Wow. That’s a lot to take in. Thanks for the detail and explanation. After more reading, it sounds like digitalWriteFast could be a better option for me at this stage of my understanding of direct port manipulation especially switching boards? I didn’t see a speed but I saw comments of “close to” direct port manipulation without the complexities or “maybe 10x faster” than digitalWrite. I definitely have a better understanding of what is going on thanks to the helpful replies here.