I am using the SPI Arduino Due library. Everything works fine except the voltage level at MOSI is approx. 1.3 V and not close to VDD (3.3V) what I would expect. It seems that there is some pulldown resistor configured by mistake. If I use the GPIO manually I get the correct voltage levels. Does anybody have an idea what am I doing wrong?
Please post your code, or a simplified version that shows the problem. Please post a schematic of your circuit.
1.3V is not a value that should ever appear on a digital pin. Either you are measuring it incorrectly or something else is wrong.