Adaptor Possibility?

[TesseractE]

Is it possible to create a simple adaptor to run Atari 5200 games on the 400/800/XEGS?

[_The Doctor__]

no point, they've pretty much been converted and made into executables and can be run already.

Edited June 23, 2019 by _The Doctor__

[+slx]

The 5200 has (at least some) hardware addresses different than the 8-bits, i.e. chips like ANTIC and GTIA map to different memory locations. Carts contain program code (machine language). It would be very hard to impossible for a converter to deduct what part of the code refers to such addresses. 

[Rybags]

In the modern day a device could probably sit in the middle (of the cart port and cart), run the 6502 code in an emulator and override the necessary addresses for GTIA and Pokey.

A piece of bootstrap code could put a modified copy of the 5200 Bios into RAM (so 64K XL/XE required).

 

But as stated, practically every game is already on the computer and there'd also be the problem of either having to emulate the 5200 analog controllers in software or make an adaptor for them also.  The sticks would be no problem to interface but the keypads somewhat harder since Pokey scans them but only the XEGS would be able to use them without modification or significant extra interface hardware.

[+DrVenkman]

The good news is, the 5200 games which are actually better than their A8 equivalents (Centipede, Missile Command, Dig Dug ...) have all been converted and are easily available. Just stick them on your flash cart of choice, or onto the FAT partition of your CF card device and you’re ready to rock.  

[TesseractE]

5 hours ago, slx said:

The 5200 has (at least some) hardware addresses different than the 8-bits, i.e. chips like ANTIC and GTIA map to different memory locations. Carts contain program code (machine language). It would be very hard to impossible for a converter to deduct what part of the code refers to such addresses. 

Thanks!  That was the answer I was looking for.  I don't have a 5200, but I DO have an XEGS.  Since 5200 carts are so much easier to find than the 8-bit, I was hoping there's be a simple way to do it, but I guess not.

[+slx]

8 minutes ago, TesseractE said:

Thanks!  That was the answer I was looking for.  I don't have a 5200, but I DO have an XEGS.  Since 5200 carts are so much easier to find than the 8-bit, I was hoping there's be a simple way to do it, but I guess not.

It's probably easier to have all the 5200 ports written on a flash cart. Or get yourself an SD based cart and play tons of games from one cart.

 

All these "play one machine's games on another one" are not that simple. Either you have "dual" machines like the 7800 or the "adapter" is more or less the whole system (like the VCS adapter for the 5200). Don't know about the Coleco-Atari-adapter but that's probably similar. 

[TesseractE]

1 minute ago, slx said:

It's probably easier to have all the 5200 ports written on a flash cart. Or get yourself an SD based cart and play tons of games from one cart.

 

All these "play one machine's games on another one" are not that simple. Either you have "dual" machines like the 7800 or the "adapter" is more or less the whole system (like the VCS adapter for the 5200). Don't know about the Coleco-Atari-adapter but that's probably similar. 

Yeah, most of the time the simple adaptors are there because the machines are so similar the cartridges don't know the difference.  Like with the Power Base for the Genesis.  Sounds like that's just slightly not the case between the 5200 and the 8-Bit.

I tend to avoid flash carts for the most part...  If I'm going to play something other than genuine hardware, I'm just going to go with a full emulator for the convenience.

[ACML]

3 hours ago, DrVenkman said:

The good news is, the 5200 games which are actually better than their A8 equivalents (Centipede, Missile Command, Dig Dug ...) have all been converted and are easily available. Just stick them on your flash cart of choice, or onto the FAT partition of your CF card device and you’re ready to rock.  

Do you have a copy of the 5200 version of Missile Command?  Never knew it was different.  Would greatly appreciate a link to its location as Missile Command is a top 10 for sure.

Thanks

 

 

[+David_P]

There are several challenges:

 

1.  Hardware address differences.  GTIA, ANTIC, POKEY and PIA are all in different places, so there needs to be a way to shift around those addresses.

 

2.  Hardware difference.  The 5200 joysticks are different; you'd either need a port to plug in a 5200 joystick, or a mechanism to translate a "normal" Atari joystick to the 5200 inputs.  Since there are more buttons (including a keypad) on the 5200, that's a big potential problem,

 

3.  Software difference.  The 5200 has a small (2K?) ROM that isn't present in the Atari 8-bit line.

 

[TesseractE]

21 minutes ago, David_P said:

2.  Hardware difference.  The 5200 joysticks are different; you'd either need a port to plug in a 5200 joystick, or a mechanism to translate a "normal" Atari joystick to the 5200 inputs.  Since there are more buttons (including a keypad) on the 5200, that's a big potential problem,

For this one, I thought that the keypad might just map to the XEGS Keyboard.

[+DrVenkman]

49 minutes ago, ACML said:

Do you have a copy of the 5200 version of Missile Command?  Never knew it was different.  Would greatly appreciate a link to its location as Missile Command is a top 10 for sure.

Thanks

 

 

Ah, I got carried away and misspoke, sorry! The versions are functionally and visually identical, even down to the Trak-Ball support, so disregard. 

[Rybags]

5200 has no PIA.

 

Another problem is that 5200 uses CONSOL as an output to determine which keypad is being read.  So we have the dual problem of not being able to do that as well as only the XEGS presenting the Pokey keyboard IO lines to the outside world.

Though I guess addressing interception could be used.

 

But the final product would then be:  Device with passthru and onboard PIC or AVR which emulates 6502 and modifies addresses for redirection to GTIA and Pokey.  Additionally performing function of CONSOL IO switching and providing Pokey keyboard IO, both these physical functions also.  And with onboard 5200 Bios which is copied to the host.

 

Thinking further - the device would not be able to modify indirect accesses to the IO space, e.g. LDA ($C0),Y although these would be a very rare (if ever) occurrence.

 

Bottom line - given the small catalog of the 5200, fact that games worth having are already converted, and the widespread dislike of the controllers, is it something worth doing?

[TesseractE]

1 minute ago, Rybags said:

Bottom line - given the small catalog of the 5200, fact that games worth having are already converted, and the widespread dislike of the controllers, is it something worth doing?

Are there any 5200-exclusive games?  I mean, likely not enough to be worthwhile... Only REAL thing would be the availability of 5200 games vs 8-bit carts.

 

I'm RELATIVELY new to the Atari family...  My uncle had a 2600 when I was a kid, but I only started getting into the 7800 and XEGS last year and I'm enjoying both. ^^d  Just didn't want to feel I was missing out on any 5200 games.

[Rybags]

Maybe Adventure II ?  Because it's commercial and special permission was obtained to use the name.