25 replies to this topic

[OldSchoolRetroGamer]

Out of all the Atari 7800 specific games which ones absolutely required the 2nd button to play properly? Thanks.

[rmaerz]

OldSchoolRetroGamer, on Thu Oct 14, 2010 9:48 PM, said:

Out of all the Atari 7800 specific games which ones absolutely required the 2nd button to play properly? Thanks.

Rampage

[AtariLeaf]

I'm pretty sure Hat Trick and One on One Basketball did. Xevious also used it but it could be played with a one button stick but both guns would fire at the same time. Choplifter too maybe? I'm going by memory here but I know Hat Trick and One on One need two buttons for sure.

[Harry Potthead]

I think Ikari Warriors & Commando need the 2nd Button for Grenades.

[CRV]

Scrapyard Dog
Ninja Golf

[Rex Dart]

Jinx
edit: Choplifter too, yeah

Edited by Rex Dart, Fri Oct 15, 2010 9:39 PM.

[thursday83]

C'mon. Hat Trick is a one button game.

[CRV]

Basketbrawl
Dark Chambers
Double Dragon
F-18 Hornet
Fatal Run
Karateka
Mat Mania Challenge
Midnight Mutants
RealSports Baseball
Super Huey
Tank Command
Tomcat: The F-14 Fighter Simulator
Water Ski
Xenophobe

[OldAtarian]

How does the 7800 read the second button? Is the joystick port wired differently than the 2600 like how the mouse port on the ST is wired differently from the joystick port on the XL/XE? If the port is wired exactly the same on the 7800 as on the 2600, then shouldn't you be able to enable the second button in 2600 games?

Edited by OldAtarian, Sat Oct 16, 2010 5:43 AM.

[tkarner]

Planet Smashers - Right button cloaks your ship
Motor Psycho - Right button jumps

[frunobulax]

OldAtarian, on Sat Oct 16, 2010 5:42 AM, said:

How does the 7800 read the second button? Is the joystick port wired differently than the 2600 like how the mouse port on the ST is wired differently from the joystick port on the XL/XE? If the port is wired exactly the same on the 7800 as on the 2600, then shouldn't you be able to enable the second button in 2600 games?

I wonder the exact scheme too.

I know that the Proline stick is compatible with the 2600 (and 2600 games run on the 7800) because it ties the "Button" (aka fire) pin to ground with either controller button press. However, at the same time it's doing that... it connects the pins on the controller port that would be used for analog paddle inputs on the 2600, to Vcc or +5v in this case.

I found this out while debugging the NES controller adapter I am currently working on for 7800. It is major reason I decided to not make both "b" and "a" buttons on the NES controller equal a "fire" in 2600 mode. It would require another gate or some more components from what I know now, as connecting both buttons to the 2600 "fire" pin also allows current to flow between the 2 buttons when in 7800 mode. Effectively making the 7800 think you are pushing both at once no matter which you pushed. I was able to exclude one button from this fiasco with a diode, but adding a diode to the other line caused the button not to work properly in some 7800 games.

I think I need to just understand what is going on a little better. Any help is greatly appreciated.

[kool kitty89]

OldAtarian, on Sat Oct 16, 2010 5:42 AM, said:

How does the 7800 read the second button? Is the joystick port wired differently than the 2600 like how the mouse port on the ST is wired differently from the joystick port on the XL/XE? If the port is wired exactly the same on the 7800 as on the 2600, then shouldn't you be able to enable the second button in 2600 games?

It's a weird hack that uses both of the analog pot lines and the 2600 fire button line iirc. (can't seem to find the shematic but I know it's been posted before) It was done that way to allow both buttons to act as normal fare buttons for 1-button games and 2600 games I believe.
Had they not bothered with the dual button compatibility they could have simply used a single pot line and pulled the 5V line through like the 2600 keypad did. (using both pot lines would actually have allowed 3 buttons in that simple set-up just as was possible for the 2600 and A8 -short of more complex multiplexing schemes and/or added resistors for more analog input values) That or they could have disabled the 5V and analog lines altogether in 7800 mode and used them as 3 additional digital lines. (but that would have required logic to switch I/O modes and additional I/O ports unless they remapped RIOT's I/O in 7800 mode)

Edited by kool kitty89, Mon Oct 25, 2010 2:03 PM.

[Atarifever]

Whatever anyone tells you, Xevious requires it. It's like saying Mario only needs one button because you can walk and not shoot fireballs and still "play." Xevious needs both guns working separately for the game to play the way it is supposed to.

[frunobulax]

I would say Pole Position II (if anyone plays it) also requires it. Although you can probably get away with breaking by downshifting, I find that the extra button as the break peddle makes it much easier to avoid collisions.

[tkarner]

I found this relevant link:

http://www.atari7800.org/7800list.htm

[jetset]

How about Asteroids? I know you can do hyperspace by pushing "down" on the controller, does the right side button activate hs as well or just fire?

[Harry_Dodgson]

Combat 1990 needs both buttons - fire and shield

[toiletunes]

IIRC it isn't possible to play 2-button games with a 1-button joystick because the missing second button will always read as "on"

So for Asteroids, you'll constantly hyperspace, pole position won't move because the brake is on, etc.

[The MilkMan]

AtariLeaf, on Fri Oct 15, 2010 6:05 AM, said:

I'm pretty sure Hat Trick and One on One Basketball did. Xevious also used it but it could be played with a one button stick but both guns would fire at the same time. Choplifter too maybe? I'm going by memory here but I know Hat Trick and One on One need two buttons for sure.

This makes sense. I just got a 7800 and only have a 2600 joystick. One on One, Baseball, and 1 other i cant remember I couldn't get to work. Looks like i'll have find some 7800 sticks!

[BrianC]

toiletunes, on Thu Oct 28, 2010 6:53 PM, said:

So for Asteroids, you'll constantly hyperspace

If I remember correctly, Asteroids detects the joystick and does hyperspace with down when using a 1 button controller.

[toiletunes]

I wish it did, but I keep jumping all over. Maybe there's two roms?

[Mitch]

toiletunes, on Tue Nov 30, 2010 9:58 PM, said:

I wish it did, but I keep jumping all over. Maybe there's two roms?

Are you using a third party joystick? There's only one ROM, other than the proto versions.

Mitch

[toiletunes]

Ah, that makes sense. I've been using a genesis controller- never thought it would cause trouble- learn something every day

[Chuplayer]

I actually just googled this because I just tried playing Hat Trick with a 2600 controller, and I can confirm the button didn't work. Bummer because the game's only a single button game.

Directions work, though. If you start the game with a 7800 controller and swap to a 2600 controller, all you can do is move your guy around. You can't shoot the puck.

[Rex Dart]

Actually, Jinks didn't utilize the second button so much as it squandered or wasted it.