
The Atari 2600 used a 6502 CPU, just like their entire 8-bit line
(400, 800,1200,1400, 1440, 130xe, 65xe computers, as well as the 5200
game machine). The 2600 had some extra ASIC chips that were basically
modified graphics chips and PIA's for the joysticks. Later model 2600
might have incorporated many of the chips into one ASCI, as the weight
of the machines and part count decreased a lot over the years.

Additionally, I think the 2600 used 2K, 4K, and up to 8K of ROM for
their games. I have no idea how much RAM it had to work with, but I
would hazard a guess of 2 or 4K RAM. Think comes from a lot of hacking
with the 800 and 130xe computers. And occasionally hacking with the
2600 (fixing it for monitor composite video use, and audio hookups).
Also I tryed to make a cartridge-less system that stored the ROM into
a RAM cartridge that could be loaded up at some prior time (a way to
backup cartridges). I've heard of a setup like this where games could
be bought (cheaply) on FSK-recorded tapes, then you would load them
into a special RAM cartidge, and play them.

Anyways, if you're interested in looking for 2600 equipment, we've got
two 2600 machines around (one composite A/V modified), and lotsa
cartridges. Willing to sell for reasonable offer + shipping and
handling. Don't play it anymore, since going to computers + Nintendo
(interested in that too?).