Expansion Connector - Digi ConnectCore 8X Hardware Reference Manual

Using the UART0 bus of the i.MX 8X CPU.
n
Using the USB_OTG2 bus.
n
The lines of these two communication buses are connected through 0-ohm resistors. By default, UART0 is connected (R62 and R63 populated) while USB_
OTG2 is not (R52 and R53 not populated).
CAUTION! The CPU USB bus connected to the XBee socket is the USB_OTG2, which is also connected to the dual USB A-type receptacle.
Connecting two devices to the USB_OTG2 port at the same time will cause a short circuit in the differential data pair.
CAUTION! The XBee socket is powered through an external DC/DC regulator(U23 - MP2316). The purpose of this external regulator is to provide
higher current than using 3V3 supply coming from the module. Disabling this regulator doesn't guarantee that the XBee socket is fully
disconnected from the module. In fact, some current travels through the I/Os to the module even after the regulator is disabled.
If your design requires fully disconnecting the XBee socket from the ConnectCore 8Xmodule, Digi recommends you use bus switches for all I/Os
connected to the XBee socket.

Expansion connector

A 2-row, 40-pin, 2.54 mm pitch header (J11) is supported by the ConnectCore 8X SBC Express board. This header acts as an expansion connector that
mimics the Raspberry Pi HAT connector specification, offering access to many different interfaces of the CPU.
The following table shows the pinout of the expansion connector:
Pin Schematic signal name
1 3V3_EXT
2 VIN
3 I2C2_SDA
4 VIN
Description
Output 3.3V power supply line
Output 5V power supply line
i.MX 8X I2C2 bus data line
Output 5V power supply line