Hi. I was wondering if anyone could point me in the right direction to better understand how my Genesis boots. I assume there is a micro-controller that has whatever firmware is used. It then does its power-on-self-test stuff and then tries to pull from the cartridge and load whatever it finds into memory. Next it must move the program-counter to some standard location. I guess I am curious about the pin-out structure, protocol used for the end result of learning what it would take to make a nice PIC (a nice PIC18 series in DIP form maybe?) based controller that could talk / translate to my Genesis from USB. I realize this is a rather loaded question, but I am hopeful someone here knows where to start looking. Thanks. P.S. It turns out my Sonic-like Special Stage engine questions from the Validation forum were solved by using Blender3D for modeling and pre-rendering the half pipe for the Sonic2-like SS mode and using some (un-)fancy trigonometry for the collision detection while spinning for the Sonic1-like SS mode. For the half pipe, http://www.youtube.com/watch?v=_kWRZsdqRBI , is a test I did, and I will upload more as I feel its ready.
On powerup the 68K will use first 8 bytes of the ROM to set up stack and PC and will execute whatever it is in the ROM using the PC it gets in the beginning. There is no POST etc, everything happens whatever 68K sees on the ROM in the cart
You forget the TMSS ROM (not all systems have it, though). In that case it first runs the program in the TMSS ROM, which checks if the cartridge ROM header is valid, then shows the message on screen and then boots into the program in the cartridge. But yeah, no hardware checks otherwise.
