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.
My journey of repairing and recycling anything I put my hands on that I believe is still useful. Not just hardware, but including software with relevant content and issues in the field of Cyber Security, Vulnerability Scanning and Penetration Testing.