4 Player Adapter

Talk about programming CreatiVision (except games programming). Projects of homebrew hardware are also welcome.
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Mobsie
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Location: Weinheim, Germany

4 Player Adapter

Post by Mobsie » Mon Sep 23, 2013 1:07 pm

As we have a keyboard on the Creativision, a half on each controller, is easy to make an 4-Player adapter.
One friend and i think about this long time because we like the 4 player stuff on the Atari`s
But with the CreatiVision is easy i think because we only have to map the Joy-Movement to keys on the 2 extra Controller.
With the Keys program from Carlson i test and see that nearly all combination are possible.
One problem is that the CV don`t use standard connector like Atari etc.
What do you think?
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MADrigal
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Re: 4 Player Adapter

Post by MADrigal » Mon Sep 23, 2013 3:45 pm

That would be a great addition to the CreatiVision! ;)
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carlsson
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Re: 4 Player Adapter

Post by carlsson » Mon Sep 23, 2013 4:47 pm

Perhaps more important than how the BIOS stores input data to be picked up by the program, is how the pinout is on each connector. I seem to recall it is a matrix, a total of 9 pins that cover 24 buttons, 16 joystick directions and two fire buttons. Did anyone document how the pins are assigned? I suppose that would be the first step on making an adapter. BIOS disassembly perhaps? Could one of the clues lie in that in the bitwise registers $18-$1B, the combined direction right-down also equals the code for "1" and "space". Then again, 5+8 bits = 13 rather than 9 pins.
kevgal
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Re: 4 Player Adapter

Post by kevgal » Thu Aug 07, 2014 2:12 am

The CV uses a scanned keyboard approach to its mapping. It seems each controller uses 2 'source' pins and 8 'destination' pins, each character or joystick button is selected when 2or more of these are shorted. Has anyone generated a keyboard matrix for all the keyboard buttons? This can be done with a multimeter and testing which pins are shorted together when each button is pressed. Unfortunately I don't have any keyboards left as I threw them away years ago but kept the console which is controlled by an adaptor.
BTW source pins are 1 and 2 for the left controller and 9 and 10 for the right.
Eg left joystick map
Up = 2+6
Down=2+4
Left=2+10
Right=2+5
Fire1=2+8
Fire2=1+8
Start=1+7+9
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