Purchase a Replica of the 1090 XL Expansion System for the Atari XL and XE 8-Bit Computers (10-15 mins)

Task: Purchase a Replica of the 1090 XL Expansion System for the Atari XL and XE 8-Bit Computers

Needed: Web browser, Atari XL or XE 

Time: 10-15 minutes

Introduction

Atari developed the 1090 XL Expansion System as a way to connect a variety of devices through the Peripheral Bus Interface or PBI located on the back of the computer. The 1090 consisted of a circuit board with slots for cards providing the additional functionality. Planned cards would expand the RAM, add Z-80 CP/M support, or allow for 80 columns of text. Numerous other cards were imagined or planned. Unfortunately, only prototypes of the 1090 were produced and thus it was never marketed.

Over the years there has been a lot of discussion about producing new 1090 boards from sketches and plans. Here is a recent thread on Atari Age about this showing progress on new designs and circuit boards. Long story short, you can now purchase newly made boards for the 1090 along with a few expansion cards!

Photo of the Atari 1090XL Expansion Module from Atarimuseum.com
Photo of the Atari 1090XL Expansion Module from atarimuseum.com (Thanks Curt!)

Instructions

First, purchase the 1090 expansion board from Tindie for $85. Thanks Brian Reifsnyder and Ken Ames for making this possible.

Second, purchase one or more expansion cards for $75 each. Three are available at the moment including an 80-column text card with HDMI out, a 320k RAM upgrade, and a card for the CX-85 numeric keypad. These are all options on the main board page.

Third, installing the unit is easy. You will need a 9V power adapter (e.g. like the one used for the Atari 800 and 1050). The unit comes with a ribbon cable that plugs into the PBI slot on the back of the 800XL e.g. Pop off the protective cover. I tested mine with the 80-column card that I plugged into a free slot and the connected to a modern LED screen with an HDMI cable.

Newly made 1090XL with expansion cards
Newly made 1090XL (right) with expansion cards (left)

Comments

I will do separate posts on using the cards.

Note that protocols for getting this to work on the XE computers are still being developed. I would only purchase this for XL computers for now.

Note that the 1090 80-column card did not seem to work with my 800XL that had an Ultimate 1MB upgrade. It worked fine with a stock 800XL.

I am very much looking forward to additional card options for this device!

I hope someone makes a nice case for this that matches the XL computers. Would be nice if it allowed 1050 drives to nicely fit on top.

Thanks to Randy Kindig for giving me a demo of this device at VCF SoCal 2024.