I'm trying to control a SSR using my Due but the voltage out on the digital pins is ~2.9V. The spec says it should be 3.3V which should activate my SSR which requires 3V. I switched out the Due with an Uno and things work fine; however, I went with the Due for the 12-bit ADC. Any ideas what may be causing the 2.9V out? There's nothing in between the Due except a trace on a shield and a wire so there shouldn't be THAT much voltage drop. The 3.3V pin is showing 3.23V.
do you have the internal pull-up resistor set. If not either, Set it to use an internal pull-up resistor, or use an external pull-up resistor.