Thanks.I read the source code these days and I have understand the memory, cpu, timer and interrupt processes. But the video process is so complex and hard to understand.Here is some question:

1. How does the pallet and the pen work? What's the virtual pallet?

2.Input adjust do what?

3.What's the Hold and Assert interrupt?

4.Input and interrupt process is in vblank callback,so it's not real time process?

5.Can you tell me the detail of the pallet process(includes adjust pallet, dirty pen etc) and gfx process?Here is too complex.

BTW:Who's the author of drawgfx.c?It includes itself several times to generate diffierent functions. But it's the best way?I think there should be better way and write the more readable code.:)

6. How does the sounds work? Can you give me a sample?