So, after a long hiatus, I've recently come back to the XL as a fun hobby to do stuff with. It's ridiculously easy these days to put together something that would be next-to-impossible back in the 8-bit heyday, not to mention that I was 11 years old then, as opposed to being (*cough*) significantly older and having more pocket-money these days.

It seemed to me that it wouldn't be that hard to hang something off the XL parallel bus (or XE cartridge/ECI slots) that provided a slot-based interface and a standardised way of talking back to the XL. Once I'd started down that route and evolved the idea a bit, I wondered… Why limit it to the Atari ? With that in mind, I came up with the following goals:

  • The expansion box ought to be designed to interface with its host seamlessly, but provide easy integration with modern electronics. I didn't want every bus card having to work with 5v, for example.

  • I didn't want an ugly ribbon cable coming out of a port on the 8-bit computer, snaking off to a nondescript box. I wanted something aesthetically pleasing, or at least as pleasing as an expansion box can get.

  • Following on from that thought, given that the 1088XEL has been successfully launched, I wanted to allow for an integrated system with slots.

  • It ought to be easy to work with from a software perspective too; given that there aren't too many things that expansion cards will want to do, most of the driver code can end up being generic, and the individual card can pitch in to provide only the card-specific stuff.

  • Price was also an important part of the deal. It's always expensive to design and make something like this, so keeping the costs down as much as possible is a good thing.

  • Having said that, it'd be good to offer something unique if the user only gets the interface part, to allow for easy adoption - buy X now and get features {A,B}; buy Y later and get {A,B,C,D}…

  • This isn't so much of a goal as a statement. I'm engineering this with the potential to be popular and easily integrated into common applications, but it's really a project of mine that I want to do, for me, because it's fun. I do intend to provide full documentation on the bus protocol, and a worked example card so people can see how easy it is to work with.

What I am specifically not trying to accomplish is to re-engineer the same layout or experience that Atari came up with. Another non-goal is to be all things to all (wo)men; as a wise man once said, "it is what it is".

With all that said, progress details are on the progress page, and design details are here - enjoy :)