Originally Posted by charliegolf 
What is this 6-step drive that you are referring to?
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I have built the most basic brushless drive I could make. It takes a PWM signal from the controller, plus the industry-standard "Hall" signals for commutation. Six of the possible 8 codes of the commutation signals are actually used, which correspond to power being applied to one motor terminal and ground to another, with the 3rd terminal left floating. This is commonly called a six-step drive. This is also sometimes called Trapezoidal Commutation. More modern (and more expensive!!!) commercial drives mostly use Sinusoidal Commutation, which provides current to all 3 terminals all the time. A few motors seem to really notice the difference, but most work pretty well with my 6-step drive. I have run SEM, Fanuc, Panasonic, Pittman, IMTT and Keling motors so far with good results.
Some motors, like Panasonic and Fanuc use proprietary schemes for the commutation signals, so I had to make a decoder for those motors.
I also have a "controller" for these applications. It counts encoder pulses, and produces the PWM waveform to control the servo amp. It handles 4 axes, and another board can be added for 4 more axes. EMC2 comes with a driver for this board. Mach was not designed as a servo program, so it would be harder to use it, but I suppose the Galil card could be used with it.
Jon