Appendix: Connecting Cables

Explore when and how to use all the cable ports on the Arduino* expansion board for the Intel® Edison compute module.

While plugging in every cable is not required all the time, a cable setup for initial development purposes with the Arduino* expansion board would look like the photo below:

A photographic cable and microswitch diagram with numbered callouts

USB Device Mode vs USB Host Mode

Before connecting USB cables to an Intel® Edison breakout board, you should know the difference between USB device mode and USB host mode.

When the Intel® Edison board is in host mode, the board acts like a computer. A USB peripheral (such as a mouse, keyboard, or webcam) can be plugged into the Intel® Edison board.

When the Intel® Edison board is in device mode, the board acts as a computer peripheral to your computer. Connect the Intel® Edison board to your computer while in device mode in order to:

  • Supply 5V power to the Intel® Edison board
  • Read/write to the onboard flash memory from your computer like a disk drive
  • Program the Intel® Edison board over USB using the Arduino* IDE
  • Program the Intel® Edison board using the Intel® XDK and Intel® System Studio IoT Edition IDEs via Ethernet over USB (instead of Wi-Fi*)

Setting the USB Mode on the Arduino Expansion Board

The hardware slider on the Arduino expansion board switches between USB device and host mode.

Device Mode

The microswitch is toggled down towards the two micro USB ports. A USB cable with a micro-B type connector can now be plugged into the top micro USB port and the other end plugged into your computer.

Animated gif: Using device mode on the Arduino* expansion board

Photographic diagram for setting the microswitch for device mode

Host Mode

The microswitch is toggled up towards the standard USB port. A USB peripheral with a standard type connector can now be plugged into the USB port above the hardware slider. In addition, you must supply 7-15 V DC external power via the DC power barrel.

Animated gif: Using host mode on the Arduino* expansion board

Photographic diagram for setting the microswitch for host mode

UART/Serial

Connect to the shell on your Intel® Edison board using a serial connection via Terminal or PuTTY. Use these commands to flash firmware, configure Wi-Fi, or identify the board’s IP address.

Plug a USB cable with a micro-B type connector into the bottom micro USB port, and the other end to your computer.

Animated gif: Connecting to the UART/serial port on the Arduino* expansion board

A USB cable connected to the UART/serial port of the Arduino* expansion board

Supplying External Power

The Intel® Edison board can be powered via the device mode micro USB port, an external power supply, or both.

This is especially important to note since the USB ports on some computers do not reliably supply 5V power. An external 7-15 V DC power supply is the most stable and reliable way of powering the Intel® Edison board.

If you are going to use more power intensive features such as Wi-Fi, a servo motor, or an Arduino shield, use a DC power supply. You must always use an external power supply when using USB peripherals in host mode.

Animated gif: Plugging in a DC power supply to the power barrel connector on the Arduino* expansion board

An external power supply connected to the power barrel of the Arduino* expansion board

What external power supply should be used?

Use a direct current (DC) power supply rated as follows:
  • 7-15 V DC
  • At least 1500mA
  • Center/inner pin is positive pole

We suggest an EMSA120150 or similar supply.

Next Steps

You should now have a better understanding of the USB modes and cables required for development. Use your browser's back button to return to the previous article you were reading.

If you have not finished assembling the Arduino* expansion board, go to Step 1: Assemble the Arduino* Expansion Board. Otherwise, continue to Step 2: Run the Setup Tool.

Would you like to know more about the Arduino* expansion board?
Refer to the Intel® Edison Kit for Arduino* Hardware Guide (PDF) for technical specifications and detailed diagrams.

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