Counter IC Expansion

Discussion in 'Homework Help' started by mghg13, Oct 17, 2013.

  1. mghg13

    Thread Starter Member

    Jul 17, 2013
    63
    0
    Hello,

    Can I please get some help in designing a digital counter circuit?
    Here is the problem:


    The 74LS161 IC is a 4-bit MOD 16 UP counter. Here is the datasheet:

    http://pdf1.alldatasheet.com/datasheet-pdf/view/5675/MOTOROLA/74LS161.html

    The inputs are clock, CEP , CET, asynch CLEAR', synch LOAD' and 4 input to load data.

    The outputs are terminal count and the 4 register outputs.

    I want to use 2 of this component to generate an 8-bit MOD 256 UP counter.

    How do I connect them together? What external component do I use?
     
  2. JohnInTX

    Moderator

    Jun 26, 2012
    2,348
    1,029
    Figures 1 and 2 of the original datasheet shows how to do it. It should not need any external components just to count to 256 as the counters are designed to cascade ad infinitum. SInce you want to count to 256, you'll need 2*4-bit counters. Nice.
     
    Last edited: Oct 17, 2013
    mghg13 likes this.
  3. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,365
    It is explained in the paragraph at the top of page 2 of the datasheet.

    Connect the clocks together. Connect RCO of the first stage to ENT of the next stage.
     
    mghg13 likes this.
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