Great Reasons to Web Enable a Device
Incorporating an embedded web server is a remarkably powerful mechanism for
easily implementing a variety of key features and functions in your device.
A user sitting at any standard browser sees a web enabled device as a web
site. The device presents itself and its state graphically and responds to
buttons, hot links, and the entire array of familiar browser controls. The
potential for this kind of interface is essentially unlimited.
Although the word "server" is often associated with
things that are heavyweight, web servers can actually be
implemented efficiently and in a small footprint. For example, TargetWebTM
adds only approximately 30 KB of code and 30 KB of data to the application.
It is the web client, the browser, that is the large and sophisticated component
of the client/server pair, having to parse the HTML and render the graphic
output. Fortunately, there is no need to incorporate the browser code when
web enabling a device.
Consider the advantages of incorporating a web server into an embedded
Eliminate Implementing Both Target and Host Software to Interface to Your
External monitoring and control of embedded devices has
traditionally been done in one of three ways: (1) front panel, (2) dumb
console interface, or (3) custom protocol connected to a client program
running on a computer. All of these methods require special purpose
programming on the target to support their operation in addition to the code
that actually implements the desired activity. For example, the console
interface requires at least rudimentary parsing of text input and formatting
of text output. Because of the effort involved and footprint constraints,
interfaces to devices were often pared down from what would have been
Front panel and console interfaces are inherently primitive,
but the client program method carries the additional burden of the
implementation of the client program on a host computer, usually a Windows system. Not only does
this involve a lot of effort, but also it is typically outside of the expertise of
embedded developers. Another disadvantage of this approach is the need to
install the client program on any computer to be used as a controlling host
Web enabling devices provides a new method of interfacing to devices
that requires essentially no target side programming and works with universally available,
standard client software.
Universal Availability of Clients
Any standard browser can be used on a computer to interface to your
device. Automatically your device interfaces to Windows, Linux, Solaris, and
the Macintosh. Client software to interface to your device is already
installed everywhere and everyone knows how to use it.
Remote or Local Access
A web enabled device can be accessed anywhere in the world if it is
connected to the Internet or can be locally connected on a LAN with equal
ease. Remote management and running field diagnostics can be done from literally anywhere and, because
the data transfer is guaranteed to be error free, remote field upgrades can be
done reliably. Eliminate completely issues relating to overseas dial-up,
transmission speed dependencies, and custom protocols or cabling used to
connect to your device.
Easily Create Graphic User Interface
It is a lot of work to implement a graphical user interface for a non web
enabled embedded device. In contrast, extremely user friendly and good looking interfaces
are very easy to create and maintain for web enabled devices. Target
side resource demands for these interfaces are very light, consisting of just
the HTML pages in text format.
Leverage Commercially Available Web Design Tools
Use advanced web content design tools, such as Macromedia HomeSite
or Microsoft FrontPage,
to design and debug user interfaces on desktop computers before embedding the
pages on your target.
Easy to Maintain and Enhance Interface to Target
By simply uploading new web pages to the target, the interface can
be maintained and enhanced. In web enabled devices, the user interface
is data, not code. Although it would be possible to custom write an
application specific user interface engine which was data driven,
incorporating an embedded web server provides this functionality as a
standard, commercially available component.
Uses Universally Accepted, Standard Communication Protocol
Instead of starting out with a blank sheet of paper and designing
your own protocol for remote device monitoring and control, use the
established, powerful, and universally available HTTP standard protocol.
In summary, it makes sense to web enable just about any device that either needs
or could benefit from a nontrivial user, monitoring, or control external
interface, possibly even at the cost of adding an otherwise unneeded network
port. Now-a-days networking hardware is quite inexpensive and can often be
incorporated by simply selecting a CPU variant that has integrated Ethernet
(e.g. the Motorola MCF5282
ColdFire). Certainly, for any device already having a TCP/IP port, this
approach is strongly indicated.