Thanks for that. Helps me understand a little about how components are referenced.

I did find my problem. The code I snipped came from the generic_gpio example which creates a define in the Kconfig.projbuild file which I didn't have.

This should be very simple... I have over 30 years of embedded devlopment experience with makefiles of various flavors. I've started with the hello_world example project from the IDF tree. Compiled and flashed it fine and it works. Now I want to add a simple GPIO toggle LED to the same project. I co...