Atari 7800 Expansion Module (XM) will offer more RAM, better sound & expansion ports
Backwards compatibility is an amazing thing. Nintendo has always done a great job of prolonging game life with each new hardware release. In particular, they have had Game Boy options for a surprising number of their consoles. I've always felt that many gamers don't give up on their existing game library simply because a new console arrives.
Atari took more of a self-preservation approach to backward compatibility. The success of the 2600 lasted beyond the life cycle of the poorly received 5200. Atari did some new math and merged the enhanced capability of the 5200 and added compatibility with the 2600 - all rolled into the 7800. For you Mathletes... 2600 + 5200 = 7800.
Atari 7800 Expansion Module (XM)
There has been a push for a few years to expand the capabilities of the Atari 7800 by creating a pass-through module that would allow homebrew games to take advantage of more RAM and a better sound chip. The guy heading up this project has been updating progress on the AtariAge forum as well as this 7800 XM Status page at the Atari Museum site.
Of particular interest is the design of the 7800 XM. It's a completely external solution that requires no modifications to the original Atari 7800. It rests on top of the console and accesses it via the cartridge slot. By using a pass through concept, new (homebrew) games can make use of XM enhancements while original 2600 & 7800 games play normally.
7800 XM Enhancements
Pokey and Yamaha sound chips - will enable enhanced music & sound effects. The POKEY sound chip was developed at the same time as the 7800 with the intention of placing it inside specific 7800 game carts for enhanced sound beyond what the 7800's native hardware could produce. Due to Atari budget cuts, only the original 7800 games Ballblazer and Commando were released with it. The Yamaha YM2151 is an 8 channel FM sound chip used in some arcade machines in the mid to late 1980's. While never used in an Atari console, it adds the possibility of more accurate arcade sound.
RAM - The XM contains an additional 128KB of ram for use in creating enhanced graphics pallets, additional sprites and larger levels.
Expansion Ports - The XM has 2 expansion ports: a SIO Port and a 15 pin expansion port. The ports are intended add-on projects such as keyboards or storage devices but have no specific purpose at present.
7800 XM games will fall into 2 categories relative to the XM module. Some games will make use of XM features if it is detected in the system (reliant only on enhanced POKEY/Yamaha sound and HSC). Other games will require the module and won't work without the XM (reliant on its mappers and 128K RAM). Its up to developers to decide how their game will interact with the XM.
This project has been ongoing for quite a long time, but one can hope that it will continue to fruition. It seems to have had a few stops and do-overs along the way. Don't be discouraged if some of the online info appears very dated - the project is ongoing.
We recommend joining the rally to give support to this project. The XM is an expensive add-on if more developers don't begin to release games. This can easily become a catch-22 in which the XM will stimulate more game development, but gamers won't buy it until they see there are enough new games to warrant it's price tag. Show support and lets hope this amazing project is completed soon!
7800 XM interaction with Atari 2600 Games
We love the idea of enhancing the 7800! Being a combination of the best of Atari's 2 former consoles, the only thing we don't like is the small 7800 game library. An external (non invasive) upgrade to add hardware enhancements and stimulate additional game development for the 7800 seem great!
But does the XM have any positive effect on a 2600 game? What I mean is- would one be able to make a 2600 game that might take advantage of the additional RAM and/or sound chips. Sure, one can wonder why bother with an enhanced 2600 game when it could be stepped up to 7800 standards and beyond. My main curiosity revolves around experimental games like Halo or Super Mario for the 2600 (both exist). Might games like these be more feasible or enhanced via the XM?
We suspect that 2600 games wil simply be compatible with XM as they were with the original 7800 and new homebrew cartridges will not take advantage of any XM features. But we can dream a little, right? :)
When is a 7800 not a 7800, asked the purist...
Naturally in the midst of insane wonderment over enhancing the hardware capability of the Atari 7800, someone had to come a long and imply that such an upgrade renders the console - no longer a 7800. OK, for these individuals, it can now be a 7801. I understand the purist argument of altering a console in ways outside it's original intent.
First of all the Pokey was to be integrated into game carts back in the 80s, so it's inclusion seems inline with Atari standards. Secondly, the non-invasive nature of the pass-through concept adds features that are essentially inherent to the original. More RAM and improved sound chips simply allow for beter games, but doesn't change the fundamental coding of the game - for the most part. It's not like the Enhancement Module converts the 7800 into an aquarium!
