Modifying outputs of 3-to-8 decoder

Discussion in 'Homework Help' started by dnkschn, Mar 29, 2009.

  1. dnkschn

    Thread Starter New Member

    Mar 29, 2009
    8
    0
    Hi fellas,

    Assume we have a 3-to-8 decoder and the outputs should look like this:

    When input is 000 output will be 10000000
    .................. 001 .................. 11000000
    .................. 010 .................. 11100000
    .................. 011 .................. 11110000
    .................. 100 .................. 11111000
    .................. 101 .................. 11111100
    .................. 110 .................. 11111110
    .................. 111 .................. 11111111 -> (the outputs labeled as f0f1...f7)

    How can i get this result? You have any suggestions?
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,764
    2,535
    I believe if you use a standard decoder, such as a CD4514, and follow it with XOR gates (taking the least significant bit high on the bottom XOR gate, the spare input) you will get what you're after.
     
  3. dnkschn

    Thread Starter New Member

    Mar 29, 2009
    8
    0
    Well, it was with 74138.
    Thanks.
     
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