generate pulse only on rising edge

Discussion in 'The Projects Forum' started by James Gordon, Jan 13, 2015.

  1. James Gordon

    Thread Starter New Member

    Jan 13, 2015
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    Hi,

    I'm looking for some help: I need a digital circuit that will output a short pulse, wavelength unimportant, only upon receiving the rising edge of a pulse.

    Thanks
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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  3. James Gordon

    Thread Starter New Member

    Jan 13, 2015
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    Hi Max,
    Thanks for the reply.
    Do you know of a solution that only utilises only basic gates and flip-flops please?
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The 555 does it in a single 8 pin IC, is there a reason you want to make it a bit more complicated?
    Max.
     
  5. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    Max has a good point.
    Otherwise maybe one XOR, one AND, one R & one C - in a particular topology.
     
  6. ronv

    AAC Fanatic!

    Nov 12, 2008
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    Do you mean digital only? No resistors or capacitors?
     
  7. James Gordon

    Thread Starter New Member

    Jan 13, 2015
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    No capacitors or IC can be used, resistors acceptable. Thanks again for the continued effort :)
     
  8. MaxHeadRoom

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    Is this some kind of masochistic challenge??:confused:
    Max.
     
  9. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Probably homework.
     
    #12 likes this.
  10. MrChips

    Moderator

    Oct 2, 2009
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    One capacitor and one resistor.
     
  11. James Gordon

    Thread Starter New Member

    Jan 13, 2015
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    It's to be implemented onto a CPLD/FPGA chip which only supports basic gates and flip flops.
     
  12. ronv

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    Since you have lots of gates, this should work.
     
  13. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    ronv's circuit is the classic approach. Be sure to tell the CPLD compiler not to reduce the inverter string. For Lattice software it is an option under net properties.

    ak
     
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