Known 1090XL documentation
Antic PBI Article
This is a four part series by Earl Rice on the Parallel Bus Interface of the XL line published by Antic in issues January,Febuary,March and April 1985. The series culminates in a barely usable serial I/O device design. But considering no other Atari magazine at the time even attempted a PBI design, it does pretty well.
Analog Expansion Connector Article
This a short article by Michael Alan Barton on the XL Expansion Connector published by Analog in issue 29. While focusing on the 600XL as the computer module used, this article barely scratches the surface of the PBI. Instead it uses a simple memory interface to verify the pinout of the connector and provide an example of how to interface with the expansion connector.
MyAtari.net PBI Article
This four part series by Roland Scholz on the Parallel Bus Interface of the XL line published by MyAtari.net in issues May, August & November 2001. The series goes into great detail for the first time about the PBI and how to develop for it. The final installment goes into great detail on how to design a PBI device that allows you to interface ISA style PC cards to the Atari.
Supra Microport XL Manual
This is a pdf of the Supra Microport XL manual. This is the only known prototyping device for the PBI interface.
Misc PBI/Bus information
This is a collection of misc bits and pieces of information on the PBI and 6502 Bus timing.
Atari 1064XL Memory Expansion Module
This is the only known PBI device created by Atari that connects directly to the PBI on the back of the 600XL modal computer. This compressed file includes schematics and official Atari specifications
Atari 1090XL Technical Notes
Although these specs were never released officially, they remain the only information we have of the intended plans for the 1090XL Expansion Box. This file consists of three different specs, one dated 7/27/83, then later 10/14/83 and finally one dated 05/11/1984. It references additional reference material that seems lost to history at this point.
This is the only known set of schematics available for the 1090XL. A few prototypes were made before the project was canceled. sup8pdct did circuit tracing on the one he possessed and I created a board schematic based on his information. sup8pdct also created a schematic on the power supply.
Various 1090XL Pics
This is a collection of various pics on the 1090XL and the four prototype cards that were created for it.