OLIMEX A20-OLX-LIME [12/49] Serial connection at uart0

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.

2.5.1 Serial connection at UART0

The default and recommended way to communicate with the board is using the serial connection

available at UART0 connector. You would probably need an USB<->SERIAL cable for such a

connection. Even if you intend to use HDMI or LCD it is a good idea to have it as a basis – the

video output is not always reliable and if you set wrong display settings you would be unable to

recover the software without an alternative connection.

We distribute a ready-to-use cable. 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: Product page

If you decide to make your own cable you would need to consider that the levels at board's UART0

are in CMOS level (3.3V) and you would need a convertor to bring them to the TTL level of your

computer or cable! That is true for the RX and TX also!

The cable probably needs drivers – after successful driver installation a COM port device would

show up in the hardware manager of your computer. Then you would need to connect the serial

cable wires to the board as follows: RX line to UART1-TX pin; TX line to UART1-RX pin; GND

to GND. The last pin of UART1 connector is named 3.3V and it can be used to power the board, if

you have other ways of power the board leave 3.3V pin unconnected! Be careful to avoid the

connection to the serial cable else there would be a short-circuit. Make sure that the serial cable is

connected to your personal computer and recognized properly after driver installation.

Then open a terminal program on the serial (COM) port which the cable is associated with. The

settings for the connection are 115200 baud, 8-N-1.

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

board”.

2.5.2 HDMI monitor

All official Debian and Android images for A20-OLinuXino-LIME have HDMI output enabled by

default. The board would work out-of-the-box with a native HDMI monitor.

Make sure to use a tested HMDI cable.

The default HDMI resolution in the official images is 720p60 (1280×720p at 60Hz). In order to

change that setting the video output on the LCD display you would need to run a configuration

script (if you use Debian Linux) or download a suitable image (if you use Android). Video output

settings are hard-coded in Android images but there are ways to edit the images. You might more

information about editing pre-built Android images at this wiki article: how to edit prebuilt Android

images.

More information about the video output settings and the usage of video settings script might be

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