I'm looking to use a couple of Nema23 3-phase steppers paired with 3MD560 drivers as well as Sparkfun's level converter. Here's my dilemma: the spec sheet on the driver says the logic circuit needs a minimum of 7mA to operate while the smoothieboard says it's logic pins can only ouput a maximum of 4mA. I'm very new to all of this. Will it work, is there a workaround, or are the steppers & drivers just too large?
The Sparkfun level converter you mentioned should be capable of sinking or sourcing plenty of current to drive the 3MD560 drivers, but honestly if you wanted to save a couple bucks you could accomplish the same thing with a non-inverting CMOS buffer like the 74HCT125 and save a few bucks.