2021-07-13T21:05:45Z Photos, electronics, cnc, and more Jeff Eplerjepler@unpythonic.net 2021-07-13T21:05:45Z 2021-07-13T21:05:45Z https://gamma.unpythonic.net/01626210345 <b>Updated 2021-09-25</b>: For compatibility with CircuitPython 7.0.0. <p> <a href="https://blog.adafruit.com/2021/05/16/n-key-rollover-nkro-with-usb-keyboards/">It has been suggested</a> that it's possible to have both N-key rollover (NKRO) and be compatible with computer early boot screens (BIOS/UEFI/etc) by ensuring that the first 8 bytes of the report are compatible with the standard keyboard protocol. <p>On the <a href="https://gamma.unpythonic.net/01625944378">heels of my earlier experience</a> with how easy CircuitPython 7 made it to try a custom descriptor for NKRO, I tried implementing this too. And it works! On a sample of one Dell notebook computer, the hybrid descriptor can navigate in the boot menu but also enjoys full NKRO once Linux has booted. <p>You have to configure the descriptor in <tt >boot.py</tt> and then use the HybridKeyboard class in your code. It is compatible with the adafruit_hid.keyboard.Keyboard class, except that if you ask it to press more than 6 keys in a row, it doesn't throw an exception! <p>The original NKRO descriptor is also in this <tt >boot.py</tt>, in case you want to try both and compare how they work for you; <tt >code.py</tt> is intended to auto-select the correct interface class. Remember that you need to fully restart the Feather when modifying <tt >boot.py</tt>! <p>The first file below is <tt >boot.py</tt> and the second is <tt >code.py</tt>, and the code is designed for an Adafruit Feather RP2040 with custom 4x5 keypad, <a href="https://learn.adafruit.com/desk-calculator-with-circuitpython">detailed in a Learning System guide</a>. <p><script src="https://gist.github.com/jepler/3f507711de499fa4f3cb756680bea927.js"></script> <p><br>