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General Category => Amstrad CPC hardware => Topic started by: AlexGS on 23:37, 26 April 21

Title: GX4000 pause button/controller question
Post by: AlexGS on 23:37, 26 April 21

I've decided to build a joystick (Sanwa parts and a project box) for my GX4000, so that I don't have to endure the official controller.

Many of the GX4000 conversions for use with the C4CPC use the console's pause button for various functions, (https://www.cpcwiki.eu/index.php/Converted_GX4000_Software) so my question is this:

Given that the GX4000 seems to have two(?) unused pins on the joystick port, would it be feasible/possible to extend pause button functionality to a button on the joystick?

While I'm comfortable with soldering and such, I don't know much about CPC hardware so thought I'd ask the experts before poking about inside the console.

Cheers!
Title: Re: GX4000 pause button/controller question
Post by: eto on 08:57, 27 April 21
Quote from: AlexGS on 23:37, 26 April 21Given that the GX4000 seems to have two(?) unused pins on the joystick port, would it be feasible/possible to extend pause button functionality to a button on the joystick?

Not without doing some internal modifications of the GX4000. Pin 5 of the GX4000 is not connected internally. Probably also not 9. The GX4000 is more or less just a normal Amstrad home computer in a different form factor and the soundchip is used for keyboard and joystick. The Pause button of the GX4000 is mapped to the keyboard matrix as if it would be a "P" of a normal CPC keyboard. You can't recreate a P with the joystick port.


If I am right that both 5 and 9 are not connected, I could imagine that this could be a feasible workaround, albeit of course not compatible with anything but your specific GX4000 and joystick: solder pin 5 and 9 in the joystick to the pins of a third button and then solder pin 5 and 9 of the connector inside of the GX4000 to the pins of the pause button (not sure how that looks in the GX4000). The third button on your Joystick would then close the connection instead of the Pause button and would "press the P".
Title: Re: GX4000 pause button/controller question
Post by: AlexGS on 20:01, 29 April 21
Thanks for the info, I'll try that out.  :)
Title: Re: GX4000 pause button/controller question
Post by: GUNHED on 00:41, 30 April 21
On my 6128plus I did solder a diode in for Fire 3 (if 2 if you start counting at 0).
Take a look at the joystick port and you see it.
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