potatohead's Blog - Just picked up a new toy.

RSS Bot · October 17, 2006

It's not really Atari related, though it may well end up being useful for something that is related down the road.

Here the toy: http://www.parallax.com/propeller/index.asp

Here's a better description: http://www.parallax.com/dl/docs/article/RO...-PropReview.pdf

I bumped into this device on a lark basically. Was discussing CPU's on a thread here, mentioned the desire for a nice computer that's cheap sort of like the classic ones we all know and love. Somebody pointed me to the Xgamestation based on the SX chip. Interesting, but not exactly what I was looking for.

From there, I landed on the Parallax site and read about this chip and just had to have one. The details are in the review I linked to above. What I liked was the very original multi-processing design, easy development, low barrier to entry for little hardware projects and built in software controlled graphics capability. I've been watching what some of the hardware wizards here do and it's interesting frankly. This toy will let me dip my toes into the hardware scene as well.

It's a fast design, with a lot of flexibility and tradeoffs. Very intriguing from a computing for fun point of view. And that was the point really. I'm on the road a lot these days. During the evenings, I enjoy working on computing projects, such as the 2600 game I wrote with bB a while back. The portability of this device really makes it ideal for continuing to enjoy computing. The unique design really is interesting and looks to be a lot of fun. Haven't ever seen anything like it. The hotel room television can be used as the monitor to boot! How can you beat that!

The most interesting aspect of the design is it's completely deterministic nature. There are no interrupts, just the 8 32 bit CPU's all equipped with their 512 longs of RAM, supplied from a 8K long central memory pool. All the CPU's share access to on chip resources in a round robin fashion, being able to execute their local code independantly. The assembly language is interesting as well. It's a complex instruction set design, featuring conditional execution, but not featuring indexing!

So, self modifying code is the norm and one can get a lot done in a few instructions!

One can develop programs either in the interpeted high level spin language, or low level assembly or a combination of both. The beauty of the interpeted language is the byte code interpeter is located on chip.

The graphics are generated in software, with a couple of on chip bits providing low-level functionality. So, graphic modes are for the most part, what you make of them. This is very interesting to me as it's the funnest aspect of the Atari machines. I suspect the same innovation elements we've seen for the Atari chips will end up being in play here on this chip as well.

BTW: This chip can output broadcast video on it's own! Not needed, since there is composite and VGA outs on the demo board I linked to.

On chip RAM is a bit limited, but that really just adds to the fun of it. Data can be loaded from memory card devices, or eeproms, so larger programs are possible with some effort. No biggie.

The guy that build the Xgamestation has built a game system around this chip as well. It's not available for ordering, but will be soon. I might get one of these, depending on where this initial step takes me. Info on that can be found here: http://forums.parallax.com/forums/default....25&m=131973

The biggie with that whole project is the sample programs and game development book that comes with the system. I think the book can be had by itself. If so, most all of the code will run on the demo unit I just ordered.

I've had a rough few months since my failed move. Haven't been that active anywhere really. None of this means I'll be leaving the AA community. There are still things I want to do with Atari stuff. However, this new piece of hardware really looks to be fun in it's own way --fun in the same way classic machines are. Maybe somebody will craft an emulator so more folks can give this a try without having to get hardware. It's memory constraints would make it a perfect addition to the minigame compo!

That's it for now. I'm waiting for the package and just thought I would check in!

http://www.atariage.com/forums/index.php?a...;showentry=2202