Discussion in 'Homework Help' started by Justine1, Jul 28, 2010.

  1. Justine1

    Thread Starter New Member

    Jul 26, 2010
    Please tell me what will be the block diagram of a 16:1 MUX using two 8:1 MUX!!....:confused::confused:
  2. tom66

    Senior Member

    May 9, 2009
    Is this homework?

    It is very simple.

    You cannot use two muxes however.

    You must use two 8:1 muxes and one 2:1 mux.

    The 8:1 muxes select channel 0-15 and produce two outputs.

    You then select the right mux using the 2:1 mux.

    If you must use 8:1 muxes then with the last mux only two channels are used and only one select bit is used.

    Actually there may be a way to use two 8:1 muxes, if they have a chip select. However, you will need to implement external logic to select the first or second mux.
  3. JDT

    Well-Known Member

    Feb 12, 2009
    It can't be done using two 8-input multiplexers alone. Depending on the type of 8-input multiplexer, some other logic will also be needed.

    The circuit attached shows how two multiplexers with "3-state" outputs (that can be made open-circuit using an enable input) can be combined using an additional inverter.

    The output goes open-circuit when the /EN input is high.