Want to know how many pulses there have been on a signal? Without "watching" constantly? Without interrupts?
Use the spare electronic circuit present on the Atmega328... and most other microprocessors. But the specifics on the page cited below work EXACTLY as shown, fot the 328. (Minor tweaks only, I would guess/ hope for other processors.)
The page gives just a VERY BASIC explanation, using the counter as SIMPLY as possible... a starting place for you.
My thanks to the forum's Nick Gammon: What he had on the web gave me what I needed to make this work... something that has been a want for years.
I hope you find it useful... If you do, Facebook likes, etc, very welcome... not just to stroke my vanity, but also to help others find it. I spent HOURS searching this forum, Google, before Nick got me close enough to be able to push through to the page I've written. It only interprets what Nick has published... but stripped of some elegant enhancements which might distract a beginner, and with a few "gotcha"s underlined.
Tutorial on using the timer1 counter is at...
Good for...
Anemometers and rainfall recorders, among other things.