Hardware Touch Screen Protocol?

[gudenau]

Anyone got documention on how the 3DS talks to the the touch screen to get the input?

 

[Ryccardo]

The 4 wires that go to the touch panel are simple, basically they're 2 giant variable resistors (one for vertical and one for horizontal position), the touch screen cables are their inputs, and the variable pin of the two is connected together when clicking!

If you mean how to talk to the touch screen controller, I don't know. I've heard it's i2c...

 

[GerbilSoft]

http://problemkaputt.de/gbatek.htm#dstouchscreencontrollertsc
http://problemkaputt.de/gbatek.htm#dsitouchscreensoundcontroller

On DSi, the touchscreen has two protocols: one for DS mode, one for DSi mode. I suspect 3DS still uses the DSi mode protocol, but can't confirm it.

 

[master801]

Are you planning on adding touch screen support for Citra?

 

[gudenau]

The 4 wires that go to the touch panel are simple, basically they're 2 giant variable resistors (one for vertical and one for horizontal position), the touch screen cables are their inputs, and the variable pin of the two is connected together when clicking!

If you mean how to talk to the touch screen controller, I don't know. I've heard it's i2c...

I know how the screen itself works, thanks. From what I can tell it is SPI though.

http://problemkaputt.de/gbatek.htm#dstouchscreencontrollertsc
http://problemkaputt.de/gbatek.htm#dsitouchscreensoundcontroller

On DSi, the touchscreen has two protocols: one for DS mode, one for DSi mode. I suspect 3DS still uses the DSi mode protocol, but can't confirm it.

I would guess that it has a 3DS mode, that is a very Nintendo thing to do; so if anyone could actually get info on this I would be happy.

Are you planning on adding touch screen support for Citra?

Nope, I am not going to touch Citra; plus you should not need to emulate the touch hardware with hoe abstracted the 3DS is. :-D