Steve, this uses just two lines.
Alright. I'll admit it. This muddle headed wombat is still very confused.
1 x Pin to pulse counter in 4017 decade counter to select band pass filter
+1 x Pin to reset 4017 decade counter to default known start state
= 2 pins
2 pins + 1 pin for controlling the low pass filter selection = 3 pins.
vs
3 pins Binary Coded Decimal (BCD) to control *both* low pass filter
selection and the output band pass filter selection.
Two different ways to arrive at the same level of control. But is it not
still 3 pins = 3 pins?
So where are we saving an IO line?
I'm probably being completely daft and missing the flaming obvious but I
just can't see it.
Help!
73, Steve.
