Compile a Moxa Serial Widget Device Driver on Ubuntu Linux

We needed a Linux serial device driver for the Moxa U1250 series multi-port USB to Serial adaptors.  The released driver on the Moxa web site only works with Ubuntu Linux up to version 11 and with Fedora Linux up to version 16, so you need a Virtual Machine of the right version for it.  Otherwise, ask Moxa support for a Beta version of their driver for the newer kernels.

Ubuntu Software Installer

There are basically three Linux development streams:

• Slackware
• Debian 
• Red Hat

The Ubuntu distribution is part of the Debian family.
The Fedora distribution is part of the Red Hat family.

Each of these families has their own incompatible code packaging systems.  Each distribution has its own set of file servers and when you install a system, it will be configured to look at those servers for updates.  These servers are distributed all over the world at universities and large corporations.  Because they are perfect copies of each other, the servers are also known as 'mirrors'.

The update program used by Ubuntu is known as 'apt'.  To get a program from a mirror, you run a program called 'apt-get'.

To install stuff, you need super user (administrator) privileges.  You can elevate your permissions temporarily using a program called 'sudo' (set user do).  So therefore the command to get all system updates is:
$ sudo apt-get update

Similarly, to install a program, you would run:
$ sudo apt-get install programname

Apt keeps a database of installation data, so you can also use apt to remove a program, or upgrade an installed program to the latest version.  The graphical software wizard, is simply a nice looking front end for apt.

Low level programs such as device drivers, are operating system kernel modules that can be loaded and unloaded at run time - on the fly.  When you plug a new thing in, the system will automatically load the required driver if it is available,  For that to work, the driver needs to match your running kernel exactly. 

The Linux system is changing all the time.  It has a very rapid development cycle.  Therefore, most drivers are distributed as C source code and you have to compile it on your system before you can use it.

Software Development Tools

To do software development and compile device drivers for example, you need GCC (the GNU Compiler Collection) and the interface definition for your kernel version (the kernel header files).  These can be installed using apt. The command is something like:
$ sudo apt-get install linux-headers(versionnumber)
$ sudo apt-get install build-essential

The kernel version number can be displayed with the 'uname' command.  The command 'uname -a' will show all version parameters of the current running kernel.  The command 'uname -r' will show only the version number, so one can make a generic install command like this:
$ sudo apt-get install linux-headers-$(uname -r) build-essential

Compile and Install

After the above, one can download and compile the U1250 Linux device driver from http://www.moxa.com (or email their support guys for a Beta version).

Compile and installation of any program usually follows a simple recipe, explained in the README and INSTALL files that come with each package.  The recipe is usually the same, but once in a blue moon it isn't, so it is always a good idea to read the readme file and in this case it is indeed different from the norm:
$ make driver_make
************************************************************************
 Ubuntu 12.04.2 LTS 
 \l 3.5.0-23-generic
 MOXA UPort 1200/1400/1600 series driver ver 1.2.5
 Release Date: 2013/04/03
************************************************************************

If and only if there are no errors above:
$ sudo make install
[sudo] password for herman: 
************************************************************************
 Ubuntu 12.04.2 LTS 
 \l 3.5.0-23-generic
 MOXA UPort 1200/1400/1600 series driver ver 1.2.5
 Release Date: 2013/04/03
************************************************************************
************************************************************************
 MOXA UPort 1200/1400/1600 series driver ver 1.2.5 installed successfully.
************************************************************************

Configure the Port

Now, when you plug the Moxa U1250 in, it should show up in /dev as ttyMXUSB0 and ttyMXUSB1.

Configure the device for RS232:
# setserial /dev/ttyMXUSB0 port 0x0

or for RS422:
# setserial /dev/ttyMXUSB0 port 0x2

and for RS485 2-wire:
# setserial /dev/ttyMXUSB0 port 0x1

It is all explained in the readme.txt file and I recommend you use it with Cutecom.

La voila.