Getting grbl

Alden Hart edited this page Apr 19, 2014 · 3 revisions

Downloading grbl

At the current time 0.8c is the official stable version. The grbl hex files and sources are available here: []
Look in the readme for the hex file.

Supported Arduinos

Grbl + grblShield works on Arduinos running the atmega328p chip. That means it works on the Unos, the "newer" Duemilanove's with the 328 chips (not the 168s) and most Uno variants that use the standard Uno pinout configurations. We normally use standard Arduino Unos (SMT or 28-pin DIP variety), or the Seeeduino as in the grblShield Shapeoko bundle.

Grbl does not work on the old atmega168-based Arduinos, the Arduino Megas, or the ARM-based Dues. Some work is being done on grbl to make it will work on the Leonardo's but that's also not currently supported. Here are some other boards we know won't work:

  • Arduino Mega - any version
  • Lilypad - non-standard IO pinout
  • Arduino Nano, Mini and Stamp - non-standard IO pinouts
  • Arduino Fio
  • Any Arduino using an atmega168 chip - not enough room of the current grbl loads

Getting grbl

Please refer to the grbl wiki for flashing grbl onto an Arduino - Flashing grbl onto an Arduino

We also offer pre-loaded options.

  • Purchase a Pre-Loaded Arduino Uno with the lastest version of grbl loaded.
  • Purchase a Pre-Loaded ATmega328p chip with the lastest verison of the grbl firmware.
  • Use AVR Studio 4 with an external AVR Programmer to flash grbl onto your Arduino.  

Method 1 - Purchase a Pre-Loaded Arduino from

This is the easiest method to get your grblShield up and running out of box. Synthetos recommends this method for users that are new to microcontroller development, the Arduino world in general or just what something to work without any problems.

You can get a pre-loaded Arduino [here]( here).


  • Works out of box
  • Cheaper than purchasing an external AVR programmer
  • grblShield and Arduino has been tested at Synthetos


  • Unable to update grbl to future firmware releases without the purchase of an external programmer

Method 2 - Purchase a Pre-Loaded ATmega328p from

This is not as easy as Method 1. However its the next best solution for people that don't want to have to purchase another Arduino and have experience in pulling DIP ([ dual inline pins]).

You can get a pre-loaded ATmega328p [here]( here).


  • Cheaper than purchasing an external AVR programmer.
  • Cheaper than buying a whole Arduino if you already have one.
  • Arduino's processor (ATmega328p) has been pre-loaded with grbl.


  • This method only works on Arduino's that do not have SMD (surface mount) ATmega328p's

Method 3 - Use AVR Studio 4 to load grbl onto your Arduino.

This is the most "involved" way to load grbl onto your Arduino, but also the most flexible. This method requires that you have access to a Windows based machine (or a Windows VM), download AVR Studio 4 and have access to an AVRISPMKII programmer. If any of the above mentioned requirements seem unknown to you you might want to use method 1 or 2 instead.  

Method 3 instructions can be found: [here]( here)/


  • Able to update grbl to future firmware versions as many times as needed / you like.
  • You can use any version of the Arduino UNO to load grbl onto.


  • Requires the use of Windows.
  • Requires registration at AVR to download AVR Studio 4.
  • Requires the purchase of an [ AVRISP mkII]. ($33.75)
  • YOU have to walk through the loading steps to load grbl.
  • If you click any wrong settings in AVR Studio (fuse sections) you can brick your Arduino.'''
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