Hi all,
For those following dev on the EC, I've just tested transposing the matrix rows and columns, which worked as expected, that is, exactly the same as before transposing (including ghosting), but doing 40 GPIO accesses for a whole scan instead of 64.
The only problem I hit was specific to the NUCLEO: I had already replaced keyboard GPIOs PA2, PA3 and PA5, which are used on the NUCLEO, with PA13, PA14 and PA15, but I only just noticed that PA13 and PA14 are also used (for ST-Link/V2.1) so I had to change again, this time for PA8, PA9 and PA10 which are unused as far as I can tell from scrubbing the NUCLEO reference manual.
I'll push the changes tomorrow.
I have not started implementing priority policy or ghost jamming yet, because I'm still thinking over how to implement both in the most economic way.
Amicalement,