ARDUINO-SI5351 VFO SKETCH
My sketch for an Arduino and si5351 to implement a VFO, BFO, CW, keyer, and control lines is here. Make sure you look at read.me first. I have used it for at least a dozen homebrew transceivers and transmitters over the past four years (including all of my Summit Prowler SOTA QRP portable rigs), with constant refinement.
VFOs around the World
Mladen 9A3XZ tried out my script in a ‘al fresco EI9GQ transceiver… https://www.youtube.com/watch?v=W5QgSOsWgi8