I've connected one LCD display and was able to make it work perfectly. However I think I missing something.
I'm using a UNO board connected to the main Mega board. It’s connected as describe on this page : http://simvim.com/svc_lcd.html
Whatever pin I use on the UNO board will disable the pin on my Mega board.
For example, On my main board (Mega) I have an Input Multiplexer connected to pin 2. Using Pin 2 on the Uno board for the LCD display will disabled my pin 2 on the main board. Therefore, none of the switches connected that multiplexer works. The only way I was able to make everything work all together was to use a pin on the Uno (slave) board that matches a free pin on the main board. In my case I am using pin 4.
Any clue what I am doing wrong? In the configurator do I have to specify what is connected to pin 14 &15 (RX3 & TX3) or I just leave if blank?
Thank you for your help.