Retrogaming is cool, retroprogramming is cooler ;-) What I provide here are sources and documentation that I've written. I only briefly got involved with programming the MegaDrive but it taught me a lot: especially nowadays people can't imagine that 64kB RAM can be a lot of RAM to have. With all my little test programs I never managed to need more than about one kilobyte of RAM on the MegaDrive.
I've written down what I learned about the MegaDrive, maybe some other nerds can put use to it.