>> I'm not sure this is actually true; I think I could probably design
>> a non-scanned matrix keyboard.
> It is definitely doable.  Think about a single line of five switches,
> for example, connected to ground on one side, the other side being
> connected to interrupt lines (negative-edge-triggered) with pull-ups.

Well, I'd hardly count that as a matrix keyboard, since one axis of the
"matrix" is of size 1.

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