The IDE allows for multiple versions of the same core to be installed simultaneously. This can be useful for testing purposes, or for solving compatibility issues with a specific core version.
In this guide, we’ll create the appropriate folder structure and install a core.
1. Creating the folder structure
You can skip this step if you already have a folder.
In the commands below,
<sketchbook> refers to the location of your sketchbook folder. It is typically located in the
Arduino subfolder of your Documents folder, but you can find the location in the IDE preferences under
The preferred folder structure is
We recommend you follow this naming convention as this will ensure proper determination of library compatibility and permit referencing resources from other cores of the same architecture.
For Arduino cores, the
<architecture> name may correspond to the
ArduinoCore-x. Consulting relevant documentation is recommended, however.
Follow these steps to create the appropriate folder structure.
- Open the sketchbook folder.
- In the sketchbook folder, create a folder called
hardware. Open it.
- Inside the
hardwarefolder, create the
<vendor>folder. This can have any arbitrary unique vendor name, e.g.
2. Installing the core
The core can be downloaded with a web browser or by cloning the git repo.
Using your web browser
- Download the git repo. In GitHub this is done by clicking
Code > Download ZIP.
- Extract the core into
Simply navigate into
Arduino/hardware/<vendor> and clone the repo into a folder named
cd <sketchbook>/hardware/<vendor> git clone <repo URL> <architecture>
If we wanted to clone arduino/ArduinoCore-avr into the vendor folder
arduino, we’d use the following command.
cd <sketchbook>/hardware/arduino git clone https://github.com/arduino/ArduinoCore-avr avr
Often the bugfix may not be on the main branch. After cloning the repo, we can switch branches with the following command.
git checkout <bugfix-branch>
3. Installing the ArduinoCore-API
The Mbed OS, SAMD, and megaAVR boards platforms (as well as AVR in the near future and any new platforms that are created) use ArduinoCore-API, which contains all the non-architecture specific code that can be shared between all core libraries. This must be installed in addition to the board platform.
Installing the ArduinoCore-API
You can skip this step if you already have the ArduinoCore-API installed, or if it’s not needed by your platform.
Download and extract the API, or clone it, into a directory of your choice.
git clone email@example.com:arduino/ArduinoCore-API
Symlink the ArduinoCore-API
On macOS/Linux (using Terminal):
ln -s "<ArduinoCore-API_path>/api" "<core_path>/cores/arduino/api"
On Windows (using cmd.exe):
mklink /D "<core_path>\cores\arduino\api" "<ArduinoCore-API_path>\api"
4. Using the core
Restart the IDE if open. The new core will now be available in
Tools > Board > [core_name] (in sketchbook).