Shift register loop

Discussion in 'General Electronics Chat' started by GopherT, Oct 15, 2015.

  1. GopherT

    Thread Starter AAC Fanatic!

    Nov 23, 2012
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    I have not worked with shift registers in a while and when I did, it was fairly straightforward in to out. Now I have a question for a chaser project, is it possible to put two or more 'serial in/parallel out' shift registers together head-tail in a loop to pass the bits in a circle?

    I am sure it can be done with a buffer flip-flop bit at the end of a head/tail series of shift registers (e.g. 'carry bit' for a rrf/rlf command) but can it be done only as a loop?
     
  2. kubeek

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    Sep 20, 2005
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    Yes you can, but you will need some glue logic to let you feed the pattern inside in the first place and then switch to circulation.
     
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  3. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    An alternative to kubeek's suggestion is a more complex shift register part that can be parallel loaded with the pattern. This is sometimes called a universal shift register because it is parallel in and out and serial in and out. 74195.

    ak
     
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  4. GopherT

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    Nov 23, 2012
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    Yes, I already have the glue logic with a feed-in switch, a toggle for the logic level and a push button clock to feed in the first pattern. Then I'll flip the feed-in switch back to form the loop, start the real clock and away I'll go.
    Thanks! Just wanted to make sure I wasn't missing out on something if they were cascading like dominos on each clock tick or if they all happen in unison. Cheers.
     
  5. cmartinez

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    Jan 17, 2007
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    Gopher, do you have a digital logic simulator? If you don't, then I suggest you take a look at digital works. It comes with some predefined logic chips and all.
     
  6. GopherT

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    Thanks, I already have one but it did not include a shift register for some reason. Also, some little things do not simulate reality very well.
     
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