What is the port on the 5200 Mobo?

[TheNixer]

I opened up my new 5200 from eBay to give the case a good safe clean and noticed an extra port on the motherboard that is accessed from the back if you take the small cover off. I'm sure this has been covered here before but I went back four pages and didn't see anything so I thought I would ask.

 

Was this some sort of expansion port or add-on that was never realized? Or is there something that could go there?

 

Sorry if it's a stupid question.

[+Allan]

I opened up my new 5200 from eBay to give the case a good safe clean and noticed an extra port on the motherboard that is accessed from the back if you take the small cover off. I'm sure this has been covered here before but I went back four pages and didn't see anything so I thought I would ask.

 

Was this some sort of expansion port or add-on that was never realized? Or is there something that could go there?

 

Sorry if it's a stupid question.

Yes, it's an expansion port that was never used. It's an equivalent to the SIO port on the 8-bit/xe/xl computers.

 

And no there was never enything made for it. Atari considered both an Computer keyboard add-on as well as a musical keyboard but neither made it past the drawing board.

 

Allan

[JagFan422]

wow never realized that. I guess much like the port on the bottom of a SNES. Such waste, the 5200 was so amazing, it such a shame it was so overlooked.

[Urchlay]

Yes, it's an expansion port that was never used. It's an equivalent to the SIO port on the 8-bit/xe/xl computers.

 

And no there was never enything made for it. Atari considered both an Computer keyboard add-on as well as a musical keyboard but neither made it past the drawing board.

 

 

Hmm, do you know whether it'd be possible to use it for something in a homebrew game? If it's an SIO port, it should be possible to borrow and tweak the SIO handler code from the Atari 800XL OS. Then you'd need an adaptor to plug in a regular SIO peripheral to the funky 5200 port... but are the pins on the 5200 port actually hooked up to anything?

 

Hm, wonder what useful uses there could be for it...

 

Save game progress on disk/cassette?

 

A 5200 drawing program that could print your pictures (and/or save them on disk)?

 

A 5200 cart that contains a boot loader for a disk or cassette drive attached to the port? Done right, it could make a nice development system, and it'd be a lot cheaper/easier to distribute homebrew games on tape or disk than to build carts (assuming it became a standard, you'd need one "Boot Loader" cart, and you could use it to load hundreds of games. If done right, the same binary should be loadable from either disk or tape, too).

 

Hmmm. It shouldn't be too hard for someone knowledgeable to hook up an Atarivox to an SIO port (basically it'd be the same as the SIO2PC for the Atari 8-bit)... talking 5200 games that run at full speed while talking, and can have 4 channels of POKEY audio at the same time? (Admittedly this could be done over the joystick port, the way it works on the 2600)

 

Or you could use the SIO ports on two 5200s as a null-modem connection and play 2-player games... Or use it with a modem and play 2-player games with your out-of-state friend, or even dial up a server of some kind and play massively-multiplayer games over the Internet. 64-player Ballblazer, anyone?

 

Being an SIO port, you'd be able to connect a whole daisy chain of devices to it, so it'd be possible to hook up multiple disks, printer, modem, tape, etc, all at once... though at that point, you might as well replace the 5200 with an 800XL or 130XE (tons of software already exists for the Atari computers that knows how to talk to disk/printer/etc, but nothing for the 5200 right now).

 

The one Atari peripheral you can't hook up to an SIO port is the keyboard (not even the detachable XEGS keyboard).

 

Anyway I'm just throwing out ideas, I'm not really a 5200 guy, probably I'll never do any of this stuff. If anyone more motivated than I wants to use any of this stuff, go right ahead

 

Ehhh, one possible fly in the ointment: do all 5200s have the expansion port, or only some revisions?

[+Allan]

Yes, it's an expansion port that was never used. It's an equivalent to the SIO port on the 8-bit/xe/xl computers.

 

And no there was never enything made for it. Atari considered both an Computer keyboard add-on as well as a musical keyboard but neither made it past the drawing board.

 

 

Hmm, do you know whether it'd be possible to use it for something in a homebrew game? If it's an SIO port, it should be possible to borrow and tweak the SIO handler code from the Atari 800XL OS. Then you'd need an adaptor to plug in a regular SIO peripheral to the funky 5200 port... but are the pins on the 5200 port actually hooked up to anything?

 

Hm, wonder what useful uses there could be for it...

 

Save game progress on disk/cassette?

 

A 5200 drawing program that could print your pictures (and/or save them on disk)?

 

A 5200 cart that contains a boot loader for a disk or cassette drive attached to the port? Done right, it could make a nice development system, and it'd be a lot cheaper/easier to distribute homebrew games on tape or disk than to build carts (assuming it became a standard, you'd need one "Boot Loader" cart, and you could use it to load hundreds of games. If done right, the same binary should be loadable from either disk or tape, too).

 

Hmmm. It shouldn't be too hard for someone knowledgeable to hook up an Atarivox to an SIO port (basically it'd be the same as the SIO2PC for the Atari 8-bit)... talking 5200 games that run at full speed while talking, and can have 4 channels of POKEY audio at the same time? (Admittedly this could be done over the joystick port, the way it works on the 2600)

 

Or you could use the SIO ports on two 5200s as a null-modem connection and play 2-player games... Or use it with a modem and play 2-player games with your out-of-state friend, or even dial up a server of some kind and play massively-multiplayer games over the Internet. 64-player Ballblazer, anyone?

 

Being an SIO port, you'd be able to connect a whole daisy chain of devices to it, so it'd be possible to hook up multiple disks, printer, modem, tape, etc, all at once... though at that point, you might as well replace the 5200 with an 800XL or 130XE (tons of software already exists for the Atari computers that knows how to talk to disk/printer/etc, but nothing for the 5200 right now).

 

The one Atari peripheral you can't hook up to an SIO port is the keyboard (not even the detachable XEGS keyboard).

 

Anyway I'm just throwing out ideas, I'm not really a 5200 guy, probably I'll never do any of this stuff. If anyone more motivated than I wants to use any of this stuff, go right ahead

 

Ehhh, one possible fly in the ointment: do all 5200s have the expansion port, or only some revisions?

 

Yes, all very interesting questions.

 

Obviously as you stated the biggist problem is that there is no system software to use the port other than the basic I/O for the SIO. With most of the 8-bit peripherals it's kind of a waste with a DOS. Something like printers would be a waste as well. But something like a High-score cart would be great.

 

An SIOtoPC might be useful but why not just get Classics USB cart.

 

A development system is not worth it because using a PC/Mac is a LOT faster.

 

I'd like to see a high-score device for one thing.

 

You could also use it store data for a game as well like an adventure. There already is a cart board that can hold 512K with the use of bank-switching.

 

I'm sure we can think of other uses.

 

Just to plug this idea since we are talking about the 5200, I'd like to see someone try expanding the 5200's RAM to 64K. It's couldn't be that hard with all the 8-bit memory expansions out there.

 

Now for a little secret. The expansion port may seem weird but look at it closer. It looks really familar. In fact it's just a reverse cartridge port. So all you would need are cartridge connectors from the 5200 board and a SIO female connector (as well as all your electronics and a box) in order to hook up something to the expansion box.

 

As far as hooking up a keyboard goes, your right you can't hook up a keyboard to the expansion box, but you can hook one up to the joystick port. Just look at the XEGS connector. It's the same. Now are all the lines available? I don't know. And you'd have to write software (handlers and the actual program) to use it. It's also possible that you'ld have to mod the electronics of the keyboard as well.

 

Allan