Counter IC Expansion

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

  1. mghg13

    Thread Starter Member

    Jul 17, 2013

    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:

    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


    Jun 26, 2012
    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


    Oct 2, 2009
    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.