An embedded system is a computer integrated into a larger physical product to perform a specific set of functions. Its software interacts directly with sensors, actuators, communication interfaces or other hardware rather than only with abstract files and user interfaces.

A microcontroller combines a processor core, memory and hardware peripherals on one chip. Typical peripherals include digital I/O, timers, serial interfaces and analog converters.

Unlike a general-purpose computer, an embedded target often has tight limits on memory, power, processing time and physical interfaces. It may also need predictable responses to events from the environment.

The software stored on the device is commonly called firmware. Some firmware runs directly on the hardware with no operating system; more complex systems may use a small real-time operating system.

Embedded design therefore crosses the hardware/software boundary: correct behavior depends not only on algorithms, but also on register configuration, timing, electrical signals and the physical system being controlled.