• A4988 driver board widely used in 3D printers 
• Simple step and direction control interface
• Thermal protection, over-current protection, ground fault protection
• Five different step resolutions: full-step, half-step, quarter-step, eighth-step, and sixteenth-step
• Adjustable current control lets you set the maximum current output with a potentiometer, which lets you use voltages above your stepper motor's rated voltage toachieve higher step rates

-Intelligent chopping control that automatically selects the correct current decay mode (fast decay or slow decay)

-Over-temperature thermal shutdown, under-voltage lockout, and crossover-current protection

-Automatic current decay mode detection / selection

-Internal UVLO

-Mixed with slow current decay modes

-Synchronous rectification for low power dissipation

-Crossover-current protection

-Thermal shutdown circuitry

-3.3 and 5 V compatible logic supply

-Thermal shutdown circuitry

-Ground Fault Circuit

-Load short-circuit protection

-Of five optional step mode: full, 1/2, 1/4, 1/8 and 1/16