By DhiaLearn VHDL with Mike Field's free book written specifically for the Papilio and LogicStart MegaWing. Step by step examples and full source code walks you through using all the peripherals on the LogicStart.
Mike Field wrote a great ebook to help beginners learn VHDL and FPGA technology. We asked Mike what would be the perfect hardware for his proposed book and the end result was the LogicStart MegaWing!
Find all code examples on the ebook's github repository.
Wiki page with more material that pre-dates the book.