Hi,
I have not tried this and not sure but if u change the percent low value as 90% and percent high as 10% in rise time then u can get fall time..
see if you can get the result by this way..
BR
Vabzter
but if i use the rise time funcion to an interval where just falling edge is, then it measures something, maybe it is the right fall time. so maybe, the same special function for measure the fall- and rise time, as well with the name risetime.