Hi Babar,

Your scheme will work, but the point of the ISR for a key is that it has to see if the key is valid by checking if the key is down for a certain period.
Your scheme will work, providing you recheck at the end of the ISR that the key is still pressed, but this may STILL not work, because of noise or something. Its usually better to scan the key for a period, and count the number of valid scans befire accepting the keypress.

Steve