I would just like to drop in and say thanks to all those who offered advice during my assembly learning experience. I know a double buffered video system is not the best way to learn AVR assembly, but I always choose the hard way!
After a lot of late night learning, my video system is now generating perfect sprites, text, and can pull of 60 frames per second with over 100 sprites on the screen at once!
The system is made of nothing more than a single Mega324P with a handful of 20 cent gates. My goal is to write a few decent classic arcade conversions and then post the entire thing as an open source project.
I will post a lot more details soon, but here is a video of the unit in action...
The video capability is VGA or NTSC at 256x240 using 256 colors. Sprites are unlimited in size, number, and shape and have full transparency, collision detection and priority. Graphics capabilities are about the same as a Super Nintendo, or a C64 on steroids.
I also plan on adding another 324P to create a stereo sound option that can handle speech, wave tables and simply FM synthesis.
Again, thanks to all who humored my beginner questions. The experience was certainly worth it.