Sega Genesis Controller on Atari 7800?

[Berzerker]

So I know that you can play Atari 2600 with a Sega Genesis controller because it has the same plug. Also, this plug was used for the Colecovison, the 7800 and many more consoles and computers. I know that the Sega Genesis controller works with the 7800, but do the BUTTONS work? I mean, both of them? The 7800 had 2 buttons, and the original Sega Genesis had 3 not including start. Would 2 of the 3 buttons work just fine like with a standard awful Atari 7800 controller? Or would only one work, and would the 7800 only recognize it as a 1 button controller (Thus firing and bombing at the same time in games like Xevious)

 

Also, what about SIX button controllers? Would they also work just fine, with both buttons? I know that the SIX BUTTON ARCADE STICK (Which is something I would love to use) Works on the 2600, but would you be able to use both buttons with it on a 7800?

 

Thanks for your help, this shouldn't be too hard to answer if you have a lot of knowledge or any experience.

[+save2600]

Short answer: no.

 

Long answer: Now might be a good time to learn how to use the search function of this site.

Edited December 10, 2010 by save2600

[Berzerker]

Short answer: no.

 

Long answer: Now might be a good time to learn how to use the search function of this site.

 

No? No to what? I ask many questions. Please be more specific as to what part works and what doesn't.

 

I did search. Nothing had my question, and it's an awful search. I don't want to start an argument, but look try searching it. It doesn't even just search 7800, it has to search EVERYTHING. There were 1000 results, none of them helped me.

 

Thank you for commenting.

[Bakasama]

I think the only button that works is the B button. A and C buttons don't work. If you want to have a 2nd button that works, you have to mod the Genesis controller.

 

I know games can be hacked or programmed to use the C button.

[tz101]

Short answer: no.

 

Long answer: Now might be a good time to learn how to use the search function of this site.

 

No? No to what? I ask many questions. Please be more specific as to what part works and what doesn't.

 

I did search. Nothing had my question, and it's an awful search. I don't want to start an argument, but look try searching it. It doesn't even just search 7800, it has to search EVERYTHING. There were 1000 results, none of them helped me.

 

Thank you for commenting.

 

You're better off ignoring responses like that. There is no valid reason that a poster has to search thousands of threads before he or she posts. I've seen this argued on more gaming forums than just AA, but it is idiotic to say the least. Posters who do not offer a valid and helpful response, but pick at the fact that you did not waste hours searching through too many posts to count are basically being jerks. I would not have even offered a "thank you" for that response...

[+save2600]

You're better off ignoring responses like that. There is no valid reason that a poster has to search thousands of threads before he or she posts. I've seen this argued on more gaming forums than just AA, but it is idiotic to say the least. Posters who do not offer a valid and helpful response, but pick at the fact that you did not waste hours searching through too many posts to count are basically being jerks. I would not have even offered a "thank you" for that response...

Oh c'mon... it was in half-jest. Besides, there's plenty of docs here explaining the difference between the controllers. Then there's pinouts.ru. Google, Yahoo, Bing, Google Groups, etc.

Edited December 10, 2010 by save2600

[Underball]

Short answer: no.

 

Long answer: Now might be a good time to learn how to use the search function of this site.

 

No? No to what? I ask many questions. Please be more specific as to what part works and what doesn't.

 

I did search. Nothing had my question, and it's an awful search. I don't want to start an argument, but look try searching it. It doesn't even just search 7800, it has to search EVERYTHING. There were 1000 results, none of them helped me.

 

Thank you for commenting.

You absolutely can search specific forums.

[Rex Dart]

No? No to what? I ask many questions. Please be more specific as to what part works and what doesn't.

 

 

 

Really, you asked two questions: does a 3-button sega pad work as a 2-button 7800 pad, and the same for a 6-button sega pad. "No" applies to both. One button will work, the other button will register with the 7800 as being permanently held down. If you thought Jinks couldn't get any worse, play it with a sega pad.

[kool kitty89]

Same thing for the master system, just one button will work... and nothing will work on the MSX/x68000 as the ground line is different.

 

The 7800 uses an odd (and unique) analog hack for the 2nd button, not just using 1 analog line for a button (or even remapping a pot line to an unused RIOT line when in 7800 mode), but an odd hack that allows both buttons to act as the normal fire button for VCS games.

 

Most of the 8-bit consoles/computers using digital joysticks with DE-9 ports (vectrex is analog) used a fairly common pinout with general cross-compatibility for at least up/dn/L/R and one fire button. (the SMS has an added button -which the Genesis is backwards compatible with- and that second button line is also compatible with the 2nd fire button/right mouse button on the ST and Amiga, but the +5V and 3rd button on the ST/Amiga don't match up with the 5V line on the SMS/Gen and there is no 3rd button line on the SMS but one reserved for a photo diode and used as a select line for the Genesis) None outside of the 8-bit atari machines had compatible analog pinouts to the VCS AFIK.

 

I'm not sure about the colecovision's pinout... I think at least the usual directions+fire button match up (and ground), but I'm not sure about the 2nd button, let alone how the keypad comes into play. (at least 4 lines would need to be dedicated to the keypad if it's a pure parallel interface, so the 2nd button is probably multiplexed among the keys and intended not to be used simultaneously -the 5200 multiplexed the 2nd fire button along with the keys too- but that might mean that the 2nd fire button matches the Sega pinout -and by extension the ST/Amiga pinout)

Incidentally, if the CV controllers work like I think they do, that would have been the very same mechanism Atari could have used to provide similar controllers for the VCS/A8/7800 (or 5200 had they used PIA and the same A8 ports) with the exception that you'd be hacking 2 analog lines as digital lines like the VCS touchpad. (rather than using direct digital lines... or using the analog lines for the joystick )

[Rex Dart]

 

 

The 7800 uses an odd (and unique) analog hack for the 2nd button, not just using 1 analog line for a button (or even remapping a pot line to an unused RIOT line when in 7800 mode), but an odd hack that allows both buttons to act as the normal fire button for VCS games.

 

 

Really? And here I thought it was just sloppy 80's design. I guess I would've found this out if I had any 7800 controllers in working condition, but they're such garbage. Good to know!

[kool kitty89]

There's a schematic floating around (saw it on AA at least once), but I haven't been able to dig it up again... As I recall, it actually used BOTH analog lines and the normal fire button to make the circuit for the 2nd button. (honestly I don't see why they bothered doing that rather than just making the left button the VCS button and pulled one of the pot lines through for the 2nd button, let alone possibly 2 pot based buttons... not only that but then VCS games could use the added buttons too ) Or cut off the POT lines when in 7800 mode and configured the pot lines as normal digital lines to be read by RIOT. (I believe there's at least 2 unused RIOT lines unused, maybe 3 -no BW/color switch on the 7800 but I think the difficulty switches were retained)

[Bakasama]

This thread might be of some interest.

 

I do recall, vdub_bobby I think, talking about 7800 games could use the C button, if programed or hacked to use it. I also remember GroovyBee saying it's possible to program a game to use the six buttons on that particular Genesis controller.

[kool kitty89]

This thread might be of some interest.

 

I do recall, vdub_bobby I think, talking about 7800 games could use the C button, if programed or hacked to use it. I also remember GroovyBee saying it's possible to program a game to use the six buttons on that particular Genesis controller.

 

I'm not sure how you could use that on the 3/6-button genesis controller (6 button actually has 8 buttons including start and mode) without modifying the 7800 even if you could manage a proper software protocol to poll the multiplexed output from the Genesis pad.

namely, the lack of a 5V output to the controller on pin 5 (to power the multiplexing circuit), and the fact that the multiplexing I/O line is on pin 7 which is +5V on the 7800/A8/VCS/Amiga/ST. So the only useful I/O lines would be pins 1/2/3/4/6/9, and 9 would have to be hacked as it's a pot line.

Hmm, OTOH you have the possibility of the multiplexing circuit pulling through the pin 5 POT line and +5V in an odd manner (as they're flipped) in conjunction with the pin 9 pot line, so that might be useful if it operates in a reliable fashion. (not sure how the multiplexing circuit would behave with the voltage and select lines flipped like that)

 

Give your statement, it sounds like that phenomenon has already been studied and tested (probably with a fair bit of trial and error), and found to be useful to some extent. (it's not clear how CPU intensive it would be or if it would allow full functionality of all 4/8 buttons on the 3/6-button genesis controllers)

 

 

 

Interesting thread you posted though... so the SMS/Genesis uses pull up resistors to output digital 1 values when buttons aren't pressed, perfect for pin 9 on the 7800 (or VCS for that manner). I wonder if the VCS uses pull-up resistors inside the controller for a similar purpose.

I don't remember seeing resistors in my genesis controllers (there are definitely some on the controller ports on the motherboard), but they could be surface mounted and less visible.

 

But I didn't see any mention of the C button (or start), just the A button used as a 2nd button in the manner that I'd have expected the 7800 pad to use originally. (rather than the odd dual pot line+button line hack it uses) So the SG-1000 or SMS pads should also work. (not sure about colecovision)

 

 

Wait... if the VCS/A8 sticks and Genesis/SMS pads are already functionally compatible, wouldn't that mean they used a similar mechanism overall? (including pull-up resistors?) Though the VCS and SMS both lack 5V input on the gamepads, so I'm not sure how that would work.

Edited December 12, 2010 by kool kitty89