Bonxy,

I don't see your other thread but I wanted to comment that you're correct in that you should be able to poll push button switches without any problem, even at relatively slow clock speeds, since switches produce a very slow and very easy to capture signal.

If you need lots of switches (you mentioned up to 33) then you might also consider Charlieplexing or multiplexing them. That is, organize them into columns and poll one column or row of switches at a time. You could Charlieplex 30 switches using just 6 I/O pins (and 30 diodes), or 42 switches using 7 I/O pins (and 42 diodes), or you could multiplex 32, 35, or 36 switches using just 12 I/O pins in a 4x8, 5x7, or 6x6 matrix, respectively.

On the other hand if you want to put the mcu to 'sleep' while waiting for a switch press then using one I/O pin per switch with diode 'OR' wiring to an IOC pin makes perfect sense.

Good luck on your project. Regards, Mike