Dear Srikanth,

If you have seen a discussion on "Trial and error approach" and "proper approach" on this forum, then you can do it with trial and error approach very well.

Just program the micro to display the strobe value on the 3 digit display, and two external interrupts. One interrupt (with a switch) to increase the strobe value and the Second interrupt (with a switch) to decrease the strobe value. (By strobe value I mean the speed).

Change speed up or down with these switches and read the display where you think is just right i.e. no flickering (too slow) or too dim (very low duty cycle or very high speed).

Just an idea, no need to calculate duty cycles to match Oscar award movie speeds of 30 frames per second. hehehehe

Warning:

Trial and error approach should not become your habbit. You must know in any case what's happening.

Good Luck

Babar/