Dave Tweed wrote:
> No, and if you think about it a bit, you'll see why.
>
> A ripple counter is made of flip-flops that change state on the
> high-to-low transition of the clock. So, because of causality, a
> given stage has to go low before the stage that it drives can go
> high. As a result, you can never see a count that is "too high", even
> as a glitch; you'll only see glitch values that are too low.
> Therefore, this method of creating a programmable divider works just
> fine.
>
> -- Dave Tweed

If you observe the time diagram below, where each division output is
delayed a little bit, you will see that (in this particula example), the
8th clock bit missis completely the F raise, and F should raise at the 8th
A bit.  In this example, due the extreme delay from A to F, an imaginary
74HC00 with A and F at the inputs, will only activate output when A=10,
since F raises only after (same time) of dropping of 9th A.  It means, an
hipotetical AND A.F would identify A.F = 10 and not 9 as expected.

Of course, the internal delays between stages can gives you only DELAYS and
LOWER Counts.


1   2   3   4   5   6   7   8   9   10  11  12  13
   _   _   _   _   _   _   _   _   _   _   _   _
A_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_
                                |
  ___     ___     ___     ___   | ___     ___
B|   |___|   |___|   |___|   |___|   |___|   |____
                                |
       _______         _______  |      _______
C_____|       |_______|       |_______|       |___
                                |
                _______________ |               __
D______________|               |_______________|
                                |
                                 _________________
F_______________________________|

                              A   A
                              |   |
                              |   |
Count of "9" should happens HERE  |
when F and A should be HIGH.      |
                                  |
But in this example, it happens HERE at count of "10"
due internal propagation delays.

Wagner.

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