Hi,
I need to write specification for an electronic device I'm developing in my Uni. 
I don't know where to start because I never wrote such a document.

The answer should cover:
1. Explanations on how to write such specification in a practical way. 

2. What should be covered in such a document.

3. Templates for such a document.Very Important!!!
Please be sure to add such Templates.

4. Examples for such documents.

Please keep in mind before answering this question that I need the
specification for an electronic device and not software or web
application.

I found few links but they are not exactly what I'm looking for.
http://www.mojofat.com/tutorial/index.html
http://www.yart.com.au/article.asp?ID=6
http://www.devshed.com/c/a/Practices/Writing-A-Functional-Specification/

Thanks in Advance
Roy