Now whats this got to do with anything? Well have a look at these videos
Very cool indeed, more so because its not a particually expensive chip. So I was wondering what more you could do with it, and I've been having a look at some videos, and the specs. Now I've always used PIC Microchips, but I've noticed an increasing number of projects using these ATmega things and after looking at the datasheets, I can see why. The assembler is actually pretty nice! It looks normal! PIC stuff is okay, but I'm not a fan where as the ATmega has 32 registers, hardware multiplys, and most instructions take a single cycle! Now that IS interesting! Now have a look at this video....
This guy does various demos with it, and he gets some pretty cool results for such a small little device. So, I've ordered myself a little kit to playwith, and I might try hooking it up to a VGA monitor (I'm still struggling with PAL colour output, this phase shift stuff is a tad confusing). The other thing this little chip can do that PIC's simply can't, is address external RAM without having to do all the work yourself! Thats awesome! It means you could have megs of addressable SRAM (in the same way a Plus/4 could) without any speed loss, where as a PIC would really struggle as you have to set address lines, read and write data lines et..
What I would really like to try is making a GPU for a plus4. If I use dual port RAM, I could get the plus4 to write into the ATmegas ram, then get it to use it as a frame buffer and render things. This means you could switch the plus4's screen off (saving lots of CPU time), and then output the signal from the cartridge's ATmega chip. You could then add sprites, sound and all the rest without too much effort. if you really wanted to, you could have multiple chips each doing a different job - one for 10 channel SID emulation (or something), another for pure sample playback, and perhaps one to deal with chatacter maps, and another could add sprites etc... kinda like an arcade machine does.
Course...that won't happen. but i'd love to try and hook one up to a Plus4 and see what it would be like. Having already done a RAM expansion without opening up the plus4, I don't see why something like this couldn't be done - it'd be neat!