Single axis A3977 stepper motor driver board for CNC Router Mill current 0-2A,12-36V input voltage This version ... 4-aisle adjustable current 0-2A rated output 2-phase bipolar stepper motor drive;2, standard parallel port interface, support for MACH2 ... decay mode;5, supports four step options :1/1,1 / 2,1 / 4,1 / 8;6, 12-36V single power supply ...