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Sega Genesis controller interface?


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#1 cbmeeks OFFLINE  

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Posted Thu May 17, 2018 7:40 AM

Is there a converter for the TI that would allow me to use a standard Genesis pad and have access to all buttons?

Thanks!

#2 AMenard OFFLINE  

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Posted Thu May 17, 2018 8:11 AM

Are there TI-99/4A games that are so complex as to need more than one or two buttons at most, or is it for a homebrew project?



#3 cbmeeks OFFLINE  

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Posted Thu May 17, 2018 8:15 AM

Its for a home brew project one day.

#4 AMenard OFFLINE  

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Posted Thu May 17, 2018 8:56 AM

The TI can have two joystick pluged in, either the TI branded or the Atari model via an adapter.

 

Personnaly I would use an adaptor (atari) and modify it so the directions are mapped to joystick 1 and the extra buttons are mapped to the functions of joystick 2. You'll then have to program the behavior when some of the J2 functionality is activated.



#5 cbmeeks OFFLINE  

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Posted Thu May 17, 2018 9:10 AM

Ive tinkered with that idea before. Hmmm

I wonder how hard it would be to latch the Genesis pad values and then stream them in via the fire button? Sort of like a parallel to serial conversion. Of course Id have to write a driver for it on the TI. And it wouldnt work with legacy games.

#6 AMenard OFFLINE  

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Posted Thu May 17, 2018 9:13 AM

Ive tinkered with that idea before. Hmmm

I wonder how hard it would be to latch the Genesis pad values and then stream them in via the fire button? Sort of like a parallel to serial conversion. Of course Id have to write a driver for it on the TI. And it wouldnt work with legacy games.

 

Depends on how the TI reads up the data from those pins. Does the TI support paddles? If yes than you may have the possibility of reading a range of value from the coresponding pins (0 to 255 for example).



#7 OLD CS1 OFFLINE  

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Posted Thu May 17, 2018 9:14 AM

The MBX communicates with the TI via the joystick port.  Depending upon the pin-out of the Sega controller, and getting 5V to it in the first place, it should be possible to interpret a data stream from the controller.



#8 chue OFFLINE  

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Posted Thu May 17, 2018 9:48 AM

There's this thread about a homebrew adapter:

 

http://atariage.com/...or-the-ti-994a/



#9 iKarith OFFLINE  

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Posted Thu May 17, 2018 10:07 PM

The wiring of the 3 button Sega controllers is pretty easy: https://gamesx.com/w...is_controller_3

 

I'd post the image but the board says I'm not allowed to post a link to a png file.  (wat?)

 

This explains why they work on the Atari 2600 the way they do.  Atari provides power on pin 7, but Sega uses pin 5.  However, if you plug a Genesis controller into an Atari, the selector line is held high, which incidentally powers the chip.  This allows you to read the D pad on pins 1-4, the B button on pin 6, and the C button on pin 9.  If you power pin 5 instead so that you can toggle pin 7, you can read A and Start.

If you try to read with pin 7 low, left and right will both be pressed at the same time.  If they're not, you're not reading a genesis controller.

 

The six button controllers have a more complex protocol.

 

If you want an easy conversion, NES and SNES controllers are 8 and 16 bit shift registers.



#10 Osgeld OFFLINE  

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Posted Thu May 17, 2018 10:12 PM

 

If you want an easy conversion, NES and SNES controllers are 8 and 16 bit shift registers.

 

join like 20 years ago and get a micro and make an adapter for 3 bucks



#11 arcadeshopper OFFLINE  

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Posted Thu May 17, 2018 11:23 PM

I just sever the chip lines and rewire the 6 button so the extra buttons are joystick 2 button and directionals

And they are in stock at arcadeshopper

The wiring of the 3 button Sega controllers is pretty easy: https://gamesx.com/w...is_controller_3
 
I'd post the image but the board says I'm not allowed to post a link to a png file.  (wat?)
 
This explains why they work on the Atari 2600 the way they do.  Atari provides power on pin 7, but Sega uses pin 5.  However, if you plug a Genesis controller into an Atari, the selector line is held high, which incidentally powers the chip.  This allows you to read the D pad on pins 1-4, the B button on pin 6, and the C button on pin 9.  If you power pin 5 instead so that you can toggle pin 7, you can read A and Start.

If you try to read with pin 7 low, left and right will both be pressed at the same time.  If they're not, you're not reading a genesis controller.
 
The six button controllers have a more complex protocol.
 
If you want an easy conversion, NES and SNES controllers are 8 and 16 bit shift registers.


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#12 iKarith OFFLINE  

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Posted Tue May 22, 2018 2:55 PM

What's your mapping Greg?  I think it's probably important to have that documented so that people who do their own make something compatible with the ones you're selling.  That way people can start safely using them in new games.  :)



#13 OLD CS1 OFFLINE  

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Posted Thu May 24, 2018 8:23 AM

In systems which do not recognize the controllers for what they are, the "B" button is fire, "A" and "C" are ignored.



#14 iKarith OFFLINE  

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Posted Thu May 24, 2018 11:20 AM

I know how they work on Atari and other systems—they don't work that way on the TI without modification, and the  button controllers may not work at all on something that doesn't put 5v on pin 5.  (Atari standard puts it on pin 7, which powers the 74LS157 incidentally.)

Greg's got these 6 button controllers wired up using buttons other than B as joystick 2's inputs.  He can define 5 buttons and a start and mode button I suspect he's not using at all.  I was wondering what he's got A, C, X, Y, and Z mapped to on the second joystick port.



#15 OLD CS1 OFFLINE  

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Posted Thu May 24, 2018 2:40 PM

What I posed was for Greg's benefit.






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