D-pad Modification Project In Progress- Need A Bit Of Info!


Epicenter

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I am currently in the process of adding a D-Pad to my GP2X (MK1, Non-First Edition unit). I'm using equipment generously provided to me by Radek with some modifications-- I'll be providing photos upon completion along with information on what exactly I did. Once I have the relevant info which is why I'm posting this thread, it should not take long at all, assuming my GP2X does not explode in a maelstrom of fire, sparks and fury.

Anyway! I'm to the point where I must know which pins on the GP2X stick connect to each other when the 4 ordinal directions on the default stick are pressed; UP, DOWN, LEFT, and RIGHT. I will quote Bacteria's thread (http://www.gp32x.de/board/index.php?showtopic=27227&hl=) with this bit:

Bacteria said:
C & I seem to do the same thing and only one is required, so I use "I" (try using "C" if you prefer).

A+I = up
D+I = left
G+I = down
J+I = right
F+L = centre push

However, there was a picture once showing where A, D,G, J, F and I *were* on the board. As it stands, none are labelled and the names seem to be mostly arbitrarily assigned, so this diagram was really all I had to go on-- however, it seems to have fallen off the face of the internet.

So I did a little more detective work. Grahf went ahead and stuck an NGC d-pad on his '2x and posted a few images. The most useful were these two:

contact%20pad%20back.jpg

contact%20pad%20front.jpg


Inverting the image of the NGC pad's contact board, I could faintly make out traces, so I drew over them as below and labelled them as I Believe they are wired to the GP2X board. Note how the one I marked as going to pin I or C (in all probability) does not terminate at a switch but forms the common trace that touches one side of EVERY direction's switch. This leads me to believe it is a HI (3.3v?) or GND trace hooking to I/C that is coupled with the appropriate direction line when a switch is closed.

invertcu8.jpg


.. here is another image from Grahf I inverted which shows the same trace structure.

labelledpadbackzb3.jpg


The other 4 lines appear to lead to the pins I labelled above. Look legit? What I've made are of course just educated guesses; very educated but still just guesses. Since the stick is dismantled already I'm unable to do continuity checks to confirm anything, so any useful information before I go experimenting some more and wasting a lot of time would be extremely helpful. Thanks a ton to anyone who can offer a tidbit of advice here or there! (oh yes, and of course; I've PM'ed Radek, Grahf and Reesy about this one..) ;)
 
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forget crappy d-pads, hurry up and release your game!


*cough*

about the dpad though...cant help... whats radeks status though on selling his kits?
 
You pretty much got it. Unfortunatly i didnt write anything down, but its real easy to double check with a meter.

Hopefully everyone notices that the gamecube pcb is rotated to fit, so of course the directions printed on it are wrong. I know its obvious, but i had someone ask me that already.
 
@ Epicenter - just sent you a PM in reply to your PM to me - hopefully this will give you some useful assistance.

My reference to "A" is the connection with grahf's green wire on your first picture, working clockwise; so "C" is on the right, etc - so the picture at the bottom of your topic ("to pin A?" etc) is correct.

Using a tin-foil and mounting board construction D-pad can make a slim and externally mounted unit without the issues about mounting rubber membranes and cutting holes in the GP2x itself. It is robust, surprisingly; the one I made at the end of April is still being used extensively. Problem is making this design look nice instead of "home-made".

Post your pictures and updates on your progress. If I can add advice to your project, I will - after all, I spent a considerable time on R&D on this, which might help.
 
Excellent; it looks like this should work fine. I'm glad to see my bizarro-reverse-engineering just might pay off after all. :D

We're taking lots of pictures along the way, there'll be no shortage of documentation! :) If all goes well we'll record some video too. I prefer it be an internal modification since my GP2X feels just like a GBA, and a low-sitting D-Pad like the NGage QD one sits nice and low just like a Nintendo D-Pad.

Doing the rest of the modification tonight-- stay tuned for updates (I'll probably be up all night again.. ;) )
 
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