> Hi PIC gurus!
>
> A friend of mine needs accurate frequency measurement in the range cca.
> 10 Hz - 250 KHz, with at least 3 digits precision (ie. 48.035 Hz). I

that's a 5 digits readout, although it might be imprecise :)

> remember there were threads about frequency counters some time ago.
> Does someone of you, gurus, have any suggestions, piece of code,
> pointer, anything related?

look at my home page, there is a frequency meter based on an idea taken
from the PIC application notes. Data is fed into the prescaler and the
counter, so as to implement a 16-bit counter, and counting is enabled
for a fixed time. After that, an output pin is used to toggle the
prescaler's input and cause it to overflow, so that the residual count
can be read out.

        Luigi