74ls163 counter need help

Discussion in 'General Electronics Chat' started by vead, Sep 16, 2016.

  1. vead

    Thread Starter Active Member

    Nov 24, 2011
    621
    8
    Hello
    I understand 74ls163 is counter that count 0-15 state. I have downloaded datasheet. I understand meaning of data input pins, data output pins I don't understand what is ENT, ENP and RCO? Can someone tell me what is use of that pins in counter?
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,137
    1,786
    I don't have my datsheet handy (it is packed away in preparation for a move), but ENT and ENT pins are used to enable counting. They are useful in designing state machines where you need to "hold the present state" until a specified condition occurs. Look at the truth table for details. RCO or Ripple Carry Output is used to cascade counters to make a longer count word. I believe that RCO can be tied to ENT/ENP directly without additional logic.
     
    vead likes this.
  3. bertus

    Administrator

    Apr 5, 2008
    15,646
    2,345
    Hello,

    Have a look at page 11 of the attached datasheet.

    Bertus
     
    vead likes this.
  4. GopherT

    AAC Fanatic!

    Nov 23, 2012
    5,997
    3,751
    RCO is ripple-carry-output. It allows the chip to trigger a second chip to count how many times this one rolls over (from 15 back to 0) - that way, you can cascade multiple chips and make it an 8, 12 or 16 bit counter (or more). Not used if only 0 to 15 is needed. It goes high on the 15th pulse and stays high until the roll-over pulse that causes the output to zero.

    The LS163 chip is synchronous
    - when the clear pin is LOW when a clock pulse goes low to high, the outputs clear

    - if the enable P (ENP) pin is High, the output will increment with each clock tick (if clear is not low). If ENP is low, it will not advance the output count on a clock pulse

    - ENT enables/disables the RCO (Ripple Carry Output - see top of page 2 of Bertus's datasheet above.
     
    vead likes this.
  5. vead

    Thread Starter Active Member

    Nov 24, 2011
    621
    8
    Hello
    I looked that page. This counter do two things, increments or load the new value. I think when counter in increments mode the input should be following
    Code (Text):
    1. Clock      reset    load  enable
    2. ^           low    low    high
    3.  
    And if counter load the new value than
    Code (Text):
    1. Clock       reset  enable load
    2. ^            off    on       on
    Is it correct?
     
  6. Papabravo

    Expert

    Feb 24, 2006
    10,137
    1,786
    I think so, but you should either use low/high or on/off. Don't mix the two values sets. It can get confusing.
     
  7. vead

    Thread Starter Active Member

    Nov 24, 2011
    621
    8
    What is meaning of preset, I think suppose counter is preset with 6 decimal(0110) number. counter start to count from 6,7,8,9,10,11,12,13,14,15 than again count from 6,7...15
     
  8. Papabravo

    Expert

    Feb 24, 2006
    10,137
    1,786
    I think preset usually means to set the counter to all 1's, but I don't see a way to do that or do what you want unless you explicitly load a particular starting value.
     
  9. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    If you do a preset to 6, the counter will go 6,7,8,...,14,15,0,1,2,..,15,0,1,2,... if you want to go again from 6 you´d need to do the preset again every time you reach 15.
    As you can see in the internal diagram, the counter has only one set of flipflops that are used to hold the count, so there is no way it could remember that you want it to allways start beginning with 6.
     
    absf, Papabravo and vead like this.
  10. Papabravo

    Expert

    Feb 24, 2006
    10,137
    1,786
    You can make a single counter chip have any modulus you want. For example you could do a modulo 3 counter with states 7,8, and 9. You decode state 9 and load state 7. If you want to be really slick then you decode all the illegal states and load state 7. Counter chips are very flexible in this regard.

    Bit 0 --> 1,0,1 Two states high, one state low
    Bit 1 --> 1,0,0 One state high, two states low
    Bit 2 --> 1,0,0 Same as Bit 1
    Bit 3 --> 0,1,1 Two states high,one state low, different phase from Bit 0
     
    Last edited: Sep 16, 2016
  11. vead

    Thread Starter Active Member

    Nov 24, 2011
    621
    8
    I am looking LTspice model file for 74ls163 counter. Someone can tell me where to get LTspice model file for 74ls163
     
  12. GopherT

    AAC Fanatic!

    Nov 23, 2012
    5,997
    3,751
    It works fine.

    Just pull everything high (except ground pin and outputs (pins 9-13) and apply a clock to pin 1 And it will count away.
     
Loading...