Arduino Mega - Ext Interrup to read Serial Data

Greetings Everyone

Actually i have a RF Alert system controlled with one Arduino Mega interfaced with an LCD Touch Screen 4D uLCD-43p (Just a interfaced with serial Output, and a few digital pins)

I am trying without successful Implement a external interrupt with the digital pins of the screen. To make an almost sync serial communication. The function inside the interrupt must be larger enough to understand the incoming data. Until now i can't make it works and I've only seen examples of interruptions to read encoders.

Any idea to made this work?


The thing you must remember about interrupt functions is they must be short. You can't use delay in them and you should not do a serial print in them.
So use the millis timer to time between successive edges of your signal and don't hang about in the ISR.