OpenWrt and Devolo dLAN USB Extender building, flashing and configuration instructions.

In order to build OpenWrt, we recommend using a Linux-based machine with the usual GNU software development tools such as GCC, Make, ncurses etc.. Use your Linux distribution package manager to install these tools. If there is any missing tool, OpenWrt will check for it and warn if it find it missing or ineadequate.

To download the OpenWrt sources the subversion and git tools are required.

Note: OpenWrt can also be built under FreeBSD or MacOSX, but their are not officially supported as build platforms.

The OpenWrt sources are made available using subversion. Complete instructions can be found here: https://dev.openwrt.org/wiki/GetSource

You should start defining a directory which will serve as the root directory for the OpenWrt sources and build system.

OpenWrt does not require being built as root, and will actually prevent you from building it as root. Assuming you are in your home directory ($HOME), create a directory in which you will download OpenWrt sources:

We can now start downloading the OpenWrt sources in this current directory by doing the following:

The sources are now checked out, and are ready for building.

Prior to building OpenWrt we need to download third-party software, which is responsible for making the Power Line Communication (PLC) part of the Devolo dLAN USB Extender device working.

The Power Line Communication part of the dLAN USB Extender device requires some proprietary software which is made available using an OpenWrt "feed".

A feed should be seen as a repository in which packages maintained by third parties can be added.

Move to the previously downloaded OpenWrt sources at step 1.2) using the following:

At the root of this directory, edit the file feeds.conf.default, which is going to contain the download method, name and url of the feed. Alternatively you can use the following:

The first column tells the feeds script how to download (using git), the second is a name to reference to this "feed" and the third one is the url where to find the package makefiles.

Once this is done, we need to get a copy of this feed, in order to do so, use the following command:

Now that we have got a copy of the feed, we can add the packages to the build system:

Since foot depends on confmgr and hpav-firmware to run, these packages are listed as dependencies and the feeds script handles that for us.

foot also depends on another package called hpavcfg which is available in a different feed which is the default repository for OpenWrt packages. To install this package we need to proceed with the following:

The build system will have integrated these packages just like regular packages.

The OMS repeater software is also packaged in the dlan feeds repository and should be installed using the following:

Prior to building OpenWrt, we need to instruct the build system about which target we want to build for. In order to that, remain in the same directory ($HOME/projects/openwrt/trunk) and run the following:

You will be prompted with a console-based menu with which we will interact for configuring OpenWrt propertly.

In the Target System menu, choose "Moschip MCS814x" and press enter. The OpenWrt build system has already preconfigured a certain number of base packages, but still we need to tell the build system to also include the dLAN USB Extender specific package set.

In order to do that, go to the "Target Profile" menu, and switch from "Generic" to "Devolo dLAN USB Extender", this will now select the "foot" package which is required for proper Power Line Communication operation. To select the "hpavcfg" package, now go to the "Network" section and type "y" as well.

Exit and save the configuration.

We are now ready to build the entire firmware image, to do so, just run:

The build usually takes some time (up to one hour on a relatively recent build machine) due to the building of the toolchain, packages and kernel.

Once the build is done, we will have built the base firmware, which contains the Linux kernel, and all the selected packages.

Remain in the same directory ($HOME/projects/openwrt/trunk), once the build is finished you will find several files in the directory bin/mcs814x/ relative to this directory which correspond to various files useful for flashing the target.

OpenWrt produces an image which can be used by the dLAN USB Extender firmware with the USB autoupdate feature. This image is:

bin/mcs814x/openwrt-mcs814x-dlan-usb-extender-upgrade-squashfs.bin

You will need to prepare an USB Stick with specific parameters in order to use the USB autoupdate feature of the dLAN USB Extender. The specific parameters of this USB stick are:

an unique FAT32 partition with the label autoupdate. You should then copy the file bin/mcs814x/openwrt-mcs814x-dlan-usb-extender-upgrade-squashfs.bin to this USB stick and name the file autoupdate_image. You can for instance use the following:

Your device is now ready to be flashed with this OpenWrt firmware, in order to let the autoupdate feature start, just plug in the USB key, and power cycle your device.

The USB LED will start blinking fast indicating that it is reading the firmware file from the USB stick.

For all OpenWrt devices IP networking is configured using the file /etc/config/network and contains the following:

The Ethernet MAC address of the interface can be changed at any time by using the configuration option "macaddr", this option should be added to the file /etc/config/network, like this:

If you want to configure your device to instead obtain its IP address via DHCP, just replace the "static" protocol by "dhcp". You should then issue the following command for the settings to be applied:

Power Line Communication networking is configured through several means among them:

To repeat OMS data, the setup must be comprised of two USB sticks and two dLAN USB Extender devices at least. The dLAN USB Extender devices must have been preliminary paired to be connected to each other in the same HomePlug AV network (see documentation above to pair the dLAN USB Extender devices).

The typical setup will look like this:

See section 4.2 below to see how to configure wmbus-repeater in T1 meter and T2 other mode.

OMS wireless data sent to USB Stick 1, configured as T1 meter mode, will be sent over the HomePlug AV network interface of dLAN USB Ext 1 and be received over the HomePlug AV network interface by dLAN USB Ext 2. dLAN USB Ext 2 will then forward this OMS wireless data to the USB STick 2 attached to it and set the "hop" counter to 1 (data is repeated).

By combining several times this basic network topology you can very easily create repeated wmBus networks using the HomePlug AV network as a backbone for repeating wireless data.

The wmbus-repeater software is handling the repeated packet in such a way that:

This is to ensure that devices too close to each other, typically a T2 other device close enough to receive data from two T1 meter emitters will not repeat twice the same data received both over the HomePlug AV interface and over the USB stick.

The configuration of the wmbus-repeater software is done in /etc/config/wmbus-repeater. The default configuration is the following:

Mode can be:

Depending on your setup and Wireless and HomePlug AV network topology, you will have to configure the wmbus-repeater daemon to be in one of the mode presented above. The "retain" mode is a special value which is to be used when you do not want to change the mode pre-configured in the USB stick.

By default, when a USB stick is hotplugged on a dLAN USB Extender device the wmbus-repeater software will be started on the corresponding /dev/ttyUSB<N> device with the mode specified in the configuration file /etc/config/wmbus-repeater. You can still control the execution life of wmbus-repeater by issuing the following commands: