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Need Explanation of this Master Slave D Flip Flop

  1. Nov 23, 2011 #1
    Please look @ the pictures below. I have drawn a master slave D flipflop with preset and clear option as mentioned in the book.

    http://i28.lulzimg.com/7e22bfc016.png [Broken]

    Can any one tell me what is the necessity of the wires that are highlighted in the image? isn't the wire @ last stages of NAND gates enough?
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Nov 23, 2011 #2
    The pairs of U5+U6 and U7+U8 both form memory elements. So if you really want to preset or clear the entire circuit you most do that action on both memory elements. If you only did it to U7+U8 then you could force the desired output, but as soon as you release the preset or clear the circuit would just revert back to whatever was stored in U5+U6.
  4. Nov 23, 2011 #3
    Hmm, i think thats the answer of my question. Thank you. :)
  5. Nov 24, 2011 #4
    Well after studied what i have found that it is a must. You can't set ouput 0 by pressing clear = 0 when the slave is active (clock = 0) unless u give those connection that i mentioned.
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