I have 3 4-bit p. encoders and set it up as (3*4) 12 inputs and 4 outputs with Valid and Enable signals. I'm having trouble trying to use the Boolean eqautions to make it 3 4-bit p. encoders. I not sure how my top level design should be port mapped and how to use the boolean equations...Any suggestions. thanks in advance. It works fine when it;s set up 12-4.