This originally came from acidmods.
http://www.acidmods.com/forum/index.php?topic=22502.0

Posted at 9:17 am on Feb 22nd, 2009 by Tri-edge

The author submitted his blog. We prefer a nice blog writeup when possible. But its cool to see the progress and variations on those forums. I’ll update the post to add that link.

Posted at 9:54 am on Feb 22nd, 2009 by calebkraft

It looks like he failed on compatibility, the buttons are wired to the GBA slot pins. Yep you guessed it, the game crashes every time he presses a button.

I wonder if a pair of ATiny chips communicating over a 1-wire bus would be better? I am sure he could find a spare single pin not attached to the rom chip on the cartridge slot.

I wonder if the output from the button controller is hackable, he could just mimic the output and transmit the values directly into the CPU.

Cool, makes me want to hack :)

Posted at 9:55 am on Feb 22nd, 2009 by nubie

So far the best I have come up with is this: http://www.bottledlight.com/ds/index.php/Hardware/Chips

“Pxx = Pin? xx (goes to keys register, i.e. P00 is bit 0)

* P00, P01, P02, P03, P04, P05, P06, P07, P08, P09 ”

That is clearly just the raw pins, I wonder if there is a chip between the buttons and the main SOC that outputs the buttons on a bus-interface.

It would be sick to do a 1-wire mod to the DS and use a chip only in the controller.

Posted at 10:10 am on Feb 22nd, 2009 by nubie

@nubie

its only gba games that crash, and im not even sure if it crashes on actual gba games, as i have only tested it on the ezflash 3in1

Posted at 10:40 am on Feb 22nd, 2009 by cause

I wouldnt mind seeing a commercial product that was a GBA Cart with a SNES/NES female plug adapter on the end (stickin out of course)

^ profitable

Posted at 11:17 am on Feb 22nd, 2009 by Reezy

Would a similar method also work for an SNES controller?

Posted at 11:20 am on Feb 22nd, 2009 by michael

@michael
yes, i actually made a crappy tutorial on doing it, you can find it in the acidmods thread linked in the description

Posted at 11:24 am on Feb 22nd, 2009 by cause

I see that you misunderstand me,

Note here: http://www.hardwarebook.info/Game_Pak

The cartridge pins are fully utilized, so you are shorting the data pins directly when you do this.

(do you understand how a rom chip functions?), a flash cart and a ROM cart function by necessity in the same manner, the data is transmitted along the same pins.

This is interesting, but how hard would it have been to find a different connector to use?

I suppose if all you do is play DS games and (illegal) roms then you don’t need the GBA port to function. Not smart mentioning how you sold all of the games and now have them illegally (you could have just said “this is my game collection”)

Posted at 11:56 am on Feb 22nd, 2009 by nubie

Awesome…nothing like a bit of nostalgia to add to the experience.

Posted at 10:09 pm on Feb 23rd, 2009 by The Electronic Toy Room

Poor choice using pins and a connector that do other stuff. (?)
Just use a tiny multi-pin connector of some kind and get that stuff away from there, problem solved.

Straightforward hack otherwise.
Pretty cool!

Posted at 6:31 am on Feb 25th, 2009 by strider_mt2k

Wow, that is really cool! now I want to try it, just for the heck of it, because I own a DS!

Posted at 3:54 pm on Sep 28th, 2009 by djdrewsgrl09