I know there are chips that convert the NES controller to USB HID`s, are there anyway to easily reverse the process inside the NES? I`m supposed to do a casemod for a friend, and I would like to hook him up with USB nes controllers he can use on his PC, but also on his NES?

I dont suppose its as simple as connecting the chip the oposite way inside the NES?

If only it were that simple.

Most USB peripherials do not have the internal logic necessary to function as a USB host, though they do have trancievers, etc. You would need to force the chip to initialize the USB bus, send/recieve packets, decode the HID information, and output the data to the NES.

Or you may

1. get a cypress.comUSB host microcontroller
2. cypress.comdesign, integrate and build a PCB that will support it (power, oscilator, ROM, I/O, reset, etc)
3. implement a usb.org (pdf)HID interpreter
4. suceed in providing support for your custom NES gamepads
5. excitely share your results with your peers
6. respond to inquiries as to how long it will take for support for logitech.comlogitech gamepads to appear
7. throw up your hands in fustration when people demand to know why the LCD screen on their logitech.comLogitech G13 Advanced Gameboard doesn't navigate the inventory in StarOcean like in the PC advert...
8. ???
9. profit

Either way it's a tall order.

It's not going to be simple. If you asked me to do it, I'd probably use a Viniculum host chip by FTDI. If you have experience programming microcontorllers it may be within your ability.

Just hook up the USB adapter to a controller port on the computer, then you'll be able to use them with that computer or any NES.

... I suppose that could work.

So you are suggesting
(EDIT:) to attach the NES controller to a USB adaptor;
to attach a USB gamepad to a PC;
The PC would translate the gamepad buttons into key presses;
the key presses would output through the paralel port and into the controller port.

That would require grabbing PC NES transfer cable v1.30 by sepi from nesdev.parodius.comNES Dev, and conficuring the PC to boot up into translation mode; cramming it inside the NES shell. and implementing a video switch between the NES and the PC... swallowing a spider to eat the fly...

(edit:) I don't know why I didn't think of that sooner. That would make much more sense to make a detachable adaptor from NES to PC.
raphnet.net4 NES and/or 4 SNES controller(s) to USB