8-bit counter, 7-segment display

Discussion in 'Homework Help' started by kdgnei4g, Apr 29, 2010.

  1. kdgnei4g

    Thread Starter New Member

    Apr 29, 2010

    To implement a 0-69 counter that counts 0, 1, …, 68, 69 and then repeats the cycle by using two 74x163’s in LogicWork 4.


    For this assignment, you are required to wire two 74x163 counters in a cascade fashion to implement the 0-69 counter. The state of the counter is to be displayed by two seven-segment display devices. The implementation is to be made by using LogicWork 4, where the default parameters of clock, gates, and 74x163 counter should be used.

    I know how to use LogicWork. That isn't the issue here. My issue is the implementation. I have the counter running correctly; there are eight outputs that represent a binary number, starting at 00000000 up to 01000101 and then restarting at 00000000.

    Getting them to display correctly on the 7-segment displays is the tricky part. You see, I'm also told that I must use two 74x49's (immediately before the two 7-segment displays) that translate a 4-bit binary number that then causes the correct segments of the display to light up. For example, 0000 displays 0, 0001 displays 1, 0010 displays 2, etc.

    Now, I can't connect the 8 outputs of the counter directly into the two 4-bit inputs of the two separate display sections (the 4 lower to one and the 4 higher to the other). Once the lower 4 bits reach 1001, they continue on 1010, 1011, etc. The displays, though, can't light up anything past 9 correctly.

    So, then, what can I throw in between the 8-bit binary outputs and the two 4-bit inputs of the 74x49's so that the both the counter outputs from 0 to 69 (in binary) correctly and the displays count (in decimal) along with it?

    I apologize for the lack of pictures; some screenshots would have made describing my issue so much easier, but I don't have LogicWork on the computer from which I'm posting.
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    You may have noticed that a '163 counts in binary, while the decoders need BCD. If the use of '163 counters is mandatory, then your only solution is to do binary to BCD decoding between the counters and the display drivers using extra gates.

    Life would be simpler is you just used 74LS162's.

    At any rate, making a table that relates 4 bit binary to BCD is a way to start.