I am building a rover (4WD/off-road) and it has 2 RoboClaw 2x30A motor controllers that I am manipulating via Packet Serial. After thinking the problem was a wiring problem for the better part of 6 hours, I finally decided to try something ridiculous: I took the Core out of the Shield Shield and put it back in a breadboard.
As if like magic, my TX/RX wires started working and my motors were humming, and my rover then escaped my grasp and drove into my puppy… But, that’s a story for another day.
The real heart of the question is this: Is there something that the Shield Shield does to the Core that prevents the normal use of Serial1.xxx and Serial2.xxx ? I tried every possible combination of Serial1 and Serial2 (Serial1 is TX/RX and Serial2 is D0/D1). I had my wires running from the D0/D1 (also labeled TX/RX on the Shield Shield) to my controllers.
I would like to be able to use the shield shield because it’s more durable and I’ve got nice mounting clamps for it, and would really like to not have to mount my breadboard inside my rugged vehicle.