Optiboot (an older version) is installed by default on the Arduino Uno and (as of 2018) official Arduino Nano boards. It can be installed on all older mega8, 168 or 328 based Arduinos. As of 2019, ...
This is a library for the Si5351 series of clock generator ICs from Silicon Labs for the Arduino development environment. It will allow you to control the Si5351 with an Arduino, and without depending ...