8-bit binary adder using two 7483s and 7seg displays

Discussion in 'Homework Help' started by JoeyB, Feb 21, 2007.

  1. JoeyB

    Thread Starter New Member

    Feb 21, 2007
    For my digital electronics class, we've been presented with a challenge that not even the teacher knows how to do. The easy part is adding the two 8-bit binary numbers by using the carry out of one and the carry in of the other. The result is a 9-bit number in binary (currently being displayed with LEDs). The next step is to display each 8-bit number (which is being added) with 7-segment displays (displaying the decimal equivalent) and to display the 9-bit sum using 7-segment displays.

    We input the 8-bit numbers with 8 switches (representing high or low) per number to represent each bit.

    For example, using our switches, we add 10101010 and 00001110 for a sum of 010110000. We then need to display each one of those numbers with a seven segment display. We have no idea how to (efficiently) do this. Are there any chips or demuxes or anything that we could use to convert the 8 and 9 bit binary into seven segment displays? We would need 3 displays per number, since it can be up to three digits in base10 form.
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    Without using a microprocessor to accomplish what would then be a trivial task, you'll need a bit of extra logic. You might load the sum of the adders into a pait of parallel-load counters, plus togling a flip=flop for the carry bit.

    Count that counter string down to zero, while counting up a decimal counter string. Have 7 segment drivers run off the BCD outputs of the decimal counter string.

    You will need extra logic to latch the original binary data into the binary counter string, a clock source, and logic to stop the binary counter decrement at zero.
  3. mrmeval

    Distinguished Member

    Jun 30, 2006
  4. Michael Zerafa

    New Member

    Mar 22, 2007
    How did you tackle this since i have a similar problem for my project. most prob it's a pic i'll have to use but i can't afford to program the stuff since the number display is rather a 'comodity' which i have to do without for the moment. how did you solve the prob please?