I just recently bought the Rock Pi X (revision 1.4). With libmraa I am trying to control the GPIO pins. Setting them to high and resetting them to low works as it is supposed to. Unfortunately the voltage on any pin is only 1.8 Volts when set to high.
A friend with way more understanding of these things studied the schematics and the data sheet of the UM3204 level shifter and following the logic it seems as if there was a possibility that this part was connected the wrong way (UM3204 B channel to CPU, A channel to GPIO connector) and therefore not compliant with the UM3204 rule VCCA <= VCCB.
The available schematics for V1.3 show correct connection but V1.4 board layout and UM3204 placement point to a modification there… or the footprint drawing was mirrored.
Both 1v8 and 3v3 voltages are measurable and ok (only 3v3 measurable directly at um3204 due to ball grid layout).
Can anyone confirm this?