> > A scope probe will allow you to see if there is > > a clock signal. That's all. You can't determine > > its quality. A 4-inch ground lead on the scope > > probe will result in 10-20% overshoot and undershoot > > being observed.
> I don't understand this 10-20% figure. > (0V + 10-20% is still 0V.) If you're jumping from a 900 foot marker to a 910 foot marker, does a 10% overshoot mean you jumped 1 foot too far or 90 feet too far? The percentage is of the distance you were trying to go, not of where you started or where you ended up. > AFAIU, the nominal peak-to-peak voltage is 3.3V. The observed > peak-to-peak voltage is 6.08V (3.3V + 84%). So a 10% undershoot would mean that rather than going from 3.3V to 0V, you overshot 0V by 10% or the distance you travelled. The voltages could just as well be 100V and 103.3V, the transitions would still be the same. What you call zero is, at least in principle, arbitrary. DS -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
