I've recently got a Nexys 4 DDR and I'm trying to find a keyboard that works with it. Any mouse I have works, so I'm assuming the USB connector and the PIC24 are all soldered on properly and working.
I know that older and/or 'simple' keyboards are supposed to work but so far I haven't found any that actually do. I'm still looking, and I've ask around (on this forum and elsewhere) for specific make/models that are know to work.
In the meantime, I've observed that when I connect the keyboard I'm using right now to type this post to the Nexys4 DDR, and run the Nexys-4-DDR-Keyboard, I keep getting 0xAA messages. If I keep a key pressed for a long time, sometimes I observe the proper scancode for the key, and then it's endless 0xAA again.
According to the Nexys4 DDR reference manual: "When a keyboard or mouse is connected to the Nexys4 DDR, a “self-test passed” command (0xAA) is sent to the host."
What I think is happening is that keyboard or the connection with the keyboard keeps getting reset by the PIC, which continuously sends 0xAA codes when it re-detects the keyboard. I was wondering if anyone knows what code the PIC24 is executing, if there are any patches for it, or if it's possible to see the source code to maybe fix this problem or improve compatibility. As it is, using a Nexys4 DDR is *really* hard because very little modern hardware seems to work with it.