I eventually decided that putting graphics on the FPGA would not be a good idea for two reasons:
- The CPU would be drawing the graphics
- I would only have enough memory for 8-color 256 x 256 pixel graphics
This just wasn't going to be enough, so I brought in my Parallax Propeller chip. The propeller is perfect because it runs on 3.3v, has great ability to generate graphics, and will do the video processing for the main CPU. I set it up with UART at 115200 bps and connected it to my FPGA. It took some trial-and-error to get some signs of life from my Propeller saying that it was getting a transmission, then from there I got a Hello World program working.
From here I decided that between the FPGA and the other devices there will be a standard protocol using UART. Don't worry, the UART won't be as slow because there are hardware FIFOs allowing a program to run without waiting for data to finish transmtting.