I am trying to get my A4988s to 16th step. I am using an Arduino and 24V 2A power supply to do so. I wired according to the minimal wiring diagram to begin with and then tested it out. The motors worked just fine. I then tried connecting MS1, MS2 and MS3 to digital pins and changing nothing else. Even having them connected and the Arduino pins low caused the motor to stop moving. I tried with 5V supplied to the MS pins as well and I got the same result. The Arduino even browned out. Does anyone have suggestions to fix this (well, prevent it happening again. The A4988 I was using is now dead)?