Adding More SERCOM Ports for SAMD Boards
Contributors:
M-Short
M-Short 
Steps to Add a SERCOM Port
Note: This example assumes you are using the latest version of the Arduino IDE on your desktop. If this is your first time using Arduino, please review our tutorial on installing the Arduino IDE. If you have not previously installed an Arduino library, please check out our installation guide.
We basically have 4x steps we are going to follow for each type of port we are going to add. The steps are the same for all types, but they are implemented a bit differently. Because the charts and datasheets are used for each type, they are listed at the end of the document. Make sure to have an extra window open when referencing the pins.
1.) Figure out which pins to use.
2.) Add your code.
3.) Update the pin definitions based on the pin mux.
4.) Putting it all together.