Gp2x Dpad mod help?

palmertech · Post by **palmertech** » Fri Feb 29, 2008 12:10 am

Mods, i know i have another thread, but this is a separate problem that dserves its own thread (I think). As per my gp2x home console thread, i hooked up an snes controller to my gp2x by simply extending the traces to the the snes controller ones. When i was done, i checked in tool mode to make sure that all the buttons work, and they did. However, when i entered pocketsnes, i was able to choose a game, but when i selected it, the screen froze and the gp2x locked up! I then tried gnuboy2X...Same problem! In fact, all my emulators freeze up at boot, at menu, or at rom launch! What could be causing this? All my homebrew works, and doom, quake, descent, vektar, and payback all work fine! Only my emulators freeze up. My only clue is that if you tried to start a game in pocketsnes before while holding down a button (like Start)it would freeze until you let go. But i have never observed this in any other emu. Please, what in the world could i be doing wrong?! All i did was extend the gp2x buttons...could it be that there is not enough power going to the traces? Do i need to "pull down" the signal? Thank you in advance.

bacteria · Post by **bacteria** » Fri Feb 29, 2008 3:15 am

It is not just a case of wiring from the GP2x buttons to the SNES ones, you have one other issue to deal with (which I discovered on my Nintendo 64 Advance project) - if you have one mobo working with another one (especially a SNES or N64 controller I add), due to the way they carry data, you can easily have a situation where data is sent from one path to another and that path to another, etc - causing unpredictable results. What you need to do, if you want this to work, is to stop signals moving about on the SNES controller by scraping or dremeling off the contact traces from the SNES traces, so you literally only have contact to the button traces themselves. This also means you need to wire to the other side too (one side is ground the other is the contact).

The pic below is for an N64 controller, however the principle is the same. The yellow circles show the ground contacts (you wire to the other side), the yellow square are good places to solder a ground wire to, white lines show the places you would cut away the traces from the mobo to break their original contacts.

palmertech · Post by **palmertech** » Fri Feb 29, 2008 11:21 am

Thank you! I will try that, i figured it had something to do with a messed up signal (due to the fact that it had the same symptoms as a button pressed down). So just a few questions! First, does the wierd signal have something to do with the snes controller chip? Could i just remove that from the board? Someone else once hooked up a snes controller to a gp2x, and instead of soldering to traces, he just removed the circuit and put the wires in its place. Second, the snes board is one sided, with a huge trace going around the perimeter of the board. Can i just solder one ground wire to that, as all the buttons are already connected, or do i need a wire for every contact? I am thinking maybe not? So can i just remove the controller circuit from the board, or do i have to actually get rid of trace connections? Thank you for your help bacteria! After i get this working, i will revert to my old thread.

bacteria · Post by **bacteria** » Fri Feb 29, 2008 1:47 pm

Yes, it will be to do with the controller chip in the SNES; however with my method it is far better as you are severing the contacts from going anywhere. You can easily scrape the green silkscreen off with a small screwdriver to expose the metal contact, what you do is to scrape/dremel off the contacts in the manner I shown on the previous post, and then double check with a multimeter that there is no contact on both sides of the trace - then you are ok.

Ground is ground, what you do is to connect the ground from the GP2x and connect that to the ground in the SNES controller. If there is a break somewhere (as per my pic), you simply solder a wire from one ground connection to somewhere else on the board (see pic, the orange squares?).

You can visually see the traces on your SNES mobo so can easily decide what you use and what you terminate. The ground is common to all the buttons, so the one which connects to multiple buttons is ground, the other side is the other button contact.

You only need to solder wires to one or two ground contacts, and then one wire to each of the buttons on the opposite side (non ground side).

The huge trace you mention around the board is ground.

This is far better than removing parts from a board, and anyway, somewhere else might share the connection, so you are back to square one - with my method you are severing the links, so you know it works!

palmertech · Post by **palmertech** » Fri Feb 29, 2008 2:06 pm

Thanks. The main reason to remove the chip instead of cutting traces is that i can then use the chip to make a custom snes controller to replace the one that i took for this project!

So i think i will do that. Another reason is that i have already soldered the connections near the center of the board, near the chip, so i would have to make sure that i dont detach any of the wires as i cut traces. I already lifted one side of the board, but i have to go to my classes.

So i will finish tonight most likely (unlike some people who havemonths long ongoing projects, i cant rest until i finish, so most of my projects dont take very long! If this works (which i am sure it will) i will revert to posting in my main thread.

palmertech · Post by **palmertech** » Sat Mar 01, 2008 12:00 pm

NOOO! I tried to remove the chip, but it still does the same thing. How is this possible? I only have one ground wire right now, could that be it? If not, i will do what bacteria says and cut the contacts...

palmertech · Post by **palmertech** » Sat Mar 01, 2008 4:06 pm

I was reading online, and some guy that hooked up an nes controller to a dreamcast the same way that i am doing my mod said that you have to take the chip on the nes controller mobo, or it might fry the controller. I just cut all the wires from the snes controller to the gp2x, and....using the normal controls, it still does the same thing! :cries: Does this mean that i have damaged my gp2x? Are there two kinds of input, because all my homebrew, ports, and commercial games work, just not emulators! Also, the music player is affected, but not the video player...What should i do?!? Am i totally screwed? Please help!

bacteria · Post by **bacteria** » Sat Mar 01, 2008 5:01 pm

If your GP2x works fine without the connections to the SNES controller (snip the wires if they are connected, or desolder them first), then all is fine.

You obviously haven't tried the method I suggested in previous posts to connect to the traces and cut the traces at the other side so only the trace going to the button part works.

palmertech · Post by **palmertech** » Sat Mar 01, 2008 5:08 pm

I did cut the wires. When i said it does the same thing, i meant that it still has a problem! So even without the controller connected, it still freezes on emulators. This tells me that something on the gp2x side is wrong.

And i did try your method, but same symptoms! So either something is wrong with the wiring on the gp2x side (dont see how that is possible), or something is wrong with the gp2x. But what? Any other suggestions, no matter how wild?

bacteria · Post by **bacteria** » Sat Mar 01, 2008 5:27 pm

If the GP2x plays up without any connections between the two devices, then it is likely that the GP2x has developed a fault.

Only other thing is if you have overclocked the GP2x too high, which can give all sorts of issues; test your system at no more than 240mhz.

palmertech · Post by **palmertech** » Sat Mar 01, 2008 5:29 pm

I was testing at standard clock speed. Bummer. looks like i fried my gp2x. I think i will register at the gp32x forums and see what they have to say.