What is the purpose of the 'LOAD' input in a counter?

Discussion in 'The Projects Forum' started by asulikeit, Dec 13, 2012.

  1. asulikeit

    Thread Starter New Member

    May 1, 2012
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    I'm building a code breaker which basically works on trial and error. The counter provides me inputs and stops when the code matches. I have the rest figured out but don't know the purpose of the input 'LOAD' or pin 11 in IC 74191. Datasheets aren't helping either.
     
  2. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    Right in the 3rd paragraph of the first page.

    This counter is fully programmable; that is, the outputs may be preset to either level by placing a low on the load input and entering the desired data at the data inputs. The

    It is for preloading the counter.
     
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  3. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    There are 4 data inputs that will be transferred to the counter outputs when the load input is low, independent of clock (asynchronous load). This allows you to "jam" the counter to any count you desire, at any time.
     
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  4. davebee

    Well-Known Member

    Oct 22, 2008
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    Here's an example where you might want to use counter LOAD. You can retrofit an old AM radio with a digital frequency display by measuring the frequency of the local oscillator, but since the LO is 455 kHz above the received frequency, you want to preset the counters 455,000 below zero, then count cycles for a second. These chips let you do this sort of thing.
     
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  5. asulikeit

    Thread Starter New Member

    May 1, 2012
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    The idea of 'jamming' the counter makes absolute sense! Thank you!
     
  6. MrChips

    Moderator

    Oct 2, 2009
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    Great example!

    Here is my AM radio receiver digital frequency readout that has been preloaded with the -455kHz value:

    [​IMG]
     
  7. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    That looks like an FM station to me.:)
     
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