brushless DC motor on which cases it both uses sensing to decide the next step against it's internal EMF comparators. How is this none sensing?