Lpc2000

Just a quick question to see if there's anyway of using the inbuilt timer
functionality of a LPC2119 as a counter. Ie to count the number pulses
(rising or falling edge) from an external source over a given time frame.
Basically we have a pot that changes a source input frequency from 36khz to
around 48khz and driving an IRQ for each pulse doesn't strike me as being a
good idea. All I need to realistically know is roughly what frequency it's
being driven at.

Ideas?

Andy