4017 internal logic

Discussion in 'General Electronics Chat' started by Barrie, Aug 18, 2009.

  1. Barrie

    Thread Starter New Member

    Aug 18, 2009
    4
    0
    I am trying to make a module (in a logic simulator) that is equivalent to a 4017 decade counter. The data sheet logic diagram for MC14017B (ON Semiconductor) shows 5 flip flops that show CDRQ labels. Can anyone please let me know what type of flip flops they are?
    Thank you
    Barrie
     
    Last edited: Aug 18, 2009
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    C = clock
    D = data
    R = reset
    Q = Q output

    It is a D type flip flop.
     
  3. Barrie

    Thread Starter New Member

    Aug 18, 2009
    4
    0
    Many thanks for your quick reply. Can I assume that the Reset is equivalent to the Preset pin on the simulator flip flop?
    There are also two more complementary inputs of C and R on the logic diagram. I am trying to match them to the simulator pins which are labeled "enable" and "clear".
    Will you please confirm the following is correct.
    C(bar) = enable
    R(bar) = clear
    Thank you
    Barrie
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Look up the data sheet for a CD4013 or a 7474 to get the full turnout of a d flip flop.

    They are clocked devices, so the C input must be the clock. R is reset. The reset input always places the flip flop into the state where Q is low, and Q^ is high.

    A "normal" D flip flop has an S input as well. It is the overriding SET input that forces Q high and Q^ low. The S input would be the equivalent of the simulator Preset. To get the simulation working properly, tie the Preset to a logic level that disables it.
     
  5. Barrie

    Thread Starter New Member

    Aug 18, 2009
    4
    0
    Thank you again for your help and guidance. I can now start my project.:)
     
  6. rspuzio

    Active Member

    Jan 19, 2009
    77
    0
  7. Barrie

    Thread Starter New Member

    Aug 18, 2009
    4
    0
    Wow. That is exactly what I needed. Thank you very much.
     
Loading...