PE4 is used for some mysterious purpose on the RCM6600W. It's also hard wired to external interrupt 0 (I0CR). If I need to set I0CR to priority 2, is that going to mess with anything that the RCM6600W is doing with PE4? I'm hoping PE4 is just being used as GPIO and it's a moot point, but I want to make sure I have my bases covered.