Before I provide a link for pre-ordering the Atari 7800 Expansion Module, I will be telling what I know about the Atari 7800 Expansion Module since the only people know about it came from the Atariage form community or was at the 2010 Classic Gaming Expo.
The Atari 7800 Expansion Module works for All Atari 7800 units including Pal.
Here what the expansion module adds to the Atari 7800:
• Built in High Score keeping capability (compatible with approx 20 existing titles and any HSC coded games/programs in the future)
• 128K of Program Available Memory
• POKEY audio/interfacing IC Chip for enhanced audio/voice synthesis and I/O Interfacing capabilities.
• 2nd Audio Processor for higher end Arcade sound effects and music
• SIO (Serial I/O) Port for potential future use of Atari 8bit computer peripherals such as Disk Drives, Printers and Modems.
• 15 PIN Port for potential future use with a detachable computer keyboard.
• Will come professionally boxed in original Silver styled "Atari XL" type box with extensive User Guide and Technical Data manuals.
• Cartridge Port ontop to allow all 2600/7800 cartridges to plug onto the unit to play games/programs.
Any games that have High Score capability will immediately be enabled when using the module, new games that take advantage of all of the ram, or audio chips or both will have major enhancements.
Connecting new peripherals will be possible with the module like Atari 1050 disk drives for use with possible future applications/programs for the module. This would most likely also be used in concert with a future keyboard attachment that will plug into the 15pin keyboard connector on the side of the unit.
So it enhances the 7800's capabilities and gives it future expansion capabilities with peripherals and keyboards.
The 2nd Audio Processor for the Atari 7800 Expansion Module is a ym2151. It is a eight-channel four-operator sound chip that was found in a lot of Arcade games in the mid and late 1980’s by Atari, Capcom, Konami, Namco, and Sega. The first game the used the sound chip in the Arcade was Marble Madness.
So it enhances the 7800's capabilities and gives it future expansion capabilities with peripherals and keyboards.
There are at least 3 game developers that are working games for the Atari 7800 Expansion Module. The games that are known to work on for sure for the Atari 7800 Expansion Module is an improved version of Pac-man Collection and top down dungeon crawler called Dungeon!.
Curt Vendel of Legacy Engineering Group mentioned there will be computer programs coming later for Atari 7800 module after the module is finished. The programs for the module are OSS/7800 Basic, as well as 7800 VideoWriter, 7800 StarTyper, 7800 Atarilab Light and Atarilab Temp.