On Sun, Jul 31, 2016 at 8:34 PM, Albert ARIBAUD albert.aribaud@free.fr wrote:
Thinking more about it, maybe you were thinking about up to 16 keys being depressed rather than 8, and the inputs' fan-ins adding up to twice more and the output's fan-out not being able to cope, leading to the input voltage not falling low enough for the keys to be detected as down.
not quite... maybe i was but hadn't quite got it through from subconscious into words.. but that's a good point - i was thinking if you used 8 fan-in and press 9 keys... if you have 16 fan-in and press 9 keys...
basically the 16 fan-in it "activates" 50% less of the matrix.
Technically, I should have taken the switches' impedance (about 200 Ohm) into account in case it worsens things; but those 200 Ohms would increase the pull-up impedance and reduce the current, so actually a 0 Ohm switch impedance is the worst case already.
So I think that's OK, but you know what? Let me try it. :)
:)