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Nexys 4 DDR Keyboard: Wrong scancodes



Hi, I recently discovered that the wrong scan codes are sent for certain keys.

This is tested with my own PS2 keyboard controller, and the same behaviour is present with the official demo: https://reference.digilentinc.com/learn/programmable-logic/tutorials/nexys-4-ddr-keyboard-demo/start

I have tested two keyboards: One Logitech K120, and one Microsoft comfort curve 3000. The following behaviour is exhibited:

Left arrow set 2 scancode should be: E0 6B / E0 F0 6B. Actual: 6B / F0 6B

Up arrow set 2 scancode should be: E0 75 / E0 F0 75. Actual: 75 / F0 75

Down arrow set 2 scancode should be: E0 72 / E0 F0 72. Actual: 72 / F0 72

Curiously, the right arrow scancode is correct.

Numpad division set 2 scancode should be: E0 4A / E0 F0 4A. Actual: 4A / F0 4A

Can anyone confirm?

Online Documentation for Altium Products - PS2 Keyboard Scan Codes - 2017-09-13.pdf

Edited by maximb
Fix erroneus scancode
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Hi @maximb,

There was a firmware error with the PIC24 on the usb host  as discusses in this forum thread.  We have a firmware fix for the error. If you would like the PIC24 Host firmware to be fixed you will need to send the Nexys 4 DDR board back to us for re-programming: either to the US or to Romania. If you are not wanting to send the board back then you will have to use a work around that works for your setup.

thank you,


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