LCD display changing text with button press

Hi all. I have some RGB LED controllers and they have a sequence which changes on pulling an input on the uC low. There are two inputs, one selects the program, the other sets variables such as speed in that program. Here is the sequence RGB CHIP GREEN VERSION.

Because the chip is a pre-programmed PIC there is no real way of me knowing which program I'm in.

I want to use an arduino to display this on a LCD. I want to basically input all the program names and make them scroll on the LCD with a low input on a pin. I could sync it by pressing both buttons together (which reverts to prog 1 on the PIC) or sync it manually so I think it will be ok to run the two uC's independently.

I'm not sure how to code an arduino to change display on keypress?

Thanks

Maybe I should have posted this in the display sub-forum?