How to count PWM Pulse coming on GPIO?

[RPriy]

Hi,

I am a newbie in writing code on MCU's.

I am using STM8S003K3 with which several fan controllers are attached on different GPIO. I need to count PWM pulse whenever it comes on any port and then identify the pin no of that port. How to count pulse using ext interrupts on falling edge???

Thanks

Ritu.