Question

A student uses a demultiplexer to construct a data distributor. The demultiplexer routes its input data to one of its 8 output paths: let’s call them Y7, Y6, Y5, Y4, Y3, Y2, Y1, Y0. Determine the 3-bit SELECT input necessary to route the incoming data to Y5. S2 is the MSB of the SELECT word. The SELECT input is active-LOW

Answer 1

The below given figure is of a table which determines the high input at the eight output paths with different combination of SELECT (S2,S1,S0) inputs and enable(E) key. The enable key will be active high throughout the operation. Now we see for 101 i.e. 5(in decimal) we will get high input at Y5 so the 3-bit select will be S2 ~S1 S0 (101). (The answer is marked in a box)