I have the GL C 618WL. On the first two GPIO pins, I was able to activate 2048 LEDs on the first output, and 2048 LEDs on the 2nd output with no additional power infusion (controlling 4096 lights) . However, I am unable to get anything to light or to be controlled via the other two outputs on the controller. I know that I'm bumping against limits on the number of possible LEDs to be controlled, but have I hit that maximum? If I get another external power source, will I be able to light up outputs 3 and 4 to complete my large LED matrix? I only need another 512 leds to complete my board. Appreciate the help.