Connect with us

Timing Diagrams

Discussion in 'Electronic Basics' started by Ron J, Dec 7, 2005.

Scroll to continue with content
  1. Ron J

    Ron J Guest

    Happy Holidays!

    Where can I find info on timing diagrams? I would like to learn them
    because I am trying to learn PIC programming and also I2C bus, but I am
    confuse with timing diagrams.

    Any help?

  2. PeteS

    PeteS Guest

    Timing diagrams show the relationships required between various signals
    (when in a datasheet) for something to work. There are specific timing
    statements such as 'setup time' (the amount of time data must be stable
    before an active clock edge) and 'hold time' (the amount of time a
    signal must remain stable after a valid clock edge).

    They really aren't difficult to understand at all.


  3. Ron J

    Ron J Guest

    Hello PeteS,

    Thanks much for the kind reply! Do you know of a website with pictures
    so I can understand more?
  4. Guest

  5. Ron J

    Ron J Guest


    I have that document and the timing diagrams are Greek to me -- for
    now. For instance, I don't understand Figure 4 very well especially
    when the timing diagrams "cross" each other. Can you explain?
  6. Pooh Bear

    Pooh Bear Guest

    Think of them as being like what you'd expect to see on a scope if you
    probed the pins.

  7. Pooh Bear

    Pooh Bear Guest

    The 'cross' as you call it on SDA, the serial data line, indicates
    where the data state is meant ' allowed to change ( if it needs to ).
    See the text note underneath and the relationship to SCL, the serial
    clock. I.e. data shouldn't change when SCL is high.

  8. Rich Grise

    Rich Grise Guest

    Well, it's a chart of what happens when. The X axis is time, as if you
    were timing a race, and the Y axis is the states of various signals
    along that time-line.

    What part is it that you're having trouble with?

  9. Jasen Betts

    Jasen Betts Guest

    Think of them as, a stack of a graphs of voltage against time
    you'll need to use a fixed pitch font to read the rest of this
    courier is a good choice.

    _____ ____ ____ ____
    \ / \/ \/

    voltage ||voltage ||high||high|| high
    is high ||is low || or || or ||
    || ||low ||low ||
    || || || ||
    ~~~~~~~~~~~~~~~~~~~~~~~~~~ voltage is changing (or not)

    _____ ______
    \ /
    A \________/
    | |
    __________ <5ms
    B \_____________

    | | | |
    voltage B stays high for atleast 10ms after voltage A goes low
    voltage A stat low for atleast 20ms after voltage b goes low
    the rise time on voltage A is less than 5ms.

  10. Ron J

    Ron J Guest

    Thanks, all! Thanks Jasen!

    That is really helpful!
  11. ehsjr

    ehsjr Guest

    Nice drawings!
  12. Rich Grise

    Rich Grise Guest

    Me, Too!
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day