A4988 Arduino CNC shield

From ElectroDragon Wiki


  • Arduino CNC Shield PCB
  • 100uF 50v 8mm High Capacitors (493-3289-ND)
  • Jumpers (A26228-ND)
  • 8-Pin Female Headers(S7006-ND)
  • Male Headers(A26514-40-ND)
  • Tactile Switch (450-1650-ND)
  • Screw Terminal 5mm (A97996-ND)
  • Pololu Stepper Drivers . (Please note that the shield was designed to work with A4988 compatable polulu drivers)
  • 10K pull-up resistors


GRBL Software/Firmware

GRBL is opensource software that runs on an Arduino Uno that takes G-Code commands via Serial and turns the commands into motor signals.

The GRBL source Code is located here.


  • For the M0-M2 configuration, set is low when no jumper connected and high when jumper connected, check on A4988 board configuration for this.
  • A.STP and A.DIR is to copy/clone the motor setting from X, Y or Z axis to the fourth motor if you have.

First Run Debugging

  • Check all the solderings to make sure all soldered well
  • Adjust A4988 breakout board when necessary, and carefully install the A4988 driver board
  • Connect external power to power up
  • upload arduino firmware and test communication via serial port for gbrl, send demo G-code for testing all four axis.