but I do believe one can copyright an idea, just by writing it down
No that just copyrights the writing, not the idea it contained.
See this:-
http://www.lawdit.co.uk/reading_room/room/view_article.asp?name=../articles/8123-JC-Can-Copyright-Protect-My-Idea.htm
Quoting from it:-
Can Copyright Protect my Idea? .......
The simple answer is no, an idea in itself cannot be protected. The Chambers 21st Century Dictionary defines an idea "a thought, image, notion or concept formed by the mind" so by its very definition an idea is a totally intangible thing. In order for there to be any protection of an idea, it must first make the idea exist in some tangible way. In the case of copyright law, it is the work that realises the idea that is protected (i.e. a document), and it is the act of recording that work that fixes copyright in the item itself.
the Due is way over due (oh a new Arduino joke!)
Like 
Yes it does sound like that, although they said they had prototypes at the September Maker Fair although I didn't see it. I offered to help with the development and they said I could, wrote my name down and everything. Expressed surprise I had ARM experience, but I had one of the first ARM computers in 1987. And used that and it's successor the RISC PC until 2002.
Needless to say I heard nothing.
It could be many things, chip shortages or difficulties with the cross compiler / environment are my guess.