Posted on May 17, 2011 at 14:01It’s clear that English is not your favorite language. I’m also guessing that you are fairly new to embedded microcontrollers. Neither is a problem except that I had to guess what you need.
Simple almost useless answer: ports are memory mapped. Read just like reading RAM. It would also be a good idea to Read The Fine Manual - its only a little over 1000 pages.
I can only guess at your “I must detection the [duty cycle] of 5 PWMs.�? For the rest of this note I will assume that you have 5 PWM inputs with unrelated duty cycles.
If the period of the fastest PWM is around 100 Hz or less you can (for each input) sample in a 1KHz ISR recording ISR counts and GPIO high levels. Divide to get duty cycle. 10 seconds should be more than enough. (With a 72 MHz CPU clock a 1 kHz event happens every 72,000 clocks. This is far from serious overhead.)
In the 500 Hz and above range a different approach works better. Use external hardware to route your processor clock into a timer input pin when your duty-cycle-to-be-measured is high. Read counter(s) before they overflow. Every 0.5 seconds should be enough..
