This is confined to pure ASCII, but does support Alt Gr. This is enough
to make a French keyboard layout work:
* home row is "qsdfghjklm"
* numerals are all shifted
* keys like {} require Alt Gr
While not tested, this should also support layouts like Colemak with
the necssary keymap file.
Layouts can be produced from Neradoc's keyboard layout modules on the
device & loaded at runtime. Code to do so is at
https://gist.github.com/jepler/597c0a00e0eb014a433e03c0ae363a08
as well as a sketch of how an extended format could support dead keys &
the full Unicode BMP instead of just ASCII.
This allows you to list and explore connected USB devices. It
only stubs out the methods to communicate to endpoints. That will
come in a follow up once TinyUSB has it. (It's in progress.)
Related to #5986
Jeff Epler
Scott Shawcroft