The GPIO pins on Odroid-XU4 operate at 1.8V. They don't tolerate voltage higher than that. However, most sensors and peripherals in the market operate at 3.3V or 5V. So, you need to use this level shifter board so that you won't smoke your XU4 unnecessarily.
This level shifter board is powered by 3 TSX0108E chip. It is bi-directional. It means that it can shift the voltage going to and from the XU4. There is a small selector switch that you can set to use 3.3V or 5V. Not only that, this board also map all GPIO pin on XU4 to a 40-pin header with 2.54mm pitch which has the similar arrangement that you can find on Odroid-C2 and Raspberry Pi boards.
Take note like any other development boards, the pins can only provide small output current (around 4mA). External power might be needed if you want to drive peripherals which need higher current.
