This board hosts an Arduino Nano compatible controller and up to 3 stepper drivers (A4988/DRV8825). It is very similar to the UNO CNC shield.
The GRBL G-code interpreter firmware turns this into an easy 3-axis CNC controller.
Note that there is a design flaw/bug with these boards that disables microstepping. Microstepping will NOT work without some soldering. The issue is that the 3 jumpers connecting to each stepper driver should pull the MS0/MS1/MS2 pins high (5V) when active, but these boards connect to ground. The easiest way around this, if you require multistepping, is to remove the jumpers and solder the pins directly to +5V where you want to pull the MS0/MS1/MS2 pins high. See below for an image showing how to easily enable microstepping with a small amount of wire and some solder
Using GRBL 1.1, you will need to modify the following file as shown (essentially, you need to swap the step/dir pins in software):
We recommend building your firmware from source and uploading using the Arduino IDE. This allows you to do some simple customization — for example, you can enable/disable PWM spindle control.
PWM spindle speed control is possible with GRBL v1.1, however it will swap one of the endstop pins (no big deal, but the marking on the board will be wrong if PWM is enabled)
Video of this board controlling 3 steppers: