5.3/Add an enable signal, en, to the 2-to-4 decoder discussed in Section 5.4.1. When en is ' 1 ' , the decoder functions as usual. When en is ' 0 ' , the decoder is disabled and the output becomes "0000". Use an if statement to derive this circuit and draw the conceptual diagram. 5

.4 5.5 Repeat Problem 5.3, but use a case statement to derive the circuit.