Okay, I can kind of see how it makes a difference for n-key rollover.
> The switching time is like 20-50ns on these parts, so while it's not quite as fast as a GPIO register read, it's still pretty quick, more than fast enough for keyboards.
I guess my point was that if you change which input you're reading from the mux and then immediately sample with the MCU, you'll get unstable data. 50ns is 20MHz, I can easily see an MCU used in a keyboard being fast enough to hit this.
It's obviously easy to work around, but so is ghosting.
> The switching time is like 20-50ns on these parts, so while it's not quite as fast as a GPIO register read, it's still pretty quick, more than fast enough for keyboards.
I guess my point was that if you change which input you're reading from the mux and then immediately sample with the MCU, you'll get unstable data. 50ns is 20MHz, I can easily see an MCU used in a keyboard being fast enough to hit this.
It's obviously easy to work around, but so is ghosting.