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Can we read all Sega Genesis buttons?


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Pin 7 is normally NC on Atari sticks (+5V) unless used e.g. to drive an autofire circuit or other accessory item.

 

On the Sega stick +5V is expected on pin 5 and pin 7 is used as Select to choose which buttons are returned.

So, an unmodded controller won't allow all functions.

 

I recall there being at least one Sega controller that was supposedly unsafe to use on Atari and C= machines, not sure which one though.

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I've tried several models, original sticks, and later models with more buttons, and third party remakes. None worked well with BASIC and stick() functions. After a few minutes the sega stick stops responding. Maybe there is some kind of polling protocol/PIA setup to write something top the port before reading the values.

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The problem is we can only control output to pins 1-4 via PORTA/B.

 

The STRIGs are read only. Amiga CD32 controllers I believe use output from the computer on this line for extra functions.

The POTs are read only, connected from +5V/GND to the paddle pots.

GND and +5V are fixed in their function.

 

As I mentioned, from the pinouts guide, Sega chose to supply +5V on pin 5 and reassign Atari's +5V pin as a select line.

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I've tried several models, original sticks, and later models with more buttons, and third party remakes. None worked well with BASIC and stick() functions. After a few minutes the sega stick stops responding. Maybe there is some kind of polling protocol/PIA setup to write something top the port before reading the values.

 

I've never had an issue with real Sega Genesis controllers, I use them in all of my Ataris. I do have a newer knock off controller that exhibits the same issue. But, it only happens in a machine with expanded memory.

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  • 3 weeks later...

Correct. I wrote a Tetris game in 1991 (Tetricize) that uses the B and C buttons on the Genesis controller for rotating blocks left and right. The controller can also be used on Bill Kendrick's "Gem Drop" and also possibly on the Atari 2600 Super Mario clone "Princess Rescue" (I can't remember if the programmer added this functionality or not).

 

You can read the B button as the regular fire button and the C button (I think it's tied into the paddle inputs). Other than that, the A and the Start can't be read without hardware modifications.


Sent from my iPhone using Tapatalk

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