Have a homework problem i need help on 7483 IC's

Discussion in 'Homework Help' started by Geoffr67, Mar 2, 2012.

  1. Geoffr67

    Thread Starter Member

    Dec 5, 2011
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    0
    hello on one of my homework assignments i have about 10 problems where i must demonstrate a solution to a problem.I am going to post one of the questions in hopes someone could demonstrate how it is done so i may complete the remaining problems by myself. Im just a little confused here.

    1.Show how to Cascade two 7483 IC's to add two 8bit numbers together. Clearly identify which chip handles the LSN&MSN (Nibble)

    What is the sum and carry for 59h+3Dh ?

    on the diagram show where to place 59h and 3Dh on the ic's to support this addition.

    Could someone help me out on this one? it would be GREATLY appreciated.
    G
     
  2. Georacer

    Moderator

    Nov 25, 2009
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    1,266
    Let's see. You have two 8-bit numbers that you want to add and two 4-bit binary adder ICs.

    Don't be perplexed by the "hex" nature of your input. Hex numbers are still binary with a digit grouping.

    So in effect your problem is how to add two 8-bit numbers with two 4-bit adders.

    Any thoughts? Make an effort for yourself first, if you please.
     
  3. Geoffr67

    Thread Starter Member

    Dec 5, 2011
    69
    0
    Well given i have 2 of these IC's i would convery each hex number to binary and decimal so i know what bits to place on each pin of each IC, I would label each IC A and B On A i would place the binary equivelent of 59h (89d) on the corrosponding pins,and the same for IC B 3Dh (61d). My question really is how would i connect 2 of these Ic's together pin wise to support this addition. this i am not sure of.
     
  4. Georacer

    Moderator

    Nov 25, 2009
    5,142
    1,266
    Ok, for starters leave the decimal system out of the conversation. Your input isn't in decimal, your ICs work with binary and no one asks you to have the output in decimal. So just forget about it. Work exclusively in binary.

    Read here a bit: http://www.allaboutcircuits.com/vol_4/chpt_1/4.html
    The hexadecimal system is nothing more than taking a binary number and saying that every 4 digits will be grouped. It's the same binary number. That means you don't have to convert your input. It will be given to you as a binary sequence.

    As for the cascading method, at the end of this page, an intuitive method is given: http://www.allaboutcircuits.com/vol_4/chpt_9/3.html

    Basically, addition in binary in its simplest form is a string of 1-bit full adders stringed together from one figure binary place to the next one.
    The first two Least Significant Bits of the two addendums are added. The sum is driven to the output and the carry is fed to the next step of the addition, towards the next significant pair.

    The same can be done with your 7483. Take the carry out of the first 4-bit addition and drive it as carry in to the next 4-bit more significant addition.

    Is that clear? Try to make up a schematic or block diagram, so that we can talk over it.
     
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