I've uploaded a book on understanding programmable logic that I've been working on in the files area. It's meant to help understand the GAL22V10 and how it will be used on future N8VEM boards.I hope you find it useful.
http://n8vem-sbc.pbworks.com/w/file/82152591/Programmable%20logic%20devices%20-%20v1.6.pdf
-Neil