A course I understand we have magic chips inside these devices, but occasionally there's info leaked about these and people start hacking them. Look at the GameBoy for example. Even with a hairy ASIC, most people use a standard core, so that's a headstart. Probably not an 8051 methinks! Funnily enough I did some searching on some USB->IDE chips the other day and found it contained a 8051 core cpu as did a few of the other products.

At the moment I've got an idea to use cheapy color lcds for information display but its a matter of finding a product that can be hacked, new code loaded and a brand new application for cheap, easily available consumer goods. So hacking one of these USB-> composite video devices or something like a portable DVD player might be the go. I've opened a cheap chinese manufactured portable dvd player to see what's in it - nothing out of the ordinary really. The main ASIC is an ALI m3355 device that unfortunately ALI don't publish data on. At a guess it probably has a MIPS cpu core and some magic hardware for mpeg decoding (which I don't need) and hardware for the video generation. If I'm lucky it might just have a serial port to get some data in and out. So hopefully some info will emerge and allow some code hacking to be done. The start is usually finding upgrade files that are loaded via the dvd, then you can try to pull apart the file and determine what's what.