https://raw.githubusercontent.com/sparkfun/Arduino_Boards/master/IDE_Board_Manager/package_spark
fun_index.json
You can add multiple URLs by clicking the window icon, and pasting in one URL per line.
Click OK. Then open the Board Manager by clicking Tools, then hovering over the Board selection tab and clicking
Board Manager.
Search for '
sparkfun
' in the Board Manager. You should see the
SparkFun AVR Boards
package appear. Click
install, wait a few moments, and all the *.brd files you'll need should be installed, indicated by the blue 'Installed'
that is printed next to the package.
You should now be able to upload code to a number of SparkFun Arduino-compatible products, including Pro
Micro.
Manually Installing the *.brd Files
If you are using an older version of the Arduino IDE and do not have access to the Arduino Board Manager, then
you’ll need to install the *.brd files the old fashioned way.