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First contact with CarambolaA few weeks ago I stumbled across an article in the german computer mag c’t about a small embedded MIPS based board called Carambola manufatured from the company 8devices. The device is equipped with a Ralink RT3050 MIPS CPU that runs at 320 Mbit/s, it has two ethernet interfaces and one Wi-Fi interface, a USB and a serial port, 8MByte Flash and 32MByte RAM. Since the 35x45mm board comes at an affordable price of 22,-EUR per module and for 67,-EUR the module, a breakout board, a housing and the shipping costs was included. Last week the module arrived on my desk and today there was time for the first contact. After hitting nearly every wall on the way from Power on, finally a Radiofaro board and a Raven RZUSB stick gets enumerated. Even if the 8devices Wiki is a good ressource for information, the information for OpenWRT novices is quite sprinkled over the net. In the following sections I summarize the todays lessons learned. Power Up and Serial ConnectionThe power up of Carambola requires basically a 9 to 24V DC power source. In my case it was the power supply of an old mobile CD Player, which comes at 9V, 500mA. I also own a prehistoric PC with a real RS232 interface, which was a great help bringing up the board. First I connected the RS232 cable with the PC and used the Now you can type At the serial terminal messages from the syslog appears, so you will see e.g.
events from plugging and unplugging USB devices. It allows you also to issue
some basic commands, for instance Connecting to the NetworkCarambola comes with two ethernet interfaces. One is configured to use the static
IP address 192.168.1.1 (eth0), the second one gets its address via DHCP (eth1).
If the static IP address does somehow not fit in your existing network
infrastructure, use the second ethernet port. Connect the ethernet cable an
watch, if the aproriate LED on the Carambola module ligts. Now you can easily
find out the assigned IP adresses by typing Before you can connect via ssh to Carambola, you need to assign a root password
in the serial terminal. Type Thats because of the firewall on Carambola blocks port 22. TODO: how to configure the firewall The way out is easier if your PC runs a ssh daemon and the firewall of the
desktop PC does not block port 22. For an Ubuntu you can open the firewall for
port 22 with the command Compiling a new ImageThe steps how to compile a new firmware image are described pretty good in the
Carambola-Wiki.
After installing the prerequisite Linux tools, cloning the git repository and
before doing the first Do not modify the Rebuild the Carambola firmware after this initial minimal modification with
the comand Flashing the first ImageThe firmware image that is going to be flashed is the file
In order to abbreviate the typing in the serial terminal, copy this file to a location with a shorter path name, e.g. From the serial Carambola terminal enter the commands After the Connecting Serial USB DevicesIn order to get Radiofaro and Co enumerated by the Carambola kernel, the support
for ACM and FTDI needs to be added. Since I somehow did it not get managed to
include the kernel modules Now proceed like in the previous steps for flashing the image. After booting the new kernel you should see the following messages when plugging the USB connector:
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| Last modified: 2017-06-04 |