Arduino has two interrupts.
can use diode for like OR logic gate for each input pin to share interrupt pin?
when some input has pulse, diode also send to interrupt pin,
interrupt function read all input pin, finding pulse logic 1 .....
it can work?
sorry for my english.
Re: share interrupt concept for pulse counting more then two....
Yes, that would work but there may be a simpler solution.
The ATMega IC that the Arduino is built around has Pin Change Interrupts, where the state of up to 8 input pins are internally ORed to a single interrupt.
The user can read those input pins when an interrupt is generated and find which pin has changed state, then react accordingly. The advantage is that no external logic is required.
A google for "arduino pin change interrupt" will find you links to 2 Arduino Pin Change Interrupt libraries and code examples.
HTH