[Coladam] analog vs. digital joystick input

Kevin Powers kjpmail at gmail.com
Wed Sep 4 16:07:56 CEST 2013

Huh. Yet another instance in which the SmartBASIC manual is wrong? (See the
page for the PDL command.)
 On Sep 4, 2013 9:47 AM, "Geoffrey Oltmans" <oltmansg at gmail.com> wrote:

> Nope, that won't work. Still no ADC inputs on the joystick interfaces.
> The Atari driving controller (that is used for Indy 500 and a scant few
> other games) might be directly adaptable to work, since those controllers
> are quadrature-encoded like the Roller Controller is (similar to what is
> done for mice), but it would only work for games that use the roller
> controller  (and then you'd be missing a fair few buttons). There's no
> analog inputs at all on the CV/ADAM. When paddle controllers are used on
> the CV or ADAM, it's as Rich describes... the controllers are plugged into
> the expansion module, and those are interfaced directly to the TIA chip,
> which does have inputs for up to four POTS (the game Warlords would allow
> for four paddle players for example). Actually going back and reading the
> TIA manual, it appears that these inputs are not "real" ADC inputs, but
> rather the potentiometer on the paddle controller is hooked up to a
> capacitor. This capacitor is discharged by setting a digital output to dump
> the charge and then released. The capacitor is charged and while charging
> the system counts how long it takes for the digital input connected to the
> capacitor circuit to change to transition from a 0->1 state (or vice
> versa). Clever way of doing it really, and probably more akin to how light
> pen inputs are done on older computers that had such things (since it
> appears to be related to the refresh timing circuitry in the TIA chip).
> Probably not near as fast as a real ADC either. At any rate, you could
> probably do something like this on the CV, but it would require external
> circuitry to support, and either you would have to patch the BIOS or bypass
> the joystick scanning routines to do it, but there's enough signals
> available through the joystick interface that something similar could be
> constructed.
> On Wed, Sep 4, 2013 at 6:16 AM, Kevin Powers <kjpmail at gmail.com> wrote:
>> What about via a pair of Atari paddles?
>> On Tue, Sep 3, 2013 at 11:42 AM, Geoff Oltmans <oltmansg at gmail.com>wrote:
>>> Only digital. There are no adc inputs in the joystick ports.
>>> Sent from my iPhone
>>> On Sep 3, 2013, at 10:35 AM, Kevin Powers <kjpmail at gmail.com> wrote:
>>> > Does the Coleco stick send both analog and digital joystick data to the
>>> > ADAM?  Or is it only digital?
>>> > _______________________________________________
>>> > Coladam mailing list
>>> > Coladam at adamcon.org
>>> > http://adamcon.org/cgi-bin/mailman/listinfo/coladam

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