I can't find any solution to use the I2C Interface? Has anyone experience with it or what level shifter is the right one? Is the 74LVC245A the right one? The goal is to communicate with 3V3-device.
In the Udoo X86 GPIO documentation is a link given with example: http://www.geduino.org/site/archives/284
My experience with boards using TXS0108E as level shifter hasn't been very good for I2C communications, spent many hours debugging the issue, low capacitance tolerance at high data rates. I would suggest trying a board with the PCA9306 which is designed for I2C/SMBus which you can also find on ebay.