9+ input decoder

Hi there,

I currently have an 8-3 priority encoder, the 74 148, in my circuit. However I think I need 9 inputs.

I have 8 buttons on each of the 8 inputs and I want the circuit to do nothing when none of the buttons are pressed. Unfortunately the 'idle' position, when no buttons are pressed, gives me 1,1,1 on my 3 outputs. The same as if the lowest priority button is pressed. So I think I need an extra input that can give me a 9th combination, that I can assign to do nothing in my code.

So the first question is, what are my options for a larger encoder? Is there an alternative to the 74 148 that simply has more ins/outs?

Or, if you can de-cypher my confused ramblings, am I doing something wrong with the execution my current encoder?

Thanks!

You can use a 74147 which is a 10-4 BCD encoder.

Fantastic, that's exactly what I was looking for. Thanks!