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Lanugo

Nexys4 DDR -- USB interface reset with keyboard?

Question

Hi,

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.

Thanks!

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Hi @Lanugo,

I am out of the office today. I tested the Microsoft comfort curve keyboard 2000 model 1047 with a Nexys 4. I believe these boards are the same in reference to the usb HID. I also had a co-worker verified the keyboard i have at work with the nexys 4 ddr works as well..The keyboard is a Microsoft Wired Keyboard 600; Model 1366.

thank you,

Jon

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I too have a problem with keyboard connected to nexys-4.But here i have no problem of receiving keys instead busy light is glowing when there is break in pressing the keys. I have used hp keyboard.

 

Edited by Gireesh

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Hi @Gireesh,

Is the HP keyboard a standard mechanical keyboard? Are you sending data through the uart in your project to see whats happening?  Here is the Nexys 4 DDR keyboard demo that's in HDL that should be very easy to alter to work for the Nexys 4. All you need to do is use the xdc for the Nexys 4 using the projects xdc as a reference.

thank you,

Jon

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