If the server does not have a display output, the JTAG/UART interface of the processor can be used to get access to the serial console of the processor. On a Plugcomputer, the JTAG- and UART-ports are usually accessible from the outside. For the Sheevaplug and the GuruPlug, there is even a JTAG-Board which connects the JTAG/UART interface over USB to your computer which you use for administrating the Plugcomputer.

The serial console is a text based communication using a terminal. For Linux, a well known terminal emulation is minicom.

Installation of minicom

On most Linux-systems, minicom can be installed from the packet manager:

$ sudo apt-get install minicom

The configuration is described in the following chapters.

Setting up minicom

The command

$ sudo minicom -s

will open a text-based gui for editing minicom settings. Select "Serial port setup" to configure the serial port.

In the menu which shows up after selecting "Serial port setup", press E to edit the communication parameters. It will open the "Comm parameters" menu. To change the communication parameters, press the required key, for example E to set the Baudrate to 115200 and Q to set the databits, parity and stopbit to 8-N-1. This is the required setting for the GuruPlug Server Plus.

Aknowledge the settings by pressing ENTER. Back at the "Serial port setup" dialog, it might be necessary to set the right serial connection. The connection might be different on different operating systems, but on my Ubuntu it is /dev/ttyUSB0. Also make sure that Hardware and Software Flow Control are set to NO.

After typing the correct path to the serial device, press ENTER twice to get back to the start menu of minicom. Select "Save setup as..." and enter a name for the settings, for example "marvell" (or any other name you can remember) to use these settings for the GuruPlug. After saving, exit the minicom settings to get back to your console.

Connecting with minicom

You have saved a file with the required minicom settings called "marvell" before. To start minicom with these settings type

$ minicom -o marvell

and it will open a terminal connection if the serial port is available. Minicom shows a welcome message when the connection is ready.

To exit minicom at any time, press "Ctrl+A", then "X" and select "Yes" to reset the connection.

Links:

• Continue reading the first steps of settung up the GuruPlug to see minicom in action.
• linux serial console howto
• Getting the serial console to work on a MAC