74LC151 is an 8to1 input multiplexer.
i used 2x 74LC151 for the whole sequencer, clocked by the same signal and they also share the adress-pins on the controller, so they run completely in sync.
each one has one dataline that gets fed back into the controller.
total pins for the inputs so far : 6
i will add another MUX for the rest of the buttons, like “play” “up” “down” etc.
that would use another dataline so all in all 7 I/O ports on the controller, of 13 possible I/O ports
i need five non-MUXed outs for triggering the sounds.
and if i manage to use the same clock and adresslines as in the input MUX’s i can use one single line for muxing 16 LEDs.
so either i will use the analog inputs which the controller has 7 (!) as inputs from the input MUX’s or buy the next bigger processor, which is a 54 I/O beast 🙂
thats whats going on at the I/O ports of the controller