Is it possible to construct a 6-to-64 line decoder using a 3-to-8 line decoders

Discussion in 'Homework Help' started by electrogirl, Oct 2, 2010.

  1. electrogirl

    Thread Starter Member

    May 2, 2010
    47
    0
    Is it possible to construct a 6-to-64 line decoder using a 3-to-8 line decoders? if it is then how?

    I know how to construct a 4-to-16 line decoder using a 3-to-8 line decoders by using 2 decoders and using one input as the enable input. But this one is different because it has lots of inputs and I don't know what to do with those other inputs.

    Supposedly this is the given problem: Implement F(A, B, C, D, E, F) = ∑m(1,2,5,7,10,11,13,15,22,23,24,25,30,31,32,33,54,55,56,57,61,62,63) using a) 3x8 decoder

    Just give me an idea on how this is done... i'll be the one who will do the implementation thanks ^^,
     
  2. Georacer

    Moderator

    Nov 25, 2009
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    1,266
    The way I see it, you will need 9 3-to-8 decoders. 8 of them will work in parallel and will service the 3 LSB's and one in front of them all will take the 3 MSB's and output the correct enable signal for the appropriate decoder.
     
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  3. electrogirl

    Thread Starter Member

    May 2, 2010
    47
    0
    thanks you are very helpful
     
  4. idmond

    Member

    Oct 5, 2010
    18
    1
    Georacer is right. you can take outputs of one 3x8 decoder [Enable Decoder] as Enable Inputs for each one of the other eight decoders in such a way that only one decoder will produce its 8 combinations while the others are disabled by the Enable Decoder.

    as for the 3 LSB's inputs, you can take them from any one of the 8 parallel decoders, but then you have to connect all the inputs of the other 7 parallel decoders to the one you first choose for the LSB's inputs.


    here is a schematic for the 6-to-64 decoder in the attachments.
     
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  5. Georacer

    Moderator

    Nov 25, 2009
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    Thankfully, there are some people that are not afraid to bust a second sweat and design a diagram for the student.
    Or do they actually hurt the student by giving him ready work?

    I know I don't because of the first reason, anyway...
     
  6. iam

    New Member

    Dec 19, 2010
    1
    0
    so helpful...
    thnx a lot !!!!
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    We usually insist that the student post up some work to see that the exercise is not just a straight gimmie. Very little learning takes place when someone simply obtains a complete answer

    See the post from the latest OP. He gets the grade, and I suspect that idmond gets no credit for actually having done the work.

    I would not particularly care to erase all such problem-solving schematics, but rather encourage everyone to recall the educational aspect and not simply hand over complete solutions on demand.
     
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