R1 is obvious and R2 seems to me both protective (to the quad switches) and also perhaps to provide a semi-known/predictable output impedance (2:1, depending on output state is "close enough".) You may want to apply a Schmitt trigger. The 74AC14 or 74HC14 might be an example which also support the rail voltage you show. (And Digilent recommends either 3.3 or 5.0, as I gather from their web page.)
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