hi,

Is it possible to get interrupts on both the transitions i.e. High to lo and low to high both. Is there any trick to do this.

There are derivatives with PCA. Its modules may be configured to generate interrupt at negative, positive and both edges on pins CEXn.
As well, there are derivatives with Keyboard interface, which input pins may be configured to generate interrupt at either rising or falling edges.
With standard derivatives there is "trick" to control low-to-high transition with timer/counter configured to count input pulses via gate - read Peter`s comments.

Regards,
Oleg