Timing diagram

Discussion in 'General Electronics Chat' started by xxxyyy, Oct 7, 2011.

  1. xxxyyy

    Thread Starter Member

    Oct 7, 2011
    34
    1
    Hi!
    Can someone give me tutorial about drawing timing diagrams of flip-flops,latches..?
     
  2. #12

    Expert

    Nov 30, 2010
    16,283
    6,795
    I don't think so. Nobody taught me. I just looked at a timing diagram and understood it.

    You start with a piece of paper and a sharp pencil. Graph paper works for me. Declare a horizontal line for each "point of interest", and label it well. Leave enough room between horizontal lines to represent positive and negative voltage (if that's what you have to work with). Declare a starting condition and mark that condition for each point of interest. Decide that time has passed so the next mark will be farther right, decide what changes first, and mark it. Then mark all the other points of interest as what would result at that time. Lather, rinse, repeat.

    That's the best I can do. Maybe somebody else can do better.
     
    xxxyyy likes this.
  3. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,009
    1,530
  4. xxxyyy

    Thread Starter Member

    Oct 7, 2011
    34
    1
  5. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    Well, think about what an RS latch does, find if it works on falling or rising edge of CLK or is level-triggered or asynchronous, and... suprisingly decide what the output is.
     
    xxxyyy likes this.
  6. crutschow

    Expert

    Mar 14, 2008
    13,006
    3,232
    Typically you draw the timing of the various inputs being used (clock, D, J, K, set, reset) on a readable scale. From that you use the behavior of the FF, latch, etc. to draw what the Q and /Q outputs are doing.
     
    xxxyyy likes this.
  7. xxxyyy

    Thread Starter Member

    Oct 7, 2011
    34
    1
    I'm not sure that I can do it correct... :( Can someone do for me example I have posted?
     
    Last edited: Oct 7, 2011
  8. xxxyyy

    Thread Starter Member

    Oct 7, 2011
    34
    1
  9. Sparky49

    Active Member

    Jul 16, 2011
    834
    417
    Here's an example I've just drawn.

    The X (horizontal) axis shows time, which could be anything on an unmarked axis like this. Just remember that the further to the right you are on the x axis, the further in time you are.

    The Y axis (vertical) shows voltage, or current. The higher the line is, the greater the current or voltage.

    In this example, start at the origin (where both axis are 0). At this exact point we can see that when the time is 0 seconds, there is no voltage as the Y axis shows.

    Moving across the X axis, we are now going forward in time, look at the labels, 1, 2, 3 seconds from the start.

    Between 0 and 2 seconds we can see that the voltage has been increasing steadily to 5 volts. Moving further forward in time, the level line shows what?

    It shows that the voltage has stayed the same over this second because the line has not moved up or down the voltage scale, but has moved along the time scale by one second.

    What has happened between 3 and 5 seconds? The straight line at 3 seconds tells us that the voltage has suddenly dropped to 0 volts. As we just learnt a level line means that the voltage level hasn't changed. By looking at the x axis, we can see how long the circuit has stayed at 0 volts.

    The answer should be clear as two seconds, the difference between 5 and 3 seconds.

    Suddenly, we see the line move up again at 5 seconds suggesting a sudden increase in voltage back to 5 volts. It stays at 5 volts for the rest of the time which the graph shows, up to 9 seconds.

    I hope this has been helpful.

    Sparky
     
    xxxyyy likes this.
  10. xxxyyy

    Thread Starter Member

    Oct 7, 2011
    34
    1
    It was helpful,thanks Sparky49 :)
     
  11. Sparky49

    Active Member

    Jul 16, 2011
    834
    417
    Good stuff, is that your problem solved?

    Or is there any more?
     
  12. xxxyyy

    Thread Starter Member

    Oct 7, 2011
    34
    1
    After collecting all these advices,I think I realized principle :)
     
    Sparky49 likes this.
Loading...