Gameboy as a USB Controller (Page 2 of 3)

Personally, I'm not a programmer, but a friend of mine (a data scientist), when I've send him a link to this topic, said to me that, apparently, the gameboy can handle USB, then he linked me this, and said the gameboy can handle a serial link of about 9600bps (I don't really know what this means), and then he tells me USB can largely handle this.
I've tell him to create an account for cm.org, but actually he's at work.

Also, he talked about a cable, Link to USB, he had when he was young, to replace a Gameboy Printer by a normal USB serial printer. He had this with his Pokémon Gold collector edition.

edit: double post

Last edited by HimsyPimsy (Feb 15, 2016 6:19 pm)

Happy to discuss this with your friend. The main 2 reasons it can't work are the electrical interface - USB uses a differential data pair. These are both inputs and outputs. This requires the gameboy to have total control over 2 io pins. The gameboy has a primitive shift register and only one input and output pin.

Second is timing. The USB spec is very timing sensitive and you have a very small window to acknowledge a token/request/reset. This cannot ever be achieved at 9600bps. Ever. Even on the GBC it doesnt have the speed.

Then there is the frame construction, crc, error handling, address handling. These are all usually handled in a hardware usb engine due to the speed they must run at.

Then we get Into the software layer which is a little easier and given the rom space we could have datastreams ready to shift out so the gameboy doesnt have to think.

Small avr's have managed a software only usb engine but they are very primitive and can really only shift a byte back and forward at very slow speed and not do much else.

His cable is likely the madcatz LPT cable. It isn't usb. The later versions are usb and have a usb micro in the cable.

Happy to be proven wrong on this. Its amazing what people get old hardware to do.

Well you better wip up a VNC screen of the emulator output while you are at it

It would also be cool to see this as a means for sending MIDI notes out to a PC...

Also is there any reason this wouldn't work on other GB models? GBC specifically.

It works just as good on a GBC/GBA. MIDI out? Is there nothing that already does this?

Not sure if you've ever held a Chinese clone controller, they are far from 'nice'. Flexible body, sharp edges on the buttons. You really need that 2 decades of finger mashing to round those edges. Or a legitimate dogbone controller which are rare in these parts.

I had a sync issue last night so it looks like I'll need to do some kind of handshaking. This shouldn't slow the response down at all as both the GB and ARM run at a higher rate than the USB packet request.

Back to the MIDI thing, just one note per key, polyphonic?