Using an Atari 2600 paddle controller in a genesis homebrew

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ComradeOj
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Using an Atari 2600 paddle controller in a genesis homebrew

Post by ComradeOj » Sun Aug 16, 2015 7:04 pm

Hi, everyone!

I have been working on a Genesis game, and it's almost completely done. But, before it's done I want to switch the control scheme from using the d-pad, to using an analog paddle. It's one of those games where you have to move a character through gaps in a constantly moving wall. Kind of like flappy bird, I guess.

Anyway, is it possible to read the Atari 2600 paddle controller using the Genesis? I know the plug is the same, but what about the pin config? I was reading a thread on Atari Age, and some people were saying that the Atari 2600 has a capacitor inside the console that gets charged by the paddles. Does that mean a Genesis couldn't make use of the paddle controller no matter how it was programmed?

http://atariage.com/forums/topic/126180 ... e-paddles/

I also noticed that some paddles up for sale online were labelled "Driving" and some were labelled "Paddle". Do they actually work different, or are they just named different?

Charles MacDonald
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Re: Using an Atari 2600 paddle controller in a genesis homeb

Post by Charles MacDonald » Mon Aug 17, 2015 1:41 am

Does that mean a Genesis couldn't make use of the paddle controller no matter how it was programmed?
That's right. The Atari systems that used the paddle had dedicated hardware for converting the the two analog inputs on the connector to a digital value for the CPU to read. For that reason it's not compatible with the Genesis.
But you could make a pass-through circuit that goes between the paddle and console which has a microcontroller to read the paddle voltage and present that information to the Genesis.

There's a lot of different approaches, I think I would use something like a PIC12F675 that reads the analog inputs and shifts out the digital values to a 74LS595 shift register, which the Genesis can read using a 74LS157 multiplexer. This way D0-D3 would carry the 8-bit data, TH could select which 4-bit half is being read, TR could be a paddle button input, and TL is free.

That's for one paddle, the Atari joystick connector supports two paddles with one button each so it's a little more complex if you want to support a second paddle.
Shame the Genesis can't do serial at rates over 4800 bps otherwise you could use that to simplify transmitting data to the console. But at 60fps you could only get 8 bits per frame of analog data (assuming 8-N-1), so no two-player mode. :)

I may be mixing up the Atari 8000XL paddle with the 2600 one a bit, but the principle is the same. The Driving and Paddle controllers work differently according to this review:

https://www.youtube.com/watch?v=r4T7r_cQLwM

ComradeOj
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Post by ComradeOj » Mon Aug 17, 2015 2:36 am

Thanks for the reply!

That's too bad that it wouldn't work by just plugging it directly into the Genesis. I was hoping I could program the game to use the paddle with no modifications or extra hardware, that way anyone with an Atari 2600 paddle could play it.

I'll just try to make the game work as best as I can with a regular controller.

bgvanbur
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Post by bgvanbur » Mon Aug 17, 2015 2:11 pm

In high school (15 years ago) I made a converter box for atari paddles to the PC game port (just a straight connection of a few lines) and made a few Visual Basic games that used the paddles (5 total but only remember breakout and tetris specifically). So I first started with genesis programming I was hoping to use the paddles once again but found out just like mentioned above the genesis doesn't handle the analog inputs.

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