If you are using your AUX connection to connect an OpenBuilds Interface, see https://docs.openbuilds.com/doku.php?id=docs:interface:start instead , otherwise continue below

NB: The following section of the documentation relates to an advanced use-case configuration. Ordinary users should not have any need to work with this, but it is a feature provided to those who know and understand the systems, electronics and software (aka Hacker Friendly) who want to extend BlackBox beyond its default Configuration

OpenBuilds BlackBox 4X incorporates a circuit that can disconnect the USB-Serial (FTDI) IC from the Microcontroller, and connect the microcontroller to the header pins on the AUX1 header on the USB side of the controller.

• If the USB cable is connected and delivering 5v to the controller, the AUX1 header is DISABLED
• If the USB cable is connected and not delivering 5v to the controller, the AUX1 header is ENABLED
• If the USB cable is NOT connected to the controller, the AUX1 header is ENABLED
• Whenever the AUX1 header is ENABLED, the USB-Serial connection is DISABLED. The USB endpoint is active, but data will not be sent to/from the Microcontroller on the Brains board.

The port has the following connection parameters:

• Type: UART TTL Serial
• Baud Rate: 115200
• Port voltage: 5v TTL (Use your own level shifting hardware if you intend connecting to 3.3v systems)
• 5V output is provided for powering microntroller based devices, do not exceed 500mA current draw. Can not power a Single Board Computer from this pin