Whell, there isn't much information that the one I already posted. The code was the complete code I wrote. The hardware uses a 16f84a as I mentioned before, a mc14511 to drive the 7 segments displays, thre bc548 to multiplexed them, and a photomicrosensor to count the pulses.
If you want to know anything else, just ask.

I will try the diferent aproaches you all mention.

I'll post the results when I have some code to begin the test.