OLIMEX A20-SOM-EVB-8GB [11/41] Interacting with the board

2.5 Interacting with the board

The typical and recommended way of interacting with A20-SOM board is via a serial cable

connected between the UART-DEBUG header and a personal computer. You would probably need a

cable suitable for such a connection due to the fact that most personal computers lack a serial port

nowadays. Even if you have serial port you should respect the CMOS levels of the board which are

incompatible with the TTL levels of your computer. We distribute a ready-to-use plug-and-play

cable – it is called USB-SERIAL-CABLE-F. Even if you already have such a cable or you decide to

purchase it elsewhere it is advisable to check this product page for a reference:

https://www.olimex.com/Products/Components/Cables/USB-Serial-Cable/USB-Serial-Cable-F/

You need to connect the serial cable lines as follows: RX line to UART0-TX pin; TX line to

UART0-RX pin; GND to GND. Make sure that the serial cable is connected to your personal

computer and recognized properly after driver installation.

After the hardware connection is established, open a terminal program on the serial (COM) port

which the cable is associated with. The typical baud rate is 115200, the rest of the settings should be

left as per default.

After everything else is set, you would need to power the board as explained in “2.3 Powering the

board”.

In the command line interface of the official Debian images you are automatically logged as root.

The default superuser username/password combination in the GUI (LXDE) of the official images is:

olimex/olimex

If the A20-SOM is attached to A20-SOM-EVB, in addition to the serial communication, you might

also use one or more of the following mediums to interact with the board:

1. a monitor via HDMI connector

2. a monitor via the VGA connector

3. SSH via the mini USB connector trough a mini USB cable

4. SSH with a remote computer via LAN connector

5. a display via LCD_CON connector

Refer to the A20-SOM-EVB's datasheet for more information on each connection.

Note that not all interface options are available for all images. Furthermore, some of the ways of

interaction are not suitable for Android OS. The official Debian image should give you the most

possible options of interfacing the board!

Using HDMI, LCD_CON or LAN might require additional configurations. Furthermore, it is

possible to corrupt the output settings over those interfaces and, thus, lose the output. In such cases,

you can always use the serial cable USB-SERIAL-CABLE-F as a reliable way to establish

connection to the board.

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