MPLAB® Harmony 3 is a software development framework consisting of compatible and interoperable modules that include peripheral libraries (PLIBs), drivers, system services, middleware and third-party libraries. The MPLAB Harmony Configurator (MHC) is a GUI-based tool that provides an easy way to enable and configure various MPLAB Harmony modules. The MHC is a plug-in to the MPLAB X Integrated Development Environment (IDE). More Details about MPLAB Harmony v3 can be found at This video explains how to create a simple application on Microchip's ARM® Cortex®-M4 based flash SAM E51 microcontroller using Harmony v3 MHC. This application demonstrates an LED (LED0) toggling on a periodic basis and print the LED toggling rate on a serial terminal. The periodicity of the timeout will change from 500 milliseconds to one second, two seconds, four seconds and back to 500 milliseconds every time you press the switch SW0 on the SAM E51 Curiosity Nano Evaluation Kit. Reference Links SAM E51 Curiosity Nano Evaluation Kit and getting started demo: https://www.microchip.com/DevelopmentTools/ProductDetails/PartNO/EV76S68A GitHub Repo: https://github.com/MicrochipTech/MPLAB-Harmony-Reference-Apps GitHub link for SAM E51 Curiosity Nano: https://github.com/MicrochipTech/MPLAB-Harmony-Reference-Apps/tree/master/apps/sam_e51_cnano Demo user guide: https://microchiptech.github.io/MPLAB-Harmony-Reference-Apps/apps/sam_e51_cnano/same51n_getting_started/readme.html Getting Started with SAM E5x MCUs Video: https://www.youtube.com/watch?v=KTEajJQ4ukc&t=116s MPLAB Harmony: https://www.microchip.com/mplab/mplab-harmony