thanks mel for the information. About also to my previous question regarding dealing with buttons. Until now I cant get it, I hope you can give me an idea on how to deal with buttons.

I want to get the corresponding digital output of the 3 analog inputs namely RA0, RA1 and RA3 one at a time by using a buttons such that when I press the first button it will enable RA0, if button2 enable RA1 disable RA0 and RA3 and lastly if button3 is pressed it will enable RA3 and disable RA0 and RA1. Maybe buttons will be connected to PORTC because PORTB and PORTD are being used already for the LCD.