Question?

An "embedded controller" is simply a microcontroller used inside of a
non-computing device.

Examples include the processors that control a car's fuel/air mixture,
programmable light timers and thermostats, cell phones, digital cameras,
traffic lights, microwave ovens, VCRs, printers, multifunction TV
remotes, vending machines, bread makers, and rice cookers.

Many (most?) embedded systems don't really run an operating system; they
just have a single program that starts when the power is connected.
Those that do generally use a specialized real-time OS.

Hope that helps,
Daniel

Yeah that helps. I have just seen the term used every once in a while
and wondered what exactly it referred to.

Joe McKibben

The answer here will be : "it depends on the application".
Usually an embedded controller refers to a complete system being
mechatronical, meaning that includes a mechanical device, power
source, electronic and control. All this to perform tasks which have a
physical impact. Hence, you controller receives inputs from sensors
and has outputs that operates motors or all sorts of actuators.
Example: a washing machine or your favorite vending machine where you
get your espresso from.

Now, there is issue of scale. For small applications such as small
alarm systems and the like, the engineers do program everything simply
with interrupts, that's all no need for OS there.

When the system is a bit larger, then they do provide their
proprietary OS if the system will have to deal with a variety of tasks
such as a printer that contains a scanner.

In more complex systems such as ATMs, then they apply small versions
of OS such as QNX, OS2 and the like. These machines have to deal with
a certain number of activities.

In your car, you see more and more of those devices fitted with these
mechatronic systems where the control is made with the embedded
controller dedicated or not. Even, the active suspensions in Citroen's
medium range cars have them. Some will include a real-time OS such as
Windows CE

Finally, like in those mobile robots such as the Pioneer ones, your
robot controller will include a proprietary real-time OS.