@coding badly
Thanks for the detailed reply. I read this version (3.0) GNU Lesser General Public License v3.0 - GNU Project - Free Software Foundation, and I apologize for not being able to decipher everything clearly. I'm just asking questions in the only place I know so I can make sure I'm doing the right things. Thanks for the other link, I'll be sure to go through that as best I can.
My guess is that you can provide a reference to what you used (I don't understand the second paragraph).
Do you mean if I use an open source library, then I can just provide a reference to that library? Based on this answer
See Section 4. For the libraries you use, yes (or source code).
I'm still a little hazy on whether or not I need to provide binaries for my 'overall' compiled program that's running on the AVR, or just binaries/references for the open source libraries that I used.
However, linking a "work that uses the Library" with the Library creates an executable that is a derivative of the Library (because it contains portions of the Library), rather than a "work that uses the library". The executable is therefore covered by this License. Section 6 states terms for distribution of such executables.
I'm not really sure what that means, I'll try reading through the link you provided to see if I can make more sense of it.
BTW, what I meant by
To be more specific, I'm not redistributing software or anything...
is that I'm not making something like a Gameduino or RedBearLabs shield or something where I'm putting out a library of my own. The embedded code will only be on the AVR. Sorry for the misunderstanding.