Follow these instructions to add hardware support for different microcontroller boards in the Arduino IDE software. You always need to have the right board selected in order to upload code properly, otherwise the compiling and upload will fail!
1. Open the Arduino IDE software.
2. First, see if the microcontroller you are using is already listed. Go to Tools > Board > and scroll through the list. If you see your microcontroller on the list, select it and you are done. If you don’t see your microcontroller, proceed to the next step.
3. To add additional boards to our board manager, we need to tell the Arduino IDE software where to look to find them. I will provide detailed instructions for ESP8266-based hardware and Adafruit third party boards. To add other types of boards, you will need to find the appropriate .json link and follow the same instructions here. The .json links can often be found on the manufacturer’s site. In the Arduino IDE, navigate to File > Preferences. A new window will open.
4. To add search locations for firmware, we will click on the small window button to the right of the text entry line “Additional Board Manager URLs:” to open a new window.
Your text input may be blank If you have never gone through this process before, or it may have previously input links – either is fine, the process is the same.
5. A new window will open to let you input multiple URL links for different board packages.
Each URL link needs to be entered on its own line. For example, copy and paste the following links, each on their own line, into the “Additional Board Manager URLs” window for Adafruit's Feather ESP8266.
Click “OK” to close the “Additional Boards Manager URLs” and then click “OK” again to close the “Preferences” window.
6. Return to the Board Manager. Go to Tools > Board > Board Manager, see image from step 2 if you need a refreshed on how to navigate there. Search for the boards you need to install in the search bar.
You will see the boards associated with the links you entered in step 5 appear. Click on the board package you want to install, and then click the “Install” button.
7. After you have installed the boards you need, click the “Close” button to exit.
8. Navigate once again to Tools > Board > and select your board from the list and you are done!