BCD to Binary using logic work

Discussion in 'Homework Help' started by Forza_Inter, Nov 14, 2010.

  1. Forza_Inter

    Thread Starter New Member

    Nov 14, 2010
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    First of all, I'm asked to design a 4-bit calculator that accepts tow inputs which are in BCD and I have to convert them to Binary, so when i use the truth table the inputs and outputs will be identical because it is a 4-bit calculator.

    should I get the logic diagram for BCD-to-Binary?,because the BCD and Binary numbers are the same in the digits for example 0001 in Binary is the as 0001 in BCD which is 1

    Also,in logic work I used the ic 7447 to show the number in 7-segment as u can see here ( of course u should have logic work installed to open the following file)
    http://www.zshare.net/download/827023905c043b91/
    but it doesn't work I dont know why
    sorry for that but I'm really really really confused
    thank you
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    If you are supposed to do the arithmetic unctions in binary, then you will have to convert coming and going, so to speak.

    I might remind you that 99 in BCD is not the same value in binary. Just as a hint, an input of 15 should become 1111 in binary.

    Not everybody has Logic Work.
     
  3. Forza_Inter

    Thread Starter New Member

    Nov 14, 2010
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    thank your for the fast response.
    but i'm working on a 4-bit calculator with tow inputs and every inputs is 4-bits( for example 5+5 or 9+3 but I can't calculate 11+2 with the 4-bits calculator because 11 is more than 4 bits in BCD but the answer will be more than 4-bits for 9+3 which is ok)
    ,so I dont think that I can use the number 99 as an input which is more than 4 bits, am I right?
    , so If I wanna convert from BCD to Binary I have to make a truth table with four inputs,but how many outputs?
     
  4. Forza_Inter

    Thread Starter New Member

    Nov 14, 2010
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    bump
    .............
     
  5. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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  6. Forza_Inter

    Thread Starter New Member

    Nov 14, 2010
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    thx
    I wanna convert from BCD to Binary I have to make a truth table with four inputs,but how many outputs?
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
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    BCD stands for Binary Coded Decimal. Notice the Binary part?

    BDC goes from 0 - 9 using 4 bits, while the 4 bits in straight binary go from 0 - 15.
     
  8. Forza_Inter

    Thread Starter New Member

    Nov 14, 2010
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    ok thx for your help :)
    ,so after I get the output in binary I need to convert it in BCD.
    the output in binary will be 8 digits in BCD unless it was less or equal to 9( for example 3*9=27 and 27 is 0010 0111 in BCD)
    so that means I create another truth table for Binary-to-BCD with 8 outputs?!!!!! that doesn't make sense!
    sorry for my stupid questions but I'm really confused :(
     
  9. beenthere

    Retired Moderator

    Apr 20, 2004
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