Wow, thanks for this detailed response. I did take a microprocessor class in college… but that was 20 years ago. So a lot of what you’re saying looks familiar but still pretty fuzzy. If I need to really understand anything, I’ll read up. But it sounds like I can use pin 10 as an output… which is what I need. I’m still a little concerned that the library code lit up an LED on pin 10 however.