hey lovely people. just need some advice on a few things so I was looking at the A4988 boards and from what I understand they only need 2 pins from an arduino (with shared power) 1 for rotation and 1 for steps..... so hypothetically on a arduino mega that' possibly 27 (54 digitial pins) a4988's can be controlled right? or am I limited as only 15 provide PWM to 7.5? also with the a4988 I see there are 3 pins used to decide step rate. so with these can i use standard pins on the arduino to software select? this way if I set up the machine it will move faster in areas where no material is and move slower and more precise when working. if so can someone show a brief layout of the schematic to use? I was thinking of in gcode to add a function for step rate to enable faster rates. I was also going to use an encoder to go absolutely overboard and ensure no missed steps but thats another design and software issue for later. I got most of my info from http://howtomechatronics.com/tutorials/arduino/how-to-control-stepper-motor-with-a4988-driver-and-arduino/ so i wanted to use an external source to check items.