[Coco] joystick on fpga (was Why do a next Gen CoCo? was Any news on the so called CoCo4 or NextCoCo)

[Mark McDougall]

On 19/11/2010 11:12 AM, Aaron Wolfe wrote:

> I'm wondering, would it be more difficult to interface with tandy
> joysticks?  I'm not too familiar with the controllers you mention, but
> I thought most game systems used dpad,  4 or 8 position switches
> rather than the x/y analog axis found in the coco joysticks.  seems it
> would be hard to play some games without that.. plus everybody
> probably has the tandy sticks already.

The Gamecube controller has *2* analogue joysticks and you need 1 resistor 
to interface it to the DE1.

The Tandy joysticks will require analogue-to-digital converters.

I have had a Gamecube controller hooked up to Coco3FPGA on the DE1. The only 
problem atm is that the controller needs to be calibrated for the Coco 
because it doesn't report the full range of each axis, and some Coco 
software requires that it does so (eg. Clowns & Balloons IIRC).

What this requires is a calibration routine & scaling/offsetting the values 
before they are passed to the Coco3FPGA core - not difficult but also not 
trivial (multipliers in the FPGA).

Dreamcast controller require a couple of level-translators IIRC, but we also 
have a Maple Bus (Dreamcast) interface which works. What is really cool is 
that you can get 'arcade' joysticks and steering wheels for the DC that you 
could also hook up to Coco3FPGA. Jot to mention fishing controllers, light 
guns, marraccas, and dance mats! ;)

Regards,

-- 
|              Mark McDougall                | "Electrical Engineers do it
|  <http://members.iinet.net.au/~msmcdoug>   |   with less resistance!"