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D type Flip Flop

Discussion in 'Electronic Basics' started by Chris W, Feb 17, 2005.

  1. Chris W

    Chris W Guest

    Let me see if I understand this. If I were to take a D Flip Flop and
    connect the Q' output to the D input, every time the clock input fell
    from 1 to 0, the state of the Q output would be opposite of what it
    was? Is there a way to change this so the Q output changes as the clock
    rises from 0 to 1? Also can someone recommend a part number at Mouser
    or digikey for an IC that has from 4 8 or 16 D flip flops that can be
    hooked up this way? The ones I have seen don't have the Q' output, so
    it would require the addition of an inverter.

    --
    Chris W

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  2. Some D flip flops clock on the falling edge and some clock on the
    rising edge. The CD4013 dual D clocks on the rising edge.
    http://rocky.digikey.com/WebLib/Texas Instruments/Web data/CD4013B.pdf
    I think that most chips with more than 2 D flip flops have a common
    clock that clocks all or groups of them. Is that okay?

    If so, look at the CD4042.
    http://rocky.digikey.com/WebLib/Texas Instruments/Web data/CD4042B.pdf
    It has a clock polarity input that lets you chose which edge flips the
    flops.
    Yes.
     
  3. Chris W

    Chris W Guest

    That looks like what I asked for, thanks!
    No I need the clocks and Qs to be independent. However, a common reset
    pin like I have seen on some of them would be nice.

    I guess I should tell what I am really after. I want a chip that
    alternates the outputs when the inputs rise from 0 to 1. With each
    input and output independent of each other. I want as many of them in a
    single DIP as I can get (well up to 16 anyway). A global reset would be
    a nice too. I can do that with the one you sent the link to, by hooking
    it up right and using 8 of them. But it would be nice if I could find
    one that is already hooked up that way.

    --
    Chris W

    Gift Giving Made Easy
    Get the gifts you want &
    give the gifts they want
    http://thewishzone.com

    "They that can give up essential liberty
    to obtain a little temporary safety
    deserve neither liberty nor safety."
    -- Benjamin Franklin, 1759 Historical Review of Pennsylvania
     
  4. How is this different from a simple JK flipflop? Examine the SN74HC109, for
    example, and consider the J=1, \k=0, with your input tied to the clock (CLK).

    Jon
     
  5. Rich Grise

    Rich Grise Guest

    He wants a whole bunch of T flip-flops in one package. The most I've ever
    seen is 2. ("T" is for "Toggle".)

    Although, it could be done with a microprocessor (if it doesn't have to
    be fast) or some kind of gate array.

    Cheers!
    Rich
     
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